Awareness and recall during general anesthesia

Effect of bispectral index on intra-operative awareness: A meta-analysis of randomized controlled studies

Background

Randomized controlled trials (RCTs) investigating the efficacy of bispectral index (BIS) to reduce intra-operative awareness (IOA) have reported conflicting results. The purpose of this meta-analysis is to consolidate results from RCTs to assess the efficacy of BIS in reducing IOA when compared to controls. Secondary outcomes included time to extubation, time to spontaneous and/or verbal eye opening, PACU discharge time, and utilization of inhaled anesthetics.

Methods

RCTs which reported on one of the primary and/or secondary outcomes were included. Literature search utilized keywords "randomized control trial" and "intraoperative awareness." Meta-analysis was performed using RevMan 5.

Results

Twenty-seven RCTs were included in the study with a total of 35,585 patients, with 18,146 patients in the BIS and 17,439 in the control group. Eighteen of 14,062 patients (0.12%) and 42 of 16,765 (0.25%) reported definite IOA in the BIS and control group, respectively, with no statistically significant difference. BIS was effective in reducing the time to spontaneous eye opening by an average of 1.3 minutes and the time to extubation by an average of 1.97 minutes. There was no difference in PACU discharge times among the groups. There was a significant decrease in consumption of sevoflurane but no difference in desflurane and propofol compared to the control group.

Conclusion

While BIS monitoring results in decreased incidence of intra-operative awareness by half, it was not statistically significant. BIS provides modest benefits with regard to reducing the time to extubation, the time to spontaneous eye opening, and consumption of sevoflurane.Level of evidence: I.

Incidence, Associated Factors, and Behavioral Consequences of Intraoperative Awareness and Dreams During General Anesthesia Among Adult Patients: A Prospective Cohort Study

Background  The intraoperative awareness with recall phenomenon involves the memory of intraoperative events. The reported incidence is 0.001%. Awareness is rare intraoperatively but has profound implications. This research aimed to study intraoperative awareness and dream experiences in the Omani population undergoing general anesthesia. Methods This prospective cohort study involving 300 adult patients was conducted at a tertiary-level hospital between July and December 2021. Awareness was assessed in the post-anesthesia care unit and then at home on the seventh day and one month telephonically using a modified Brice questionnaire. The study's primary outcome was the incidence of IOA and dreams in adult Omani patients undergoing GA. The secondary outcome was identifying the factors associated with intraoperative awareness and dreams under GA. Results In this study, the incidence of awareness was 0.3% while 7.6% of patients reported intraoperative dreams. The patient who experienced IOA underwent an endoscopic retrograde cholangiopancreatography under GA with neuromuscular blockade and had a prolonged recovery. A total of 49.33% developed psychological effects postoperatively; anxiety, irritability, fear of surgery, change in memory, and repetitive nightmares were the most common ones. Because of the limited sample size, no factor associated significantly with these outcomes was found. Conclusion This study observed a higher incidence of intraoperative awareness and dreams. Awareness might be due to prolonged recovery and the use of neuromuscular blocking agents, but a focused study is required to confirm this finding. The incidence of intraoperative dreams and postoperative psychological effects of GA was also high. It may be worth exploring these findings with larger population-based research.

Intramedullary Kirschner Wire Fixation for Metatarsal Fractures: A Comprehensive Review of Treatment Outcomes

Metatarsal fractures pose significant challenges in orthopedic practice, necessitating effective treatment methods to ensure optimal patient outcomes. This comprehensive review focuses on intramedullary Kirschner wire fixation as a promising intervention for metatarsal fractures. Beginning with an overview of metatarsal fractures and the imperative for effective treatments, the review delves into intramedullary fixation's definition, historical background, advantages, and disadvantages. Indications for its use in metatarsal fractures are discussed, providing a foundation for understanding its application. The surgical technique section outlines critical aspects, including patient selection criteria and preoperative planning. Before presenting a detailed step-by-step procedure for intramedullary Kirschner wire fixation, anesthesia considerations are explored. Emphasizing precision, fluoroscopic guidance, and meticulous postoperative care, this section provides insights for surgeons and healthcare practitioners. Considerations for rehabilitation follow, addressing postoperative care, expected recovery timelines, and physical therapy recommendations. Early mobilization, weight-bearing guidelines, and a structured rehabilitation program play pivotal roles in recovery. In the conclusion, key findings are summarized, highlighting the efficacy of intramedullary Kirschner wire fixation, its advantages, and recommendations for clinical practice. Additionally, areas for future research are identified, guiding further exploration and refinement of this surgical approach. This review is valuable for clinicians, researchers, and healthcare practitioners involved in metatarsal fracture management, contributing to the evolution of treatment strategies and improving patient care.

