Investigation of suspected anaphylaxis during general anaesthesia requires several different skills. The differential diagnosis is often wide and the specialist must have the ability to identify complications of anaesthesia which may mimic some of the clinical features of anaphylaxis. This includes problems associated with tracheal intubation, equipment failure or covert haemorrhage. In some cases adverse reactions may be related to underlying medical conditions such as septicaemia, COPD, asthma or chronic urticaria. Non-allergic reactions to drugs must also be considered such as beta-blockers resulting in bronchospasm or hypotension resulting from a combination of anaesthetic agents. Even when the patient has suffered anaphylaxis, the investigation of the trigger can be challenging as the patient is often exposed to numerous co-administered drugs and agents any of which may be implicated. Neuromuscular blocking agents remain the major cause for anaphylaxis during general anaesthesia but other drugs such as antibiotics, chlorhexidine, NSAIDs, dyes or latex must also be considered potential causes. There are no reported cases of allergy to inhalational anaesthetics.
The BSACI guideline on investigation of suspected anaphylaxis during general anaesthesia provides expert and evidence-based guidance for the allergy specialist. The NICE drug allergy guideline (CG 183 2014) recommends referral of ‘people who have had anaphylaxis or another suspected allergic reaction during or immediately after general anaesthesia to a specialist drug allergy service’. Referral should be undertaken by the anaesthetist responsible for the patient’s care at the time of the suspected anaphylaxis. The referral letter should be accompanied by a completed AAGBI referral proforma and also a copy of the anaesthetic charts, surgical notes and drug charts related to the patient’s hospital admission at the time of the reaction. The Royal College of Anaesthetists is currently auditing every case of suspected anaphylaxis during general anaesthesia in the UK over a 12 month period. Results are expected in the summer of 2018 and should help to identify deficiencies in care.
Investigation of suspected anaphylaxis during general anaesthesia (2009), please click here for details