FortifyMDHypothermia
Most patients are elderly and do not complain of, or feel, cold, so they have not tried to warm up; In the young, hypothermia is usually from cold exposure.
Have a high index of suspicion and a low-reading thermometer.
Most patients are elderly and do not complain of, or feel, cold —so they have not tried to warm up.s
In the young, hypothermia is usually from cold exposure (e.g. near-drowning), or is secondary to impaired consciousness (e.g. following excess alcohol or drug overdose).
Definition Hypothermia means a core (rectal) temperature <35°C.
Investigations
- Check oral or axillary
T°. - If ordinary thermometer shows <36.5°C, use a low-reading one PR. Is the rectal temperature <35°C? Infra-red ear thermometers can accurately reflect core temperature.
- Urgent Urea & Creatinine
ElectrolytesPlasma glucoseAmylaseThyroid function testsCBCBlood cultures- Consider
blood gases ECGmay show J-waves
Treatment
- ABCDE, but don’t expose to cold.
- All patients should receive
warm, humidified O2; Ventilateif comatose or respiratory insufficiency- Remove wet clothing, slowly rewarm, aiming for rise of ½°C/h using blankets or active external warming (hot air duvets). If T° rising too quickly stop and allow to cool slightly. Rapid rewarming causes peripheral vasodilation and shock. A falling BP can be a sign of too rapid warming.
- Check temperature, BP, HR, and respiratory rate every 30min
- Warm IVI
Cardiac monitoris essential (AF, VF, and VT can occur at any time during rewarming or on stimulation)- Consider
antibioticsfor the prevention of pneumonia. Give these routinely in patients over 65yrs with T° <32°C - Consider
urinary catheter(to monitor renal function) - In case of arrhythmias (if there is a cardiac arrest continue resuscitating until T° >33°C, as cold brains are less damaged by hypoxia)
- Do not declare anybody dead until they are warm and dead. (see below, Human Records)
Note!
Sudden Hypothermia
In sudden hypothermia from immersion or profound hypothermia with cardiovascular Instability/cardiac arrest, the temperature needs to be raised rapidly.
Options include warmed fluid lavage (intravesical, nasogastric, intrapleural, intraperitoneal) and intravascular warming (cardiopulmonary bypass, dialysis).
In the event of cardiac arrest, defibrillation is usually unsuccessful if T° <30°C (consider amiodarone, bretylium). Resuscitation must continue until core T° >33°C.
Note!
Human Records
Remember that death is a process not an event, and that in hypothermia, all processes are suspended: metabolism may slow to as much as 10% of baseline, drastically diminishing the oxygen requirements of all tissues.
13 month old Canadian Erica Nordby came to life 2 hours after her heart stopped (core T°: 16°C).
Anna Bågenholm, a Swedish trainee orthopedic surgeon, became trapped under freezing water covered by a layer of ice for 80 minutes following a skiing accident, suffering a cardiac arrest (core T°: 13.7°C). After resuscitation and 20 days in intensive care, she regained consciousness, suffering no permanent brain damage. She is now a radiologist.