Minimising risk of anaphylaxis fatalities

Anaesthetists have been issued with new guidelines on how to prevent and handle emergencies involving the small, but growing, number of people who have a severe and potentially fatal allergic reaction during anaesthesia. “Although anaesthetic anaphylaxis is still relatively rare, we have noticed a rise in the number of patients being referred to specialist allergy clinics after an adverse reaction during surgery,” said Dr Nigel Harper, one of the country’s leading experts on anaesthesia and anaphylaxis and chair of the working party set up by the Association of Anaesthetists of Great Britain and Ireland (AAGBI). “We believe that this may be due to more patients having a severe reaction to antibiotics. “All anaesthetists are trained to deal with anaphylaxis, which can trigger dangerously low blood pressure and may cause severe breathing problems, but most anaesthetists will only see a small number of cases during their career. That is why it is so important to keep them up-to-date with the latest information on diagnosis and treatment and provide emergency guidance for use in operating theatres.” Studies from France and Australia indicate that the incidence of life-threatening anaphylaxis during anaesthesia is between one in 10,000 to 20,000 patients. This suggests that there could be approximately 500 severe reactions in the UK each year and that they are more common when drugs are administered intravenously. However, when the working party looked at the UK figures, they found that only 361 reactions had been reported to the UK Medicines Control Agency over six years and 10% of these were fatal. This compared with 789 incidents in France over a two-year period, which has a comparable population and a well-established culture of reporting anaesthesia-related reactions. “It is important to interpret the UK data with caution because it is likely that less-severe reactions are not reported and the true number could be much higher,” stressed Dr Harper. “The situation in the UK is similar to other countries, where the true incidence of death and illness relating from such incidents remains poorly defined and the accuracy and completeness of reporting is not as good as it could be.” Commenting on the launch of the new patient safety guidelines, Suspected Anaphylactic Reactions Associated with Anaesthesia, Dr Harper suggested that having operations under local anaesthesia rather than general anaesthesia may reduce the risk of some patients having an allergy-related reaction. “It is estimated that approximately 60% of adverse reactions are associated with muscle relaxant drugs, which are only administered when a patient is under a general anaesthetic,” he explained. A review of research carried out by the AAGBI working group also found: • Reactions to neuromuscular blocking agents and the latex gloves worn by surgical staff are more common in female patients. • Antibiotic anaphylaxis is more common in smokers, possibly because of increased exposure to repeated courses of antibiotics for respiratory tract infections. • Patients with a history of allergic skin diseases, asthma and food allergies appear to face a greater risk from latex, but not from neuromuscular drugs or antibiotics. • Individuals who have asthma or take beta-blocking drugs may suffer a more severe reaction. • People who suffer allergies to common environmental chemicals in toothpastes, washing detergents, shampoos and cough medicine may be more sensitive to neuromuscular blocking agents. • Reactions to local anaesthetics are very uncommon. “Patients who have concerns about a possible allergy to anaesthesia should talk to the anaesthetist before they undergo their procedure,” said Dr Harper. “Any patients who are affected should be investigated by specialist allergy clinics.” The AAGBI states that it is widely recognised that more specialist allergy services need to be made available so that patients do not have to travel long distances or face delays, especially when they are waiting for surgery. The expansion of these services will need extra Department of Health funding. The detailed guidelines – which are available on www.aagbi.org – are being supported by an A4 laminate, which is designed to be kept in operating theatres so it can be readily available in an emergency. This covers initial management and drug advice, secondary management, investigation and later investigations to discover what caused the reaction.