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21-03-2013 | Surgery | Article

Awareness during general anesthesia ‘may be underestimated’


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medwireNews: There is a low rate of accidental awareness during general anesthesia (AAGA) in the UK, survey results show.

In 2011, 153 new cases of AAGA were identified by the senior anesthetists questioned, giving an incidence of one in 15,414 patients.

"These data imply that just one senior anesthetist out of around 47 will know of a new case of anesthesia awareness each year," say Jaideep Pandit, from Oxford University Hospitals, UK, and co-workers.

Furthermore, "over the course of an anesthetist's career, we estimate that a senior anesthetist will have personal experience of one case of AAGA for every 36 years of practice," they add.

The survey's findings contrast with previous data, however, which suggest that one to two patients in every 1000 experience this anesthetic complication every year.

"If the incidence is indeed lower in the UK than previously reported elsewhere, it is important to consider why this might be in order to reinforce good anesthetic techniques, and to inform practitioners in other countries," say US commentators.

Michael Avidan, from Washington University School of Medicine in Saint Louis, Missouri, USA, and George Mashour, from the University of Michigan in Ann Arbor, USA, warn that the incidence may not be as low as it seems. They suggest that the use of spontaneous patient reports rather than direct patient questioning could have led to the incidence being vastly underestimated.

The survey, which is part of the 5th National Audit Project (NAP5) of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland, involved 329 hospitals, and a questionnaire was issued to every consultant, staff, and associate specialist in the UK. In total, 82% (n=7125) of the senior anesthetists took part.

"Most patients experiencing AAGA were young or middle-aged adults," Pandit and co-workers report. They note that most (47%) cases of the complication occurred around the time of induction of anesthesia, with 30% occurring during surgery, and 23% after the completion of surgery, but before full emergence from anesthesia.

Patients who reported AAGA during surgery more often experienced pain or distress from the side effect than those who reported AAGA during induction or before full recovery (62 vs 28 and 23%, respectively).

Depth-of-anesthesia monitors were being used routinely by only 1.8% of anesthetists, despite such equipment being available in 62% of centers.

"Although [National Institute for Health and Clinical Excellence] guidance recommends the consideration of depth of anesthesia monitoring in certain situations, this would seem to require a considerable change in the normal practice of the UK anesthetic community," Pandit and team observe.

Their data are published in Anaesthesia and the British Journal of Anaesthesia.

By Sara Freeman, medwireNews Reporter