Awareness during anesthesia: the results of a questionnaire survey in Japan. J Anesth. 2011;25:72-77. [PMID: 21153846 DOI: 10.1007/s00540-010-1050-y]

Pausing propofol during neurosurgery to record intraoperative electrocorticography is feasible;10 years of clinical experience

OBJECTIVE

Intraoperative electrocorticography (ioECoG) during neurosurgery is influenced by anesthetics. In our center we stop the propofol to enable interpretation of ioECoG. We reported our clinical experience and evaluated awareness and hemodynamic changes during the propofol-free periods (PFP).

METHODS

We retrospectively included surgeries with paused propofol administration to record ioECoG (period: 2008-2019). Clinical reports were screened for symptoms of awareness. We compared mean arterial blood pressure (MAP; mmHg) and heart rate (HR;bpm) during PFP to baseline (ten minutes preceding PFP). An increase > 15% was defined as clinically relevant. The association between hemodynamic changes and clinical characteristics was analyzed using logistic regression models.

RESULTS

Propofol administration was paused 742 times in 352 surgeries (mean PFP duration 9 ± 5 min). No signs of awareness were reported. MAP and HR increased > 15% in 54 and six PFPs. Five PFPs showed both MAP and HR increases. Prolonged PFP was associated with having MAP and HR increase during surgery (OR=1.18, 95%CI [1.12-1.26]).

CONCLUSIONS

Signs of inadequate sedation depth were rare. MAP and HR increases were related to the length of PFP.

SIGNIFICANCE

We summarize 10 years of clinical experience with pausing propofol administration during epilepsy surgery to record ioECoG without evidence of awareness.

Total Intravenous Anesthesia Compared to Inhalational Anesthesia in Patients Undergoing Arthroscopic Rotator Cuff Repair

Background Inhalation anesthesia (IA) and total intravenous anesthesia (TIVA) are common general anesthesia techniques. During rotator cuff repair (RCR), an interscalene block is beneficial for intraoperative and early postoperative pain control. This study aimed to evaluate postoperative outcomes and opioid usage in patients undergoing arthroscopic RCR with an interscalene block and either IA or TIVA. Methodology A retrospective observational study was performed of 478 patients undergoing RCR at a single institution. Demographics, surgical details, intra and postoperative medications, and 90-day outcomes were collected. Univariate and multivariate analyses were performed to evaluate differences between groups. Results In total, 309 (64.6%) patients received IA and 169 (35.3%) received TIVA. Patients receiving IA were more likely to have comorbidities, such as diabetes (p = 0.002), sleep apnea (p = 0.006), gastroesophageal reflux disease (p < 0.001), and hypertension (p < 0.001). After adjusting for differences between groups in the multivariate analysis, patients who received TIVA had significantly shorter surgical time (β = -14.85, p < 0.001) and perioperative time (β = -21.01, p < 0.001) and significantly lower first post-anesthesia care unit Pasero opioid-induced sedation scores (β = -0.022, p = 0.040). Patients who received TIVA were less likely to receive intraoperative narcotics (odds ratio = 0.38; p = 0.031). Conclusions TIVA appears to be a safe and effective anesthetic for patients undergoing arthroscopic RCR. TIVA is a potentially beneficial alternative to IA for this patient population.

The ED-AWARENESS Study: A Prospective, Observational Cohort Study of Awareness With Paralysis in Mechanically Ventilated Patients Admitted From the Emergency Department

STUDY OBJECTIVE

Awareness with paralysis is a devastating complication for patients receiving mechanical ventilation and risks long-term psychological morbidity. Data from the emergency department (ED) demonstrate a high rate of longer-acting neuromuscular blocking agent use, delayed analgosedation, and a lack of sedation depth monitoring. These practices are discordant with recommendations for preventing awareness with paralysis. Despite this, awareness with paralysis has not been rigorously studied in the ED population. Our objective is to assess the prevalence of awareness with paralysis in ED patients receiving mechanical ventilation.

METHODS

This was a single-center, prospective, observational cohort study on 383 mechanically ventilated ED patients. After extubation, we assessed patients for awareness with paralysis by using the modified Brice questionnaire. Three expert reviewers independently adjudicated awareness with paralysis. We report the prevalence of awareness with paralysis (primary outcome); the secondary outcome was perceived threat, a mediator for development of posttraumatic stress disorder.

