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Golden Rebreather Rules By Jill Heinerth

Trauma: the pain within

By Dr Richard Cullen

To Rent or Bring Your Gear BY Dan & Betty Orr



Editor-in-Chief Chantelle Newman Editor Elsibe Loubser McGuffog Technical EditorS Andrea Zaferes, Gareth Lock Designers Allie Crawford, Sarah Crawford Medical and Diving Specialist Consultants Dr Anke Fabian Dr David Charash Diving Consultants Dan and Betty Orr Advertising and Subscriptions Chrissie Taylor Contributors Thank you to the following contributors: Dan and Betty Orr, Jill Heinerth, Michael Tipton, Carl Bradford, Dr Adel Taher, Dr Ahmed Sakr, Dr Richard Cullen, Dr Suzanne Gaskell, Yvonne Tatchley, Dr Anke Fabian, Gareth Lock, Dr Peter Bucknell, Ellen Cuylaerts, Rod Hancock, Suunto, DAN Europe, AquaMed and Women Divers Hall of Fame PHOTOGRAPHERS Cover Image and 4th page by Marco Mattana Photography, Little Sam, Jill Heinerth, Paul Heinerth, Ysbrand Cosijn, Juanan Barros Moreno, Carsten Medom Madsen, Oleksandr Briagin, Galina Barskaya, Ethan Daniels, Volodymyr Goinyk, AstroStar, Maxisport, Rolf Wiberg, John Gomez, Przemek Tokar, kaninstudio, Feng Yu, Anchiy, Andrey Kuzmin, heromen30, Odua Images, Gareth Lock, Ammentorp Photography, Ethan Daniels, ILeysen, A. Lesik, Ewa Studio, Science Pics, Blue Orange Studio, Paul Brown, Ellen Cuylaerts, yingphoto, Anatoli Styf, Pichugin Dmitry, Brandon Johnson, 'A Cotton Photo' Magazine address The Diver Medic Ltd Great West House, Great West Road, Brentford, TW8 9DF Telephone +44 020 8326 5685 EMAIL

ISSUE 04 | MAY 2015

Contents 4 Quiz 6 Golden Rebreather Rules 8 Moving in Extreme Environments 14 Dive Medical Centre in the Red Sea 32 Trauma: the pain within 40 Energy Drinks - the Essential Information 52 To Vinegar Or Not To Vinegar? 60 Long-term effects of a sting 71 To Rent or Bring Your Gear 72 The Human Error Factor in Diving 78 Safety While Shooting Video 84 Dive Love and Lessons By Dan & Betty Orr

How Clued Up Are You on Technical Diving? By Jill Heinerth

By Michael Tipton and Carl Bradford

By Dr Adel Taher and Dr Ahmed Sakr By Dr Richard Cullen

By Dr Suzanne Gaskell By Yvonne Tatchley By Dr Anke Fabian

By Dan & Betty Orr By Gareth Lock

By Dr Peter Bucknell

Dive Love and Lessons By Dan & Betty Orr We have all come to scuba diving from different walks of life with our own perspectives. When we first decided to shrug off the chains of gravity to experience the freedom of diving it was fueled by the images we have grown up with, created by the likes of Jules Verne, Irwin Allen, Mike Nelson, Jacques Cousteau, and James Cameron. When our faces went underwater our visions were not limited by the low green visibility of an Ohio quarry but carried by our imagination to pristine Caribbean reefs or Pacific lagoons with giant octopus guarding trunks of black pearls from pirate ships with masts unfurled sitting totally intact on the bottom after hundreds of years. Now, after more than 40 years for me and 50 years for Dan, we are both pleased to say we have seen the wonders of those Caribbean reefs and seen octopus (not that big), the Pacific lagoons (no trunks of pearls) and sunken schooners (a long way from intact) but were never disappointed. Through all of our courses, both given and taken, our adventures and our travels, the common thread that has kept us enjoying and living out our dreams has been safety. Spending time evaluating destinations, equipment, fellow divers, environmental conditions, and potential problems with any and all has never felt like a side bar to nor detracted from the experience. We never thought of it as a waste of time or a necessary evil, just a part of what it takes to be fully prepared. Whether a dive is for research,

Photo by Marco Mattana Photography


ISSUE 04 | MAY 2015

recovery or pure enjoyment, being prepared for what could occur and working your way mentally (or practising for the techniques you may need to use) allows you to evaluate situations and know how to handle them. Practising and visualising activities will permit you to mentally work through possible issues in a safe, controlled environment preparing your mind and reflexes to handle situations competently. You are obviously committed to diving safety as you are continuing your education and broadening your perspective by reading Diver Medic and Aquatic Safety. The articles in this magazine are written by professionals from all walks of life and with amazing diving experiences. Take this opportunity to visualise yourself in their place and learn from what they do. Actively working towards a safer and more enjoyable diving world will make you a part of our goal to create and perpetuate a culture of diving safety: our vision of diving come true. 5 3


The Diver Medic & First Responder Challenge

How clued up are you on technical diving? Accept the challenge and answer the ten questions below to find out. ANSWERS: 1A, 2B, 3D, 4A, 5D, 6C, 7D, 8A, 9B, 10D Photo courtesy of Brandon Johnson


What’s the difference between an SCR and a CCR?


A. Venting - A process that creates bubbles every few breaths

A. Because humans would look funny in an E-collar.

by venting out gas to maintain PO2.

B. To prevent potentially harmful movements of the cervical

B. The lead singer’s raspy voice. C. Shunting - A process that squeezes the counterlungs for you so that they’re always empty on inhalation. D. The circuit is only halfway closed on the loop. 6

Why would you put a C-collar on a conscious trauma patient?

spine. C. To prevent the patient from looking at their injuries, which

may cause shock.

D. To support the spinal column from spina bifida.

ISSUE 04 | MAY 2015

Photo by 'A Cotton Photo'


What is the current world depth record for scuba diving?


What is the optimal gas for maintaining body heat in a drysuit?

A. 308,45 m (1012 ft)

A. Helium

B. 245,66 m (866 ft)

B. Air

C. 336,80 m (1105 ft)

C. Nitrogen

D. 332,54 m (1091 ft)

D. Argon



What is the optimal hypoxic gas blend for a dive to 94 m (310 ft) to maintain An END of 24m (80 ft) and PPO2 of 1.4?

When is it ok to call a dive?

A. 13/61

A. At any time for any reason.

B. 17/40

B. After at least one thing went wrong.

C. 8/65

C. After at least two things went wrong.

D. 21/80

D. After more than four things went wrong.



Which of the below are common symptoms of decompression illness?

What is hypercapnia?

A. Tingling or itchy skin

A. A person who’s had too many nightcaps.

B. Dizziness

B. High partial pressures of carbon dioxide.

C. Loss of coordination

C. High water levels in the lungs.

D. All of the above

D. Excited electrons in the lungs causing shortness of breath.



A gas with a partial pressure of Oxygen below 0.21 at the surface is considered what?

Which of the below diving-related maladies is the most likely to be fatal?

A. Normoxic

A. Sunburn

B. Hyperoxic

B. Shark bites

C. Hypoxic

C. Air embolism

D. Hydroxic

D. Pneumothorax



Bob Ferguson prepares to enter the cave at Ginnie Springs.

Golden Rebreather Rules

Shifting the Culture of Rebreather Diving to Reduce Accidents By Jill Heinerth

ISSUE 04 | MAY 2015

Closed Circuit Rebreathers (CCR) have been connected to approximately 20 deaths per year in the sport diving community. Significant evidence supports that these fatalities are often tied to failures of the human machine interface (HMI) as well as risky choices and behaviours that begin well before entering the water. This article aims to suggest a cultural shift in CCR diving that minimises and prevents future deaths. According to recent statistics, approximately twenty of our rebreather colleagues are dying on their rebreathers each year. I propose a cultural shift in CCR diving that might lower this number significantly. This shift consists of adopting five basic rules in your personal diving behaviour as well as insistence that your buddies follow the same responsible guidelines. The rules fall into the following categories: trained/upskilled, checklists, pre-breathe, decision to dive, and aborting dives. Whether you are new to rebreathers or an experienced CCR diver who feels very comfortable with them, these rules could save your life. Rule 1. Recognise and prevent complacency in yourself and others around you

Photo by Jill Heinerth

Accidents are frequently labelled as ‘pilot error’, so it is worth examining the nature of pilot error. Technical diving and, specifically, rebreather diving is a continual learning process. If we closely examine how we learn, we can better prepare for the pitfalls associated with each stage of the learning process. For example, an internationally recognised climber threads the rope through her harness on an easy climb. She is temporarily distracted by someone with a question, and while answering, she stops to tie her shoe. She returns to her preparation of her harness and when she leans back to rappel, she falls 22 metres, narrowly escaping her death when cushioned by tree branches. In her case more training would not have helped. Experience actually contributed to her accident. She tied off when she was supposed to routinely tie off – but rather than her harness, it was her shoes. Exploring how we learn and how we can continue to stay sharp in all of our activities will help us

understand where complacency can seep into our processes. There are four basic steps in the learning process, and if you understand the path to learning and experience you can increase your skill level in anything to which you aspire and become safer in the process. Gordon Training International is popularly considered to be the originator of the Conscious Competence model, which describes the steps involved in the process of learning any new skill. This model is particularly applicable to rebreather diving. The model describes the first stage of learning as Unconsciously Unskilled. This stage accurately characterises the rebreather diver on his or her first day of class; the rebreather diver is unaware of the proper function of the unit and incapable of quantifying the risk of the activity. The learner simply doesn’t know what can kill or how it might happen. Stage two, and each stage thereafter, illustrates a sensation of awakening, when the person feels ‘like a light bulb went on’. As the learner takes this step forward, he or she enters the realm of Consciously Unskilled. At this point, the diver is beginning to understand the function of the unit and become able to assess risks, but still needs close supervision. Next, the learner reaches the point of Consciously Skilled. This may be the point when he or she completes initial rebreather training. At this level, the diver has mastered basic controls, has a good assessment of risk and is able to complete ‘self or buddy-rescue’. This may be the point at which the diver is the safest rebreather diver ever. He or she still has a healthy fear that the unit may fail and is consciously driving the rebreather with great care. The final stage of learning occurs when the diver reaches the Unconscious Skilled level. This is akin to someone who has been driving a car for a long time. They make their daily commute and barely recall the route they took or the things they saw along the way. When this occurs in rebreather diving, it is often the point when complacency kicks in. 9


Brian Kakuk lifts a Lucayan skull from the depths of Sanctuary Cave in Andros during a National Geographic Project.


ISSUE 04 | MAY 2015

I have often thought that new rebreather divers with roughly 50 to 100 hours after their initial training may be at the greatest risk in their diving careers, especially if nothing has scared them along the way. The human brain is exquisitely tuned to detect novelty, but when everything becomes routine, we tend to stop paying attention. Yet, according to Dr Jeffrey Schwartz at the UCLA School of Medicine, humans can literally alter the anatomy of the brain by the demands required of it. He noted that the hippocampus of cab drivers grew larger as they learnt the layout of a new city. The hippocampus is responsible for map-making, and he noticed profound neural changes that occurred within a few days. When a rebreather diver experiences a serious gear malfunction, it often frightens the diver back to the previous level of learning, when he or she becomes conscious of actions again. A long absence from diving will also result in the diver stepping backwards in the model until they catch up with their skills and practice. The climber who experienced the fall was attempting to use a behavioural script to prepare her harness. Using her memory, she conducted a series of steps she had done repeatedly without incident. At the moment when her mental model indicated that she should tie her harness, she was distracted and instead tied her shoe. This action likely satisfied her behavioural script and she moved on to the next phase of her climb. Her mental checklist had become routine.

Photo by Jill Heinerth

To avoid the pitfalls of complacency, proper procedures and a commitment to pre-dive checklists and pre-breathe sequences are critical. Vigilant watch on displays is crucial. A diver who carefully reviews their personal preparedness as well as their equipment readiness will be better poised to deal with the issues he or she may encounter ahead. Rule 2. Always use a written or electronic checklist to prepare your rebreather Many fatalities could likely have been prevented by using a paper or onscreen checklist. Distractions and lapses in memory are human factors that we need to account for in all diving activities. It is incumbent on instructors, mentors and prominent

divers to change the culture of rebreather diving to something equivalent to flight training. Checklists have to be viewed as 'cool' to be popular. When failing to use a checklist is frowned upon at the grassroots level, then they will be more widely used. Role models and thought leaders within our sport need to be conspicuous in using checklists and insistent that diving partners do the same. Rule 3. Always conduct a five-minute pre-breathe in a safe, comfortable place with your nose blocked A five-minute pre-breathe should become the norm throughout our industry. Students and diving partners need to be encouraged to conduct this activity in a seated and safe location so that they can observe their handsets, listen for their solenoid and evaluate their physical condition prior to reaching a place of danger where they could fall and injure themselves or drown. Initial prebreathe sequences should never be conducted while walking to a site entry, putting on fins or floating in the water. Although they cannot guarantee safe operation of all rebreather subsystems, they should prevent many common preparation errors. Rule 4. Do not dive if your rebreather has not completely passed all pre-dive checks and tests Significant numbers of accidents and fatalities are attributed to high risk behaviors such as beginning a dive with a known technical fault such as a single sensor failure. These faults may not be detected until a pre-breathe is attempted, so if it is still critical to do the dive, then it is incumbent on the diver to have alternative equipment available to make the dive safely. Rule 5. Abort your dive in the safest possible mode In the early history of rebreather training, we often encouraged divers to find a way to stay on the loop if possible. Culturally, this flawed practice may have led to incidents where divers felt it reflected poorly on them when they bailed to open circuit. In most cases today, a properly equipped CCR diver has sufficient personal gas to execute an open circuit bailout. If you have sufficient gas for abort, open circuit is the safest option and definitely preferred when diving alone. 11


Photo by Paul Heinerth

Jill Heinerth during the NOAA Deep Caves of Bermuda Expedition


ISSUE 04 | MAY 2015

Whether the abort takes place on the boat deck or during a dive, the community needs to be encouraged to follow safe role-model behaviours. Refuse to dive with those who do not abide by essential safety measures. Refuse to dive with those who take unnecessary risks for themselves and their team. Dr Andrew Fock’s research has revealed that most fatalities are attributed to diver choices and behaviours rather than any particular model or style of rebreather. Given that revelation, we have a unique opportunity to grow the market in a safer way by encouraging and applauding safe diving practices and focused attention to procedures.

