As the core body temperature falls there may be:
- Altered level of consciousness
- Slurring of speech
- Muscular incoordination
- Slowing of heart rate
- Slowing respiratory rate
- Development of cardiac arrhythmias such as sinus bradycardia (normal but slow heart rate), atrial fibrillation (top two chambers of the heart, the collecting chambers have uncoordinated electrical activity), ventricular fibrillation (lower two chambers of the heart, the pumping chambers have uncoordinated electrical activity) and asystole (no electrical activity “flatline”).
The severity of hypothermia can be classified into mild, moderate and severe depending on the patient’s core body temperature. Measurement of temperature outdoors can be very difficult without the ability to measure the core temperature.
The Swiss clinical staging of hypothermia defines signs and symptoms in the table at the following link: