Dreaming is a common and fascinating part of the anesthetic experience, but it remains a poorly understood phenomenon. Although other studies have been done on this subject, few have assessed the relationship between dreaming and depth of anesthesia, and their results were inconclusive. The January issue of the journal Anesthesiology features a new Australian study, "Dreaming during Anesthesia and Anesthetic Depth in Elective Surgery." The study was conducted at three university hospitals in Melbourne and Perth and documented that, not only do many patients have dreams, but most of their dreams are pleasant or even prompted by an overheard conversation while under anesthesia.

The investigation of dreaming during anesthesia is important, because it is one of the most common side effects of anesthesia, which patients can sometimes confuse with having been aware during surgery. The study consisted of 300 healthy patients, ranging in age from 18-50, who were having elective surgery with general anesthesia. In addition to the usual monitors utilized during surgery, each patient was also monitored with a device that measures an effect of anesthetics and sedatives on the brain.

For the study, patients were first interviewed about their dreams when awakening from anesthesia, with a second interview taking place two to four hours after the operation. Patients were asked the following questions during both interviews:

What was the last thing you remember before going to sleep?
What was the first thing you remember when you woke up?
Can you recall anything between?
Did you have any dreams during your anesthetic?
If dreaming did occur, describe the character of the dream.

Of the 300 patients, nearly one-third (86) reported dreaming during anesthesia in one or both of the interviews. At the first interview, 47 patients described having a dream, and at the second interview, 53 patients described having a dream. Of the 35 patients who reported dreams at both interviews, 31 reported the same dream both times, and four patients reported different dreams at each interview. There were no clinically significant differences between dreamers and non-dreamers in the monitor value used during anesthesia to measure the effects of anesthetics and sedatives.

The findings showed that most dreams were pleasant and meaningful to the patient, because they incorporated family, friends, work, or recreation. Others were inspired by overheard conversations among the surgical team members. "The evidence from this study supports our hypothesis that dreaming actually occurs during recovery and is not associated with light or inadequate anesthesia in the vast majority of cases," said the study's lead author, Kate Leslie, MB, BS, MD, MEpi, F.A.N.Z.C.A. [Fellow of the Australian and New Zealand College of Anaesthestists].

For additional information on this study, go to: http://www.anesthesiology.org.
Founded in 1905, the American Society of Anesthesiologists is an educational, research, and scientific association with 41,000 members, organized to raise and maintain the standards of the medical practice of anesthesiology and improve the care of the patient.
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