References • Fock, Andrew. RF3 Proceedings ref. • The Learning Stages model was developed by former GTI employee, Noel Burch. workplace-articles/learning-a-new-skill-is easier-said-than-done/ developed 30 years ago • Rewire your Brain, Aalto University Executive Education, Feb 03, 2012. brain-11400486 • Dr Simon Mitchell, study July 2014, presented at Eurotek Diving Conference, 2014

Jill Heinerth works for Heinerth Productions Inc., High Springs. Find them on From the most dangerous technical dives deep inside underwater caves, to searching for never-before-seen ecosystems inside giant Antarctic icebergs, to the lawless desert border area between Egypt and Libya while a civil war raged around her, Jill’s curiosity and passion about our watery planet is the driving force in her life. Jill’s accolades include induction into the Explorer’s Club and the inaugural class of the Women Diver’s Hall of Fame. She received

the Wyland ICON Award, an honour she shares with several of her underwater heroes including Jacques Cousteau, Robert Ballard and Dr Sylvia Earle. She was named a 'Living Legend' by Sport Diver Magazine and selected as Scuba Diving Magazine’s 'Sea Hero of the Year 2012'. In recognition of her lifetime achievement, Jill was awarded the inaugural Sir Christopher Ondaatje Medal for Exploration. Established by the Royal Canadian Geographical Society in 2013, the medal recognises singular achievements and the pursuit of excellence by an outstanding Canadian explorer.




EXTREME ENVIRONMENTS: open water swimming in cold and warm water

This story is reproduced in its entirety with kind permission from Extreme Physiology & Medicine 2014, 3:12. DOI: 10.1186/2046-7648-3-12

By Michael Tipton and Carl Bradford Open water swimming (OWS), either ‘wild’ such as river swimming or competitive, is a fast growing pastime as well as a part of events such as triathlons. Little evidence is available on which to base high and low water temperature limits. Also, due to factors such as acclimatisation, which disassociates thermal sensation and comfort from thermal state, individuals cannot be left to monitor their own physical condition during swims. Deaths have occurred during OWS; these have been due to not only thermal responses but also cardiac problems. This 14

paper, which is part of a series on ‘Moving in Extreme Environments’, briefly reviews current understanding in pertinent topics associated with OWS. Guidelines are presented for the organisation of open water events to minimise risk, and it is concluded that more information on the responses to immersion in cold and warm water, the causes of the individual variation in these responses and the precursors to the cardiac events that appear to be the primary cause of death in OWS events will help make this enjoyable sport even safer.

ISSUE 04 | MAY 2015

Photo by Ysbrand Cosijn



"...both competitive and leisure swimmers have died in swimming events in warm and cold water." 16

ISSUE 04 | MAY 2015

Open water swimming (OWS) includes competitive distances of between 5 and 25 km, including the first leg of triathlon events (e.g. up to Ironman, 3.8 km). OWS became an Olympic event in 2008; this acted as the stimulus for growth in a number of international competitive events taking place in a wide range of environmental conditions. In terms of numbers, perhaps even more importantly, OWS has caught the imagination of many thousands of people worldwide who now regularly engage in ‘wild swimming’ in rivers and remote waterways, or in open water mass participation events. These events are amongst the fastest growing mass participation sports worldwide with up to 25,000 participants entering single events. With the increase in the number and variety of OWS events comes an increased risk of adverse medical events; both competitive and leisure swimmers have died in swimming events in warm and cold water. However, these deaths should be considered in the context of the potential improvements in health and longevity experienced by those who engage in such physical pursuits. This comparison is seldom made as the perception of risk has a temporal component, with acute risk (entering extreme environments) appearing much more hazardous than chronic risk (sedentary lifestyle). Attempts to determine safety guidelines for swimming in open water have mostly focussed on thermal responses, but even in this limited area, such efforts have served to underline how difficult it is to prescribe limits when so many variables may interact, and the threshold between ‘safe’ and ‘unsafe’ may be very small. Obvious sources of variability in the thermal response include water temperature, metabolic heat production and insulation worn. More subtle causes include skill level, body morphology, wet suit ‘fit,’ acute asymptomatic infection and radiant heat load. In addition to these considerations, others should be considered: the USA Triathlon Fatality Incidents Study reported that 79% of deaths in triathlons in the USA between 2003 and 2011 occurred during the swim, with unexplained sudden cardiac death, rather than hypothermia or hyperthermia, being the most likely cause of death in most cases. Thus, the evidence indicates that an open water swim represents the greatest relative hazard associated with mass participation sports events, and those searching for the cause of this hazard and ways of reducing it should look beyond just thermal responses. This article, which is part of a series on ‘Moving in Extreme Environments’, briefly reviews pertinent topics associated with OWS. Relevant regulations

Photo by Juanan Barros Moreno

There is no internationally accepted definition of ‘cold water’ or ‘warm water’. For most unacclimatised individuals, ‘thermoneutral’ water temperature (in which people can remain at rest and maintain deep body temperature without shivering or sweating) is within the narrow range of 35°C–35.5°C. The narrowness of this range, resulting from a combination of the physical characteristics of water and the relative ineffectiveness of the physiological 17


"Many agencies define cold water as a temperature between 10°C and 15°C."

Photo by Carsten Medom Madsen

effector responses of humans to counter heat gain and loss in water, is the reason why the threshold between safe and unsafe water temperatures is more critical in water than in air. A water temperature of 25°C is generally regarded as the point below which exercise will accelerate the rate of deep body temperature cooling compared to remaining still. However, the range of water temperatures at which even naked individuals can achieve thermal balance when swimming is so varied, due to factors such as work intensity (heat production) and body morphology, that it is very difficult to set a single average figure for any form of guidance. For example, Costill et al. observed that well-conditioned, non-obese individuals could demonstrate a slight increase in deep body temperature after 20 min of high-intensity exercise in water at 17°C. Average swimmers swimming at similar speeds in water at 18°C and 10°C show 18

a wide range of deep body temperature responses, including the re-establishment of thermal balance after an initial fall in deep body temperature (Figure 1A,B). Many agencies define cold water as a temperature between 10°C and 15°C. Historically, such decisions have been based only on a consideration of deep body temperature and the threat of hypothermia (deep body temperature below 35°C). This is despite the fact that the most dangerous responses to immersion in cold water (‘cold shock’; see below) peak between 10°C and 15°C in naked or lightly clad individuals. Indeed, the pre-occupation with hypothermia, which arose from the Titanic disaster and was maintained by events in World War II, is still reflected in the guidelines, policies and protection produced for cold water immersion.


In the UK, British Triathlon has the following guidelines: • The minimum water temperature at which wetsuits are optional is 14°C. • At temperatures less than 11°C, it is recommended that no OWS takes place. At the following temperatures, the maximum swim distances are obligatory: • 13°C, 2,000 m • 12°C, 1,000 m • 11°C, 500 m The use of wetsuits is forbidden/mandatory if the following combinations of distance and water temperature are attained:

<1,500 m, >22°C/<14°C 1,501–3,000 m, >23°C/<15°C 3,001–4,000 m, >24°C/<16°C Although well intentioned, the evidence base for these regulations is limited and virtually non-existent when it comes to OWS in warm water. Recently, some underpinning research has been sponsored and conducted to investigate endurance swimming in warm water and, latterly, cold water, with FINA (Fédération Internationale de Natation, the international governing body for aquatic sports), the ITU (International Triathlon Union) and IOC (International Olympic Committee) sponsoring this work and introducing a guideline of 31°C as the upper water temperature limit for OWS. In warm water, there is the likelihood of solar radiant heat (electromagnetic energy from the sun in the wavelength of 400–750 nm) adding up to 1,000 W.m−2 to the overall thermal load. 19


Hazards associated with OWS in cold and warm water As with all environmental stressors, the threat associated with OWS in thermally stressful water ranges from deterioration in performance to life-threatening pathology. The threats to life associated with immersion in cold water include drowning, cardiac problems, hypothermia and cardiovascular problems on exiting the water. In warm water, the corresponding threats are hyperthermia and cardiovascular problems on exiting the water. 20

The cardiovascular problems on leaving the water are caused by reduced circulating blood volume in cold and warm water. In cold water, this is due to hydrostatic squeeze and cold-induced vasoconstriction, producing a diuresis during immersion. In warm water, it is due to hydrostatic squeeze and sweating, resulting in hypovolaemia and the demand for high skin blood flow during immersion. Both sets of responses can compromise the maintenance of arterial blood pressure when leaving the water and assuming an upright posture (loss of hydrostatic squeeze plus orthostatic stress). This problem may be compounded by the removal of a tight-fitting wet suit at this time.


Cold Water In cold water, the cold shock response on initial immersion includes a gasp response, uncontrollable hyperventilation, tachycardia, hyperventilation and an increase in circulating levels of stress hormones. The response is initiated by the dynamic response of the peripheral cold receptors; it peaks in the first 30 s of immersion and adapts over the first 2 min. The loss of control of breathing on immersion can be a precursor to drowning. That most of the deaths during OWS are thought to be due to cardiac problems raises interesting questions concerning the mechanisms associated with these deaths and why they tend to occur in competition or events rather than open water training or non-competitive swimming. Recent work has suggested that coincidental activation of the sympathetic and parasympathetic inputs to the heart (‘autonomic conflict’) may provoke cardiac arrhythmias which, in individuals with predisposing conditions, can descend into fatal arrhythmias. This is more likely to occur in competition or other mass participation events because these more often involve, in addition to immersion in cool/cold water and exercise, extended breath holding, aspiration of water into the nasopharynx and anger. Of all the emotions, anger is the one most associated with ventricular fibrillation; it increases the sympathetic tone while maintaining parasympathetic tone. Acceptance of this theory has some implications for the design of mass participation swimming events (see below).

"Of all the emotions, anger is the one most associated with ventricular fibrillation"

Following skin cooling, the next tissues to be affected are the superficial nerves and muscle, particularly in the upper limbs which have a high surface area to mass ratio. The contractile force of muscle is significantly impaired when its temperature falls below 27°C due to factors such as reduced enzyme activity, decreased acetylcholine and calcium release, slower rates of diffusion, decreased muscle perfusion, increased viscosity and slower rate of conduction and repolarisation of action potentials. The deep muscles of the forearm can reach this temperature after about 20 min at rest in 12°C or 40 min in 20°C water. Below Tlocal of 20°C, rate of conduction and amplitude of action potentials is slowed; for example, the conduction velocity of the ulnar nerve falls by 15 m.s−1 per 10°C fall in Tlocal. As a consequence of these changes, maximum power output falls by about 3% per degree Celsius fall in muscle temperature. These changes in physiological function as a result of cooling can result in early swim failure across the spectrum of novice to elite swimmers, with novice swimmers suffering the biggest decrements, probably due to a lack of acclimatisation (see below) and having a less entrained motor programme for swimming and therefore more vulnerable technique. In addition to direct local effects, with more generalised muscle and deep body cooling, there is a decrease in limb blood flow; this has occurred by the time deep body temperature reaches 36°C. It is probable that the exercise hyperaemia normally observed in thermoneutral or warm conditions is attenuated in cooled individuals by a sympathetically mediated vasoconstriction of muscle resistance vessels. As a consequence, oxygen Photo by Oleksandr Briagin



Photo by Galina Barskaya

delivery to, and utilisation by, cooled working muscle and the removal of the end products of metabolism may be reduced in cold water. This is compounded by a left shift in the oxygen dissociation curve with cooling. Cooled muscle is therefore required to use anaerobic metabolism at lower sub-maximum workloads; this can result in an earlier appearance of blood lactate and more rapid depletion of carbohydrate stores and, as a consequence, an earlier onset of fatigue. Higher oxygen consumptions have been noted in cold compared with neutral environments during exercise requiring oxygen consumptions of up to 2.0 L.min−1 [11,19,22,23] (Figure 2), but not at 3.0 L.min−1 [3]. In water at 25°C and 18°C, average oxygen consumption during arm and leg ergometry is increased by 9% and 25.3%, respectively, when compared to that seen in water at 33°C. The increase in oxygen consumption is greater in leaner individuals. The twofold increase in the viscosity of water at 0°C compared with 25°C may contribute to the greater energy expenditure seen during swimming in cold water. However, this effect is compensated to some extent by the increased pulling power per stroke which results from the increase in viscosity. Although the efficiency of each stroke may improve, the shivering and increased muscle tone during exercise in cold water may further reduce the mechanical efficiency by increasing the activity of antagonistic muscles. Maximum aerobic capacity falls in relation to muscle and deep body temperature, with a 0.5°C fall in deep body temperature resulting in a 10%–30% fall in V̇ O2 max and maximum cardiac output (Q̇ max). In water at 18°C, the subjective sensations associated with exhaustive swimming are related to muscle function rather than cardio-respiratory distress. There is little evidence to indicate that the alterations associated with cold water immersion impair respiratory function to an extent that it interferes with oxygen up-take during exercise. With regard to cardiac function, once the cold shock response has subsided, cold water immersion reduces resting, submaximal and maximal heart rates when compared with those seen in warm water, with cardiac output being maintained during submaximal exercise in cold water by an elevated stroke volume. The central redistribution of blood volume on immersion in cold water, caused by peripheral vasoconstriction and hydrostatic pressure, results in a cold-induced diuresis that can reduce circulating plasma volume by 24%. This can further reduce muscle perfusion and, as mentioned, cause problems on exiting the water.