Unwanted spontaneous responsiveness and burst suppression in patients undergoing entropy-guided total intravenous anesthesia with target-controlled infusion: An observational prospective trial

STUDY OBJECTIVE

To estimate the incidence of unwanted spontaneous responsiveness and burst suppression (BSupp) in patients undergoing state entropy (SE) and surgical pleth index (SPI)-guided total intravenous anesthesia (TIVA) with target-controlled infusion (TCI).

DESIGN

Observational, prospective, single-center study.

SETTINGS

Operating room.

PATIENTS

107 adult (<65 years) and elderly (≥65 years) women undergoing breast surgery.

INTERVENTIONS

Propofol-remifentanil TIVA-TCI-guided by SE for depth of anesthesia monitoring (target value 40-60) and SPI for antinociception monitoring (target value 20-50) without neuromuscular blockade.

MEASUREMENTS

Age; body mass index; American Society of Anesthesiologists physical status classification; concentration at the effect site of propofol (CeP) and remifentanil (CeR) at loss of responsiveness (LoR), median during anesthesia maintenance (MdM), and at return of responsiveness (RoR); propofol infusion duration; incidence of postoperative delirium (POD) with Confusing Assessment Method for the Intensive Care Unit.

MAIN RESULTS

During SE-SPI-guided TIVA-TCI, 13.1% of patients showed unwanted spontaneous responsiveness, whereas 45.8% showed BSupp. Unwanted spontaneous responsiveness was observed mainly in adults (p < 0.05), and higher CeP RoR (p < 0.05) was registered. BSupp was observed mainly in patients showing a lower CeP MdM (p < 0.01) and CeP RoR (p < 0.05). Unwanted spontaneous responsiveness and BSupp were not associated with significant differences in CeRs. An age-related hysteresis effect was observed, resulting in higher CeP LoR than CeP RoR (p < 0.001). 12.2% of patients showed POD. Only preoperative serum albumin was associated with increased likelihood of POD (p = 0.046).

CONCLUSIONS

The SE-SPI-guided TIVA-TCI did not prevent unwanted spontaneous responsiveness and BSupp. CeP RoR may be used as a proxy for anesthetic sensitivity.

Patient Safety: Cognitive Assessment at Intensive Care Unit Discharge

Topic

Assessing functional cognition is a critical need for intensive care unit survivors transitioning to another level of care.

Clinical Relevance

Up to 62% of patients discharged from an intensive care unit have significant cognitive impairment that is not associated with severity of illness, number of comorbidities, or length of hospital stay. For more than 20 years, researchers have published an array of potentially effective interventions, including case management, patient and informal caregiver education, and home health care services.

Purpose

To describe the impact of and potential interventions for cognitive decline at intensive care unit discharge and discharge readiness on 30-day readmission rates.

Content Covered

Assessing the patient’s functional cognition assessment and advocating for appropriate resources are needed to improve patient and clinical outcomes.

Bispectral Index (BIS) Monitoring and Postoperative Delirium in Elderly Patients Undergoing Surgery: A Systematic Review and Meta-Analysis With Trial Sequential Analysis

OBJECTIVE

To examine the effect of bispectral index (BIS)-guided anesthesia on the incidence of postoperative delirium (POD) in elderly patients undergoing surgery.

DESIGN

A systematic review, meta-analysis, and trial sequential analysis (TSA).

SETTING

In the operating room, postoperative anesthesia care units (PACU), and ward.

PARTICIPANTS

Elderly patients (>60 years old) undergoing surgery.

