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Table 1. Studies evaluang incidence of awareness between 1990 and 2008

Study (Coun-

try)

Dates

performed

Design Sample

size

Populaon

Sandin et al.

(Sweden)

1997-1998 Prospecve cohort

study

11,785 All paents > 15 yo who have had

GA

Myles et al.

(Australia)

1993-1999 Prospecve cohortstudy

10,811 All paents receiving GA (exclud-ing obstetrics and paediatrics)

Wennervirta et

al. (Finland)

April 1998-June

1999

Prospecve cross-

seconal study

3,843 All paents > 15 yo undergoing

surgery using general anesthesia

Errando et al.

(Spain)

April 1995-April

1997 & Decem-

ber 1998-No-

vember 2001

Prospecve obser-

vaonal study

4,001 All paents > 15 yo scheduled for

elecve or urgent surgery requir-

ing GA, excluding cardiac surgery

and paents transferred to Cri-

cal Care Unit

Ranta et al.

(Finland)

January

1995-January

1996

Prospecve cross-

seconal study

929 All cardiac surgery paents

Paech et al.

(Australia)

June 2005

January 2007

Prospecve obser-

vaonal study

1,095 All women > 18 yo undergoing

Caesarean Secon under GA

Sebel et al.

(USA)

Pollard et al.

(USA)

April 2001

December

2002

January 2002

December

2004

Prospecve,

nonrandomized,

cohort study

Prospecve obser-

vaonal study

19,575

177,468

All paents > 18 yo receiving GA,

normal mental status, able to

provide informed consent.

All paents > 18 yo who under-

went GA

GA = General Anesthesia

yo = years old

Table 2. Modified Brice interview10

1. What is the last thing you remember before going to sleep?

2. What is the first thing you remember waking up?

3. Do you remember anything between going to sleep and waking up?

4. Did you dream during your procedure?

5. What was the worst thing about your operaon?

and able to fully recall the experience aerwards. The ma-

jority of awareness cases, however, are brief and without

experience of pain/anxiety.4

The causes of awareness are sll uncertain and the

problem is thought to be mul factorial. However, there are

a few plausible causes that may explain the occurrence of

awareness. Firstly, central nervous system target receptors

may have inherited variability in their expression and/or

funcon, which may result in unpredictable paent-specificvariability in dose requirements of anesthec drugs. The

basis underlying this theory is yet to be elucidated, but

preclinical studies involving mice have uncovered a genec

deficiency in one type of receptor for the inhibitory neu-

rotransmier g-aminobutyric acid (GABA) that presented

resistance to the memory-blocking properes of etomidate.

Secondly, low physiologic reserves (e.g. poor cardiac func-

on, severe hypovolemia) may render the paents less ca-

pable of tolerang an amnesic level of anesthesia because

it may catastrophically worsen their state of hypotension.

Insuffi cient anesthec drugs could then result in aware-ness. Thirdly, a pacemaker or drugs such as -blockers may

conceal the physiologic characteriscs that normally indi-

Kesadaran Intraoperatif dalam Anestesi Umum dan Pembentukkan Post-traumatic Stress Disorder I Intraoperative Awareness in General Anesthesia and theDevelopement of Post-traumatic Stress Disorder

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cate the need for a dose change. And lastly, equipment mal-

funcon or misuse may compromise drug delivery systems

pu ng the paents at risk for awareness.1

Previous studies have shown that the incidence of

awareness in general anesthesia is approximately 0.18%

when neuromuscular blockers are used and 0.10% in the

absence of such drugs.5,6 Assessing anesthec depth when

muscle relaxants are used is parcularly diffi cult because ofthe absence of motor responses to smuli.4 Muscle paraly-

sis is perhaps the reason for higher incidence of awareness

in view of the fact that the paents are unable to signal the

anesthests when they are aware.

