Hypothermia

Question 1

Hypothermia classification

Answer 1

Temp <35°C and is classified as follows:
1. mild (32°C to 35°C): characterised by tachycardia, tachypnoea, vasoconstriction and shivering
2. moderate (28°C to 32°C): may have cardiac arrhythmias, hypotension, respiratory depression, reduced consciousness and may cease to shiver
3. severe (<28°C): markedly reduced consciousness/coma, apnoea, arrhythmia, fixed and dilated pupils

Question 2

Hypothermia features: ECG

Answer 2

1. Bradyarrhythmias e.g. sinus bradycardia, atrial fibrillation with a slow ventricular response, slow junctional rhythms and varying degrees of AV block
2. Osborne Waves (‘J waves’) = positive deflection at the J point between the end of the QRS and beginning of the ST segment
3. Prolonged PR, QRS and QT intervals
4. Shivering artefact
5. Ventricular ectopics
6. Cardiac arrest (VT, VF or asystole)

Question 3

Hypothermia mx

Answer 3

1. warming the patient by covering with a warm blanket, and supplying warm drinks.
2. Passive warming may be supplemented by intravenous administration of warmed fluids and application of warm air (e.g. using a Bair-Hugger).

Patients are at high risk of cardiac arrest and CPR may be required.

Question 4

RFs for hypothermia

Answer 4

General anaesthesia
Substance abuse
Hypothyroidism
Impaired mental status
Homelessness
Extremes of age

Question 5

When does frostbite occur

Answer 5

Frostbite occurs when the skin and subcutaneous tissue freeze, causing damage to cells.

Question 6

What not to do in hypothermia: risk of cardiac arrest

Answer 6

Don’t put the person into a hot bath.
Don’t massage their limbs.
Don’t use heating lamps.
Don’t give them alcohol to drink.