"There is no doubt that immersion in cold water stimulates release of the stress hormones." 22

During resting immersions in cold water, a conductive gradient between the deep body tissues and the skin is established down which heat flows. In this situation, the deep body tissues always have a higher temperature than deep and superficial muscles which remain at a higher temperature than the skin. In contrast, during swimming, the exercise-induced hyperaemia destroys the ‘variable’ insulation provided by unperfused muscle (providing approximately 70% of total body insulation) when at rest, leaving only the ‘fixed’ resistance of subcutaneous fat. This may be especially relevant in swimming where, combined with other factors such as the surface area to mass ratio, exercise in water


that involves the arms can lead to greater heat losses and faster decreases in deep body temperature compared to leg-only exercise at the same intensity. Additionally, and importantly, the thermal mixing that occurs, due to exercise, between the deep tissues and the exercising muscle means that these tissues have a much more uniform temperature. The major consequence of this is that it is possible for swimmers to swim to the point of unconsciousness because this occurs, on average, at a deep body temperature of 30°C–33°C, whereas muscle function is maintained down to a temperature of about 27°C. This has been reported anecdotally (Phil Rush, personal communication). Also, in 1953, Jason Zirganos (JZ), the greatest open water swimmer of his generation, swam in the Bosphorus (8°C) for 4 h; he was removed from the water semiconscious, regaining full consciousness 3 h later. Unaware of hypothermia, it was concluded that he had been poisoned. The following year, at the age of 46 years, JZ attempted to swim the 22-mile North Channel of the Irish Sea (9.4°C–11.7°C). After 6 h, and only 3 miles from the Scottish Coast, JZ became unconscious and blue; he was hauled from the water, and a doctor, using a pen knife, exposed JZ's heart to reveal ventricular fibrillation. Direct cardiac massage having failed, JZ was pronounced dead at the scene (Griff Pugh, personal communication to M Tipton, 1982). At the end of a cold water swim and for a period after it, the deep body temperature of a swimmer may continue to fall due to thermal gradients established during the swim. Thus, this post-immersion period deserves attention in terms of the supervision of swimmers who, on finishing their race, may have the lowest deep body temperature they have experienced whilst unsupervised and travelling home, or, in the case of

tri-athletes, go from swimming to cycling on a cold, wet day, and performance may be significantly impaired. Although the area of post-cold immersion rewarming has been well reviewed in the survival-related literature, it is less well considered in the sporting literature. One final word on the oft quoted anecdotal benefits of cold OWS is that those who engage in this pastime claim health benefits ranging from improved immunity to greater alertness. There is no doubt that immersion in cold water stimulates release of the stress hormones even in habituated individuals, although to a lesser extent. The alerting and arousal effect of cold immersion is likely to be one consequence of this. As for improved immunity, Jansky et al. have reported that a single, 1-h immersion in 14°C which increased metabolic rate due to shivering activated the immune system to a slight extent. Brenner et al. have confirmed that cold exposure (5°C air, 2 h) can be immune-stimulating, possibly due to increased levels of circulating noradrenaline. Having reviewed the area, Castellani et al. concluded that there was no evidence to suggest that moderate acute cold, wet exposures depress the components responsible for immune function. In contrast, Shephard and Shek's review concludes that the effect of severe chilling of mainly small mammals results in the suppression of several cellular and humoral components of the immune response, including a decrease of lymphocyte proliferation, a downregulation of the immune cascade and a reduction of natural killer (NK) cell count. Interestingly, adaptation of these responses to a given cold stimulus appears to develop over the course of 2–3 weeks. Regular short-duration cold water immersions or swimming have been associated with a 23


"Little is known about the physiological responses to high-intensity endurance swimming in warm water" 24

Photo by Ethan Daniels

ISSUE 04 | MAY 2015

‘hardening’ response to oxidative stress and a consequent protective effect against free radicalinduced tissue damage. With regard to repeated cold water swimming, we await the definitive study on the interaction between cold exposure, exercise and the immune response in humans. To be definitive, this topic should be studied in a matched group of regular indoor swimmers to isolate the changes produced by regular swimming per se from those of swimming in cold water. Warm water The effector responses of the human thermoregulatory system evolved to function in thermoneutral dry air (26°C–28°C) in which sweat evaporation and cutaneous vasodilatation are efficient effector responses for off-loading heat from the body to the environment. When swimming in warm water the negation of the primary effector response for cooling, the evaporation of sweat, can be compensated for by the fact that the body is immersed in a fluid with much better physical characteristics for removing heat. However, as the skin temperature-water temperature gradient narrows, less and less heat can be transferred to the water. If water temperature exceeds skin temperature, cutaneous vasodilatation picks up heat from the skin and returns it to the deep body tissues. This reversal of the normal function of cutaneous vasodilatation results in a rapid rise in deep body temperature. In contrast, on immersion in cold water, the physiological responses and morphological characteristics which evolved to keep individuals warm in cold air (shivering, peripheral vasoconstriction, subcutaneous fat) also function in cold water. So, it takes approximately five times longer to reduce the deep body temperature of someone in 15°C water (22°C below deep body temperature) from 37°C to 25°C (average lower lethal deep body temperature) than it does to raise their body temperature from 37°C to 40°C when they are immersed in 41°C water (just 4°C above deep body temperature). This is a powerful example of the impact of having the physiology of the body working for, as opposed to, against you. Given that the average lethal upper deep body temperature is 44°C, the rate at which this can be approached has been a cause for concern in warm water swimming events. Little is known about the physiological responses to high-intensity endurance swimming in warm water, even though its popularity is increasing. Many 5–10 km events, which require athletes to be in the water for up to 2 h or more, are being held in locations such as the Middle East and South China Sea where water temperatures are up to 32°C. At rest, such temperatures represent a comfortable aquatic environment for humans, a little below the thermoneutral range. However, the effects of exercising at high metabolic rates in these conditions on thermoregulation (both behavioural and autonomic) are largely unknown, but

the increase in metabolic heat production coupled with perceptions of comfort in these warm water environments appears to have the potential to induce ‘insidious hyperthermia’ in exercising athletes. Only a few studies have examined intense or prolonged exercise in water, and even fewer have looked specifically at swimming. Of these studies, the use of different swimming strokes, relatively low and controlled exercise intensities (e.g. 50% V̇ O2 max or lower) and short exercise durations (e.g. 30 min or less) make it difficult to apply the results to competitive race swimming, particularly of prolonged duration and in open water environments. Also, many of these studies have been conducted in a swimming pool as opposed to a swimming flume, which allows for continuous swimming that is more representative of OWS. Robinson and Somers conducted one of the few studies that have used proficient swimmers, in warm water temperatures, with exercise intensities and durations appropriate to competitive endurance swimming events. They asked six male Olympic-level swimmers to swim as far as possible in 60 min in three different water temperatures averaging 33.5°C, 29°C and 21°C. The rectal temperatures of the two fastest swimmers both increased to a modest 38.4°C after 60 min in the 33.5°C water (swimming at a metabolic rate of 500–520 kcal.m−2.min−1). One of the only other studies had competitive Masters swimmers complete a 5-km race simulation in three water temperatures of 23°C, 27°C and 32°C. Rectal temperature (measured using mercury thermometers before and after each swim) showed a rise of 1.1°C in 32°C water. The peak rectal temperatures recorded after the 5-km swims in 27°C and 32°C water (which took on average 75–80 min) were only approximately 38°C. While there may be issues with the measurement methods, these recorded temperatures after 75 min of swimming at high intensity in 32°C water are not excessively high. Thus, while there is some research examining the physiological effects of swimming in warm water, methodological limitations such as the use of pools, relatively short exercise times, discontinuous measurement of some physiological variables and a lack of radiant heat load make the application of these results to longer duration open water swims difficult. This may be important as it is immersion and exercise in warm (and cold) water for extended periods (i.e. greater than 30 min) that can lead to potentially dangerous deep body temperatures in swimmers. There is also a lack of research examining whether individuals can accurately perceive these changes in deep body temperature and initiate appropriate behavioural thermoregulatory responses when swimming in water. Recent data indicate that simulated OWS (conducted in a flume, at race pace and with radiant heat loading) by competitive swimmers and triathletes in 32°C water for 25


20, 60 or 120 min elicits modest increases in rectal temperature (mean [SD] 38.1°C [0.4], 38.3°C [0.6] and 38.4°C [0.8], respectively). The highest temperature recorded in any individual swimmer was 39.5°C, and less than 10% of swims ended in rectal temperatures over 39°C. All swims were also associated with appropriate, linear increases in psychophysical measures of thermal sensation and thermal (dis)comfort (i.e. feel hotter and more uncomfortable as rectal temperature increases), and a negative relationship with overall feeling (i.e. feel worse as rectal temperature increases). Further, when compared to terrestrial-based exercise at similar skin temperatures, these swimmers appear to feel hotter and more uncomfortable at the same deep body temperature. These data support the previous conclusion that only modest increases in rectal temperature occur when swimming in these warm water temperatures. They also show that intense endurance exercise in a seemingly heat stressful aquatic environment may not be that ‘extreme’ or insidious and that swimmers are able to perceive increases in their thermal status, even with a ‘comfortably’ clamped skin temperature (see next section). Pros and cons of self vs. prescribed acute exposure Despite the findings reported above, the fact that we see cases such as the death of Jason Zirganos or people in warm air and water who appear able to continue exercising to death, particularly in competitive scenarios, suggests that for some individuals, the average findings of others do not apply. It is not possible to determine if this is because these individuals are able to override or ignore thermally initiated drives to stop or whether for these individuals, these drives are absent. Either way, that this can happen means it is unwise to rely on the subjective assessment of some individuals to determine exposure time during OWS. Normally, the assessment of one's thermal state is driven by skin temperature, particularly changes in skin temperature. However, water clamps skin temperature, allowing the cutaneous thermoreceptors to adapt to their local temperature and thereby reduce their input to the perceptual and therefore behavioural response to immersion. This situation is observed on resting immersions in cold water where after an initial and profound reduction, thermal comfort and thermal sensation improve over the next minutes as skin temperature plateaus at a new lower temperature with a consequent withdrawal of the dynamic response of the cutaneous cold receptors and their adaptation to the new static temperature. Although deep body temperature can influence the perception of the thermal state of the body as well as the drive to exercise, it can be fooled; for example, ‘insidious hypothermia’ the undefended fall in deep body temperature occurs when this temperature falls too slowly to evoke a defensive reaction.


Finally, and as discussed in the next section, acclimation or acclimatisation to an environment can dissociate the thermal state of the body from the evoked subjective perceptions. This makes subjective assessment a particularly unreliable indicator of exposure time and physical capability. Adaptation Whilst acclimation and acclimatisation to heat are well researched and recognised processes, cold acclimatisation has been a more controversial topic. However, a fairly consistent pattern has emerged when those who repeatedly immersed themselves in cold water have been examined. In an attempt to determine why cross-channel swimmers could survive significantly longer in cold water than ship wreck victims from the Second World War, Pugh and Edholm undertook early controlled studies of these swimmers. They concluded that the swimmers had a somewhat unique combination of fatness and fitness that allowed them to maintain a high level of heat production and retain it below significant levels of insulation. Actually, the best evidence for acclimatisation to cold was seen during resting immersions in which the outdoor swimmer (JZ) demonstrated an almost completely habituated shivering response, high levels of thermal comfort but a much faster fall in rectal temperature than would be expected in someone with this morphology; this response has been called ‘hypothermic’ acclimatisation (Figure 3). The high levels of thermal comfort despite low and faster falling deep body temperatures essentially represent the disabling of the behavioural thermoregulatory system and add to the argument that regular outdoor swimmers (particularly in the cold) should not be allowed to selfregulate their exposures. Some years later, Golden et al. showed that outdoor swimmers could be thin provided they were fast, they could be fat and fast, and they could be fat and slow; what they could not be was thin and slow! Golden et al. claimed evidence of insulative acclimatisation to cold during swimming in cold water. This claim has received recent support from studies of both adult and child open cold water swimmers. Thus, it seems that the current best indications are that cold water swimmers develop a hypothermic acclimatisation to resting immersions. Recent evidence indicates that this acclimatisation is limited to the thermal profile experienced repeatedly, and an un-habituated response returns if an individual cools more than he or she is used to. During swimming cold water immersions, the acclimatised cold water swimmer demonstrates an insulative acclimatisation with greater levels of body insulation and better maintained deep body temperature.

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Photo by Volodymyr Goinyk

"Outdoor swimmers could be thin provided they were fast, they could be fat and fast, and they could be fat and slow; what they could not be was thin and slow" 27


There is a plethora of research examining the physiological and work capacity changes that occur with heat acclimation; however, almost all have been conducted in warm air and cannot be assumed to have much relevance to aquatic athletes or workers. Typical adaptations regularly observed with terrestrial heat acclimation include a decrease in basal deep body temperature at rest and during exercise, an increase in sweat rate, an increase in blood volume and reduction in cardiovascular strain during exercise, improved thermo-tolerance and improved perceptions (less exertion and thermal discomfort). These adaptations occur in response to a regular elevation in deep body temperature along with skin temperature and appear to be more complete if higher temperatures are achieved and there is an exercise component to the acclimation. Therefore, with the modest increases in deep body temperature that have been observed to date for exercise in warm water, the lack of heat-induced lowering of central venous pressure and skin temperature being clamped in warm water (i.e. 30°C–33°C), it is possible that these adaptations may not occur with heat acclimation in water, or if responses such as increased sweating power occur, they may even be counterproductive, producing faster dehydration, as has been shown for working in encapsulated ensembles. However, research indicates that certain heat shock proteins may play a significant role in the thermotolerance afforded by heat acclimation. Further, it appears that these proteins may be induced both by duration (i.e. time for which deep body temperature is raised; the ‘dose’ of heat) and intensity (i.e. lower deep body temperature but a higher rate of increase) of exercise. Thus, while the combination or level of stress imposed by repeated exercise in warm water may not result in the typical heat acclimation adaptations such as lowered basal deep body temperature and increased blood volume, it may be sufficient to provide improvements in thermotolerance. 28

The research is very limited with regard to heat acclimation in warm water. Weller et al. used 4 days and Weller and Harrison used 10 days of 30-min passive heating in 40°C water followed by 40-min cycling exercise in warm air, aiming to improve the performance of soldiers in hot environments wearing encapsulated clothing. While they observed the typical heat acclimation adaptations, it is impossible to differentiate the effects of the aquatic and terrestrial components to suggest whether hot water immersion alone would provide the adaptations. Shin et al. immersed nine males up to the waist for 30 min in 42°C water over a 3-week period (a total of ten immersions on alternate days). Although no heat stress test was conducted pre- and post-acclimation, they did observe a small but significant decrease in resting tympanic temperature (0.13°C) and an increase in whole-body sweat rate (estimated from body mass change) across the ten immersions. Lastly, Avellini et al. took untrained participants and compared physical training (cycling at approximately 75% V̇ O2 max) in water (32°C and 20°C) and on land (conditions not mentioned) for 1−1, 5 days.week−1, for 4 weeks to determine adaptations responsible for improving heat tolerance. Across the training sessions, rectal temperature increased approximately 1.1°C in the land-based exercise and approximately 0.6°C in the 32°C water-based exercise. Following the physical training period, a similar decrease in final deep body temperature and heart rate was observed at the end of a 3-h heat stress test (on land) between the 32°C water- and land-based training groups. Interestingly, the 32°C water training group also showed an increased sweat rate (by 25%) during the post-training heat stress test. Further, this physical training was followed by an actual 10-day heat acclimation period in warm air. The final deep body temperature recorded in a 3-h heat stress test after this acclimation period again fell by a similar amount in both the 32°C water and land-based training groups.

