What About Cardiac Rhythms During Cardiac Arrest?

Cardiac Tamponade (and cardiac arrest save) - post stabbing - Kings Cross Sydney [43:00 minutes] https://player.vimeo.com/video/66143304 WARNING GRAPHIC CONTENT. Demonstrates the ambulance crew’s decision the patient was time-critical, rapid transportation with BLS care while in transit to the hospital. Ultimately allowing for successful resuscitation.

Toxins

History taking is vital to identify toxins. Treatment limited to us in SAAS depends on the toxin. A detailed history is the most likely way to determine if the cardiac arrest is due to a toxin. Management will depend on the toxin, and in addition to supportive care may include administering a reversing agent. Consider all potential toxins, medications (legal and recreational), poisons, bites and stings, chemical exposure etc. Note: When responding to a HAZMAT incident, SAFETY remains the priority - DO NOT compromise your safety, that of your colleagues or the community.

Procedure - HAZMAT Incident Management [PRO-089]

What is Ventricular Tachycardia (VT)?

VT is an abnormal and often life-threatening ECG where the electrical impulse originates in the ventricles. Whilst there is still some order to the conduction, there are no obvious P waves and there is a consistent pattern of QRS complexes that are wide, bizarre-looking and fast (greater than 120 per minute).

VT originates in the ventricles and is most caused by a single re-entry circuit, which explains why it presents as a regular (showing little or no variation in the pattern on the ECG). The rapid rate of these arrhythmias reduces ventricular filling time and coronary artery perfusion pressure. Cardiac output drops due to the dissociation of atrial and ventricular activity. Treatment must be initiated as soon as possible; this rhythm is a precursor to VF and can degenerate to ventricular fibrillation quickly. Defibrillation can successfully revert this rhythm and VT should be more responsive to defibrillation. Key Points:

• VT originates in ventricles • Regular “saw tooth” pattern • Rapid rate reduces ventricular filling. Cardiac output drops due to dissociation of atrial and ventricular activity • VT can degenerate to VF quickly • Treatment is early defibrillation and HP-CPR if the patient shows no signs of life. Note: A patient can be conscious and in VT. Therefore, use extreme caution if operating a monitor Defibrillator in “AED” mode with defibrillation pads in use on a conscious patient. The AED analysis can’t tell if the patient is conscious/with signs of life or not and may charge up and advise a shock. Treat the patient not the monitor/defibrillator.

What is Ventricular Fibrillation (VF)?

VF is when the electrical impulse originates from multiple pacemaker sites in the ventricles and as a result, there is no order to the impulse generation or conduction. There will be no P waves, no obvious QRS complexes and no T-waves present in the ECG. While there is electrical activity present, it is chaotic and there is no discernible pattern to it (has the appearance of an erratic wiggly line) Key Points: • Ventricular Fibrillation (VF) is the very fast, uncoordinated, rhythm that does not produce sufficient output to sustain life • It is believed that VF is maintained by multiple irritated pacemaker cells that generate numerous re-entry circuits across the ventricular myocardium • We know coarse VF is more responsive to defibrillation • Time to defibrillation is important.

What is Asystole?

Asystole occurs when there is no electrical activity present in the heart, therefore the heart is unable to pump at all. As a result, there will also be no heart muscle contraction and therefore no signs of life. It presents as a straight and flat line on the ECG. As there is no electrical activity, defibrillation is not indicated for this rhythm and therefore chest compressions should be started as soon as possible. Key Points: • AED’s will not advise to ‘shock’ asystole. • Rarely a true flat line but often described as a wandering flat line. Sometimes occasional small waves may also be seen • HP-CPR is the treatment for this presenting cardiac rhythm until ALS support is available.

What is Pulseless Electrical Activity (PEA)?

Sometimes the electrical system of the heart is still active but there is a problem with the mechanical action of the pump or hypovolemia (insufficient blood in the circulatory system to be pumped by the heart). Therefore, the muscle is not contracting when it is supposed to or as well as it should or has nothing to pump. This type of fault (mechanical or hypovolemia) may not be seen on an ECG, hence why it is important to assess the patient, not just their ECG (e.g. look for signs of life). In these situations, the ECG can appear normal with P waves, QRS complexes and T waves. However, the heart muscle does not contract, and a pulse will not be detectable. Key Points: • In PEA, there is organised or semi-organised electrical activity in the heart as opposed to asystole (flatline) or the disorganised electrical activity of either ventricular fibrillation or ventricular tachycardia • As the issue is not the electrical system, defibrillation is not indicated • HP-CPR should be started as soon as possible until ALS support is available.