Conscious awareness with explicit recall have been

known to result in paent dissasfacon on anesthec

care, distress, and potenal long-term psychological symp-

toms.6,7 Although the numbers are not similar in all stud-

ies performed, approximately 56% of paents experiencing

conscious awareness during general anesthesia have been

found to develop PTSD as a complicaon.7 The characteris-

c symptoms of PTSD include depression, anxiety aacks,sleep disorders, and flashbacks and nightmares of the trau-

mac experience. PTSD have also been known to be diag-

nosed in paents without explicit recall of the events but

develop symptoms such as recurrent dreams about being

buried alive which indicate that intra operave awareness

may have occurred.4 In a sense, sufferers of PTSD are inca-

pable of leaving the event behind. In 1982, Turnstall and

Lowit8 gave an account of a paent who developed sleep

phobia aer experiencing conscious awareness with pain

during general anesthesia for a caesarean secon. This

paent experienced a sense of panic and a sinking feeling

when lying on her back, had recurrent nightmares, diffi culty

going to sleep, and felt unable to breathe when she finally

fell asleep. This problem dramacally altered her life and

personality in the years that followed.

This review aims to assess the incidence of intra

operave awareness in general anesthesia and the psycho-

logical impact and psychiatric sequelae that may develop

aerwards, with the intenon of increasing our knowledge

about intra operave awareness, awareness-induced PTSD,

and ways of prevenng such an unfortunate event from

occurring. This review begins by summarizing research on

the incidence of intra operave awareness and invesgates

psychological symptoms following intra operave aware-

ness. Further discussion then focuses on monitoring aware-ness in general anesthesia, risk factors for awareness, and

strategies for prevenng awareness and the development

of PTSD in paents with conscious awareness and recall.

METHODS

The literature search was conducted using com-

puterized databases including PUBMED, The Cochrane Li-

brary, and MEDLINE in order to idenfy the relevant arcles

that have been published unl April 2009. Arcles were

retrieved using the keywords: awareness AND general

anesthesia, awareness AND general anesthesia AND

posraumac stress disorder, and also intra-operaveawareness AND psychological sequelae. The search

was limited to studies that were published in English and

used human adult subjects. Publicaons on pediatric cases

were excluded because awareness in children has not been

reported to result in PTSD. This may be caused by the dif-

ference between a childs expectaons of surgery than an

adults in which an adult would expect to be fully uncon-

scious without any memory throughout the procedure.

The reported incidence of hosle behavioral changes and

sleep disturbances of children who suffered intra operaveawareness was found to be not significantly different than

those in children without awareness.9 A total of sixty-seven

arcles were acquired by the search and only seven arcles

met the inclusion criteria. Abstracts were read thoroughly

before complete arcles were obtained and the references

from the relevant publicaons were manually explored to

ascertain further potenal arcles. In the end, eleven pub-

licaons were reviewed, including one literature review.

RESULTS

All available literature on awareness in generalanesthesia and PTSD were considered for inclusion in the

review. Prospecve randomized controlled trials and meta-

analyses were originally preferred for the review; however,

given the absence of level I (NHMRC guidelines) and scar-

city of level II (NHMRC guidelines) evidence, observaonal

studies on awareness in general anesthesia, case series and

cohort studies were also considered. Retrospecve reviews

and expert opinion were not eliminated.

Study Designs

The majority of selected studies evaluated the in-

cidence of awareness (Table 1) and only a few addressed

psychological sequelae of intra operave awareness. These

studies employ different strategies in discovering the inci-

dence of awareness and PTSD. Sandin et al.5 invesgated

the possibility of awareness or awake paralysis in 11,785

paents who had undergone general anesthesia. Interviews

were performed by trained staff using the Brice modified in-

terview (Table 2) and took place before the paent le the

post-anesthesia care unit (PACU); 1-3 days aer; and 7-14

days aer the surgery. A similar method was also used by

Sebel et al.10 in interviewing 19,575 paents in the recov-

ery room and follow-up interview up to two weeks follow-

ing the surgery. Errando et al.11 also used a similar strategy

(with the excepon of ulizing their own structured inter-view) when interviewing 4,001 paents in PACU immedi-

ately aer the surgery and follow-up interviews to confirm

awareness episodes on the seventh and thireth day aer

surgery. In another study conducted in Australia, Myles et

al.12 calculated the incidence of awareness when evaluang

paents sasfacon with anesthesia. Their interviews took

place within 24 hours aer the surgery and the paents

were asked whether they were sasfied, somewhat dis-

sasfied, or dissasfied with the anesthec service they

had received. The reasons for paents dissasfacon were

further explored aerwards.

