Body temperature Flashcards
hypothermia definition
Mild hypothermia: 32-35°C
Moderate or severe hypothermia: < 32°C
causes of hypothermia
Exposure to cold in the environment is the major cause
Inadequate insulation in the operating room
Cardiopulmonary bypass
Newborn babies.
risk factors for hypothermia
General anaesthesia
Substance abuse
Hypothyroidism
Impaired mental status
Homelessness
Extremes of age
signs of hypothermia
shivering
cold and pale skin. Frostbite occurs when the skin and subcutaneous tissue freeze, causing damage to cells.
slurred speech
tachypnoea, tachycardia and hypertension (if mild)
respiratory depression, bradycardia and hypothermia (if moderate)
confusion/ impaired mental state
babies with hypothermia features
Babies with hypothermia can look healthy. However, they may be limp, unusually quiet and refuse to feed.
Heat loss in newborns is extremely common, hence a hat and clothing/ blankets will be applied soon after birth.
investigations for hypothermia
Temperature. Special low-reading rectal thermometers or thermistor probes are preferred for measuring core body temperature. The patient’s temperature should be tracked over time, to check for improvement.
12 lead ECG. As the core temperature approaches 32°C to 33°C, acute ST-elevation and J waves or Osborn waves may appear
FBC, serum electrolytes. Haemoglobin and haematocrit can be elevated (due to haemoconcentration). Platelets and WBCs are low due to sequestration in the spleen. Monitoring potassium is advised as hypothermic patients can be hypokalaemic due to a shift of potassium into the intracellular space.
Blood glucose. Stress hormones are increased, and the body can have more peripheral resistance to insulin.
Arterial blood gas
Coagulation factors
Chest X-ray
ECG of hypothermia
bradycardia
‘J’ wave (Osborne waves) - small hump at the end of the QRS complex
first degree heart block
long QT interval
atrial and ventricular arrhythmias
initial management of hypothermia
Removing the patient from the cold environment and removing any wet/cold clothing,
Warming the body with blankets
Securing the airway and monitoring breathing,
If the patient is not responding well to passive warming, you may consider maintaining circulation using warm IV fluids or applying forced warm air directly to the patient’s body
+ rapid re-warming can lead to peripheral vasodilation and shock
management of severe hypoglycaemia
In severe cases, be prepared to conduct CPR. IV drugs should be avoided if possible, as the patient is more likely to have a drastic response to the drug.
causes of malignant hyperthermia
The most common cause is an autosomal dominant mutation in the ryanodine receptor 1, increasing calcium levels in the sarcoplasmic reticulum and increasing metabolic rate.
causative agents: halothane, suxamethonium, antipsychotics
presentation of malignant hyperthermia
Patients typically present at the induction of general anaesthesia with increased body temperature, muscle rigidity, metabolic acidosis, tachycardia, and increased exhaled carbon dioxide.
management of malignant hyperthermia
Malignant hyperthermia is managed by: stopping the triggering agent, administrering intravenous dantrolene (a ryanodine receptor antagonist) and restoring normothermia.
definition of malignant hyperthermia
Malignant hyperthermia is a life-threatening syndrome triggered by inhalation anaesthetics or suxamethonium.
investigations of malignant hyperthermia
CK raised
contracture tests with halothane and caffeine
