dreaming during anaesthesia kate leslie royal melbourne hospital
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Dreaming during Anaesthesia
Kate LeslieRoyal Melbourne Hospital
Scope of this Talk
Importance of this topic
Dreaming during sleep
Hallucinations during anaesthesia
Dreaming during anaesthesia
Contributors(in chronological order)
… and all our research nurses and anaesthetists
K Leslie P Myles A Forbes
H Skrzpyek
M Chan S Swallow
T Short M Paech I Kurowski
T Whybro
w
M Stait
R Bailey
C Sleigh U Padmanabhan
C Lim
J Sleigh A Eer
“To sleep, perchance to dream: ay, there’s the rub, for in that sleep of death what dreams may come…”
Definitionsand
Importance
Definitions
Dreaming during sleepAny mental activity occurring during sleep
Dreaming during anaesthesiaAny mental activity occurring during anaesthesia or sedation that is not awareness
HallucinationPerception in the absence of stimulus in an awake patient
Importance of Dreaming
CommonUsually pleasant and harmlessOccasionally mistaken for awarenessOccasionally 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
“Such another sleep, that I might dream
of such another man!”
Dreaming during
Sleep
History of Dreaming
Dreaming has evolved and been retained during human evolutionDreaming entered scientific mainstream in early 1900s with psychoanalysisSleep scientists now dominate with electrophysiology and neurochemistry described
Sigmund Freud
Why Dream?
Brain activation during sleep must be important
All mammals have REM sleepMore REM sleep in babies than adultsSleep deprivation reduces functioning
But is dreaming important?Threat simulationMemory consolidationNeurotransmitter recoveryEpiphenomenon of neurophysiology
The EEG of Sleep
Dream recall 85% in REM and 43% in non-REMDuration, bizarreness and complexity of dreaming greater during REM sleep than non-REM sleepDreams of sleep onset and awakening are simple ruminations
Form of Dreams
Hallucinatory Delusional
Perceptually vivid
Emotional Bizarre
Poor memory
Hyper-associative
Dreaming during Sleep
A universal part of human experience
Has distinctive form and contentOccurs most commonly during REM
sleepCauses and purposes of dreaming
debated
“Dream as if you'll live forever. Live as if you'll die today."
Dreaming During
Anaesthesia
Incidence of Dreaming
Patients Year
Interview
Incidence
Women 2003
Emergence
34%
Unselected 1992
Emergence
27%
Unselected 2004
PACU 6%
High risk of awareness
2004
2-4 h 6%
Lap Chole 2003
Day 1 2.5%
TIVA 1997
Day 1 2.5%
Ketamine 2003
PACU 81%
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?
Is dreaming caused by inadequate anaesthesia?
Content relates to intra-operative eventsDreaming patients receive lower dosesAwareness patients often dreamEmergency patients often dreamDreamers more likely to moveDreamers recover more rapidlyMonitors sometimes indicate light anaesthesiaBIS monitoring may reduce incidence of dreaming
Causes 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!”
Time BIS Control p value
2-4 h 21 (2.7%) 44 (5.7%) 0.004
Predictor Dream No Dream
p value
BIS 45 (40-50)
44 (40-49)
0.72
PACU stay
55 (22-85)
65 (40-99)
0.02Contradictory evidence about anaesthetic depth
Aims of GENIE-1
1. To determine whether dreaming is associated with light or inadequate anaesthesia
2. To assess the form and content of dreams reported after anaesthesia
3. To determine whether dreaming is associated with poorer quality of recovery or satisfaction with anaesthetic care
Patients aged 18-50 years and ASA I-IIIElective surgery under relaxant GABIS monitoring from induction to 1st interviewInterview on emergence and 2-4 h postoperativelyPrimary endpoint
Median BIS values during maintenance of anaesthesia in dreamers and non-dreamers
Dreams recalled at 1st and 2nd interview not the sameDreams not usually spontaneously disclosed
Emergence 2-4 h
All dreaming 64 (22%) 74 (25%)
Dream narrative recalled
47 (16%) 53 (18%)
1 2 3 4 5
Strangeness
The Form of Dreams
1 2 3 4 5
Emotional Content
1 2 3 4 5
Memorability
1 2 3 4 5
Visual Vividness
1 2 3 4 5
Amount of Sound
1 2 3 4 5
Emotional Intensity
1 2 3 4 5
Meaningfulness
1 2 3 4 5
Amount of movement
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…
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 …
Near-miss Awareness?
0
20
40
60
80
100
BIS
No Dream
Dream
p = 0.03
Dreaming Hypothesis
Sleep During
Recovery
InadequateAnaesthesia
Types ofDreaming
Features Sleep Recovery
Near-Miss
Risk factors Dreaming
Dreaming
Awareness
Narrative Bizarre Simple Relevant
Duration Long Short Short
Memorability Low Low High
Light anaesthesia
- No Yes
EEG Sleep ? Awake
The EEG and Dreaming
More dreaming with propofol than volatilesDifferent pharmacological actionFaster emergence than older volatilesSelection bias in cohort studies
Propofol and Dreaming
Aims of GENIE-II
1. To determine the incidence of dreaming with propofol and desflurane
2. To analyse EEG patterns in dreamers and non-dreamers
3. To analyse EEG patterns in propofol and desflurane patients
Patients aged 18-50 years and ASA I-IIIElective surgery under relaxant GARandomized to propofol or desflurane maintenanceRaw EEG collected until interview on emergencePrimary endpoint
Incidence of dreaming on emergence in propofol and desflurane patients
Desflurane Propofol p
Anaesthetic dose 5.8 (3.1-9.0)
4.5 (2.5-8.0)
-
Fentanyl dose (g) 100 (50-700)
150 (50-700)
0.03
Signs of light anaesthesia 10% 31% <0.0001
BIS during maintenance 40 ± 6 38 ± 6 0.12
Eyes open – interview (min)
8 (0-57) 10 (0-100)
0.04
BIS at interview 92 (40-98) 85 (69-98)
<0.0001
Dreaming 29% 27% 0.70
No difference in quality of recovery or satisfaction with care
Evidence of REM-like EEG in dreamers during recovery
More cortical activationFewer sleep spindlesHigher 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 activityDifferent 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 harmlessYoung healthy patients with high home
dream recallNot related to anaesthetic depth
Similar with propofol and desfluraneAssociated with REM-like EEG during
recovery
“Too weird to live; too rare to die”
Hallucinations during
Anaesthesia
DefinitionsHallucination
Perception in the absence of a stimulus whilst awake
DelusionFixed belief that is either false, fanciful or derived from deceptionMay result from dreams or hallucination or arise when circumstances suggest that certain events occurred whilst the patient was unconscious
DisinhibitionLack of restraint manifested by disregard for social conventions, impulsivity and poor risk assessment
He stared ahead unseeingly, crossed himself and shouted ‘rank and number’She saw a praying women in the recovery roomHe attested that there was a flock of hens on the ward and the nurses had possums on their headsHe made amorous advances towards the recovery nurse asserting she was his wifeShe spent half an hour shouting for her orthopaedic surgeon in an amorous manner
Reports of Hallucinations
Prof AB Baker
Treatment of acute episodesExclude cardiac, respiratory and neurologic causesIntravenous benzodiazpines to calm agitated patients
Risk managementEnsure 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
ConclusionsDreaming 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
Thank You
‘Whatever you can do or dream you can, begin it.Boldness has genius, power and magic in it’
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