RESULTS

The prevalence of awareness with paralysis was 2.6% (10/383). Exposure to rocuronium at any point in the ED was significantly different between patients who experienced awareness with paralysis (70%) versus the rest of the cohort (31.4%) (unadjusted odds ratio 5.1; 95% confidence interval 1.30 to 20.1). Patients experiencing awareness with paralysis had higher mean values on the threat perception scale, denoting a higher degree of perceived threat, compared with patients who did not experience awareness with paralysis (13.4 [SD 7.7] versus 8.5 [SD 6.2]; mean difference 4.9; 95% confidence interval 0.94 to 8.8).

CONCLUSION

Awareness with paralysis occurs in a significant minority of ED patients who receive mechanical ventilation. Potential associations of awareness with paralysis with ED care and increased perceived threat warrant further evaluation.

Clinical practice in the management of postoperative delirium by Chinese anesthesiologists: a cross-sectional survey designed by the European Society of Anaesthesiology

OBJECTIVE

In this survey, we assessed the current clinical management of postoperative delirium (POD) among Chinese anesthesiologists, after publishing the European POD guideline.

METHODS

We administered an electronic survey, designed according to the European POD guideline. The survey was completed using mobile devices.

RESULTS

In total, 1,514 respondents from China participated in the survey. Overall, 74.4% of participants reported that delirium is very important. More than 95% of participants stated that they routinely assessed POD. In total, 61.4% screened for POD using clinical observation and 37.6% used a delirium screening tool. Although the depth of anesthesia (a POD risk factor) was monitored, electroencephalogram monitoring was unavailable to 30.6% of respondents. Regarding treatment, only 24.1% of respondents used a standard algorithm; 58.5% used individualized treatment.

CONCLUSION

Our survey showed that there are high awareness levels among Chinese anesthesiologists regarding the importance of POD. However, routine assessment and monitoring of all patients, including perioperative anesthesia depth monitoring, and a treatment algorithm need to be implemented on a larger scale. According to the results, efforts should be made to improve the knowledge of POD among Chinese anesthesiologists.

The Study of Intraoperative Consciousness after Tracheal Intubation

Introduction

Awareness following noxious stimuli like intubation could be as high as 25% compared to postoperative recall. The isolated forearm technique (IFT) allows us to assess consciousness by verbal command to move isolated hand. Hence we conducted study to establish IFT responses following intubation under standard general anaesthesia.

Methods

We enrolled 132 adult patients undergoing general anaesthesia. A tourniquet was applied on other arm. Following intravenous induction of anaesthesia, torniquet was inflated 100mmhg above systolic BP. After giving muscle relaxant, three minutes patients were ventilated with oxygen and inhalational agent. Before laryngoscopy first verbal command (Squeeze my hand) was given to the patient. Once intubation and tube confirmation done, second verbal command was given. Lack of paralysis in isolated hand was confirmed with TOF stimuli and tourniquet was deflated. Surgery was carried in routine manner. Postoperatively all patients were evaluated for any explicit recall using Modified Brice questionnaire. The primary outcome is number of patients who responded to verbal command postintubation. Secondary outcome is number of patients responded prelaryngoscopy and number of patients reporting explicit recall in the Modified Brice interview.

Results

None of the patients had positive IFT response. On postoperative interview none reported awareness. 10.7% of patients had dreams which were pleasant. Worst thing about surgery was pain.(43%).

Conclusion

Our study suggests that intraoperative consciousness after intubation and postoperative recall is an uncommon occurrence.

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.

Incidence of Awareness with Recall under General Anesthesia in Rural India: An Observational Study

Context:

Awareness under anesthesia is a rare but extremely unpleasant phenomenon. There are very few studies in the developing world and none from rural areas where incidence of intraoperative awareness may be higher due to increased patient load, limited patient knowledge and lack of trained hospital staff, reliance on older, cheaper but less effective drugs, and lack of proper equipment both for providing anesthesia, as well as monitoring the patient.

Aims:

To assess the incidence of intraoperative awareness during general anesthesia among patients in rural India and any factors associated with the same.

Settings and Design:

Prospective, nonrandomized, observational study.

Subjects and Methods:

Patients undergoing elective surgical procedures in various specialties under general anesthesia from over a period of 1 year were considered for this study. Approximately, after 1 h of arrival in postanaesthesia care unit, anesthesiologist (not involved in administering anesthesia) assessed intraoperative awareness using a modified form of Brice questionnaire.

Statistical Analysis Used:

Data were collected on a Microsoft Excel^® sheet and analyzed using Statistical Package for the Social Sciences^® version 23 (SPSS Inc., Chicago, IL, USA) for windows.

Results:

A total of 896 patients completed the questionnaire. Postoperatively, in response to the questionnaire, seven patients reported to have remembered something under anesthesia. Out of these, three patients described events that were confirmed by operation theater staff to have occurred whereas they were under anesthesia.

