Transcript The ENIGMA Trial

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)
K Leslie
P Myles
A Forbes
M Chan
S Swallow
T Short
H Skrzpyek
M Paech
I Kurowski
T Whybrow
R Bailey
C Lim
M Stait
J Sleigh
C Sleigh
U Padmanabhan
A Eer
… 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
Emotional
Perceptually vivid
Delusional
Poor memory
Bizarre
Hyper-associative
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."
Incidence of Dreaming
Patients
Women
Unselected
Year
2003
1992
Interview
Emergence
Emergence
Incidence
34%
27%
Unselected
High risk of awareness
Lap Chole
2004
2004
2003
PACU
2-4 h
Day 1
6%
6%
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?
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!”
Time
BIS
Control
p value
2-4 h
21 (2.7%)
44 (5.7%)
0.004
Predictor
BIS
PACU stay
Dream
45 (40-50)
55 (22-85)
No Dream
44 (40-49)
65 (40-99)
p value
0.72
0.02
Contradictory 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-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
Emergence
2-4 h
All dreaming
64 (22%)
74 (25%)
Dream narrative recalled
47 (16%)
53 (18%)
Dreams recalled at 1st and 2nd interview not the same
Dreams not usually spontaneously disclosed
The Form of Dreams
Emotional Content
1
2
3
Emotional Intensity
4
5
Memorability
1
2
2
3
4
5
2
3
4
5
3
3
1
2
3
4
5
Amount of movement
4
5
Amount of Sound
1
2
Meaningfulness
Visual Vividness
1
1
1
2
3
4
5
3
4
5
Strangeness
4
5
1
2
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 …
100
p = 0.03
80
BIS
60
40
20
0
No Dream
Dream
Dreaming Hypothesis

Inadequate
Anaesthesia

Types of
Dreaming
Sleep During
Recovery
The EEG and Dreaming
Features
Risk factors
Sleep
Recovery Near-Miss
Dreaming
Dreaming Awareness
Narrative
Bizarre
Simple
Relevant
Duration
Long
Short
Short
Memorability
Low
Low
High
-
No
Yes
Sleep
?
Awake
Light anaesthesia
EEG
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
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-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
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
8 (0-57)
10 (0-100)
0.04
92 (40-98)
85 (69-98)
<0.0001
29%
27%
0.70
Eyes open – interview (min)
BIS at interview
Dreaming
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
Prof AB Baker
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
‘Whatever you can do or dream you can, begin it.
Boldness has genius, power and magic in it’
Thank You