Another study by Wennervita et al.13

aimed toassess the incidence of awareness and recall during gen-

eral anesthesia in outpaent surgery and used inpaents

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as controls. A total number of 1500 outpaents and 2343

inpaents were interviewed during their stay in the re-

covery room using a modified version of Brice interview

method. Those found to have recollecons in the recovery

room were reinterviewed by one of the researchers on the

same day or the following day and later reinterviewed for

the third me by phone within 12-24 months aer the op-

eraon to evaluate the possibility of psychological sequelaethat may follow (e.g. sleep disturbances, anxiety, depres-

sion, preoccupaon with death). Paech et al.14 also used

modified Brice interview method in assessing 1095 cases of

cesarean secon under general anesthesia for incidence of

awareness and recall. Paents were interviewed at two oc-

casions; the first 2-6 hours postoperavely and the second

at least 48 hours aer surgery (but before being discharged

from the hospital). Brice modified interview was also used

by Ranta et al.15 in evaluang paents conscious recollec-

ons from cardiac surgery. Nine hundred and twenty nine

paents were interviewed within postoperave days 1 to

18.

Incidence of Awareness

In 2000, Sandin et al.5 reported that aer inter-

viewing 11,785 paents who had undergone general anes-

thesia, it was established that the rate of incidence of intra

operave awareness was 0.18% in cases where neuromus-

cular blockers were used and 0.10% in the absence of those

drugs. A similar incidence of awareness (0.11%) was also

reported by Myles et al.6 on the same year when invesgat-

ing risk factors for paents dissasfacon aer anesthesia.

Sebel et al.10 later confirmed that percentage with an over-

all incidence of 0.13% in 19,575 paents in a mulcenter

study in the United States of America. This rate is equiva-

lent to 1 to 2 cases of intra operave awareness in every

1000 paents who receive general anesthesia. However,

Errando et al.11 reported an incidence rate as high as 1.0%

among 4,001 interviewed paents or 0.8% if emergency pa-

ents were excluded, which is comparable to 8 to 10 cases

in every 1000 paents receiving general anesthesia.

An exceponally low incidence of intra operave

awareness was reported by Pollard et al.16 in 2007. The

authors reviewed the data collected over 3-year period

through a major regional medical system in the United

States. A different, somewhat modified version of Brice

quesonnaire than previously used in other studies was u-lized as a method for invesgang awareness in this study

and six awareness cases out of the total of 177,468 paents

was found. From this result, the authors then calculated

a substanally lower incidence rate of 0.0068%, which is

equivalent to 1 case per 14,560 paents.

Risk Factors for awareness

Types of surgery

A slightly higher incidence of intra operave

awareness than is normally reported in the general surgical

populaon had been observed by Paech et al.14 amongst

the obstetric populaon of women who underwent cesar-ean secon. The observed rate of 0.26% confirmed that

pregnant women are at high-risk of awareness. Factors that

may account for higher risk of awareness in the obstetric

populaon include physiological changes during pregnancy

(e.g. an increased cardiac output), which accelerate the re-

distribuon of intravenous anesthec agents and reduce

the establishment of an adequate paral pressure of vola-

le anesthec agent, and lighter general anesthesia which

is usually given for obstetric paents to avoid the depres-

sant effects of volale agents on the newborn and on theuterine musculature aer delivery. 14, 17

Another group of paents with high-risk of aware-

ness are those undergoing cardiac surgery. The main reason

for the increased risk is that general anesthesia in cardiac

surgery may rely only on opioids and benzodiazepines while

volale agents may oen be avoided in paents who al-

ready have considerable preoperave myocardial morbid-

ity and those who may develop complicaons (e.g. coagu-

laon problems) aer bypass surgery.17 A study by Ranta

et al.15 invesgated the incidence of awareness with post-

operave recall by surveying the experience of 929 cardiac

surgery paents. They reported an incidence of 0.5% whenonly the paents with objecve recollecons were includ-

ed which was sll a higher incidence compared to those in

general surgical populaons. However, the authors claimed

that the incidence rate was similar to those in non-cardiac

surgery populaons.

