Changes to Standard Advanced Life Support

Both ALS and BLS should be instituted [2,4,8]. However, there are some important adjustments to the usual algorithm [1]:

Defibrillation and pacing

Defibrillation is less effective in hypothermia. For ventricular fibrillation/ventricular tachycardia (VF/VT) defibrillation may be tried up to three times but is then not tried until the temperature reaches 30°C.

Do not try pacing unless bradycardia persists when normothermia is reached. Sinus bradycardia may be a physiological response and is not treated specifically.

Ventilation

Normocapnia will be achieved at lower minute volumes than normal and hyperventilation risks cerebral hypoxia through reduction of cerebral blood flow [1-2,4,5]. Aim for a normal CO2 on ABG (not corrected for the patient’s temperature).

Intubation

In a patient with a perfusing rhythm, intubation (or other rough handling of the patient) may precipitate VF, although the evidence for this is mainly animal-based and it is rare. One observational study of > 100 patients recorded no cases of intubation induced arrhythmia.

Resuscitation drugs

Drugs are often ineffective and will undergo reduced metabolism; so these are withheld below 30°C then given with twice the time interval between doses until either normothermia is approached or circulation restored. So, adrenaline would be given about every 8-10 minutes once the core temperature is above 30°C.

Chest compressions

Hypothermia causes muscular stiffness: chest compressions may be harder work than normal. Make sure that the individual performing chest compressions is swapped frequently. There are several case reports about the successful use of mechanical compression devices in hypothermic cardiac arrest.