GRAPHIC NEAL W. POLLOCK, 2016
STOPS
DEPTH
TIME
HYDRATION
PHYSICAL
ASCENT RATE
DIVE PROFILE
BREATHING GAS
PREDISPOSITIO
REPETITIVE
DECOMPRESSION SAFETY
ATM. PRESSURE
TYPE
EXERCISE
TIMING
INTENSITY
ECONOMY
Scapegoats
Quest · August 2023
TIMING
INTENSIT
BUOYANCY
The wild card of individual (“predisposition”) factors further highlights the challenges unmet in current decompression models. Not only are these parameters not measured, but it is also unclear how the information could practically guide the risk assessment at this time if available. While the importance of these factors is hard to assess, it is also noteworthy that some, most often dehydration, may be used as scapegoats to explain away decompression sickness (DCS). A state of dehydration can adversely affect circulation, potentially impeding inert gas elimination, but this almost certainly has much less impact than the dive profile, exercise, or thermal state in many cases. The impact is also not 48
THERMAL STATU
as straightforward as making it a blame agent might imply. For example, if a state of dehydration impairs inert gas elimination during the ascent and stop phase to increase decompression stress, might it not also decrease inert gas uptake during the descent and bottom phase to reduce the decompression stress? Sound levels of hydration are good for general health and probably for decompression safety, but a state of dehydration in no way guarantees an outcome of DCS, just like a good level of hydration in no way guarantees an outcome of no DCS. The blame directed to dehydration is probably related to the observation that DCS can be accompanied by clinically important fluid shifts. This, though, is more a consequence of the disease than a cause.