a breathing circuit malfunction (stuck valve, massive leak)
a hyperosmolar, hyperglycaemic state
a pericardial effusion in the context of malignancy
accidental awareness under anaesthesia
acute cord compression in the context of malignancy
an anaesthesia machine/ventilator malfunction
an ischaemic/haemorrhagic stroke
bone cement implantation syndrome
carbon monoxide poisoning
caval obstruction in the context of malignancy
cerebral salt wasting syndrome
electrical power failure in the operating suite
ischaemic, perforated or obstructed gut
local anaesthetic toxicity
perioperative peripheral nerve injury
the failure of pipeline gas supply