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Photo by AstroStar

These data indicate that repeat exercise exposure in air and in 32째C water can provide similar training benefits and adaptive responses that improve heat tolerance on land. However, this study used untrained participants and upright cycling exercise, the physical training period (discussed here as acclimation) was 1 month long, and the heat stress tests used to examine heat tolerance were performed on land. Nonetheless, together with the previous studies, they do provide some evidence for the use of a warm water medium to successfully heat acclimate individuals. However, given the different responses seen with resting and exercising immersions in cold water, it is worth noting that no research appears to have specifically examined the acute and adaptive responses to repeated warm water exposures with swimming. Recent research by one of the authors has started investigating this question with eight male competitive swimmers, in a randomised crossover study, completing a 7-day water-based heat acclimation (HA) and control (CONT) period. Acclimation involved 60 min of flume-based swimming in 33째C water with 20-min performance swims completed before and after HA and CONT. Rectal temperature rose approximately 1째C in most HA sessions. However, there were no clear differences between the pre- and post-performance swims in any of the typical adaptations regularly observed with terrestrial heat acclimations. For example, HA did not improve 20 min swim performance in warm or temperate water and did not lower resting or exercising rectal temperature or heart rate, sweat rate was not increased, and there was no consistent plasma volume expansion. Only thermal perceptions appeared to be improved, with swimmers feeling slightly cooler during performance in warm and temperate water. Thus, 7 days of flume swimming in uncomfortably hot water temperatures is minimally effective at inducing typically observed heat adaptations, possibly

associated with the lack of orthostatic stress and limited hyperthermic strain. Summary and future directions Problems during OWS can occur as a result of reductions in muscle temperature and reductions and increases in deep body temperature. There remains incomplete understanding of the responses to warm water swimming and the influence of acclimatisation, acquired from swimming in warm water, on these responses. The sources of the individual variation in the responses to cold and warm water exercising immersions are not fully understood. The mechanism that allows some people to override protective cues and exercise to the point of death remains a hazardous mystery. Cardiac arrhythmias, with or without underlying pathology, may explain some of the deaths seen during OWS and are the prime suspect for those otherwise unexplained deaths that cannot be associated with thermal changes within the body or drowning. The new theory of autonomic conflict as a mechanism of sudden death on immersion and in other scenarios requires further study. Given that autonomic conflict is most likely when swimming in large groups and that the first part of a swim (up to 400 m) is where the greatest number of general incidents occur, it would seem sensible to adopt the general guidelines listed below when organising an OWS event. These guidelines are all designed to minimise the need for breath holding, the chance of aspirating water into the nasopharynx and the potential for crowding, conflicts and anger. The level of evidence underpinning these recommendations is weak/hypothetical; this is another area that requires further investigation.



"Problems during OWS can occur as a result of reductions in muscle temperature and reductions and increases in deep body temperature."

Photo by Maxisport

1. Limit wave/group sizes. 2. Have a wide start line/course width, with the caveat that it can be properly surveyed. 3. Have reasonable time gaps between wave starts. 4. Have a good number of easily visible (from water level) buoys to prevent sharp turns. 5. At the start, have as long a straight line distance before requiring swimmers to make a turn, allowing the swimmers to spread out and find their own pace. 6. Ask swimmers to ‘self-select’ into waves of appropriate ability or ask weaker/novice swimmers to start at the back of a wave. 7. Advocate acclimatisation, anxiety reduction and anger management. 8. Increase the amount of safety cover in the first 400-m section and at turns. Brief swimmers to take their time at the start (particularly if a slower, less fit or a novice swimmer).

Conclusions OWS is an increasingly popular sport that takes place in water temperatures that can present an additional risk to those already inherent in the sport and mass participation in it. More information on the responses to immersion in cold and warm water, the causes of the individual variation in these responses and the precursors to the cardiac events that appear to be the primary cause of death in OWS events will help make this enjoyable sport even safer. Endnotes The volume-specific heat capacity is obtained by multiplying the specific heat of a substance by its density. It represents the amount of heat required to raise the temperature of a given volume of water by 1 K. At 37°C, the volume-specific heat capacity of water is 3,431 times that of air. 30



The Sharm Chamber By Dr Adel Taher and Dr Ahmed Sakr

"The experience that this team has gathered over the years is invaluable"

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Diving, like any sport, requires medical back-up when things go wrong â&#x20AC;&#x201C; and this service is especially vital in remote areas. The recompression chamber at Sharm is therefore a vital facility for divers who visit this area. The experience that this team has gathered over the years is invaluable since it is shared with colleagues in the diving community â&#x20AC;&#x201C; the centre receives diving medical specialists and medical students interested in the field for training and hands-on experience from all over the world. Here, a bit more about their setup and their remarkable work.

Photo by Chantelle Newman. Oldest chamber in the world, Pen State University Hospital, Philadelphia, PA.

Every trained diver knows how vital a hyperbaric chamber is â&#x20AC;&#x201C; a room that allows an individual to breathe 100% pure oxygen at greater than 1 standard atmosphere of pressure. Hyperbaric chambers are used to deliver hyperbaric oxygen therapy (HBOT). HBOT was developed to treat underwater divers suffering from decompression sickness. It has since been approved by the Undersea and Hyperbaric Medical Society for 13 conditions including: air or gas embolism, carbon monoxide poisoning, smoke inhalation, gas gangrene caused by certain bacteria, decompression sickness, radiation tissue damage, thermal burns, nonhealing skin grafts, crush injuries, wounds that fail to heal through conventional treatment, serious blood loss, and intracranial abscess. 33


It was in 1993, on the evening of 8 March, that the long-awaited four containers arrived on site at the land designated for the Hyperbaric Medical Centre in Sharm el-Sheikh. Three 40 inch containers housed the multi-place, double-lock CACI recompression chamber with all ancillaries and one 20 inch container had the two caterpillar 100KVA emergency generators. It took less than 48 hours and the dedicated work of a group of five people to set up the whole system. On the morning of 10 March we were fully operational. The Hyperbaric Medical Centre (HMC) introduced itself to the 15 existing dive centres in Sharm and waited for work… It took some time and then in August we received our first diving accident – strangely enough – from Hurghada, on the other side of the Red Sea. He was brought to us by a single engine Cessna flown just above sea level by the son of the ex-president Nasser. It was a bad case of neuro-muscular DCI, which received a USN TT6 (US Navy Treatment Table 6) without extensions and was fine afterwards. That was the first drop…and it certainly started raining afterwards. The second case we received was from the 'Tower' dive site in Sharm, known for its deep straight walls and easy shore entry. The patients were four young divers from Israel, all suffering from arterial gas emboli. One of them had experienced a defective inflator and the BCD filled up with air; she had shot to the surface while the other three were hanging on to her trying in vain to slow her down. Following that we received an accident that was pivotal in the development of the HMC and the international recognition it received. At the time, 1993, we had the first TRIMIX course being taught in Egypt in Sharm el-Sheikh. We were informed through the VHF radio that a bad diving accident was on its way in a speed boat coming from Hurghada and expected to arrive in 45 minutes. We aborted the TRIMIX dive and headed back to the chamber to receive a 23-year-old German girl suffering severe symptoms of cerebral arterial, as well as spinal gas embolism – and she was totally dehydrated and exhausted. On arrival she was paraplegic with a sensory loss reaching the mammary line and convulsing rhythmically every few seconds. Her symptoms had started about 32 hours earlier. At our centre she received 34

a USN TT6A with minor improvement, followed by a USN TT6 with extensions after 12 hours, also with very moderate improvement. It was then that it crossed my mind that the only treatment remaining would be a HELIOX therapy using the COMEX CX30 treatment table. This is a lengthy 7 hours and a half treatment table, for which a mixture of Helium and Oxygen 50/50 is used as treatment gas. The problems were multiple: we did not have the mix and it was never used in our area of the world for treating sport diving accidents, and Helium was quite expensive and very hard to get! We contacted the TRIMIX course organiser and asked him for his Helium and for the expertise of Ed Betts, who was co-teaching the course to help us prepare the mix. He agreed after realising it could be the girl’s last hope. We mixed the gas and treated, and the girl came out walking and fully restored. This incident gained us huge international coverage and was featured in one of the most viewed talk shows in the Germanspeaking countries. In turn, this reflected on the numbers of influxing dive tourists and the load of patients the HMC had to deal with almost quadrupled. Since 1993 the HMC has treated over 1 600 dive accidents. Not all of them needed recompression therapy; rather there were cases like mild DCI symptoms and pulmonary oedema cases. The profile of the patient population has changed markedly over the years. In the early years we had a very active group working as dive professionals in South Sinai, mainly in Sharm el-Sheikh. They were performing on average two to three dives daily, and on their free day they usually went diving too. They were enthusiastic and enjoyed life. We did not have all the knowledge then that we have now. Also, NITROX was not ‘in’ yet and most dive centres avoided it, because it meant a higher cost to mix and not enough divers were licensed to use it. Our statistics showed patterns of dive accidents relating to geographical areas and shifting over the years in relation to the ‘market dynamics’ of diving tourism. Ras Mohamed and Tiran yielded most of the decompression and AGE/CAGE accidents.

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Photo by Chantelle Newman. Pen State University, specialised ICU wound care chamber.

"Since 1993 the HMC has treated 1 600 dive accidents."


"The technical diving started to boom in Dahab around 2004 and the record-breaking fever started."

Photo by Chantelle Newman. Compressed Air Cylinders used for a Chamber like Sharm who use similar cylinders.

ISSUE 04 | MAY 2015

This was easily explained by the volume diving there as well as the fact that the dives were often against a current, which meant a higher perfusion and Nitrogen loading. The AGE/CAGE were related to deep air diving on the mesmerising straight wall in Ras Mohamed and in Jackson Reef and the Thomas Canyon in the Straits of Tiran. Then came the Thistlegorm – one of the most famous WWII wrecks – with 15 to 32 day-trip and safari dive boats mooring there per day, often in bad weather and sea conditions. Most of the accidents arriving at our centre were dive professionals and mostly due to decompression sickness. The aetiology was no secret: a single divemaster or instructor on the boat jumping in full gear to tie down 2 or 3 ropes at depths around 20 to 25 msw, then surfacing to accompany the guests on their first dive to 30 msw, which is followed by a 'short' surface interval and then the second dive to 25 msw, and after the guests finish their safety stop he goes into the water again to untie the ropes. On the way back, he makes a third dive with the guests in Ras Mohamed. All these dives were made on air. The 'short' surface interval is dictated by the remoteness of the wreck, which means a longer sail time to cover the distance and get back to the jetty before sunset according to regulations. The technical diving started to boom in Dahab (100 km North of Sharm el-Sheikh) around 2004 and the record-breaking fever started. With Nuno Gomes breaking the World Record in June 2005 and reaching 318.25 msw, many tech divers started preparing and training for breaking either their personal, national or whatever record. And all wanted to do it in Dahab, preferably close to the Blue Hole or the Canyon. This meant serious work for our chamber in Sharm as Dahab had no chamber yet. The accidents were serious and they were complicated by two further factors: the transport time of about 90 minutes, in the best case scenario, and driving over the 'Shaira' mountainous pass exceeding permissible altitude for dive accident medical evacuation. During the last seven years, we treated several cases suffering from spinal or cerebral arterial gas embolism or spinal decompression, using the COMEX CX 30

treatment table with HELIOX in conjunction with other Oxygen treatment tables and achieved good (satisfactory) results. They were mostly technical divers. We also introduced in our chamber, and as an adjunct therapy, the concept of physiotherapy under pressure, where the physiotherapist joins the patient in the chamber and works with him during the air breaks as early as during the second treatment session. The gold standard for treatment of sport and recreational diving accidents were USN TT6 and USN TT6A. The 6A, or 6 Alpha, was used mainly to treat AGE and CAGE cases, based on the great success achieved during training by the US Navy to treat accidents occurring during submarine escape tower exercises. Several cases in the chamber did not respond as favourably as expected and some worsened before getting better. It took some investigating and we opted to modify the table for good reasons, and the results were very satisfying. When the table was adopted from the navy to treat sport and recreational diving, we did not realise that the navy divers undergoing the treatment, involving an initial descent to 50 m/165’ breathing air for a duration of 30 minutes, were not loaded with nitrogen prior to their escape tower exercise; divers, on the contrary, are. This means that divers suffering AGE/ CAGE were also liable to later on develop symptoms of decompression. This meant that giving them air to breathe at 50m/165’ for 30 minutes was not a good idea. We changed the gas used to Nitrox 40/60 and achieved excellent results. Many chambers worldwide are adopting this modification when applying the USN TT6A. At times we received several accidents on the same day and sometimes the treatments meant working continuously for over 72 hours. We received in 1995 five accidents ‘without a breather in between’ and they were all quite serious. To help us with the load of work, especially during the high season months, we needed to train some tenders from the professional local diving community. This lead us to put together a five-day course for instructors and divemasters starting after their working hours and offering them academic and theoretical knowledge in the fields of 37


decompression patho-physiology and dive accident management as well as hands-on training in chamber line-up, operation, tending inside and outside the chamber, log writing and emergency procedures. The deal was simple: the course was offered for a fraction of its cost to cover expenses and, in return, learners became volunteers and were summoned whenever we needed them. This also allowed us to gain linguistically accurate information and answers as we managed to cover through our tenders all the imaginable languages up to Swahili! The system still works. In 2007, we organised in Sharm el-Sheikh the 32nd European Underwater and Baromedical Society (EUBS) annual scientific conference with over 400 guests representing the ‘world class’ diving- and hyperbaric medical minds. We offered a study detailing the trends we noted and the demography and statistics of 734 cases among the cases treated here. We noted an age shift in both directions. The new dive programmes that allow children to dive resulted in a small number of incidents, but mainly the age of divers involved in accidents was on the rise. All the divers that learnt how to dive in the early seventies are now between 50 and 60 years of age and continue to dive actively. Many of them do not recognise that they have become hypertensive, diabetic and atherosclerotic, to mention just some of the pre-existing health problems. They also take medication to treat and control their ailments and not all of these pharmaceutical agents can be used safely in a hyperbaric (raised atmospheric pressure) environment. Antidepressants are also a major concern; divers are not always happy to inform the dive centre about these, and we do not get the chance to screen them. We very often discover the problem while treating the diving accident. Elder divers are sometimes not aware of the fact that they do have a health problem. The unqualified physicians in hotels and resorts are also one of the factors contributing to dive accidents as they declare many ‘fit to dive’, because they are not aware of the absolute and relative medical contraindications. At the HMC, we perform daily ‘Fitness to Dive Certificates’, treat ears suffering from otitic barotraumas (middle ear injury 38