Hypovolemic trauma paents also have a signifi-

cantly increased risk of awareness even though they be-

come more hypotensive with the administraon of anes-

thec drugs from which cerebral perfusion is expected to

decrease and therefore, theorecally, should reduce aware-

ness17. Postoperave recall, however, has been known to

occur despite significant hypotension during resuscitaon17. The incidence rate of awareness in trauma paents could

not be obtained due to the lack of awareness studies as-

sessing this group of paents.

Paent variability

A previous history of awareness and history of dif-

ficult intubaon, which could be discovered preoperave-

ly, are both factors which significantly increase the risk of

awareness and may therefore influence anesthec require-

ments. Less readily idenfiable and more complex factors,

such as genecs, paent physiology, and drug interacons

may also play a role in the variability of response to anes-

thecs. Chronic use of alcohol, opioids, sedaves, and theacute use of amphetamines may increase anesthec drugs

doses required to produce and maintain anesthesia.17

Age and Gender

Minimum alveolar concentraon (MAC) is the

standard measurement used to determine the potency of

inhaled anesthec drugs. MAC increases as age decreases

and therefore larger inhaled concentraons of volale an-

esthecs are required in order to maintain the state of un-

consciousness in young paents.18 An increase in anesthec

requirements in young paents compared to elderly pa-

ents suggest that younger paents are more likely to suf-fer from awareness.17 In fact, a higher incidence of aware-

ness among children has been reported in the literature. A



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prospecve study of awareness by Davidson et al.18 involv-

ing 864 children undergoing general anesthesia at the Royal

Childrens Hospital in Melbourne, Australia, established an

incidence rate of 0.8% which is equivalent to 8 awareness

cases in every 1000 children. However, unlike adult cases of

awareness, no signs of distress were observed in children

who experienced awareness and the postoperave behav-

ioral disturbances are comparable to those who did not ex-perience awareness.

Gender is also a risk factor for awareness. Women

are found to be more likely to report intra operave aware-

ness and they also recover from anesthesia more rapidly

compared with men which suggests that women may be

less sensive to the effects of anesthec agents.17

Incidence of PTSD following intra operave awareness

Lennmarken et al.19 performed a follow-up study

to invesgate the long-term mental effects of awareness

by quesoning the 18 paents idenfied by Sandin et al.5

in the study published two years prior. Only nine out of 18paents were available for evaluaon (six of them declined

to parcipate) and four out of those nine paents were

found to have severe psychiatric/psychological symptoms.

All four paents could recall in detail their traumac events

of awareness and the memories showed no propensity to

diminish. They revealed common symptoms of PTSD such

as re-experiencing events, feelings of fear and helplessness,

flashbacks, panic aacks, anxiety, diffi culty concentrang,

irritaon, insecurity, sleep disturbances and nightmares. All

four of them affi rmed that these symptoms had caused im-

pairment in their social lives for the whole 2 years following

the surgery.

Samuelsson et al.7 reported 46 paents who had

experienced awareness under general anesthesia earlier in

their lives in a cohort of 2,681 paents. Thirty one of them

denied any late psychological symptoms while the remain-

ing 15 paents experienced nightmares, anxiety, and flash-

backs. These symptoms faded within 2 months in 9 out of

those 15 paents and persisted only in the form of night-

mares and flashbacks for years in the other 4 paents. The

remaining two paents developed severe mental problems

and underwent psychiatric therapy. However, only one of

the two paents was diagnosed with PTSD (while the other

was diagnosed with schizophrenia) and whether or not it

was caused by intra operave awareness was obscuredby the fact that she had been exposed to extreme mental

stress earlier in her life.