INTERVENTIONS

The EMBASE, MEDLINE, and CENTRAL databases were searched systematically from their inception until December 2020 for randomized controlled trials comparing BIS and usual care or blinded BIS.

MEASUREMENTS AND MAIN RESULTS

Ten trials (N = 3,891) were included for quantitative meta-analysis. In comparison to the control group, there was no significant difference in the incidence of POD in elderly patients randomized to BIS-guided anesthesia (odds ratio [OR] 0.71, 95% CI 0.47-1.08, I² = 76%, p = 0.11, level of evidence = very low, TSA = inconclusive). The authors' review demonstrated that elderly patients with BIS-guided anesthesia were significantly associated with a lower incidence of postoperative cognitive dysfunction (POCD) (OR 0.64, 95% CI 0.46-0.88, p = 0.006), extubation time (mean difference [MD] -3.38 minutes, 95% CI -4.38 to -2.39, p < 0.00001), time to eye opening (MD -2.17 minutes, 95% CI -4.21 to -0.14, p = 0.04), and time to discharge from the PACU (MD -10.77 minutes, 95% CI -11.31 to - 10.23, p < 0.00001).

CONCLUSION

The authors' meta-analysis demonstrated that BIS-guided anesthesia was not associated with a reduced incidence of POD, but it was associated with a reduced incidence of POCD and improved recovery parameters.

Magnitude and Associated Factors of Awareness with Recall under General Anesthesia in Amhara Regional State Referral Hospitals, 2018

Introduction

Awareness with recall of intraoperative events is an infrequent but potentially devastating complication of general anesthesia, with a reported incidence of 0.1-0.2% in low-risk patients. Higher incidence is expected in resource-limited operation room setups and in high-risk patients. Awareness can result in significant distress to patients and long-term psychological consequences, including symptoms associated with posttraumatic stress disorder, anxiety, night mares, night terror, dissatisfaction with surgical service, and sometimes even suicide.

Objective

To assess the magnitude and associated factors of awareness with recall under general anesthesia in Amhara regional state referral hospitals.

Method

An institution-based cross-sectional study was conducted on 1065 patients who underwent surgery under general anesthesia from January 1 to June 30, 2018. The study participants were selected by systematic random sampling from 4 referral hospitals. The modified Brice questionnaire was used to detect awareness under general anesthesia. Interviewer-administered structured questionnaire and chart review were employed. Data with complete information were entered in to SPSS version 20 computer software. Descriptive statics and bivariate and multivariable analysis were computed. A P-value less than 0.2 was used to select candidate variables for multivariable logistic regression. A P-value less than 0.05 was used to declare statistical significance.

Result

1065 patients were included in the study which makes the response rate of 90.7%. The magnitude of awareness with recall under general anesthesia was found to be 8.2% of which 4.9%, 2.6%, and 0.7% of patients reported hearing voice, pain, and sensation of breathing tube, respectively. Lack of premedication was the only significantly associated factor for awareness with recall under general anesthesia (AOR = 3.014, 95% CI (1.201 to 7.565)).

Conclusion and Recommendation

Our study showed higher magnitude of awareness with recall under general anesthesia. Lack of premedication was the only associated factor with awareness with recall under general anesthesia. Anesthetists should give emphasis to prevent the possibility of awareness under general anesthesia by providing premedication. Cohort studies should be done including the consequences of awareness with recall under general anesthesia.

A Comparison of Bispectral Index and Entropy During Sevoflurane Anesthesia Induction in Children with and without Diplegic Cerebral Palsy

Background: This study compared the correlation of bispectral index (BIS) or entropy with different sevoflurane concentrations between children with and without cerebral palsy (CP) during induction. Methods: For eighty-two children (40 CP and 42 non-CP children), anesthesia was induced with sevoflurane. BIS and entropy (response entropy and state entropy (RE and SE)) were recorded before and after the induction of anesthesia at end-tidal sevoflurane concentrations of 1–3 vol%. The sedation status was assessed using an Observer’s Assessment of Alertness/Sedation scale. The ability to predict awareness was estimated using the area under the receiver-operator characteristic curve (AUC) analysis. Results: RE, SE and BIS values decreased continuously over the observed concentration range of sevoflurane in both groups. The SE values while awake and the RE, SE, BIS values at 3 vol% sevoflurane were lower in children with CP than in those without CP. The AUC of the BIS was significantly better than RE or SE in children without CP. The AUC of the BIS was not significantly higher than that of the RE or SE in children with CP. Conclusion: BIS seems better correlated than entropy with the clinical state of loss of response in children without CP, but not in those with CP.