caused by pressure), manage poisonous fish stings and fish bites, and cases of pulmonary oedema. Occasionally, we get unusual cases like barracuda bites. Surgically, we received our share over the years: before hospitals were built in Sharm, we treated, on an almost weekly base, crushed finger injuries, which were caused by dive boat ladders. Several times we dealt with de-gloving hand injuries due to moray eel bites (feeding!) and some trigger fish attacks were fierce enough to warrant surgical attention. In 1993, when we started work, there was a definite lack in medical facilities in Sharm and this had its reflections on the chamber. We ended up receiving many cases we were not prepared for in the first three to four years. For example, we delivered children, fixed fractured bones, sutured lacerated injuries following car accidents, and even treated camel bites! The HMC provided then and still does all the medical care for the Bedouin community free of charge. In 1996 we carried out the rescue of a shark attack: we stabilised the case and covered an open injury penetrating the chest cage and raced with the case to the military hospital 100 kilometres away, and helped the surgeons in the theatre. The following day we went for a visit to find the patient happily sitting in bed and smoking a cigarette! He had a big smile on his face, because he was contacted by Reader’s Digest… they had offered him a handsome amount of money for the story. So, in essence, the recompression chamber with medical personnel in a ‘remote area’ without proper (sufficiently equipped) medical facilities will always function beyond the boundaries of diving medicine and act more as trauma and emergency centre. In 2011 we received our new recompression chamber from HAUX company, the Starmed 2200, together with a specially designed gas blending station allowing us to mix the gases we need in special treatments, like NITROX 40/60, 50/50 and HELIOX 50/50. It can accommodate 12 patients seated, or six seated and two lying down, and has a ventilator designated for operation under hyperbaric conditions in addition to an array of vital signs monitoring modules. We hope we do not need to use it much, but are happy that we have it, if a fellow diver should need it.

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Photo by Rolf Wiberg

"In 1993, when we started work, there was a definite lack in medical facilities in Sharm"


Trauma: the pain within Dr Richard Cullen (Order of St. John) discusses the effects of post-traumatic stress disorder (PTSD) and the role of Deptherapy to help those who suffer.

News reports and research highlight the tragic circumstances and effects of PTSD: “A soldier who struggled to come to terms with life after he recovered from terrible injuries he suffered in a roadside bomb blast in Afghanistan has been found dead at home. Now his grieving family and friends want to raise awareness of stress and depression being faced by serving and former military personnel. Bradley Paul, a hugely-respected private with the 1st Battalion, The Mercian Regiment, was 23.” (Source: Manchester Evening News , 20 February 2015) “New suicide data released by the department on Thursday showed that the rate of veterans’ suicide remained largely unchanged over that three-year period, the latest for which statistics are available. About 22 veterans a day take their own life,


according to department estimates. But while older veterans saw a slight decrease in suicides, male veterans under 30 saw a 44 percent increase in the rate of suicides. That’s roughly two young veterans a day who take their own life, most just a few years after leaving the service. 'Their rates are astronomically high and climbing,' said Jan Kemp, VA’s National Mental Health Director for Suicide Prevention. 'That’s concerning to us' Reasons for the increase are unclear, but Kemp said the pressures of leaving military careers, readjusting to civilian life and combat injuries like post-traumatic stress disorder all play a role in the problems facing young male vets.” (Source: Stars and Stripes, 21 February 2015)

ISSUE 04 | MAY 2015

Photo by John Gomez



Not everyone is aware of the benefits of Deptherapy, a revolutionary approach to rehabilitation through scuba diving. On our programme, our Deptherapy team deals regularly with those who attempt to commit or contemplate committing suicide. This scenario is a sad reality of dealing with these precious lives. The death of Paul, reported in the news clip above, whom we had not worked with, is a tragic loss of a young life. In the UK, neither the Ministry of Defence nor the National Health Service monitor the suicide rate of our Armed Forces’ Veterans. USA data suggests that the suicide rate amongst veterans is over twice that of the general population. What we witness at work Whenever I am looking for injured troops to be on a Deptherapy stand at a dive show, or to give a presentation about our work, or to be stooges on the Deptherapy Education Pros’ Course, then I ask for amputees. Why? Well their injuries can be seen and people empathise with them. Another former soldier standing next to an amputee could look unscathed; in the pool he is like any able-bodied person, but inside, in his brain, he may be suffering pain as severe, or more severe, than those with serious physical injuries. He will be likely to attempt to take his own life and often you will find an amputee who also suffers from the pernicious effects of PTSD or the equally devastating neurological injury that is Traumatic Brain Injury (TBI). I first became involved in the issue of occupational stress when in 1986 I researched and wrote an academic paper titled Stress Amongst Senior Police Officers as part of my Masters’ Degree while I was serving as a course director at the Metropolitan Police Service’s Detective Training School with responsibility for advanced and forensic training. Little did I realise that this research would lead to my being invited by the Association of Chief Police Officers (ACPO) to firstly research the need for

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and then establish the Central Advisory Facility for Organisational Health and Welfare in the Police Service (CAF) within the Home Office. The case for such a facility was overwhelming and one of CAF’s research projects was to review the need for the provision of support for police officers suffering from Post-Traumatic Stress Disorder (PTSD). At the time PTSD was simply not acknowledged in the UK and our research was seen by many as heresy. Such views, certainly amongst those of today’s enlightened culture, might seem archaic. However, the view then and unfortunately still now in some organisations, or sections of macho ‘culture’, is that PTSD is something suffered by the psychologically weak. For an individual within an organisation where such a macho culture exists to proclaim that she or he is suffering from PTSD can be a humiliating experience. It is only when I started to research PTSD that I realised that my father, a veteran of World War II, suffered from it. Furthermore, a police constable I used to play rugby with when I first joined the police and who later worked for me when I was a detective inspector suffered from it. He was known as a ‘drunk’, he had an inability to concentrate, and couldn’t remember things. He had been part of the Mounted Police escort accompanying the Household Cavalry when the Provisional IRA detonated a remote controlled nail bomb concealed in a car, killing four soldiers and seven horses. Simon had chronic PTSD, but in 1984 no one in the UK had heard the term let alone understood it. Benefits of scuba diving for PTSD and TBI sufferers I started diving in 2007 and I did not at that time think my past experiences with PTSD would be relevant to my new sport. That remained true until 2010 when I first began to work with British and American troops who had suffered life-changing injuries during the conflicts in Iraq and Afghanistan.

ISSUE 04 | MAY 2015

"In the UK, neither the Ministry of Defence nor the National Health Service monitor the suicide rate of our Armed Forcesâ&#x20AC;&#x2122; Veterans"

Photo by Przemek Tokar


When you have held a fit, tall, charismatic, bright, 24-year-old, and former Rifleman, in your arms while he sobs his heart out at the side of a swimming pool as his PTSD has suddenly kicked in, then and only then might you understand the disabling nature of this pernicious illness. Jeremy Stengel, a former US Marine, suffered from PTSD. He describes his experience of PTSD and Deptherapy as follows: “I sat in my room, I had no life, my injuries and PTSD had destroyed me. I had a loaded pistol in one hand and a coin in the other, my choice was heads I go on the Deptherapy programme, tails I put the gun to my head and pull the trigger. I flipped the coin and it was heads, the rest is history. Deptherapy and the aquatic world changed my life.” Borne of the Vietnam War PTSD was defined by US researchers largely due to the experiences of veterans returning from the Vietnam War. In context the war cost 58 000 American lives with thousands upon thousands seriously injured. PTSD research was very much seen as being an American issue and not something from which British Armed Service personnel would suffer. I guess we Brits relied on the concept of the ‘stiff upper lip’. The Americans had transported the concept of PTSD to emergency service workers, in particular police officers, and this is what we picked up on within CAF. A firing squad as solution During the First World War, soldiers who deserted the front or refused to fight were Court Martialled for cowardice; some were sentenced to death by firing squad. In the early years of that war some British soldiers were as young as 14 and many were under 17. What was known as ‘shell shock’ after the First World War is today termed PTSD or TBI.

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A new dawn – and the macho challenge During our research between 1988 and 1989 an experienced traffic officer came forward as a case for study, and a new strand of work was undertaken by Rosemary Roberts into what we called at the time ‘Unexpected Reactions’. This leading-edge research was an early look at what we now know as ‘Complex PTSD’, a specific form of the illness that relates to continued exposure to traumatic experiences. It is commonly found among those who have suffered repeated sexual abuse as children, domestic abuse, extended hostage situations, torture, and among emergency workers who are frequently exposed to traumatic incidents. In the initial research we found the traffic officer had attended dozens of fatal road traffic accidents over the years. However, at the last accident he attended (and there was nothing in particular about this accident that should have triggered PTSD), the officer almost immediately suffered a serious nervous breakdown that continued for many months with the characteristic ‘flash-backs’ so common among the majority of PTSD sufferers. Survivor syndrome (guilt) Understanding PTSD is complex, and as of yet few understand the concept of ‘Survivor Syndrome’ according to which an individual suffers PTSD as a result of someone else dying or suffering a traumatic event. Onset can be immediate or as with all PTSD triggered many years after the incident. I was writing the outline of this article some months ago in Jeddah where I was working, and in the background the story of the South Korean ferry disaster was being played out on the news, with the sad news that one of the few survivors, the Vice Principal of the School involved, had just taken his own life as he could not face living with so many of his students having died. This is an example of ‘Survivor Syndrome’ at its most destructive.

ISSUE 04 | MAY 2015

"PTSD research was very much seen as being an American issue and not something from which British Armed Service personnel would suffer"

Photo by kaninstudio



What is post-traumatic stress disorder (PTSD)?

The cause of PTSD is unknown, but psychological, genetic, physical, and social factors are involved. PTSD changes the body’s response to stress. PTSD is a type of anxiety disorder. It can occur after you’ve seen or experienced a traumatic event It affects the stress hormones and chemicals that carry information between the nerves that involved the threat of injury or death. (neurotransmitters). Having been exposed to trauma in the past may increase the risk of PTSD. What is traumatic brain injury (TBI)? Good social support helps to protect against PTSD. In studies of Vietnam veterans, those with strong TBI is basically damage caused by the rattling or support systems were less likely to get PTSD than the concussion of the brain. It can be found in those without social support. the victims of car crashes, through to those who have been in explosions. What is now emerging People with PTSD re-experience the event again is that there is a specific form of TBI associated and again in at least one of several ways. They with exposure to blasts, especially bomb blasts, that is being observed amongst veterans of recent may have frightening dreams and memories of the event, feel as though they are going through the conflicts. The blast wave from the explosion experience again (flashbacks), or become upset affects the brain immediately upon impact with during anniversaries of the event. the skull. It can cause serious physical injury to the brain, and is now being associated with Symptoms of PTSD fall into three main categories: changes in personality, PTSD, and more. 1. Repeated 'reliving' of the event, which A former US Marine Corps Sergeant describes disturbs day-to-day activity what it is like to live with TBI: • Flashback episodes, where the event seems to be happening again and again “I know my name, but I don’t know the man who • Recurrent distressing memories of the event used to back-up that name...I never thought I would have to set a reminder to take a shower, you • Repeated dreams of the event • Physical reactions to situations that remind know I am 39 years old. I’ve got to set a reminder you of the traumatic event to take medicine, set a reminder to do anything...” Causes, incidence, and risk factors PTSD may occur soon after a major trauma, or it can be delayed for many months or years after the event. When it occurs soon after the trauma, it usually can be resolved after 3 months or so. However, some people have a longer-term form of PTSD, which can last for many years. PTSD can occur at any age and can follow a natural disaster such as a flood or fire, or events such as war, a prison stay, assault, domestic abuse, or rape. The terrorist attacks of September 11, 2001, in the United States may have caused PTSD in some people who were involved, in people who saw the disaster, and in people who lost relatives and friends. These kinds of events can produce stress in anyone, but not everyone develops PTSD.

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2. Avoidance • Emotional “numbing” or feeling as though you don’t care about anything • Feelings of detachment • Inability to remember important aspects of the trauma • Lack of interest in normal activities • Less expression of moods • Staying away from places, people, or objects that remind you of the event • Sense of having no future 3. Arousal • Difficulty concentrating • Exaggerated response to things that startle you • Excess awareness (hyper vigilance) • Irritability or outbursts of anger • Sleeping difficulties

ISSUE 04 | MAY 2015

"PTSD is a type of anxiety disorder. It can occur after youâ&#x20AC;&#x2122;ve seen or experienced a traumatic event that involved the threat of injury or death."