Conclusions:

Incidence of definite awareness under anesthesia with postoperative recall was found to be 0.33% (three patients out of total 896) in our study.

Awareness during anesthesia: Current status in Japan

Intraoperative awareness is the explicit recall of sensory perceptions during general anesthesia. I presume the epidemiology and characteristics of intraoperative awareness from these surveys in Japan. A questionnaire survey was conducted via the Internet. The first survey was conducted in 2008. Our survey showed 17% of anesthesiologists experienced definite or possible awareness. The second survey was conducted to evaluate the first survey in detail in 2008. A total of 172 anesthesiologists answered. The total number of reported anesthetic cases was 85156. Twenty-four cases of definite or possible awareness were reported by 21 anesthesiologists. The most surprising finding was total intravenous anesthesia (TIVA) was used in 21 of the 24 cases. The third survey was conducted in 2011 as a continuous survey. Six cases of definite or possible awareness were reported by six anesthesiologists (7%). Two cases were maintained by TIVA, and 2 cases were sevoflurane. The survey showed 76% anesthesiologists routinely use bispectral index (BIS) for TIVA, but for sevoflurane only 27% anesthesiologists routinely use BIS. The incidence of intraoperative awareness decreased in the third survey. The continuous survey revealed the current status of daily anesthesia and the results might be used to prevent the awareness during general anesthesia.

Enhanced Recovery After Surgery (ERAS) for gastrointestinal surgery, part 2: consensus statement for anaesthesia practice

Background

The present interdisciplinary consensus review proposes clinical considerations and recommendations for anaesthetic practice in patients undergoing gastrointestinal surgery with an Enhanced Recovery after Surgery (ERAS) programme.

Methods

Studies were selected with particular attention being paid to meta‐analyses, randomized controlled trials and large prospective cohort studies. For each item of the perioperative treatment pathway, available English‐language literature was examined and reviewed. The group reached a consensus recommendation after critical appraisal of the literature.

Results

This consensus statement demonstrates that anaesthesiologists control several preoperative, intraoperative and postoperative ERAS elements. Further research is needed to verify the strength of these recommendations.

Conclusions

Based on the evidence available for each element of perioperative care pathways, the Enhanced Recovery After Surgery (ERAS ^®) Society presents a comprehensive consensus review, clinical considerations and recommendations for anaesthesia care in patients undergoing gastrointestinal surgery within an ERAS programme. This unified protocol facilitates involvement of anaesthesiologists in the implementation of the ERAS programmes and allows for comparison between centres and it eventually might facilitate the design of multi‐institutional prospective and adequately powered randomized trials.

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.

Systemic or intra-amygdala infusion of an endocannabinoid CB1 receptor antagonist AM251 blocked propofol-induced anterograde amnesia

Propofol is well-known for its anterograde amnesic actions. However, a recent experiment showed that propofol can also produce retrograde memory enhancement effects via an interaction with the endocannabinoid CB1 system. Therefore, the authors hypothesized that the regulating effect of propofol on the endocannabinoid CB1 system might also decrease the anterograde amnesic effect of propofol under some conditions, which might be a risk factor for intraoperative awareness. Since, the basolateral amygdala (BLA) has been confirmed to mediate propofol-induced anterograde amnesia and the BLA contains a high concentration of CB1 receptors, the authors investigated whether and how the endocannabinoid system, particularly the CB1 receptor within BLA, influences propofol-induced anterograde amnesia. Male Sprague-Dawley rats trained with inhibitory avoidance (IA) were systematically pre-trained using a memory-impairing dose of propofol (25 mg/kg). Before propofol administration, rats received an intraperitoneal injection of a CB1 receptor antagonist AM251 (1 mg/kg or 2 mg/kg) or a bilateral intra-BLA injection of AM251 (0.6 ng or 6 ng per 0.5 μl). Twenty-four hours after IA training, the IA retention latency was tested. It was found that systemic or intra-BLA injection of a non-regulating dose of AM251 (2 mg/kg or 6 ng per 0.5 μl, respectively) blocked the memory-impairing effect of propofol. These results indicate that the anterograde amnesic effect of propofol is mediated, in part, by activation of the CB1 cannabinoid receptors in the BLA.

Sevoflurane versus propofol sedation during periocular anesthetic injections in oculoplastic procedures: An open-label randomized comparison

PURPOSE

The purpose of the current investigation was to make an objective controlled comparison of pain tolerance, patient satisfaction and potential complications during the injection of local anesthesia in oculoplastic procedures under short-term sedation using inhalational versus parenteral sedatives.

METHODS

This was an open-label, randomized clinical trial where patients were randomized to 3 groups. Group I: Sedation with intravenous propofol. Group II: Sedation with inhaled sevoflurane. Group 3: Control group receiving no sedation.

