Advanced Life Support
| Advanced Life Support |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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Overview
Advanced Life Support (ALS) is a treatment consensus for cardiopulmonary resuscitation in cardiac arrest and related medical problems, as agreed in Europe by the European Resuscitation Council, most recently in 2005. It is practiced by in-hospital cardiac arrest teams, which generally consist of junior doctors from various specialties (anesthetics, general or internal medicine). Emergency medical technicians (EMTs) are often skilled in ALS, although they may employ slightly modified version of the algorithm.
In the US, an EMT capable of performing advanced life support is either an EMT-Intermediate or an EMT-Paramedic, commonly referred to simply as a paramedic. Canadian paramedics may be certified in either ALS or in only basic life support.
The treatment algorithms that comprise ALS were agreed by the European Resuscitation Council to improve the outcomes of cardiac arrest.
Main algorithm
ALS presumes 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 "4H4T":
- Hypoxia (low oxygen levels in the blood)
- Hypovolemia (low amount of circulating blood, either absolutely due to blood loss or relatively due to vasodilation)
- Hyperkalemia or hypokalemia (disturbances in the level of potassium in the blood) and related disturbances of calcium or magnesium levels and hypoglycemia (low glucose levels).
- Hypothermia (body temperature not maintained)
- Tension pneumothorax (tear in the lung leading to collapsed lung and twisting of the large blood vessels)
- Tamponade (fluid or blood in the pericardium, compressing the heart)
- Toxic and/or therapeutic (chemicals, whether medication or poisoning)
- Thromboembolism and related mechanical obstruction (blockage of the blood vessels to the lungs or the heart by a blood clot or other material)
As of December 2005, Advanced Life Support guidelines have changed significantly. A major new worldwide consensus has been sought based upon the best available scientific evidence. The ratio of compressions to ventilations is now recommended as 30:2 for adults, to produce higher coronary and cerebral perfusion pressures. Defibrillation is now administered as a single shock, each followed immediately by 2 minutes of CPR before rhythm is re-assessed.
Other conditions
ALS also covers various conditions related to cardiac arrest, such as cardiac arrhythmias (atrial fibrillation, ventricular tachycardia), poisoning and effectively all conditions that may lead to cardiac arrest if untreated, apart from the truly surgical emergencies (which are covered by Advanced Trauma Life Support).