Photo by Feng Yu



Suffers might also feel a sense of guilt about the event (including 'survivor syndrome guilt'), and the following symptoms, which are typical of anxiety, stress, and tension: • Agitation or excitability • Dizziness • Fainting • Feeling your heart beat in your chest (palpitations) • Fever • Headache • Paleness Signs and tests There are no tests that can be done to diagnose PTSD. The diagnosis is made based on a certain set of symptoms that continue after you’ve had extreme trauma. A doctor will do psychiatric and physical exams to rule out other illnesses. PTSD – the onset PTSD can develop almost immediately, but research is now showing that signs and symptoms of PTSD may emerge many, many years later. Some of those involved in the Falklands War have thirty years after the conflict developed late onset PTSD. Such incidents may occur as the result of an everyday event that triggers a memory, a traumatic memory. Whether onset is immediate, short term or long term, the disabling effects are the same. An example is that one of the seriously injured guys we work with on the Deptherapy programme was driving through Windsor prior to our trip to Florida. Some idiot fired a paint ball at his windscreen, which immediately triggered a flashback and PTSD. Reducing the effects Critical Incident Stress Debriefing has been shown to be effective in preventing the development of PTSD. Certainly the ability to talk about an event can be liberating and sharing the experience can reduce the psychological pain. In the longer term, counselling by a qualified person, experienced in PTSD, can reduce or eliminate the illness; in some

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cases when the condition is chronic it may never be alleviated. Medication is often prescribed by doctors. I suppose the easiest description is to describe these drugs as having a relaxing or sedative effect. Personally I am not a fan of such drugs and have seen too many who after coming off the drugs revert to the same condition they were previously experiencing. Complex PTSD As I mentioned earlier this is a compounded version of PTSD. The scars it leaves can often be far more pernicious than even chronic PTSD. Long-term support and counselling, supported by medication, is often the only solution. To explain the effects even better, I think of my own scenario: During my career I have experienced many dozens of traumatic incidents, some amongst the worst atrocities committed in the UK. To date, I have never needed medical treatment or counselling. But I know, even for me, tomorrow something could happen to trigger a response to the trauma I have seen. That is the reality of PTSD. Deptherapy case studies Let’s use the name ‘Z’ for the 24-year-old Rifleman I spoke of before. To listen to the interview from his post Deptherapy programme, which is part of the ongoing medical research into the rehabilitative effects of the programme, is a tear jerker. The vehicle he was travelling in was blown up when it hit an IED (improvised explosive device); he suffered a serious knee injury and developed PTSD. Not properly addressed, his condition has persisted. Z talks about the sudden onset of symptoms: spontaneous crying, sleepless nights, flashbacks, a feeling of emptiness, ‘being an empty shell’, and feelings of being ‘worthless’. He said to me during a particularly dark time for him:

“Rich, I want to end it all – at times I don’t recognise who I was, I just want it (the PTSD) to go away; it hurts so much.”

ISSUE 04 | MAY 2015

"Certainly the ability to talk about an event can be liberating and sharing the experience can reduce the psychological pain" Photo by Anchiy



Z came on the Deptherapy programme and found that being underwater was ‘calming’; he relaxed completely and his symptoms disappeared. He commented that as soon as he put his scuba equipment on and descended underwater his symptoms completely disappeared. This is consistent with studies by Johns Hopkins University; those studies show that US veterans reported an 80% reduction in the symptoms of PTSD when introduced to scuba diving. However, an event with Z showed me how quickly he could break down with his PTSD: We had moved on to his confined water dives for his PADI OW qualification. Everything was fine until Z had to leave the water to adjust his weights; the frustration built and suddenly for no apparent reason he broke down in tears. A second case study, Dean Upson, suffers from complex PTSD due to work in the Royal Engineers. He had seen many of his colleagues blown up while trying to disable IEDs in Afghanistan and elsewhere. Those experiences scarred him; his PTSD kicks in when he comes in contact with an amputee from these conflicts. He is working with Deptherapy to alleviate these reactions and now routinely works with amputees underwater and socially as he is a qualified PADI and Deptherapy Education instructor working on our programmes. His PTSD has not gone away, but he is capable now of controlling it when working with amputees. The team offer him 24/7 support if he needs us as we do with all our programme members. Contraindications to diving The most important thing is to check on medication. Several prescriptions used in the treatment of PTSD – such as anti-depressants – are contraindicative to diving. Some have restrictive depth limitations. We are aware that several of those we work with who are suffering from chronic PTSD have attempted to take their own lives, often

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by overdosing on the medications that they are prescribed. For these men and women we provide on-going 360 degree support. An incident of PTSD underwater is unlikely unless an individual was to be placed in a stressful situation, but all indicators show the contrary, namely that sufferers find scuba diving alleviates symptoms and is ‘calming’. As for a ‘death wish’ – there is no evidence of a diver suffering from PTSD trying to take his or her own life while scuba diving. Conclusion Overall the evidence suggests that scuba diving certainly in the short term is beneficial to sufferers of PTSD, and indications are already available that these beneficial effects may be long lived. We are currently working with Cumbria University to look at the benefits scuba provides to veterans with PTSD and we are sharing our data with Johns Hopkins University in the USA. I end with the words of Aaron, a former soldier in the Royal Anglian Regiment:

“I have wanted to take my life on so many occasions; the physical pain of my injuries, the PTSD leaves me an empty shell. Then on the Deptherapy programme I realised life could be different, my diving had to be cut short because of my internal injuries but the support from the team is what brings you through. Deptherapy, in short, saved my life.” Dr Richard Cullen is a trustee and Head of Operations for Deptherapy and Deptherapy Education an English charity ( and on Facebook Deptherapy and Deptherapy Education) who seeks to rehabilitate seriously injured Armed Service and UK ‘blue light’ personnel through specially designed scuba programmes.

ISSUE 04 | MAY 2015

"Overall the evidence suggests that scuba diving certainly in the short term is beneficial to sufferers of PTSD" Photo by Andrey Kuzmin



Energy drinks the essential information By Dr Suzanne Gaskell Consumption of energy drinks has become ubiquitous in society over recent years. The UK industry is worth approximately £792m and grew by 5% in 2013. It is increasingly common for people to seek a ‘quick fix’ in order to perform sporting activities, especially after a long haul journey or a late night out. The industry targets the youth by sponsoring extreme sports, but do people really understand what they are consuming?

Photo by heromen30


ISSUE 04 | MAY 2015

"An intake of 400mg caffeine a day is considered a threshold for safe consumption"

What do energy drinks contain? The selling point of these drinks is their ‘energy blend’, which varies between brands. It usually consists of caffeine, vitamins and sugar. Over the years there have been concerns raised about the safety of these drinks. Research into this demonstrated that the concentration of each ingredient in one can is safe. However, unlike alcoholic beverages, there is no guidance on maximum recommended daily allowances. It is also difficult for consumers to see what these drinks contain, since they are sold as ‘dietary supplements’ and not ‘foods’ and are therefore subject to weaker labelling regulations. Below is an overview of the most commonly used substances in an energy drink: Caffeine  This is the main and most physiologically active constituent of energy drinks. Its effect peaks one hour after ingestion, primarily stimulating the central nervous system, increasing alertness. It also affects the cardiovascular system by raising the heart rate and blood pressure. In addition, caffeine

may improve muscle activity and increase the availability of energy for metabolism. This is how it exerts the proposed ‘performance enhancing’ effects. For this reason, there is increasing interest in caffeine chewing-gum and slow release tablets in the field of sports nutrition. An intake of 400mg caffeine a day is considered a threshold for safe consumption. Pregnant women should not consume more than 200mg, since it may cause low birth weight, which can cause problems later in life. Even in low doses, caffeine can cause nausea, anxiety, headaches, heartburn, tremor and chest pains. Higher doses (more than 1 000mg) can cause intoxication and even death. Sensitivity to its effects varies amongst individuals and regular ingestion can lead to physical dependence, meaning withdrawal symptoms such as headaches, lethargy and nausea occur when caffeine is stopped.



"Two brewed coffees in the morning, a cup of afternoon tea and a chocolate bar takes you into toxic territory"

Manufacturers have no obligation to state how much caffeine a product contains unless it is very high (above 150mg per litre in the UK). This makes it difficult for people to keep check on their caffeine consumption. The table below provides approximate caffeine content of commonly consumed products:


Instant coffee Brewed coffee Espresso Tea Green tea

Approximate caffeine content (mg/ fl oz) 7mg 20 50 5 3

Cola – regular or diet Red Bull Monster Milk chocolate Dark Chocolate

3 9,5 10 20mg/ 100g bar 70mg/ 100g bar

Photo by Odua Images


When you add these up, it is easy to see how caffeine intake can quickly run into unsafe levels: Two brewed coffees in the morning, a cup of afternoon tea and a chocolate bar takes you into toxic territory. Taurine This is a naturally occurring chemical messenger between nerves, abundant in the brain, muscles and heart. It is used by the body at times of stress and activity. Taurine gives Red Bull its namesake since it was first discovered in the bile of bulls. However, it is also found in meat, fish and eggs. People with a balanced diet obtain their daily requirement of taurine from this without the need for supplementation. Despite its popularity as an ingredient in energy drinks, surprisingly little is known about its effects when ingested orally. Up to 3g a day of supplemental taurine is generally considered safe. Each can of Red Bull contains 1g taurine. Glucuronolactone This naturally occurring chemical assists in detoxification within the blood. These properties have also led to the theory that

ISSUE 04 | MAY 2015

energy drinks are detoxifying. Unfortunately, this has led to the misconception that consuming alcohol with glucuronolactone may lessen alcoholinduced damage on the body. In fact, there is no strong evidence that glucuronolactone exerts any significant effects on the body at the levels sold in each can. Glucose This empty sugar is our body’s main fuel source. It is quickly absorbed and is turned into energy rapidly after ingestion. The calories in full sugar energy drinks are derived from glucose (approximately 43kcal per 100ml). This equates to 200 calories a can in some cases, which is as much as a chocolate bar or 10% of our recommended calorie intake (2 000kcal/ day for women and 2 500kcal/ day for men – depending also on activity levels). Though this can be useful during activity, it will be stored as fat if it is not used, which causes obesity and increases the risk of diseases such as diabetes and heart disease. If one exercises for less than 60 minutes per day, there is no need to include carbohydrate in your drink – the hydration alone is adequate.

Guarana This is a South American plant with stimulant and energising effects. It was initially thought that these effects were due to a chemical called guaranine, but now we know it is simply the caffeine content. This plant has the highest known natural caffeine content in the world. Gram for gram, Guarana contains two to three times more caffeine than coffee beans. The effects are therefore the same as caffeine, just more. Ginseng This is a herb used in folk and Chinese medicine. It is thought to be a natural stimulant. Gingko Biloba This is taken from the leaves of the gingko biloba tree. The extract is considered to have antioxidant properties.



B vitamins B vitamins are water-soluble, which, in contrast to fat-soluble vitamins (A, D, E and K), are not stored by the body. Instead, they are excreted by the urine and losses require replacement from our diet. Most people have heard of B vitamins by different names, such as thiamine (B1), riboflavin (B2), niacin (B3) and folic acid (B9). They help regulate metabolism and assist with extracting energy from food. They synthesise cells with rapid turnover, e.g, red blood cells and cells lining the gut. In addition, they maintain healthy nerves by assisting with the regeneration of their myelin sheath. The myelin sheath helps keep the nerve signals transmitting clearly. A deficiency of these vitamins can cause fatigue, neurological symptoms and anaemia. Most people have enough B vitamins from their diet to meet their daily requirements, and it can take many years for a deficiency to appear clinically. A deficiency for young people in the UK is rare (except for strict vegans). Vitamin B12 deficiency in the UK in 2004 was noted as follows for older people: 5% amongst people of 65 to 74 years of age, and over 10% for people of 75 years and older.

Photo by Ammentorp Photography


Most energy drinks contain a high proportion of the recommended daily allowance of B vitamins, so you should exercise caution when drinking multiple cans or taking vitamin B supplements alongside. Consuming excess vitamin B is not proven to give an energy boost and can potentially cause harm. Don’t rely on the assumption that the body will get rid of excess.

Other considerations Energy drinks are sometimes confused with ‘sports’ or ‘isotonic’ drinks. It is hardly surprising these drinks get confused as they are often sitting next to each other on the supermarket shelves. Isotonic drinks help replace salts and water lost in exercise. They also increase the rate of water absorption to maintain adequate hydration. On the other hand, caffeine acts as diuretic, meaning it stimulates the body to lose water. The high glucose content of some energy drinks causes the blood to become more concentrated, and so draws water out of the blood and into the urine, further compounding dehydration.

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"Diving causes a natural diuresis and caffeine consumption compounds this further."

Of particular concern is when energy drinks are combined with alcohol – another dehydrating substance. These drinks are sweet and easy to consume quickly in large volumes. The caffeine is thought to ‘mask’ the intoxicating effects of alcohol, meaning that more alcohol is consumed. Most people do not drink enough water alongside, making the combination of alcohol, caffeine and glucose a potent ‘dehydrating cocktail’. It is more likely that these drinks are consumed on holiday when sporting activities may be undertaken the next day before the effects of these drinks have worn off and before people have been able to rehydrate themselves.

however, with increased pressure, they feel worse and could lead to panic.

Energy drinks and diving


There is little research in this specific area, but common sense tells us that if a diver is tired to the point where he or she requires energy drinks, judgement will me impaired – and poor judgement is a leading cause of diving accidents. Furthermore, one may consume an energy drink just before a dive and the effects may occur when underwater. Excess caffeine symptoms are unpleasant on the surface,

Energy drinks are a popular yet sometimes misunderstood beverage.

Diving causes a natural diuresis and caffeine consumption compounds this further. The resulting dehydration increases the risk problems such as decompression sickness, fatigue, headaches, cold stress, and muscle cramps, to name just a few.

The evidence is unclear whether the stimulating effects of energy drinks are attributable to anything other than the caffeine and glucose content. The positive effects of the other ‘energy blend’ ingredients are unproven. 57


"If you are requiring stimulants to enable you to dive or indeed perform any activity, you should be considering whether you are fit to be doing it in the first place"

It is easy to exceed the recommended daily allowance of vitamins, glucose and caffeine with these drinks, so one should always consume in moderation. Bear in mind that energy drinks are not designed to hydrate you. Indeed, some of the ingredients are dehydrating, so ensure you consume adequate amounts of water alongside energy drinks. Energy drinks are not alternatives to sleep or rest. If you are requiring stimulants to enable you to dive or indeed perform any activity, you should be considering whether you are fit to be doing it in the first place.Â

References: (downloaded April 2015) (downloaded April 2015)!backgroundsub:5 (downloaded April 2015)

Photo by ethan daniels



To Vinegar

Or Not To Vinegar? A Jellyfish Question...

By Yvonne Tatchley We all like an easy life, one of simplicity and generalised wisdoms, extending throughout all aspects of our lives. Wouldnâ&#x20AC;&#x2122;t it be great if the treatment of marine life injuries from a collective group of organisms was uniform and consistent? Unfortunately, the underwater world, and its vast array of magnificent and sometimes dangerous animals, does not make our lives so simple, especially not when we are looking at the diverse world of jellyfish. You may believe and have probably been taught that the treatment for jellyfish stings is the same for each and every jellyfish, involving a razor, sea water and a good dash of vinegar, but that is certainly not the case. Identifying the type of jellyfish and getting subsequent first aid right may prove vital to the prognosis of the affected person.

Classification of jellyfish Contrary to popular belief, the organisms that we frequently refer to as jellyfish are not all true jellyfish. They all belong to the same taxonomic group (called a phylum) known as Cnidarians, but they are then sub-classified into classes based on

Phylum Cnidaria

their traits and characteristics, which would have been developed as they evolved. Each class has a slightly different make-up (physiology) and different venom. This will mean that injuries sustained may need to be treated in different ways.

