Investigation of Perioperative Anaphylaxis

Perioperative anaphylaxis means anaphylaxis that occurs around the time of surgery. In Australia, anaphylaxis while under anaesthesia is usually said to occur in around 1:10,000 anaesthetics, although the true rate may actually be higher than this.

When counting just the types of general anaesthetics where the most complex types of anaesthetic drugs are used, the rate may be as high as one in two thousand. 

Anaphylaxis occurring under anaesthesia is more severe and can have different features than anaphylaxis occurring in other patients. It is a complex reaction involving exposure to many different drugs.

Diagnosing anaphylaxis is often more difficult due to the body’s response to anaesthesia taking place in the background. Dangerously low blood pressure is a common feature. Perioperative anaphylaxis can be life-threatening. Some patients may require substantial intervention to survive, including CPR, defibrillation, complex drug therapy and admission to the intensive care unit.

Patients who have anaphylaxis while under anaesthesia may have their surgery abandoned. Often surgery can then not be performed until the cause of their reaction has been unravelled. Sometimes these patients may be left waiting for surgery for aggressive cancers or other time-sensitive problems. 

Patients can be traumatised by waking unexpectedly in the ICU and some patients will be very anxious afterwards. Some may feel angry and confused by what happened to them and by why their surgery was cancelled after it was already underway. This is often made more difficult by an incomplete understanding of the nature of both anaesthesia and allergy.

Anaesthesia in Australia is very safe, but anaphylaxis appears to be responsible for more deaths (of those that can be directly attributed to the effects of anaesthesia) than any other cause. Anaesthetic anaphylaxis is unpredictable and can be difficult to diagnose and manage.

In addition to those very unfortunate mortalities, many cases of intra-operative anaphylaxis in Australia every year survive due only to rapid and expert management by their anaesthetist.