Intraoperative awareness with recall during General Anesthesia in Damascus University Hospitals in Syria (A Cohort Study).

doi:10.21203/rs.3.rs-2752805/v1

Background

Awareness with recall during general anesthesia is one of the frightening complications of general anesthesia, which indicates the failure of anesthesia. Awareness is an underestimated complication despite the fact that it sometimes carries devastating psychological risks for patients. To our knowledge this is the first research in Syria that reports the incidence of awareness with recall during general anesthesia.

Aims

to assess the incidence of awareness with recall during general anesthesia in Damascus University teaching hospitals.

Design:

multi-central prospective cohort study.

Setting:

Three main Teaching Hospitals of Damascus University: Al-Assad, Al-Mowassat & Maternity Hospitals during the time period between January and November 2021.

Study Sample:

3500 patients aged ≥ 18 years were included.

Results

the incidence of Awareness with recall during general anesthesia in Damascus University Teaching Hospitals was 0.66% in low risk of awareness surgery and 1.8% in high risk of awareness surgeries. The most frequent manifestations of awareness were auditory perceptions, paralysis and pain (100%, 100% & 97.4% respectively).

Conclusions

Awareness with recall rate was somehow high in Damascus University Teaching Hospitals in comparison to the figures reported by American and European studies, this difference was especially noted in a low risk of awareness surgery. The rates were similar in the high risk of awareness surgeries. Lack of premedication and low concentration of inhalational agent were the main reasons for awareness.

Anesthesiology & Pain Medicine

Intraoperative awareness with recall - General Anesthesia - Damascus University - Syria

The main goals of general anesthesia are to achieve amnesia and unconsciousness during surgery, and by achieving these two goals it is rare for memory to be built during surgery; Surgery memory is one of the feared and underestimated complications of general anesthesia¹, which is defined as Accidental Awareness during General Anesthesia (AAGA), and more precisely, it is defined as Awareness during general anesthesia with Recall (AWR), Whether this experience is expressed spontaneously by the patient or after direct questions are asked to the patient since the presence of awareness presupposes the activation of long-term explicit memory². There is another type of awareness during anesthesia, which can have translated by transcending the explicit memory and presupposes the activation of the hidden memory, which is a type of memory that is said to exist, but we do not know that we have it, and that is often called implicit memory³. There are many phenomena of awakening during anesthesia that are not classified under the term awareness or explicit or implicit memory nor it is declared spontaneously by the patient, not even by interrogation, but rather manifests clinically in the form of a sever change in behavior or performance⁴.

According to Western statistics, the incidence of AWR ranges between 0.1–0.2%. In a multicenter American study, the rate of AWR was 0.13% ⁵, and 0.16% in a Sweden study⁶, while another study in Ethiopia showed that the magnitude of AWR under general anesthesia was found to be 8.2%⁷. Although these rates seem low, only they indicate the failure of anesthesia. The psychological consequences are sometimes devastating, and are represented by fear and permanent aversion to anesthesia and surgery, through acute stress disorder, to the syndromes of post-traumatic stress disorders⁸. According to a forensic medical analysis, 2% of the lawsuits against anesthesia were related to complications resulting from awareness during general anesthesia⁹.

The incidence of AWR can rise to 1–2% in patients with a high risk of awakening, and this includes: Patients undergoing cesarean section, cardiothoracic surgery, emergency surgery, major cancer surgery, patients with a difficult airway and those developing intraoperative hypotension¹⁰.

The Modified Brice Interview questionnaire is the best model for diagnosing intraoperative awareness with explicit memory¹¹. AWR, if diagnosed, is also classified according to the Michigan Awareness Classification Instrument ¹².

The rate of AWR during general anesthesia has not been studied in Syrian hospitals before; Therefore, we conducted a prospective descriptive cohort study to establish its incidence during routine general anesthetic practice in a number of University Hospitals in Damascus, and to determine the risk factors for the occurrence of AWR during general anesthesia.

We conducted a prospective multi-center observational study at Damascus University Hospitals (Al-Assad University Hospital, Al-Mowassat University Hospital and Maternity University Hospital), for the period between January to November 2021. This study was approved by the Ethics Committee of Faculty of Medicine – Damascus University. Following signing the consent form, 3500 patients were included in the study.

Inclusion criteria

General anesthesia patients aged ≥ 18 years who are able to communicate and give correct information.

Exclusion criteria

we excluded patients with psychological and mental disorders, patients with a high risk of death after surgery and required mechanical ventilation in intensive care units for more than 24 hours.

Our study subjects were interviewed after the anesthesia protocol and surgery; thus the attending anesthesiologists were unaware of the study. None of the patients had bispectral index (BIS) neither EEG monitoring (because it was not available in hospitals at the time of the study); however, respiratory gas monitors were available in a few cases to measure end-tidal anesthetic concentration.