Sub-Phylum Medusozoa

Class Cubozoa Box Jellyfish 60

Class Hydrozoa Portuguese Man-of-War

Class Scyphozoa True Jellyfish

Photo by ILeysen

Swarming compass jellyfish Chrysaora hysoscella Photo by A. Lesik

ISSUE 04 | MAY 2015

Physiology and method of stinging Cnidarian literally means ‘stinging cell’, and unsurprisingly all Cnidarians contain stinging cells, which are called cnidocytes. One organism may have thousands or even millions of these tiny stings; the main purpose is for use in predation and feeding. Cnidarians are almost all carnivorous, predominantly feeding on plankton. However, the larger jellyfish will actively predate upon small fish and shellfish. Cnidocytes contain a structure called a nematocyst, which contains the actual stinging element. It is a capsule enclosing a long coiled thread. When stimulated, this thread is ejected

and either acts via entangling and adhering or by directly injecting into the prey. Firing of nematocysts can be caused by either chemical or mechanical stimuli. An example of mechanical stimuli is through direct contact or the change in water pressure caused when we move close to these creatures. Many cnidarians have the ability to inject a protein-based toxin called a porin into the prey through the nematocyst. It is this poison that produces the pain we regularly attribute to jellyfish stings. Although all cnidarians contain nematocysts, not all will affect humans. This is because some organisms have nematocysts that are too small to penetrate human skin.

Types of Jellyfish Hydrozoans Hydrozoans are an extremely wide-ranging class of organisms. Many are colonial (made up of a collection of structurally different individuals, performing different roles but all working together to appear as one animal) but not always. Some are sedentary such as fire coral and some such

as the Portuguese man-of-war are mobile. Of the hydrozoans, it is the Portuguese man-of-war and its closely related species (Physalia sp.) that are regularly referred to as a jellyfish. They comprise four different types of polyps:

• A pneumatophore: the gas filled blue/purple-coloured bladder, which often sits above the water level acting as a float. As physalia do not have any independent means of movement, the float is used as a sail to catch the wind. Currents also assist in their movement. • Reproductive polyps. • Digestive organisms called Gastrozooids. • Tentacles: The tentacles of the man-of-war are long and thin, on average about 10m in length. Their function is to assist in feeding. The nematocysts contain a glycoprotein-structured toxin called physaliotoxin. It has to date been shown to have various effects on humans, its effects being haemolytic (affecting the red blood cells) and cytolytic (causing breakdown of cells). It is believed to work alongside other proteins with cardiotoxic (toxic to the cardiovascular system), musculotoxic (toxic to the muscles) and neurotoxic activity (toxic to the neurological system). The amalgamation of all of these venoms is what causes the potent effects that may result from a hydrozoan sting.

Scyphozoans The Scyphozoans are what are termed the ‘true jellyfish’. They comprise about 200 species. One such jellyfish is a radially symmetrical, single organism (not colonial). They range in size and toxicity but have a common structure. The top part or ‘bell’ is usually translucent but very often tinged with other colours. They have four or eight feeding arms and tentacles of varying number and length that hang from the bell margins. Both the arms and tentacles may be covered in large numbers of nematocysts. Unlike their hydrozoan cousins, many of the scyphozoans have the ability to swim. They

do this through contraction and relaxation of muscles contained within the internal gelatinous material called mesoglea, which serves to provide structural integrity. They therefore have the ability to actively predate. Their venom is also protein-based and includes catecholamines, histamine and phospholipases, to name but a few. They have been shown to have haemolytic and cytotolytic effects. Other effects vary considerably depending on the amount and exact venom that is injected. 63


Scyphozoans that are well-known to inflict significant injuries to humans are the lions

mane jellyfish (Cyanea capillata) and the sea nettle (Chrysaora sp).

Cubozoans Unlike the two previously mentioned classes, which are found throughout the world, the cubozoans are restricted to certain equatorial areas of the world. The most famous of this group and arguably the most toxic organism in the sea is Chironex fleckeri, the ‘sea wasp’ or ‘box jellyfish’. The sea wasp is generally only found in the Indo-Pacific, and generally the highest rate of encounters with humans is on the north east coast of Australia. One of the main problems with the sea wasp is that it is almost invisible. It consists of a blue-tinged

translucent cube, with up to 15 tentacles hanging from each corner. The cube can be up to 20cm in length and the tentacles up to 3m. They tend to increase in number and move into shallow water following bad weather. The venom of the sea wasp is dermatonecrotic (causing death of skin cells), haemolytic, and cardiotoxic. The end result can be rapid death. However, the severity of the sting is dependent on the size of the organism, amount of contact, and individual susceptibility.

Signs and Symptoms Hydrozoans A sting from a Portuguese man-of-war is renowned for causing fairly intense pain. This should subside when first aid is applied and should not persist. Long, strap-like marks (very often only one) which become very red and a welt will soon appear and persist for some time (two to three days). Following the event (could be as long as six to eight weeks) the area may become irritated or itchy (similar to that of insect bites). In most cases symptoms will not be serious or long-lasting, resolving with basic first aid. However, in the case of more

severe reactions, other side effects may present. These include nausea, vomiting, muscle spasms, headache, dizziness, change in heart rate and respiratory distress. Infection at the site of the sting is a possibility after the event and will need to be monitored. If lymph nodes swell or red streaks appear between the lymph nodes and the sting, medical advice will need to be sought.

Scyphozoans It is more difficult to specify the exact signs and symptoms attributed to Scyphozoan stings because • • • • • • • •

the species and effects are so wide-ranging. The following may be experienced:

One or more raised red lines, which may welt Pain (which may be intense) and burning in the affected area Nausea/vomiting Diarrhoea Muscle spasms Severe allergic reaction, may lead to loss of consciousness, respiratory and cardiac distress (slowing of heart rate) and possible death. Confusion Later: rash that itches, dermatitis

Cubozoans A cubozoan sting will often show as multiple long red, purple or brown lines, about 0,5cm wide in a ladder-type pattern. The jellyfish tentacles may still be stuck on with a thick sticky substance. The affected person is likely to be screaming in pain and 64

may have to be restrained. They may claw at the remaining tentacles; it is imperative you prevent the person from doing so as contact could cause further nematocysts to fire and more venom to be injected. The patient may become very confused,

Phyllorhiza punctata, the Australian Spotted Jellyfish. It is endemic to the waters between Japan and Australia but has become an invasive species in the Mediterranean and Caribbean. Stings are so mild they may even go unnoticed. Photo by Ewa Studio

Beautiful but potentially deadly, the Hydrozoan, Portuguese Man-of-War or ‘Blue Bottle.’ Photo by Science Pics

ISSUE 04 | MAY 2015

irrational, lose consciousness, suffer cardiac shock and respiratory distress. Cyanosis, abdominal pain and paralysis may also occur. Death can occur within minutes if life-saving first aid is not carried

out. If the patient survives, he or she may suffer with ongoing problems at the area of the sting for some months. This includes welting, necrosis and ulceration.

Treatment As with all rescues, your primary aim should be protecting yourself from getting injured or stung in the first place. Ensure you are wearing appropriate exposure protection, bearing in mind that cubozoans have been known to sting through surgical gloves. If you witness an attack, your aim should be to get the victim out of the water. If you can identify the type of organism that has caused the injury, it will assist you in administering the most appropriate

first aid. If the patient has ceased breathing you should administer CPR without delay. In all cases you should be monitoring for anaphylactic shock and be ready to treat appropriately. Each person may have a different degree of sensitivity to venom, some showing very little reaction (such as minor dermatitis) and others suffering with far more extreme symptoms. There is evidence to show that individuals who suffer with allergies to insect bites have a higher likelihood of reacting badly to a jellyfish sting.

Hydrozoans If you suspect that the patient has been stung by a Hydrozoan, especially by a Portuguese man-of-war, you should not treat the injured person in the same way as you would for someone who had been

stung by a true jellyfish. The venom is different and therefore needs to be handled differently. The currently agreed best course of action for a Hydrozoan sting is as follows:

1. Any tentacles remaining on the injured party will need to be removed extremely carefully. You should take care that they do not come into contact with your own skin and that the injured person does not touch them any further. This is to prevent any undischarged nematocysts from firing and causing further venom to be injected. For the same reason the age-old adage of rubbing the affected area with sand should very much be ignored. 2. Rinse the affected area well with salt water. Fresh water appears to exacerbate the problem, so only use salt water. 3. There is some debate over whether hot or cold treatment is best applied next. Both appear to have therapeutic effects, so I would suggest using whatever you have available. If administering hot water, use hot salt/seawater (45 °C or 113 °F) for at least 15 to 20 minutes. If you do not have access to seawater, use hot/cold packs but not fresh water. 4. Unlike the treatment for true jellyfish, vinegar should not be applied to Hydrozoan stings. Administration of vinegar or acetic acid has been shown to increase toxin delivery into the affected person. 5. If there is any sign of allergic reaction, muscle spasms, infection, respiratory distress, swollen lymph glands or if you have any doubts whatsoever medical advice should be sought as soon as possible.

Scyphozoans If you have identified that the individual has been stung by a true jellyfish (not a Portuguese man-of-war or member of the Cubozoa), your 1. 2. 3.

actions in terms of administering first aid will be a little different:

As with the Hydrozoans rinse the affected area with salt/seawater. As a general rule the venom is a mix of proteins, which can be inactivated through temperature or through applying an acid or base substance. Commonly used substances in the past have been vinegar, 5% acetic acid solution, meat tenderiser or baking soda. For all those wondering ‘what about if I urinate on it?’ the answer is don’t. It is simply not right and rather unsanitary. Douse the affected area in the substance you are using. Vinegar or 5% acetic acid are most recommended. The above action should have deactivated any remaining undischarged nematocysts. Remove any 67



remaining visible tentacles, using forceps or similar items. Rinse the area again and monitor for any signs of allergic reaction and later infection. In the most part, any pain and symptoms should resolve over time. If the sting covers large areas of the skin, there are signs of shock, allergy, respiratory distress, infection, or concerns, medical attention should be sought.

Cubozoans For twenty years guidance on treating Cubozoan stings has remained the same as treating scyphozoan injuries (such as using vinegar or acetic acid to neutralise and disarm discharged nematocysts). The remaining tentacles could then be washed off with seawater, without fear of further problems. In early 2014 researchers from James Cook University in eastern Australia called this procedure into question. Research claims to have demonstrated that although vinegar does neutralise undischarged nematocysts, the vinegar also causes an increase in the uptake of venom from nematoycsts that have already fired (up to 70%). The question still to be answered is whether the increased uptake of venom outweighs that which would be released if the undischarged nematocysts fired. The study has been highly debated in the

scientific realm and further research will need to take place before there is sufficient evidence to cause a change to the recommended treatment advised by the relevant authorities in each affected country. As such, treat as with scyphozoans, paying most attention to the likelihood you will need to administer CPR. So, returning to the original question, to vinegar or not? The answer is depends on the jellyfish involved. If you know the area you are in, know the organisms you are likely to encounter, wear appropriate exposure protection, and arm yourself with the relevant up-to-date first aid skills, knowledge and tools, then you should be well prepared to deal with any jellyfish injury you encounter.

Photo by Paul Brown

Blistering and reddening caused by a sting from a Portuguese Man-of-War. After the initial first aid response, the site of the sting should be monitored for signs of infection, including swollen lymph nodes and red strap marks between the lymph nodes and sting. 68

Mastigias sp. has nematocysts that are incapable of piercing the majority of human skin. All but those with allergies to jellyfish stings would be safe. Photo by Blue Orange Studio


Long-term effects of a sting

The Holiday Puzzle

By Dr Anke Fabian The treatment of jellyfish stings and other marine life is not always as simple as we would like it to be, as can be seen in the case of this young diver.

Photo by Ellen Cuylaerts

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Philippines: after a fantastic dive Natascha S. (30 years) was hanging relaxed on the deco-line beneath the boat to wait for her computer to clear the safety stop. She wore a 3 millimetre Long John diving suit without a hood. There was quite a current – therefore, everybody stayed close to the rope. Suddenly, Natascha felt a very sharp pain on the left side of her neck, which increased so quickly that she almost had to abort the decostop. She felt slightly sick, nauseated, and the pain was intense. The other divers started to itch too and some felt uncomfortable at various locations of their bodies, but Natascha was hit worst. Nothing was to be seen in the water – no jellyfish anywhere for far and wide. Back on the boat Natascha suffered from a depression of blood pressure followed by a circulatory collapse. Itchiness and pain increased. She received medical first aid from the crew, who were not sure whether they were dealing with a diving accident or not. A rash developed on the left side of her neck in the form of red dots, pustules, warmth and redness as signs of an increasing allergic reaction. The crew wondered whether it could also likely be DCS Type I symptoms. The crew members rested her in the shade, encouraged her to drink water and applied normobaric oxygen – just to be on the safe side. The circulation weakness ceased slowly, the burning sensation and itchiness remained. In the evening, Natascha applied anti-allergic cream (Fenestil Hydrocort) and the rash improved until it was gone after 3 days of local treatment. Being a minor incident without a proper medical explanation, she forgot about it and continued her travels. But that was unfortunately not the end of the story. Three months after the actual incident and only having just arrived back in Germany, the same local skin rash, itchiness and pain reoccurred, this time without general symptoms but very persistent. Doctor number one, her general practitioner, was at a loss and sent her to doctor number two, a dermatologist. The allergy tests came out negative. Having travelled for several months in Asia, she then was sent to the Institute for Tropical Infectious

Diseases to exclude any tropical diseases. There she saw doctor number three. All tests showed negative. As she had been diving throughout her travels (her last dive had been 48 hours before flying), the infectologist introduced her to a dive doctor asking whether those skin symptoms could be diving-related. Doctor number four was a consultant for diving and hyperbaric medicine, luckily having a thorough education on dangerous marine animals. On examination, she presented a reddish skin rash with a maculo-pustular erythema, which was limited to the left cheek and neck region. The skin was slightly warmer, the submandibular lymph nodes swollen, but there were no other general symptoms. She had no fever and the laboratory findings were normal (namely, Complete Blood Count, White Blood Cell Count, Packed Red Blood cell, Differential Blood Count). The type of skin symptoms as well as her diving history excluded the possibility of decompression sickness. It was an odyssey for Natascha. Only after digging in her history and learning about the incident on the Philippines, the dive doctor realised the connection between the original and actual symptoms and made a final diagnosis: late allergic reaction to a hydroid sting. Therapeutically, one cannot do much for a patient in a case like this, except for the application of local anti-allergic ointments, possibly in combination with cortisone. In case of general symptoms, the medication is implemented systemically (orally or intravenously). One important issue is the education of the patient: The doctor needs to point out the possibility of recurrent symptoms up to one year. In Natascha’s case, the symptoms popped up three more times and vanished completely after eight months. Another important approach is the knowledge about one’s precondition or propensity for allergic reactions and to consequently wear proper stinger protection (such as a lycra suit).

What had happened:

Photo by Andrey Yurlov

Some jellyfish are able to reproduce by pinching off microscopic small polyps, which feed on plankton. The so-formed small larvae (Ephyra-larvae) drift in the ocean as zooplankton. The current must have washed a whole swarm of those larvae into the middle of the diving group. The exposure to the zooplankton was the same for every person – whereas the individual reaction varied greatly as could be seen in Natascha. One of the dangers from Coelenterates poisoning lies within the possibility of a fast or late allergic response. Most

substances are based on a protein structure and therefore act as antigens. Those reactions are caused by the response of the immune system to the foreign proteins. Allergy-prone victims who had contact with a similar or exactly the same antigen might react more acutely than others and in severe cases cardiovascular and respiratory assistance may be needed. Intoxications and deeper stings tend to relapse locally, even after a long time – up to months or even years. 71


To Rent or Bring Your Gear, That is the Question By Dan & Betty Orr The new year is well on its way and many of us are still trying to shed a few holiday pounds. Not the I-shouldn’t-have-eatenthat-entire-Boston-Crème-Pie type of weight, but the pounds that we all carry around in our gear bags. With airline fees for baggage soaring higher and restrictions for carry-on baggage getting tighter, we are all approaching a time of decision: Do we take our own scuba diving equipment on our diving adventures or do we rent the equipment we need when we reach our destination? That’s a question that you will each have to answer for yourselves. However, here are a few considerations to inform your decision.


ISSUE 04 | MAY 2015

Photo by yingphoto



The pros of carrying your own equipment are fairly obvious. First, you are very familiar with your own gear. You know how your gear performs under various situations so that using it comes naturally and automatically. The age and servicing schedule of each piece would be part of the gear log that you keep. All of those reasons give you a sense of comfort and confidence that makes each of your dives safe and enjoyable. The cons boil down to total weight of the items, the possibility of being damaged in transit and the likelihood of your equipment not arriving at your destination when you do. You can address the weight of equipment by investing in some of the new scuba diving products on the market. Travelling buoyancy compensators, fins made of innovative materials, collapsible snorkels, lightweight regulators, compact cameras and featherweight duffels all offer ways to shave off ounces or pounds from the total weight you carry.


ISSUE 04 | MAY 2015

Photo by Garath Lock

Of course, these new products can also shave the weight off your wallet, but it is hard to quantify the value of the peace of mind you get from using your own equipment. Damage can occur when equipment is transported or shipped. We once saw a regulator come out of a bag and the second stage was completely smashed, crushed at some point during the journey. We have also had friends arrive with equipment missing from bags or who have no bags arriving at their destination. Having your dive gear insured provides some solace at such times, but it does not make up for the immediate lack of equipment. Renting equipment at your final destination eliminates the baggage and overage fees, potential damage during transit and loss of your valuable equipment. But it also eliminates that comfort that you are accustomed to while using your personal gear. To ease your concerns, there are a few things you can do before you travel. Contact the dive shop you will be using at your destination and ask them some questions starting with what equipment is for rent. Ask for the make, the model, the purchase date, how often their gear is maintained, who does the repairs and that individualâ&#x20AC;&#x2122;s qualifications to make those repairs. The answers to such questions will help you comfortably decide about renting or not.



To increase your comfort, find a local dive store that rents the same style of equipment. Make a few dives with it, either in a pool or a local dive site. Determine if the gear fits you and your diving style. See if there are any modifications that you can easily and non-destructively make to adjust the gear to suit your needs. Trying out equipment at home does not insure that the equipment will work identically at your destination, but it does allow you to become generally familiar with it. If part or all of the rental equipment that you have given a shakedown works for you, you have just found a way to lighten your load. Once at your destination, follow these three steps. Firstly, carefully inspect the equipment you are given. Are the hoses in good shape, the mouthpieces clean and bite tabs in good repair, the straps and buckles sound and functioning, and the weight pockets easy to remove? Secondly, attach the regulator and BCD to a tank and breathe, purge, inflate, deflate and check for leaks. Finally, try that equipment out in a safe environment. Your first time in the water with your rental gear should not be over a drop off. If the equipment did not work for you at home and you are not comfortable adapting it for your needs, then your decision is made. You need to find a way to get your equipment safely to your destination. Carry the more fragile pieces on your person. That could mean taking your second stage off the hose to pack in a pocket or removing the back plate off your BCD to make it fit into your carry-on baggage. And be sure that you have all the pieces of your equipment as well as the tools to reassemble by making a very detailed checklist. Whether you decide to rent or carry your dive equipment, always make a relatively benign dive (shallow water, no current, good visibility) before your diving gets serious. That allows you to determine if there was any damage or operational issues injected into your perfectly maintained equipment. This is an ideal opportunity to practise with your safe second (octopus) and ditching your weights â&#x20AC;&#x201C; these two skills, when well-honed, are potential life-savers for you or your buddy. Carrying your gear or renting when you get there is truly a personal decision. Consider all of your options, your comfort and the costs, and then do what you really are travelling forâ&#x20AC;Śto have an amazing and safe dive trip.


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Photo by Garath Lock



The human error factor in diving By Gareth Lock Two case studies show that decision-making is never as easy as we think it is, and why we sometimes make bad decisions that end up as an incident or a fatality. 78

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Those involved in aquatic safety sometimes wonder why people made the ‘stupid’ decisions they make, since the choices were supposedly obvious. Unfortunately hindsight bias means that we already know what the outcome was. Furthermore, we forget that those involved in an incident only have the information available to them in the immediate area at the time, whereas afterwards, for those examining the case, there is much more evidence. Incident 1: Switching the O2 cylinder off on mCCR whilst in-water – hypoxic (oxygen deprivation) event An experienced OC Trimix Instructor had been diving a KISS mCCR for 2 years prior to the dive. The diver had started to follow his training by shutting down the O2 cylinder once out of the harness. This then progressed to shutting it down while wearing it. Then, while walking from the lift on the dive boat to the bench. Given the short timelines, there is enough O2 in the loop to sustain life for these periods of time, especially if the pO2 has been at 1.5/1.6 for decompression. On the day in question the diver was in the water behind another diver waiting to be picked up. Thinking that he was going to be picked up immediately after this diver, he turned his O2 off and waited. Unfortunately the boat didn’t pick either diver up and had to make another pass. The mCCR diver was second up the lift and as he reached the top he felt a bit odd and he looked down to see his handset reading a pO2 of 0.07. He immediately spat the loop out and breathed fresh air, surviving what could have easily been a drowning incident. Incident 2: Lost inside a wreck at 45m – a chain of events

Photo by Gareth Lock

Two divers who were certified as Advanced Nitrox and Decompression Procedures and were regular buddies entered the water to dive a wreck sitting in approximately 45m using a weak nitrox as their bottom gas. As they descended the shotline, the visibility started to reduce and by 20m it was less than 2m and very dark; this was due to the very heavy plankton bloom present. At this point the lead diver's primary light failed and the divers swapped positions. At the bottom of the shot they found the wreck and followed the wreck around with the large metal armour plates on their right-hand side. At one point they lost visibility of the wreck and thought that they had swum off it, so turned to the right to regain the wreck. The bloom was causing a halo effect, which limited visibility. In addition, the bright light was limiting the ability to see the ‘green light of the surface’. They found the wreck again and carried on swimming. After approximately 15 to 20 metres of swimming they reached an end wall. On the left and above were also solid parts of the wreck. Panic ensued and the visibility reduced to almost zero during the struggle. One diver made it out almost immediately, the other having lost and then replaced his mask, 79


took longer to get out following the gravel/rocky bottom for orientation. The first diver went straight to the surface, the second having incurred a greater decompression obligation decided to complete his decompression on the ascent rather than risking getting bent. On surfacing both divers were put into the chamber as a precaution despite not showing symptoms of DCI. Analysis Any decision we make in life can be thought of as having a number of different sources: rules-based decision-making, knowledge-based decision-making, and recognition-primed decision-making. Rules-based decision-making is following the 'normal' rules that society demands or expects, such as stopping at a red light, because you know it prevents a collision at a junction or roadworks, or analysing your gas to determine the fO2 to calculate the maximum operating depth (MOD) for the gas. In diving, there are few ‘rules’ that would get you into legal difficulties but there are plenty of suggestions for best practice. (This is why divers get so emotional when trying to discuss the right and wrong way to do something!). Knowledge-based decision-making is where we use the library of experiences we have directly encountered or by proxy (learning from other’s accounts or through instruction) to make the decisions, such as what you were taught on a training course or read in a magazine or internet forum. The greater the knowledge we have, the greater the library of 'books' that we can recall from to help make decisions. Those 'books' may contain incorrect information but as far as we are concerned, and until someone demonstrates something to the contrary, we believe they are correct. Recognition-primed decision-making is the basis for decisions where we do not make a conscious decision. For example, when paramedics arrive at a scene of a car accident they are picking up cues from the radio and the scene to hypothesise the sorts of injuries they are likely to have to treat. The same goes for experienced divers who notice that a diver on the surface is behaving differently, something they can't put their finger on but there is likely to be an incident occurring and they react accordingly. This comes from years of experience of similar situations. The problem with knowledge-based decision-making and recognition-primed decision-making is the way the brain's automation process works. We can’t process everything we see, hear, feel or smell, and therefore the brain takes short cuts to fill the gaps in what we have sensed, for example, when you see 56 80

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Photo by Gareth Lock



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Photo by GUE

a partially obscured object, your brain fills in what is missing. So in the case of the divers inadvertently entering the wreck, their model of the world was tempered by their previous experiences. No one had said there were diver-sized holes where they were going to be. They had never noticed suffering from CO2 or N2 narcosis and therefore didn’t think it would be a problem for them. They had never entered a wreck unexpectedly. In fact, they had never really had anything go bad on a dive before. Some might say they were overconfident, maybe, but because diving is relatively safe, this ‘model’ of ‘safe’ is not unusual. The diver on the mCCR had a ‘model’ of the O2 depletion in the loop and assumed that the time taken to get back on would be less than the depletion rate; this was influenced by previous experiences where nothing had gone wrong. If the pick up had happened on the first pass, this model would likely be correct (but still wrong to switch the O2 off!). However, the delay meant that additional O2 was being consumed. Hypoxia causes poor decision-making, and so it may be that the diver had forgotten that he had turned the O2 off. It wasn’t until another cue, feeling light-headed, triggered a response to make the decision to spit the loop out and things came back to normal. Considering rules-based decision-making it is essential to really understand why those rules are in place and what the consequences of not following them might be. So in the case of the first scenario, the diver kept on breaking the “rule” of making sure the gas was turned off on the boat and not inwater but nothing went wrong. So, the rules were ‘re-baselined’ each time until the dive in question when the pO2 was so low as not to support life on the surface. Fortunately, the diver survived and told the story for others to learn. Incidents are rarely caused by simple linear decisions, they are a network of contributory factors that are normally only apparent after the event, and therefore we should be careful not to judge right or wrong. Photo by Garath Lock



Safety While Shooting Video by Dr Peter Bucknell

The GoPro camera has become such a prevalent piece of equipment for divers of all levels that it is pertinent to address the safety issues that arise when shooting video.

The addition of this seemingly simple and innocent camera causes a surprisingly insidious division of attention. Somewhat different to still photography, the video shooter’s mind can be dangerously engaged in the act of shooting for periods of time long enough to put the diver in harm’s way, not to mention his buddy or the other divers around him. Dismayed by the invasion of bumpy blue footage on YouTube, I wrote a book ( ) about using the GoPro camera underwater. I felt that it was necessary to devote a chapter to safety while shooting, because I have seen some nearaccidents in which a video camera played a part. Teaching the PADI Underwater GoPro Course ( has given me the unique opportunity to observe divers of all skill levels using the GoPro, lights and various camera mounts.


Photo by DR Michael Rothschild

ISSUE 04 | MAY 2015



Priorities while shooting can save your life. Experience and observation has taught me what these priorities are and in what order they should be. 1. Gauges 2. Environment 3. Shoot Shooting video footage should always be the third priority. If you are alive and uninjured, there will be more opportunities to shoot. So before you even think about framing a shot, you should know your gas pressure, depth and remaining dive time. If you are on closed circuit, make sure you know what gas you are breathing. After spending the five seconds it takes to check gauges, you should then check your environment. Make sure that you know where your buddy is and that they know where you are and what you are doing.  Answer the following questions before pressing the record button: Is there a dangerous situation unfolding near you? Are there entanglement hazards? Is your depth stable or are you rising or sinking without noticing? Are you too close to the coral? Boat entries and exits involve choices when diving with a camera rig of any size. Weather conditions can add danger to the act of having a rig passed down to you when you are in the water. Even more potentially dangerous is the task of passing a weighty rig up to a crew member during a swell. Equipment lines can alleviate these problems as can lanyards for small cameras. A final request from my fellow filmmakers: set a good example for other videographers by maintaining good buoyancy and never harming the environment for the sake of a video clip, and, most importantly, remember that it’s only video, and should never affect the level of safety of your diving.


ISSUE 04 | MAY 2015

Being an underwater filmmaker, a music professor and a public speaker has led Peter Bucknell to the profession of dive instruction and more particularly underwater video instruction. The publication of his Underwater GoPro Book has introduced divers to better and safer practices for shooting video while diving. He conducts workshops at dive conventions and events and is an advocate of dive safety and responsible underwater filmmaking. Read more about him here:

Photo by DR Michael Rothschild

Watch Peter Bucknellâ&#x20AC;&#x2122;s Underwater Films:


Diver Medic and Aquatic Safety Mag Issue 4  

Diving Medical Magazine for all Divers and people who work in or out the water. Contents - Golden Rebreather Rules by Jill Heinerth, Moving...