Hypothermia is a medical emergency that occurs when your body loses heat faster than it can produce heat, causing a dangerously low body temperature.

When your body temperature drops, your heart, nervous system and other organs can't work normally. Left untreated, hypothermia can eventually lead to complete failure of your heart and respiratory system and to death



Mild Hypothermia

If someone has mild hypothermia (generally with a body temperature of 32-35C), the symptoms aren't always obvious, but they can include:

  • Shivering
  • Dizziness
  • Hunger
  • Nausea
  • Faster breathing
  • Trouble speaking
  • Slight confusion
  • Lack of coordination
  • Fatigue
  • Increased heart rate


Moderate Hypothermia


Moderate cases of hypothermia (generally with a body temperature of 32-30C) can include symptoms such as:

  • Being unable to think or pay attention
  • Confusion
  • Loss of judgement and reasoning (someone with hypothermia may decide to remove clothing despite being very cold)
  • Difficulty moving around 
  • Loss of co-ordination
  • Drowsiness
  • Slurred speech
  • Slow, shallow breathing (hypoventilation)
  • People with a body temperature of 32C or lower will usually stop shivering completely. This is a sign that their condition is deteriorating and emergency medical help is required.



Severe Hypothermia


The symptoms of severe hypothermia (a body temperature of below 30C) can include: 

  • Unconsciousness
  • Shallow or no breathing
  • Weak, irregular pulse, or no pulse
  • Dilated pupils
  • Someone with severe hypothermia may appear to be dead. However, under these circumstances they must be taken to hospital to determine whether they've died or if they're in a state of severe hypothermia. Medical treatment can still be used to resuscitate people with severe hypothermia, although it's not always successful.



  • High risk patients
    • Children and elderly
    •  Pre-operative temperature <36 C
    •  Combined general and regional anaesthesia
    •  Major or intermediate surgery
    • Prolonged surgery
    •  Patients at risk of cardiovascular complications
    • ASA 3-5 patients.


    • Increased perioperative blood loss/coagulopathy: the clotting cascade is enzymatic and platelet function is temperature dependent.
    •  Longer post anesthetic recovery due to altered drug metabolism
    •  Postoperative shivering and increased oxygen consumption 
    • Thermal discomfort
    • Cardiac events including myocardial ischemia, arrhythmias
    •  Delayed wound healing
    •  Increased rates of surgical wound infection 
    • Longer hospital stay
    • Death