Hypothermia is defined as a core temperature below 35°C
Mild hypothermia (32-35°C):
Decreased respiratory rate
Shivering may cease
Moderate hypothermia (30-32°C):
Severe hypothermia (< 30°C):
Avoid sudden motion, which may trigger ventricular arrhythmia in moderate to severe hypothermia.
Controlled hypothermia can play a positive role in managing a patient post cardiac arrest. In this situation hypothermia is used to protect the patient from the detrimental effects of reduced cerebral perfusion (32-34ºC).
Immersion hypothermia generally develops more rapidly as well as in patients where thermo-regulation is impaired (the elderly and very young).
On the ECG of a hypothermic patient, there are often characteristic Osborne (J) waves. An Osborne wave is a slow, positive deflection at the end of the QRS complex, most prominent in lead II and V3-V6.
Hypothermia in Western Australia as a cause of cardiac arrest is extremely rare and mostly accidental e.g. locked in a cool room. If you suspect that the cardiac arrest was secondary to hypothermia, the emphasis is on high performance CPR and transport.