Unusual elevation in Entropy but not in PSI during general anesthesia: a case report

Background

EEG monitoring is useful for determining an adequate level of anesthesia. However it is sometimes interfered by various reasons. We describe a case in which we successfully confirmed the adequate depth of anesthesia by monitoring the patient state index (PSI), which was computed from the SedLine monitor data in Root (Masimo) during general anesthesia. Our case showed unusual elevations in entropy, but not in PSI.

Case presentation

A 34-year-old woman was scheduled for emergency surgery for a left tibial open fracture and a right femoral closed fracture, which were sustained during a traffic accident. Forty-five minutes after intubation, the response entropy abruptly increased up to 100 and state entropy to 91. Despite the absence of other abnormal events, the entropy data led to two types of incorrect decisions. The first was owing to the effect of the EMG and the second was misleading during the surgeon’s hammering. However, PSI from the SedLine monitor seemed to be less influenced by the same events.

Conclusions

In this report, we suggest that the PSI, derived from new-generation SedLine (Root, Masimo) may be a useful parameter for clinically determining the level of sedation. The use of two monitoring devices with different EEG algorithms might be helpful for determining the anesthetic depth and making decisions.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0486-8) contains supplementary material, which is available to authorized users.

Effects of different methods of general anesthesia on intraoperative awareness in surgical patients

The purpose of the study was to investigate the effects of total intravenous anesthesia (TIVA) and combined of intravenous and inhaled anesthesia (CIIA) on intraoperative awareness in surgical patients.A total of 678 patients were recruited in the CIIA group, while TIVA group included 566 patients. The clinical characteristics and the occurrence of intraoperative awareness were compared between the groups. Mini-Mental State Examination, Generalized Anxiety Disorder 7, and Patient Health Questionnaire 9 tests were performed to estimate cognitive and psychological functions of the patients. In addition, logistic regression analysis was applied to identify the risk factors for intraoperative awareness in surgical patients.In CIIA group, 3 patients (0.44%) were confirmed with intraoperative awareness, while 11 patients (1.94%) in TIVA group underwent intraoperative awareness. The occurrence rate of intraoperative awareness was significantly higher in VITA group than that in the CIIA group (P = .029). Awareness classification demonstrated that intraoperative awareness mainly included auditory, tactile, and pain perceptions. Moreover, 4 patients showed distress after operation. Patients with intraoperative awareness exhibited poor performance in cognitive and psychological tests (P < .001 for all). Logistic regression analysis demonstrated that CIIA (odds ratio [OR] = 0.198, 95% confidence interval [CI] = 0.047-0.827), age (OR = 0.951, 95% CI = 0.908-0.997), midazolam application (OR = 0.158, 95% CI = 0.034-0.736), awareness history (OR = 10.131, 95% CI = 2.206-45.517), and duration of surgery (OR = 1.016, 95% CI = 1.001-1.032) were significantly associated with intraoperative awareness.Intraoperative awareness can significantly influence the cognitive and psychological functions of surgical patients. CIIA and midazolam application may lower the risk of intraoperative awareness.

Anesthetic dreaming, anesthesia awareness and patient satisfaction after deep sedation with propofol target controlled infusion: A prospective cohort study of patients undergoing day case breast surgery

Background

Anesthetic dreaming and anesthesia awareness are well distinct phenomena. Although the incidence of intraoperative awareness is more common among patients who reported a dream after surgery, the exact correlation between the two phenomena remains an unsolved rebus. The main purpose of this study was to investigate anesthetic dreaming, anesthesia awareness and psychological consequences eventually occurred under deep sedation. Intraoperative dreaming experiences were correlated with dream features in natural sleep.