RESULTS

A total of 396 patients were randomly assigned, and 375 were included in the final analysis. Study groups were similar in age, gender, and distribution of operative procedures performed. There was no statistically significant difference in the adjusted primary composite outcome measure between propofol and sevoflurane (pain scores and patient satisfaction). Significantly more patients in group I required restraining during periocular injections than group II or III (p < 0.001). Significantly more patients sneezed in group I than group II (p < 0.001) and none in the control group. Three patients in group II suffered severe excitation-disinhibition during emergence from sedation which was rapidly reversible, and 3 more suffered a severe bout of postoperative nausea and vomiting (PONV).

CONCLUSION

Sevoflurane and propofol during periocular anesthetic injections produce an equally favorable experience. Sevoflurane is introduced painlessly, and offers better patient control with less induction of the sneezing reflex which may provide a higher safety profile, however short-term aggression/disinhibition and PONV may be an issue in some patients.

A waking nightmare: how can we avoid accidental awareness during general anaesthesia?

Anaesthesia awareness is a terrifying prospect for any patient undergoing a surgical procedure and can cause considerable physical and psychological distress. Recommendations to reduce the risk of anaesthesia awareness include: undertaking a thorough preoperative assessment, ensuring that equipment has been checked, reducing drug error, consistent monitoring, and investment in safer technology. By implementing these recommendations it is hoped that patient safety and care can be improved during clinical anaesthesia.

A national survey of anaesthetists (NAP5 Baseline) to estimate an annual incidence of accidental awareness during general anaesthesia in the UK

As part of the 5th National Audit Project of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland concerning accidental awareness during general anaesthesia, we issued a questionnaire to every consultant and staff and associate specialist anaesthetist in the UK. The survey was designed to ascertain the number of new cases of accidental awareness that became known to them, for patients under their direct or supervised care, for a calendar year, and also to estimate how many cases they had experienced during their careers. The survey also asked about use of monitoring designed to measure the depth of anaesthesia. All local co-ordinators responsible for each of 329 hospitals (organised into 265 'centres') in the UK responded, as did 7125 anaesthetists (82%). There were 153 new cases of accidental awareness notified to respondents in 2011, an estimated incidence of 1:15 414, lower than the 1-2:1000 previously reported in prospective clinical trials. Almost half the cases (72, 47%) occurred at or after induction of anaesthesia but before surgery, with 46 (30%) occurring during surgery and 35 (23%) after surgery before full recovery. Awareness during surgery appeared to lead more frequently to pain or distress than at induction and emergence (62% vs 28% and 23%, respectively). Depth of anaesthesia monitors were available in 164 centres (62%), but routinely used by only 132 (1.8%) of anaesthetists. The disparity between the incidence of awareness as notified to anaesthetists and that reported in trials warrants further examination and explanation.

The influence of initial target effect-site concentrations of propofol on the similarity of effect-sites concentrations at loss and return of consciousness in elderly female patients with the Diprifusor system

Background:

Whether effect-site concentrations of propofol (Cep) at loss of consciousness and return of consciousness (LOC and ROC, respectively) in elderly women using Diprifusor are similar is unclear. We investigated whether differences in initial target Cep (Ctarget) alter similarities between Cep values at LOC and ROC.

Materials and Methods:

In this study, female patients (n = 58, age = 72.5 ± 1.1 years) undergoing knee arthroplasty were administered propofol with Diprifusor. Cep at LOC and ROC were estimated for different Ctarget values (3.0–4.5 μg/ml). Pearson's correlation coefficient analysis and simple regression were performed to assess the relationship between Cep at LOC and ROC for each Ctarget. Differences in correlation coefficients of regression lines obtained from each Ctarget group were determined using the t-test.

Results:

The different Ctarget groups did not show significant differences in total propofol levels and in Cep values at LOC or ROC. However, Cep at ROC was significantly higher than Cep at LOC when Ctarget was 4.0 and 4.5 μg/ml, whereas these Cep values were not significantly different in low Ctarget groups.

Strong positive correlations were observed between Cep at LOC and ROC for all Ctarget groups. Regression coefficients for the different Ctarget groups were not significantly different. Compared to low (≤3.5 μg/ml) Ctarget groups, high Ctarget groups showed significantly shorter time until LOC. Induction quality was not significantly different among the groups.

Conclusions:

In elderly women, Cep values at LOC are strong predictors of Cep at ROC when Ctarget is 3.0–4.5 μg/ml. High Ctarget groups (≥4.0 μg/ml) exhibited shorter induction times with normal cardiovascular stability.