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’