Methods

Fifty-one patients, undergoing surgical excision of fibroadenomas under a Bispectral index-guided deep sedation anesthesia with propofol target controlled infusion, were enrolled into this prospective study. Psychological assessment was performed through the State Trait Anxiety Inventory. A questionnaire was adopted to register dreaming and anesthesia awareness. Data were collected after emergence (t0), 24 hours (t1), 1 month (t2), 6 months (t3).

Results

Six patients (12%) reported anesthetic dreaming at t0 confirming the response at each subsequent evaluation. One patient (2%) confirmed dreaming during anesthesia in all, but denied it at t0. There was a high correlation between the intraoperative dream contents and the features of dreams in natural sleep. No cases of anesthesia awareness were detected. A similar level of satisfaction was observed in dreaming and no-dreaming patients.

Conclusions

Anesthetic dreaming does not seem to influence satisfaction of patients undergoing deep sedation with propofol target controlled infusion. A psychological assessment would seem to improve the evaluation of possible psychological consequences in dreamer patient.

Mechanisms underlying brain monitoring during anesthesia: limitations, possible improvements, and perspectives

Currently, anesthesiologists use clinical parameters to directly measure the depth of anesthesia (DoA). This clinical standard of monitoring is often combined with brain monitoring for better assessment of the hypnotic component of anesthesia. Brain monitoring devices provide indices allowing for an immediate assessment of the impact of anesthetics on consciousness. However, questions remain regarding the mechanisms underpinning these indices of hypnosis. By briefly describing current knowledge of the brain's electrical activity during general anesthesia, as well as the operating principles of DoA monitors, the aim of this work is to simplify our understanding of the mathematical processes that allow for translation of complex patterns of brain electrical activity into dimensionless indices. This is a challenging task because mathematical concepts appear remote from clinical practice. Moreover, most DoA algorithms are proprietary algorithms and the difficulty of exploring the inner workings of mathematical models represents an obstacle to accurate simplification. The limitations of current DoA monitors — and the possibility for improvement — as well as perspectives on brain monitoring derived from recent research on corticocortical connectivity and communication are also discussed.

A 7-Year Retrospective Multisource Analysis on the Incidence of Anesthesia Awareness With Recall in Cancer Patients: A Chance of Collaboration Between Anesthesiologists and Psycho-Oncologists for Awareness Detection

Although randomized controlled studies reported an incidence of anesthesia awareness with recall ∼1 to 2 per 1000 (0.1-0.2%), recent data from the NAP5 study showed an incidence of only 1:19,600. Although in a prospective study many tools for anesthesia awareness detection can be used, a retrospective analysis requires a careful collection of information.The aim of the study was to evaluate the incidence of anesthesia awareness with recall in a cohort of cancer patients through a multisource retrospective analysis, and the clinical description, including the psychological outcome, of the cases detected. We also tested whether our retrospective analysis would be improved by a routinely psycho-oncological assessment. As secondary endpoints we evaluated the use of depth of anesthesia monitoring over a large cohort of patients, and the correlation between the brain monitoring and the incidence of awareness.We have carried out a 7-year retrospective analysis in a large cohort of cancer patients on the incidence of awareness with recall during general anesthesia. Of 35,595 patients assessed for eligibility, 21,099 were studied. We analyzed all data from the operative rooms' database, the anesthesia records, and from the database of the surgical divisions. In addition we examined reports from psychologists and spontaneous reports to the quality team of the hospital.Two certain cases of awareness were detected, with an incidence of 1:10,550 (0.0095%). They occurred during elective surgery, in female patients without other risk factors. One case came from the report of a psychologist. In both episodes, brain monitoring was not applied and no long-term psychological sequelae were reported.Despite the limitations, our investigation suggests that the incidence of anesthesia awareness is very low, also in a specific cohort of patients, such as the cancer patients, and even when the depth of anesthesia monitoring is rarely used. The limitations caused by both the retrospective analysis and the absence of specific tools for direct awareness detection, such as structured interviews, can be filled with an effective postoperative psychological assessment which is often of routine in a cancer center. This observation could suggest the usefulness of inserting specific questions within the psychological tools commonly used by psycho-oncologists.