An incidence rate of 56.3% for PTSD following

awareness was accounted by Osterman et al.20 aer in-

terviewing 16 subjects who were recruited from adver-

sements in newspapers, fliers in hospitals, self-referred

following print and television news stories, or referred by

an anesthesiologist. Subjects reported significant postop-

erave distress during their awareness episode, with most

common and intense experiences of feeling unsafe and

helpless, abandoned by his/her doctors and nurses, feeling

betrayed by his/her doctors and nurses, terror, and inabilityto communicate. Nine out of the sixteen subjects met the

DSM-IV diagnosc criteria for PTSD with funconal impair-

ment years aer suffering intra operave awareness. How-

ever, the study is weakened by potenal selecon bias.

The more credible percentage was previously es-

tablished by Schwender et al.21 aer interviewing two

groups of paents with experience of awareness during

general anesthesia (21 paents who answered to adver-

sement and 24 paents who were referred by colleagues

from three large hospitals involved in the study). Twenty-two of 45 paents (50%) were found to suffer aer effects

of their awareness episode (e.g. reluctance to undergo fu-

ture anesthesia and operaons, suffered anxiety during the

day, and had nightmares at night) and three of them (6.6%)

developed PTSD syndrome. Schwender et al. also discov-

ered that, during the awareness episode, visual percepon

was reported by nearly 50% of paents and an incidence

of pain percepon of 25% with 17.8% of paents suffering

severe pain localized in the area where the pain smuli oc-

cured. All 45 paents reported auditory percepon during

their episodes: 20 paents could recall the remarks made

by the surgical team that were emoonally relevant tothem (e.g. derogatory remarks) while the other 25 paents

only recalled theatre conversaons and noises.

Prevenon of intra operave awareness and PTSD

The first line of awareness prevenon starts with

preoperave assessment. Paents at high risk of awareness

should be idenfied in the pre-admission clinic and their

management should be planned aerwards.2 Paents at

risk of awareness include those having high-risk of aware-

ness surgery (e.g. cardiac surgery and cesarean secon) or

surgery associated with significant blood loss, paents who

are medicated with significant doses of sedaves and an-

algesic drugs, and paents with previous history of aware-

ness.2 This group of paents should be provided with infor-

maon about awareness and assured that there would be

efforts to prevent such an unfortunate event from happen-

ing.2

BIS Monitoring

The bispectral index system (BIS) is an apparatus

created to indirectly monitor hypnoc depth and anes-

thec drug concentraons in general anesthesia by pro-

cessing electroencephalogram data through a proprietary

algorithm, which is then displayed as a calculated dimen-

sionless parameter between 0 and 100 (with 40 to 60 con-sidered appropriate for general anesthesia).2, 12 BIS moni-

tor was the first device approved by the US Food and Drug

Administraon for monitoring anaesthesic depth and it has

the capability of reducing the incidence of awareness by

alerng the anaesthests when the depth of anesthesia is

inadequate. A randomized double-blind controlled trial by

Myles et al.12 showed that BIS monitoring could reduce the

incidence of awareness by 82% in at-risk adults undergoing

relaxant general anesthesia. It also confirmed that aware-

ness during BIS monitoring is less common than during rou-

ne care. However, Avidan et al.22 challenged this finding by

proposing that BIS monitoring was not proven to be morebeneficial than a protocol based on end-dal anesthec gas

(ETAG) concentraons for prevenng anesthesia aware-

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ness. However, the study was under-powered to draw any

conclusions as there were only two cases of awareness in

each group.

Beta-Blockers

Salomons et al.23 presented two cases of PTSD that

persisted for years aer intra operave awareness in which

the pain symptoms that they re-experienced were similarin locaon to the pain they had felt during their episodes

of awareness. These two cases suggested that some smuli

that were associated with the trauma may have triggered

pain flashbacks and this could be further denoted as fear

condioning that may have occurred around the me of

trauma.23 Pitman et al.24 proposed that adrenaline release

at the me of a psychologically traumac event could ini-

ate an exaggerated emoonal memory and fear condi-

oning which consequently manifest as PTSD symptoms.

Given this theory, administraon of propanolol to block

-adrenergic receptors immediately aer a traumac event

could have a prophylacc effect. A double-blind, placebo-controlled pilot study24 proved that a course of propranolol

which begun shortly aer an acute traumac event is ef-

fecve in reducing PTSD symptoms 1 month later. Further

studies, however, are sll required to reassure this finding.

