Advanced Life Support - ALS Algorithms

ALS Algorithms

ALS assumes that basic life support (bag-mask administration of oxygen and chest compressions) are administered.

The main algorithm of ALS, which is invoked when actual cardiac arrest has been established, relies on the monitoring of the electrical activity of the heart on a cardiac monitor. Depending on the type of cardiac arrhythmia, defibrillation is applied, and medication is administered. Oxygen is administered and endotracheal intubation may be attempted to secure the airway. At regular intervals, the effect of the treatment on the heart rhythm, as well as the presence of cardiac output, is assessed.

Medication that may be administered may include adrenaline (epinephrine), amiodarone, atropine, bicarbonate, calcium, potassium and magnesium. Saline or colloids may be administered to increase the circulating volume.

While CPR is given (either manually, or through automated equipment such as AutoPulse), members of the team consider eight forms of potentially reversible causes for cardiac arrest, commonly abbreviated as "6Hs & 5Ts" according to 2005/2010 AHA Advanced Cardiac Life Support (ACLS). Note these reversible causes are usually taught and remembered as 4Hs and 4Ts—including hypoglycaemia and acidosis with hyper/hypokalaemia and 'metabolic causes' and omitting trauma from the T's as this is redundant with hypovolaemia—this simplification aids recall during resuscitation.