ArticlesAwareness during anaesthesia: a prospective case study
Introduction
Recall of intraoperative events in patients under general anaesthesia is rare (0·1–0·7%), although few prospective studies have assessed the incidence of awareness during surgical procedures.1, 2, 3, 4 Up to 54% of patients worry about the possibility of pain, paralysis, and mental distress during surgery.5 Previous studies have not recorded important background data, such as whether neuromuscular-blocking drugs were used or whether end-tidal anaesthetic gas concentration (ETAGC) was monitored. Also, memory for awareness may be delayed,1 and follow-up may have been too short to identify all cases.
We did a prospective study to assess patients' recall of awareness during surgery.
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Patients and methods
This study, which was approved by the Ethics Committee of Linköping University Hospital, was done in two Swedish hospitals. Clinical routine at the two hospitals includes an interview for awareness on discharge from the post-anaesthesia care unit in all patients older than 15 years who have had general anaesthesia. This interview, modified from Brice and colleagues6 and described elsewhere,1 is given by the nurses who attended the patients, and is recorded in the anaesthesia record. Dedicated
Results
Baseline data of the 11 785 patients included in the study are shown in table 1.
Discussion
Our findings and our inability to find non-paralysed patients who had unpleasant effects during or after wakefulness suggest that awareness among patients without neuromuscular block is not a major concern, as long as conversation between operating-room staff remains respectful to the patient. Studies on awareness should therefore distinguish clearly between relaxant and non-relaxant anaesthesia.
If the first interview had been done after the patients had left the post-anaesthesia care unit, no
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