DISCUSSION

The word anesthesia originated from the Greek

word anaisthsia which literally means loss of feeling or

sensaon. 25 Indeed, the aim of anesthesia is to arficially

induce the loss of physical sensaon, most especially pain,

with or without loss of consciousness through the adminis-

traon of various anesthec drugs, gases, and any other an-

esthec agents. The fundamental role of an anaesthest in

general anesthesia is therefore to keep a paent in a state

of unconsciousness in conjuncon with complete loss of

physical sensaon. Unfortunately, mulple factors may at

mes fail anaesthests to achieve this idyllic goal and con-

sequently result in awareness.

This review found the incidence rate for in-

tra operave awareness in general surgical populaon var-

ied between 0.10% and 1.0% (with an excepon of 0.0068%

incidence rate reported in one study 16 and equivalent to 1

to 10 awareness cases per 1000 paents. 5, 6, 10, 11 Larger per-

centages were esmated for paents undergoing cesareansecons and cardiac surgeries with incidence rates of 0.26%14 and 0.5% 15, respecvely, which are comparable to 3 and

5 awareness cases per 1000 paents. The most common

complaint reported by paents in these studies was audi-

tory percepon, whether it was the voices of the surgeons

conversing with other members of the surgical team or

barely audible noises in the background. Other complaints

include loss of motor funcon, feeling of imminent death,

feeling helpless, anxiety, panic, and pain. Most awareness

cases in the studies were detected using a modified Brice

interview quesonnaire (Table 2) and enquired during the

paents stay at the PACU and repeated at intervals of daysand weeks aer the surgery. The majority of awareness

cases were discovered within days or weeks aer the op-

eraon and not while the paents were in the PACU, which

showed that paents recollecons of their awareness

episode oen gradually emerged over me. The effects of

residual anesthecs and the paents divided aenon in

the early recovery period (which is usually more focused

on common symptoms such as pain and nausea) are the

main causes for delayed recollecons.17 Addionally, the

trauma of conscious awareness may have dissociave ef-fects on the paents mental state that leads to the division

of memory of the event into sensory fragments and ago-

nizing emoonal states, which consequently hinders these

paents from fully recounng their experience. 17

The greatest concern surrounding intra

operave awareness is the severe long-term psychologi-

cal sequelae that may develop aerwards. The extent of

psychological impact on paents following intra operave

awareness varies individually. Some may only experience

short-term psychological disturbances such as nightmares

and diffi culty sleeping which are resolved within a few

weeks, while others may develop debilitang long-termpsychiatric disorder such as PTSD. Four studies that inves-

gated the psychological sequelae of awareness found in-

cidences of PTSD in 22.2% 19, 56.3% 20 and 6.6% 21 of aware-

ness cases. Limited number of studies and the potenals

for selecon bias in the studies performed restrict the con-

fidence to draw any conclusions on the true incidence of

PTSD following intra operave awareness.

The development of PTSD in awareness may be

due to inescapable stress situaon while paents are

conscious of intra operave smuli. 26 Failure of escaping

stressful event through normal fight or flight response

results in passive coping mechanism or dissociaon. 26 Pa-

ents who suffer from dissociaon would appear expres-

sionless, silent, and indifferent toward their surroundings.20 They oen also appear calm and seemingly non-trau-

mazed by the experience.20 Coping mechanism through

parasympathec acvity would show reduced heart rate

as a physical sign.20 A dissociave state around the me of

trauma where the paents are incapable of narrang their

experience as a result of fragmented memory is a signifi-

cant long-term predictor for the development of PTSD.27, 28

Van der Kolk & Fisler 27 explained that considerable narrow-

ing of consciousness occur when people feel threatened.

