Waking Up Before the Surgery Is Completed

Survey of doctors shows consciousness during general anesthesia occurs very rarely

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Most surgeries use general anesthesia so that patients are unconscious during the surgery. General anesthesia reduces the risk the patient will feel pain, but what if they wake up?

A recent study found that waking up while under general anesthesia is extremely rare.

The study involved a survey of doctors who had given patients general anesthesia in the United Kingdom. The results showed that "accidental awareness" during general anesthesia appears much less common than previously thought.

In approximately one case out of every 15,000, the patient became aware during the general anesthesia.

"Ask the anesthesiologist about any concerns."

The study, led by J.J. Pandit, a professor at the Nuffield Department of Anaesthetics at Oxford University Hospitals in the UK, looked at how common it was for people to be conscious during general anesthesia.

The researchers gave questionnaires to all anesthetists in the UK, as well as their consultants and staff members. All the local coordinators in charge of a combined 329 UK hospitals and 7,125 anesthetists (for a 82 percent response rate) responded to the questionnaire.

The questionnaires asked how many times in the past year the respondents had known of one of their patients becoming accidentally conscious during general anesthesia.

The questionnaires also asked the respondents to estimate the number of cases this accidental awareness had occurred throughout their career.

The results of the questionnaires revealed that 153 new accidental awareness cases had been known to occur in 2011. It is estimated that approximately three million general anesthetics are administered to patients in the UK each year.

Therefore, the researchers calculated that the rate of accidental awareness during general anesthesia is approximately 1 case out of every 15,414 people receiving general anesthesia.

This is a considerably lower rate of occurrence than previous reports from clinical trials, which estimated the cases at 1 in every 500 patients receiving general anesthesia.

In these survey results, the patient became temporarily conscious during general anesthesia before surgery in just under half of the cases (47 percent).

About a third of the patients (30 percent) became aware during the surgery, and just under a quarter (23 percent) became conscious after the surgery but before full recovery.

More of the patients who became aware during surgery experienced pain and distress than those who became aware before or after surgery. While 62 percent of the patients who became conscious during surgery reported pain or distress, only 28 percent who became conscious before surgery and 23 percent of those who became conscious after surgery reported pain or distress.

The questionnaires also asked whether hospitals and practices used brain monitors that can measure how deep a person's anesthesia is. Although most of the centers (72 percent) had anesthesia monitors, only 1.8 percent of the respondents actually used them.

The authors wrote that more research is necessary to understand why there is a significant difference between the accidental awareness rates reported in clinical trials and the rates reported by anesthetists.

The study was published March 12 in both the journal Anaesthesia and The British Journal of Anaesthesia. The research was funded by the Royal College of Anaesthetists (RCoA) and the Association of Anaesthetists of Great Britain and Ireland (AAGBI). The authors declared no conflicts of interest other than their editorial duties at each of the journals where the article appeared.

Reviewed by: 
Review Date: 
March 11, 2013
Last Updated:
March 12, 2013