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Dreaming during Anaesthesia. Kate Leslie Royal Melbourne Hospital. Scope of this Talk. Importance of this topic. Dreaming during sleep. Dreaming during anaesthesia. Hallucinations during anaesthesia. Contributors (in chronological order). T Short. K Leslie. P Myles. A Forbes. M Chan.
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Dreaming during Anaesthesia Kate Leslie Royal Melbourne Hospital
Scope of this Talk Importance of this topic Dreaming during sleep Dreaming during anaesthesia Hallucinations during anaesthesia
Contributors(in chronological order) T Short K Leslie P Myles A Forbes M Chan S Swallow H Skrzpyek M Paech I Kurowski T Whybrow M Stait R Bailey C Lim A Eer C Sleigh U Padmanabhan J Sleigh … and all our research nurses and anaesthetists
Definitions and Importance “To sleep, perchance to dream: ay, there’s the rub, for in that sleep of death what dreams may come…”
Definitions • Dreaming during sleep • Any mental activity occurring during sleep • Dreaming during anaesthesia • Any mental activity occurring during anaesthesia or sedation that is not awareness • Hallucination • Perception in the absence of stimulus in an awake patient
Importance of Dreaming • Common • Usually pleasant and harmless • Occasionally mistaken for awareness • Occasionally a sign of near-miss awareness
Importance of Hallucinations • Uncommon • Usually unpleasant and may be harmful • May have professional/legal consequences
Definitions and Importance • Dreams and hallucinations are distinct phenomena with differing consequences • Increased understanding of these phenomena is warranted
Dreaming during Sleep “Such another sleep, that I might dream of such another man!”
History of Dreaming • Dreaming has evolved and been retained during human evolution • Dreaming entered scientific mainstream in early 1900s with psychoanalysis • Sleep scientists now dominate with electrophysiology and neurochemistry described Sigmund Freud
Why Dream? • Brain activation during sleep must be important • All mammals have REM sleep • More REM sleep in babies than adults • Sleep deprivation reduces functioning • But is dreaming important? • Threat simulation • Memory consolidation • Neurotransmitter recovery • Epiphenomenon of neurophysiology
The EEG of Sleep • Dream recall 85% in REM and 43% in non-REM • Duration, bizarreness and complexity of dreaming greater during REM sleep than non-REM sleep • Dreams of sleep onset and awakening are simple ruminations
Form of Dreams Hallucinatory Delusional Poor memory Emotional Bizarre Hyper-associative Perceptually vivid
Dreaming during Sleep • A universal part of human experience • Has distinctive form and content • Occurs most commonly during REM sleep • Causes and purposes of dreaming debated
Dreaming During Anaesthesia “Dream as if you'll live forever. Live as if you'll die today."
Characteristics of Dreamers • Younger • Healthier • More likely to be female • Higher home dream recall • Emerge more rapidly More likely to dream or more likely to RECALL dreaming?
Causes of Dreaming • Is dreaming caused by inadequate anaesthesia? • Content relates to intra-operative events • Dreaming patients receive lower doses • Awareness patients often dream • Emergency patients often dream • Dreamers more likely to move • Dreamers recover more rapidly • Monitors sometimes indicate light anaesthesia • BIS monitoring may reduce incidence of dreaming
Early Reports of Dreaming • “I dreamed about pain… my wife was paralyzed” • “I dreamed I was at a fairground and someone was throwing darts at my stomach” • “I dreamed I was at a party at a public house in which there was a generous supply of gin and the anaesthetist was the landlord!”
Aims of GENIE-1 • To determine whether dreaming is associated with light or inadequate anaesthesia • To assess the form and content of dreams reported after anaesthesia • To determine whether dreaming is associated with poorer quality of recovery or satisfaction with anaesthetic care
Patients aged 18-50 years and ASA I-III • Elective surgery under relaxant GA • BIS monitoring from induction to 1st interview • Interview on emergence and 2-4 h postoperatively • Primary endpoint • Median BIS values during maintenance of anaesthesia in dreamers and non-dreamers
Dreams recalled at 1st and 2nd interview not the same • Dreams not usually spontaneously disclosed
Emotional Content Emotional Intensity 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 Memorability Meaningfulness Visual Vividness Amount of movement Amount of Sound Strangeness The Form of Dreams
Content of Dreams • Was playing with daughter and her dad was there… • Took some friends out into the bay…the water was really rough… he caught a few fish… • Dreamed that she was at work serving meals… people were chatting around her…
Near-miss Awareness? • Driving on a road… The road just swallowed her up… The doctor said she was OK but the car was wrecked… She couldn't move… she was trying to tell the driver to stop but he couldn't hear her …
Inadequate Anaesthesia Types of Dreaming Sleep During Recovery Dreaming Hypothesis
Propofol and Dreaming • More dreaming with propofol than volatiles • Different pharmacological action • Faster emergence than older volatiles • Selection bias in cohort studies
Aims of GENIE-II • To determine the incidence of dreaming with propofol and desflurane • To analyse EEG patterns in dreamers and non-dreamers • To analyse EEG patterns in propofol and desflurane patients
Patients aged 18-50 years and ASA I-III • Elective surgery under relaxant GA • Randomized to propofol or desflurane maintenance • Raw EEG collected until interview on emergence • Primary endpoint • Incidence of dreaming on emergence in propofol and desflurane patients
No difference in quality of recovery or satisfaction with care
Evidence of REM-like EEG in dreamers during recovery • More cortical activation • Fewer sleep spindles • Higher frequency EEG • What does this mean? • More dreaming? • Less amnesia for dreams?
More marked oscillatory peak in 8-16 Hz band at wound closure in propofol patients • Sleep spindle-like activity • Different mechanisms of action • Propofol patients emerged at lower BIS than desflurane patients • Relationship between BIS and arousal is drug-specific At wound closure
Dreaming during Anaesthesia • Common and harmless • Young healthy patients with high home dream recall • Not related to anaesthetic depth • Similar with propofol and desflurane • Associated with REM-like EEG during recovery
Hallucinations during Anaesthesia “Too weird to live; too rare to die”
Definitions • Hallucination • Perception in the absence of a stimulus whilst awake • Delusion • Fixed belief that is either false, fanciful or derived from deception • May result from dreams or hallucination or arise when circumstances suggest that certain events occurred whilst the patient was unconscious • Disinhibition • Lack of restraint manifested by disregard for social conventions, impulsivity and poor risk assessment
Reports of Hallucinations • He stared ahead unseeingly, crossed himself and shouted ‘rank and number’ • She saw a praying women in the recovery room • He attested that there was a flock of hens on the ward and the nurses had possums on their heads • He made amorous advances towards the recovery nurse asserting she was his wife • She spent half an hour shouting for her orthopaedic surgeon in an amorous manner
Treatment of acute episodes • Exclude cardiac, respiratory and neurologic causes • Intravenous benzodiazpines to calm agitated patients • Risk management • Ensure that witnesses are present when patients are receiving or recovering from anaesthesia or sedation
Hallucinations during Anaesthesia • Reported more commonly after propofol use • May be confused with dreaming or disinhibited behaviour • Ensure witnesses are present for patients recovering from anaesthesia or sedation
Conclusions Dreaming is a common, fascinating and harmless part of the anaesthetic experience Dreaming is unrelated to anaesthetic depth or choice of maintenance anaesthetic Dream recall is associated with REM-like EEG during recovery Hallucinations may be unpleasant and a risk to patients and staff
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