This narrowing of consciousness may advance toward loss

of memory for parts or for the enre experience when anindividual is traumazed, leaving him or her unable to give

coherent account of the event. Some aspects of the trauma

may invade consciousness when the person fails to organize

the traumac memory into a narrave and results in terrify-

ing percepons, obssessional preoccupaons, and somac

reexperiences of the event.27

The three main characteriscs of PTSD are: 1).

re-experience, 2). avoidance, and 3). hyperarousal.26 Re-

experiencing usually happens in the form of nightmares

and flashbacks in which they would re-experience paralysis,

auditory percepon, sense of helplessness and anxiety, and

somemes even feel the pain of surgical smuli.20

Re-ex-periencing is usually triggered by reminders that resemble

their traumac situaon such as the state of light sleep or



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the process of falling asleep, sounds of clinking silverware,

or smell of alcohol.26 Re-experiencing and insomnia are the

two most common complaints reported by postawareness

paents in the studies. Postawareness paents have also

been known to avoid cues and situaons that would con-

front them with their traumac memories such as hospitals,

medical workers, television programs with hospital themes,

and some even develop sleep phobias.8, 20 Avoiding thesecues and situaon may oen prevent these paents from

inquiring aercare and discussing their experience with

medical personnel.26 Avoidance was perhaps the reason

for paents refusal to parcipate in the two year follow-up

study by Lennmarken et al19. For this same reason, paent

recruitment through adversements to invesgate PTSD

would be largely ineffecve. Physiological hyperarousal

symptoms in PTSD include easy startle, hypervigilance, and

irritability.20

A paents understanding of their experience is cru-

cial in prevenng psychological morbidity in postawareness

paents.4

When awareness is suspected to have happenedduring a surgery, anaesthests or surgeons should clarify

with the paent the reasons why awareness occurred and

reassure that it is unlikely to happen again in the future.1 It

should also be noted that, when awareness is suspected to

be occurring during a procedure, speaking to the paents

and telling them that the surgical team is aware that they

are awake and that they are ge ng help would significantly

diminish the traumazing effect of the experience.20, 26 Vali-

daon by medical personnel of the actuality of the traumat-

ic experience has been reported to prevent the develop-

ment of PTSD and even diminish or stop PTSD symptoms.4,

26 In conclusion, social support and acknowledgement are

the most vital protecve factors against the development

of PTSD in paents suffering intra operave awareness.26

Further studies on intra operave awareness are

necessary to establish more accurate prevalence, expand

our comprehension on its psychological impact, improve

detecon of awareness, and develop effectual treatment.26

Creang a registry for postawareness paents similar to

the one established by The American Society of Anesthesi-

ologists (www.AwareDB.org) would prove beneficial to in-

crease our knowledge of awareness from direct paent re-

ports. This program would also be a useful way to educate

paents by providing helpful informaon on awareness.

Finally, educaon on intra operave awareness for surgicaland anesthesia teams is necessary to further understand

the issue as well as gaining knowledge of managing such an

event.

CONCLUSION

It is crucial for surgical and anesthesia teams to ac-

knowledge the reality of surgical experience and recognize

the emoonal impact on paents. For a variety of reasons,

paents rarely report awareness and their sufferings oen

le unrecognized. The propensity for avoidance rather than

inquiring assistance in these paents makes it necessary toinclude awareness detecon in clinical rounes with the

aim of improving anesthec pracce. Awareness assess-

ment should be an ongoing process that begins in the re-

covery room and connued through to follow-up visits with

the surgeons. Awareness-induced PTSD should be consid-

ered for any paent with psychiatric complains following

surgery and therefore connuous postoperave assess-

ment is vital in discovering the maer. A thorough periop-

erave management of anesthesia is crucial in prevenng

intra operave awareness and postoperave professionalpsychiatric assessment and follow-up should be established

as standard pracce for those in need of further assistance

aer experiencing intra operave awareness.

KEY POINTS

Intra operave awareness can be defined as the

unexpected and explicit recall by paents of intra

operave events that occur during general anes-

thesia.

The causes of awareness are sll uncertain and the

problem is thought to be mul factorial.

The extent of psychological impact on paentsfollowing intra operave awareness varies indi-

vidually; some may only experience short-term

psychological disturbances, while others develop

debilitang long-term psychiatric disorder such as

PTSD.

Re-experience, avoidance, and hyperarousal are

the three main characteriscs of PTSD.

Further studies on intra operave awareness that

aim to establish more accurate prevalence, expand

our comprehension on its psychological impact,

improve detecon of awareness, and develop ef-

fectual treatment are indispensable.

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