Anaesthetics

Question 1

Risks of General Anaesthesia

Answer 1

Sore throat and post-operative nausea and vomiting are common adverse effects of general anaesthesia.

Significant risks of general anaesthesia include:

Accidental awareness (waking during the anaesthetic)
Aspiration
Dental injury, mainly when the laryngoscope is used for intubation
Anaphylaxis
Cardiovascular events (e.g., myocardial infarction, stroke and arrhythmias)
Malignant hyperthermia (rare)
Death

Question 2

Malignant Hyperthermia

Answer 2

Malignant hyperthermia is a rare but potentially fatal hypermetabolic response to anaesthesia. The risk is mainly with:

Volatile anaesthetics (isoflurane, sevoflurane and desflurane)
Suxamethonium

There are genetic mutations that increase the risk of malignant hyperthermia. These are inherited in an autosomal dominant pattern.

Malignant hyperthermia causes:

Increased body temperature (hyperthermia)
Increased carbon dioxide production
Tachycardia
Muscle rigidity
Acidosis
Hyperkalaemia

It is treated with dantrolene. Dantrolene interrupts the muscle rigidity and hypermetabolism by interfering with the movement of calcium ions in skeletal muscle.