New guidelines for dental anaesthesia

Anaesthetists in Ireland 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.

Most reports on anaesthesia-related anaphylaxis originate from France, Australia, New Zealand and the United Kingdom. Other case series have been described from Scandinavia and the USA. The true incidence and their associated morbidity and mortality remain poorly defined. Both the accuracy and completeness of reporting is not optimal.

Dr Nigel Harper, one of the country’s leading experts on anaesthesia and anaphylaxis and Chair of the working party set up by the AAGBI said: ‘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.

‘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.’

Dr Harper went on to suggest that having operations under local anaesthesia rather than general anaesthesia may reduce the risk of some patients having an allergy-related reaction. He explains: ‘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.’

A research review carried out by the AAGBI working group also found that:
• 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.

The AAGBI states that it is widely recognised that more specialist allergy services need to be made available so that patients don’t have to travel long distances or face delays, especially when they are waiting for surgery.

The detailed guidelines are available at www.aagbi.org.