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Intraoperative dreams reported after general anaesthesia are not early interpretations of delayed awareness
Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Departments of Anesthesiology and Intensive care, County Hospital, Kalmar, Sweden.
Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
Department of Anaesthesia and Intensive Care, Länssjukhuset, Kalmar, Sweden and Department of Physiology and Pharmacology, Section for Anesthesiology and Intensive Care Medicine, Karolinska Institutet, Stockholm, Sweden.
2008 (English)In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 52, no 6, 805-809 p.Article in journal (Refereed) Published
Abstract [en]

Background: Dreams are more frequently reported than awareness after surgery. We define awareness as explicit recall of real intraoperative events during anaesthesia. The importance of intraoperative dreaming is poorly understood. This study was performed to evaluate whether intraoperative dreams can be associated with, or precede, awareness. We also studied whether dreams can be related to case-specific parameters.

Methods: A cohort of 6991 prospectively included patients given inhalational anaesthesia were interviewed for dreams and awareness at three occasions; before they left the post-anaesthesia care unit, days 1–3 and days 7–14 after the operation. Uni- and multivariate statistical relations between dreams, awareness and case-specific parameters were assessed.

Results: Two hundred and thirty-two of 6991 patients (3.3%) reported a dream. Four of those also reported awareness and remembered real events that were distinguishable from their dream. Awareness was 19 times more common among patients who after surgery reported a dream [1.7% vs. 0.09%; odds ratio (OR) 18.7; P=0.000007], but memories of dreams did not precede memories of awareness in any of the 232 patients reporting a dream. Unpleasant dreams were significantly more common when thiopentone was used compared with propofol (OR 2.22; P=0.005). Neutral or pleasant dreams were related to lower body mass index, female gender and shorter duration of anaesthesia.

Conclusions: We found a statistically significant association between dreams reported after general anaesthesia and awareness, although intraoperative dreams were not an early interpretation of delayed awareness in any case. A typical dreamer in this study is a lean female having a short procedure.

Place, publisher, year, edition, pages
Malden, MA United States: Wiley-Blackwell, 2008. Vol. 52, no 6, 805-809 p.
Keyword [en]
Intraoperative dreams, awareness, consciousness
National Category
Anesthesiology and Intensive Care
URN: urn:nbn:se:liu:diva-15405DOI: 10.1111/j.1399-6576.2008.01634.xISI: 000256683700012OAI: diva2:114124
Available from: 2008-11-06 Created: 2008-11-06 Last updated: 2014-01-21Bibliographically approved
In thesis
1. Awareness and Dreaming during Anaesthesia: Incidence and Importance
Open this publication in new window or tab >>Awareness and Dreaming during Anaesthesia: Incidence and Importance
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The definition of awareness used consistently in this thesis is: Explicit recall of intraoperative events during general anaesthesia. Since there is no objective method to detect awareness, the patients must be interviewed after anaesthesia. The form and timing of the interview is crucial. To rely on spontaneous disclosure of awareness episodes is not sufficient. The total number of awareness-victims is considerable although the incidence may seem modest. A number of these patients look upon the awareness experience as the worst experience in their life. Suffering can include pain, mental distress and delayed psychological symptoms. However, the experience of awareness is not uniform and not all patients suffer.

A comprehensible definition for dreaming during anaesthesia is: Any recalled experience, excluding awareness, which occurred between induction of anaesthesia and the first moment of consciousness upon emergence. Some findings point in the direction that dreaming during anaesthesia may be related to light or insufficient anaesthesia, but other findings do not. Some patients find dreaming during anaesthesia distressing, but generally the overall impression is that consequences of dreaming during anaesthesia seem to be small and of minor importance to the majority of patients.

In this thesis I have found the following:The incidence of awareness is approximately 0.2% when neuromuscular blocking drugs are used and awareness also exists without these drugs, albeit to a lesser extent. These findings represent standard practice in an adult population at normal risk. 50% of awareness cases may have delayed recall of awareness.

Using a consecutive inclusion design we found initial awareness suffering comparable to previous studies, but a lower incidence and less pronounced severity of late psychological symptoms. The incidences found among the awareness-victims in our study were; experience of pain 46%, immediate mental distress 65%, any late psychological symptom 33%, and PTSD below 10%.

A memory of an intraoperative dream after general anaesthesia is not an early interpretation of delayed awareness, indicating that no routine follow up of dreaming-only patients is indicated.

Dreams reported after anesthesia are generally not related to insufficient anesthesia defined as high BIS, and should not be regarded as near awareness.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2008. 53 p.
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1082
National Category
Anesthesiology and Intensive Care
urn:nbn:se:liu:diva-15408 (URN)978‐91‐7393‐786‐3 (ISBN)
Public defence
2008-12-06, Eken, Hälsouniversitetet, Campus US, Linköpings universitet, Linköping, 11:00 (Swedish)
Available from: 2008-11-06 Created: 2008-11-06 Last updated: 2009-08-21Bibliographically approved

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