Basic patient demographic and treatment data (age, sex, ASA physical status, type of surgery, and anesthesia care details) were recorded on a Arabic-language standardized case report form (Appendix 0).

AWR during surgery was investigated using the structured modified Brice interview questionnaire (Appendix 1) in two different times: one just before discharge from the recovery room for all patients and second on the day after surgery just with cases in which possible awareness was detected.

Furthermore, AWR was also classified according to the Michigan Awareness Classification Instrument (Appendix 2).

Data analysis: The data has been entered and analyzed using IBM SPSS Statistics version 22. Descriptive statistics analysis was used to describe the sample, its characteristics and the occurrence of AWR. The software was also used to perform logistic regression models to examine the associations AWR with specific risk factors.

Of 3571 patients, 71 were excluded because they did not meet the inclusion criteria while some were not able to be questioned after surgery or were mechanically ventilated or died. The total number of patient was 3500, and they were interviewed in the recovery room by one of the study researchers.

3.1 - Demographic Characteristics of patients:

Patients' age ranged between 18–80 years, of which 48% were between 18–40 years. Females subjects accounted more than males (61.6% vs 38.4%). 58.7% of patients were ASA = 1 according to the American Society of Anesthesiologists classification. Laparoscopic and abdominal surgery accounted for 15% of all cases, while emergency, cancer and cardiac surgery accounted less than 10%, and lower rates were seen of the other types of surgeries.

Table (1) summarize the characteristics of the included patients.

Table (1) : Patient characteristics

Number of patients

percentage

Age

18–40 years

41–60 years

61–80 years

1282

1679

539

36.6%

48.0%

15.4%

Gender

Male

female

1345

2155

38.4%

61.6%

ASA

I

II

III

2055

1304

141

58.7%

37.3%

4.0%

Surgery:

Laparoscopic S

Abdominal S

Emergency S

Cancer S

Cardiac S

Neuro S

Urology

Orthopeadic S

Gynecological S

Thoracic S

Neck S

Breast S

Vascular S

ENT S

Ophthalmic S

Bariatric S

Emergency Caesarean Section

540

529

426

373

359

229

196

177

175

134

131

98

78

24

15

14

2

15.4%

15.1%

12.2%

10.7%

10.3%

6.5%

5.6%

5.1%

5.0%

3.8%

3.7%

2.8%

2.2%

0.7%

0.4%

0.1%

3.2 – Incidence of AWR: Thirty-nine patients reported awareness with recall of events that occurred between the induction of anesthesia and awakening (they answered yes to the questions of the modified Brice questionnaire, especially the third question), and those were investigated by another doctor the day after surgery, and no patient mentioned that he had dreams during anesthesia. The total incidence of awareness with recall was approximately 1.1% in the study population.

Of 39 patients with AWR, all subjects (100%) reported the feeling of being paralyzed and the inability to move or breath; 29 subjects (74.3%) did not receive premedication with Midazolam; and 11 subjects (28.2%) had low and insufficient concentrations of inhalational agent for maintenance of general anesthesia.

Dividing the sample according to whether it’s a AWR high risk or not, two subgroups were identified: * 1374 Patients with high risk of AWR (cardiac surgery, emergency surgery, major cancer surgery, Bariatric surgery, cesarean section, patients with a difficult airway and those who developed intraoperative hypotension), of which 25 patients reported AWR (AWR's Incidence was 1.8%), and * 2126 non AWR high risk patients, of which 14 subjects reported awareness with recall (AWR's Incidence was approximately 0.66%) .

Table (2) summarize the incidence of AWR in our study patients

Table (2) : Incidence of AWR
	Number of patients	Awareness	Percentage %
All patients	3500	39	1.1
Patients with high risk of AWR	1374	25	1.8
Rest of the patients	2126	14	0.66

3.3 Awareness manifestations: By investigating the patients who reported awareness during general anesthesia, all patients did describe that they heard voices and conversations in the operating room, and also they mentioned how they sensed surgical maneuvers, complete paralysis and inability to move. 38 patients suffered from severe pain during surgery and only one patient did not feel pain. 25 patients evaluated awareness during anesthesia as a very bad, terrifying and unforgettable memory, while the patient who did not feel pain, evaluated the awareness to be less bad considering it in his own language as a "complication that may occur".

Table (3) shows the percentages of awareness manifestations.

Table (3) : Awareness manifestations

Numbers of patient

percentage

Auditory perceptions

Unable to move or breathe

Pain

Sensation of endotracheal tube

Feeling surgery without pain

Anxiety/stress/fear

39

38

14

1

25

100

97.4

35.9

2.6

64.1

The incidence rate of AWR during general anesthesia recorded globally ranges between 0.1–0.2%¹³, and it can rise to reach 1–2% in patients with high risk of awareness¹⁰.

