2-8

Peri-operative hyperthermia

If prolonged or ≥ 39°C this is a clinical emergency: permanent organ dysfunction and death can result. Treatment depends on the aetiology. Distinguish early between: excessive heating (most common), inadequate dissipation of metabolic heat, excessive heat production, actively maintained fever.

START.
1
Call for help
2
Remove cause
3
Initial diagnosis
4
Active cooling
5
Sedation / paralysis
6
Antipyretics
7
Serotonin syndrome
8
Monitor complications
Box A CAUSES OF HYPERTHERMIA

COMMON

Excessive insulation, high ambient temperature, external warming devices, especially infants and children (most common)

Surgical devices, e.g. HIFU, diathermy, radiotherapy

Prolonged epidural anaesthesia

Sepsis (→ 3-14) e.g. during manipulation of a urological device

Blood transfusion

Allergic reaction / anaphylaxis (→ 3-1)

Drug induced:

Neuroleptic malignant syndrome (e.g. haloperidol and other antipsychotics)

Malignant hyperthermia crisis (late sign) (→ 3-8)

Serotonin syndrome (cocaine, amphetamine, phencyclidine, MDMA)

Anticholinergic syndrome (tricyclic antidepressants, antipsychotics, antihistamines)

Sympathomimetic syndrome (cocaine, MDMA, amphetamines)

Toxic:

Radiologic contrast neurotoxicity

Alcohol withdrawal

Endocrine:

Thyrotoxicosis

Phaeochromocytoma

Neurologic:

Meningitis

Intracranial blood

Hypoxic encephalopathy

Traumatic brain injury

Box B CHLORPROMAZINE DOSE

Chlorpromazine (Largactil) 25–50 mg i.m. 6–8 hourly. Caution in elderly.