Hyperthermia and Hypothermia

Question 1

What are the definitions of hypothermia?

Answer 1

Mild - Temp 32-35
Moderate/severe - Temp < 32.

Question 2

Causes of hypothermia?

Answer 2

Exposure to cold environment
Inadequate insulation in theater.
Cardiopulmonary bypass.
Newborn babies

Question 3

Risk factors for hypothermia

Answer 3

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

Question 4

What are the signs of hypothermia

Answer 4

Shivering,
Cold/pale skin,
Slurred speech,
Tachypnoea, tachycardia and hypertension if mild.
If severe - respiratory depression, bradycardia and hypothermia.
Confusion/impaired mental state

Question 5

What are the investigations for hypothermia?

Answer 5

Temperature - low reading rectal thermometer
12 lead ECG - acute ST elevation, J waves or osborne waves.
Bloods - FBC, (Hb elevated, platelets and WCC low), electrolytes - can be hypokalaemic.
Blood glucose,
ABG,
Coagulation factors,
CXT

Question 6

What is the initial management of hypothermia?

Answer 6

Remove patient from cold environments.
Warming blankets
Secure airway and monitor breathing,
If not responding to above then maintain circulation with warmed IV fluids or apply forced warm air directly to patients body.

Question 7

What is a potential complication of rapid rewarming?

Answer 7

Peripheral vasodilation and shock

Question 8

What are the ECG changes seen in hypothermia?

Answer 8

Bradycardia
J waves/osborne waves
First degree heart block,,
Long QT interval,
Atrial and ventricular arrhythmias.

Question 9

Describe features of malignant hyperthemia?

Answer 9

Hyperthermia and muscle rigidity seen following administration of anaesthetic agents. Autosomal dominant condition

Question 10

Causes, investigations and treatment of malignant hyperthermia?

Answer 10

Causes - halothane, suxamethonium, antipsychotics.
Ix - CK and contracture tests.
Management - dantrolene.