This study showed a total incidence of 1.1% for AWR during general anesthesia in all the studied hospitals. This rate differed significantly between the patients who were at high risk of awareness compared to the rest of patients (1.8% compared to 0.66% respectively). The recorded rate in high awareness risk patients was similar to that described in other countries¹⁰, while higher for patients at low AWR risk than that described in USA and Australia (0.13% and 0.16% respectively)^5–6, and much less than that described in North of Ethiopia (8.2%)⁷.

By reviewing the anesthetic drugs used for AWR patients, we found that only 10 patients received premedication with Midazolam (the drug was not available in hospitals). In 11 subjects, the concentrations of inhalational agent for maintenance of general anesthesia was low and insufficient, due to hypotension, a leak in the anesthesia circuit, or a lack of attention of the Anesthesia team. Due to the use of neuromuscular blocking agents in all patients, the incidence of feeling paralyzed and the inability to move or breath was 100%.

In order to determine the risk factors of AWR, the univariate and multivariate logistic regression results were showed in Table (4) and (5). Individual's gender showed no correlation to the incidence of awareness which is consistent with the results of the American study⁵ and contradicts with an European study that reported female gender to be one of AWR risk factors¹⁴.Our data showed that there is no association between ASA classification and AWR, and this contradicts the results of the American study, which found that the risk of awareness increases in patients with classification III and IV according to the ASA⁵.

Table (4): Univariate logistic regression
	B	E.S	Wald	ddl	Sig	Exp(B)
Gender	.529	.322	2.693	1	.101	1.697
ASA	− .617	.334	3.416	1	.065	.540
Age	− .859	.276	9.679	1	.002^*	.423
Surgery	.108	.042	6.738	1	.009^*	1.114
premedication	1.065	.367	8.429	1	.004^*	2.900
Low inhalational agent concentration	− .934	.356	6.894	1	.009^*	.393

Table (5): Multivariate logistic regression

B

E.S

Wald

ddl

Sig

Exp(B)

Gender

ASA

Age

Surgery

.768

− .307

− .852

.120

.327

.373

.311

.40

5.511

.674

7.482

9.014

1

0.19

0.412

0.006^*

0.03^*

2.155

.736

.427

1.127

There was a correlation between AWR and both age and the type of surgery, most cases of awareness occurred at ages less than 41 years and this corresponds to the results of a review of reported cases¹⁵ and contradicts the results of the American study⁵. And there was a strong correlation between the type of surgery and the incidence of AWR where most cases of awareness occurred in emergency surgery, which is a similar finding to the reported figures reported in many studies^{16–17−18–19}. Also we found a correlation between lack of premedication and low concentration of inhalational agents with the incidence of AWR, and this is consistent with the results of several studies^16–17−19.

Due to difficulties in performing a post- hospital discharge follow-up for the study subjects, we were not able to study the psychological effects of awareness during anesthesia on patients.

Awareness with recall during general anesthesia in Damascus University hospital is relatively common and occurs in 11 patients out of every 1000 cases of general anesthesia, we recommended more attention by the anesthesia team on the possibility of awareness during general anesthesia by providing premedication and using sufficient concentration of inhalational agent.

Acknowledgments

We would like to thank Dr Abeer Kodsy for her participation in proofreading and reviewing this research.

Funding

This research received no specific grant from Damascus University or any other funding agency in the commercial, Public, or non-profit sectors.

Availability of data and materials

All data related to this paper’s conclusion are available and stored by the authors. All data are available from the corresponding author at a reasonable request.

Ethics approval and consent to participate

This study was approved by the Ethics Committee of faculty of medicine – Damascus university All Participants confirmed their written consent by signing the consent form. Participation in the study was voluntary and participants were assured that anyone who was not inclined to participate or decided to withdraw after giving consent would not be victimized. All information collected from this study was kept strictly confidential.

Consent for Publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Authors' contributions

All the authors participated in the preparation for this study and in data collection. NR was responsible for data analysis, literature search and write-up, and AK reviewed the final draft.

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Appendix.docx

Intraoperative awareness with recall during General Anesthesia in Damascus University Hospitals in Syria (A Cohort Study).

Status:

Version 1

Abstract

Background

Aims

Design:

Setting:

Study Sample:

Results

Conclusions

1. Introduction

2. Methods

3. Results

3.1 - Demographic Characteristics of patients:

4. Discussion

5. Limitation of the study

6. Conclusion

Declarations

References

Supplementary Files

Status:

Version 1