Victims of awareness

Awareness with paralysis and symptoms of post-traumatic stress disorder among mechanically ventilated emergency department survivors (ED-AWARENESS-2 Trial): study protocol for a pragmatic, multicenter, stepped wedge cluster randomized trial

BACKGROUND

Awareness with paralysis (AWP) is memory recall during neuromuscular blockade (NMB) and can cause significant psychological harm. Decades of effort and rigorous trials have been conducted to prevent AWP in the operating room, where prevalence is 0.1-0.2%. By contrast, AWP in mechanically ventilated emergency department (ED) patients is common, with estimated prevalence of 3.3-7.4% among survivors given NMB. Longer-acting NMB use is a critical risk for AWP, and we have shown an association between ED rocuronium use and increased AWP prevalence. As NMB are given to more than 90% of ED patients during tracheal intubation, this trial provides a platform to test an intervention aimed at reducing AWP. The overall objective is to test the hypothesis that limiting ED rocuronium exposure will significantly reduce the proportion of patients experiencing AWP.

METHODS

This is a pragmatic, stepped wedge cluster randomized trial conducted in five academic EDs, and will enroll 3090 patients. Per the design, all sites begin in a control phase, under observational conditions. At 6-month intervals, sites sequentially enter a 2-month transition phase, during which we will implement the multifaceted intervention, which will rely on use of nudges and defaults to change clinician decisions regarding ED NMB use. During the intervention phase, succinylcholine will be the default NMB over rocuronium. The primary outcome is AWP, assessed with the modified Brice questionnaire, adjudicated by three independent, blinded experts. The secondary outcome is the proportion of patients developing clinically significant symptoms of post-traumatic stress disorder at 30 and 180 days after hospital discharge. We will also assess for symptoms of depression and anxiety, and health-related quality of life. A generalized linear model, adjusted for time and cluster interactions, will be used to compare AWP in control versus intervention phases, analyzed by intention-to-treat.

DISCUSSION

The ED-AWARENESS-2 Trial will be the first ED-based trial aimed at preventing AWP, a critical threat to patient safety. Results could shape clinical use of NMB in the ED and prevent more than 10,000 annual cases of AWP related to ED care.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT05534243 . Registered 06, September 2022.

Increasing rates of general anesthesia use in lumpectomy procedures: A 15-year trends analysis

BACKGROUND

Anesthesia methods in oncologic breast surgery have evolved with less invasive practices. The aims of this study were primarily to examine trends in anesthesia type used during lumpectomy.

METHODS

We analyzed lumpectomy procedures from 2005 to 2019 using the NSQIP database. Upon defining the nadir in general anesthesia (GA) and peak in monitored anesthesia care (MAC) use as 2007, we compared patient characteristics and complications in the 2007 versus 2019 GA and MAC cohorts. Multivariable logistic regression was used to examine associations with receipt of GA.

RESULTS

Of 253 545 lumpectomy patients, 191 773 (75.6%) received GA and 61 772 (24.4%) received MAC. From 2005 to 2019, GA rates increased from 66.7% to 82.5%, while MAC rates decreased from 33.3% to 17.5%. More GA patients were obese and American Society of Anesthesiologists class 3. Over time, age and body mass index (BMI) increased in both GA and MAC cohorts. Odds of receiving GA increased over time, and predictors included concurrent axillary lymph node dissection (p < 0.0001) or sentinel lymph node biopsy (p < 0.0001).

CONCLUSIONS

We demonstrate increasing use of GA over time for lumpectomy, which may be related to aging lumpectomy patient population with higher BMIs. We also find a strong association between use of GA and concurrent lymph node procedures.

[Accidental Awareness during General Anaesthesia]

Accidental awareness during general anaesthesia (AAGA) is a rare but severe complication. The reported incidence of AAGA may depend on the assessment of intraoperative awareness with explicit recall and there are substantial variations between subspecialties and groups of patients. The majority of prospective studies using structured interviews reported an incidence of AAGA at 0.1-0.2% during general anaesthesia, however, higher values were observed in paediatric (0.2-1.2%) and obstetric patients (0.47%). Risk factors that predispose to AAGA are patient conditions, ASA status, female gender, patient age, history of AAGA, surgical procedure, anaesthetic drug type, muscle relaxation, dosages of hypnotic or analgesic drugs, monitoring and malfunction of anaesthesia systems. Preventive strategies include careful assessment of risk factors, avoidance of underdosages of hypnotics and analgetics during general anaesthesia and monitoring of depth of anaesthesia in risk patients. The health-related consequences can be serious and psychopharmacological and psychotherapeutic interventions are indicated in patients who have experienced AAGA.

Recall of Awareness During Paralysis Among ED Patients Undergoing Tracheal Intubation

BACKGROUND

Critically ill patients sometimes remember periods of neuromuscular blockade.

RESEARCH QUESTION

What is the prevalence of recalled awareness during paralysis in patients who underwent emergency tracheal intubation and mechanical ventilation, and what clinical variables are associated with this outcome?

STUDY DESIGN AND METHODS

This study analyzed data from a prospectively collected continuous quality improvement database of emergency tracheal intubation in an urban, county hospital. Patients who received a neuromuscular blocking agent to facilitate emergency tracheal intubation in the ED were included. The database contained details of intubation management, including medications received and patient mental status prior to intubation. Patient recall of awareness of paralysis was assessed by trained staff during an in-person interview following extubation using a modified Brice questionnaire. For this analysis, three expert reviewers used these data to adjudicate whether patients may have had awareness of paralysis, the primary outcome. A logistic regression model was constructed to determine whether clinical variables were associated with the primary outcome.

RESULTS

A total of 886 patients were analyzed. There were 66 patients (7.4%; 95% CI, 5.8-9.4) determined to possibly (61 patients) or definitely (5 patients) have experienced and recalled awareness of paralysis. A logistic regression model revealed that a decreased level of consciousness prior to intubation was associated with lower odds of awareness (adjusted OR, 0.39; 95% CI, 0.22-0.69), whereas the class of neuromuscular blocking agent used, sedative used, preintubation shock index, and postintubation sedation were not significantly associated with recall of this outcome.

INTERPRETATION

Among patients intubated emergently using a neuromuscular blocking agent, 7.4% of patients recalled awareness without being able to move, which was more likely when patients had a normal level of consciousness prior to intubation.

Risk of serious medical events in patients with depression treated with electroconvulsive therapy: a propensity score-matched, retrospective cohort study

BACKGROUND

Previous studies examining the risk of medical complications from electroconvulsive therapy have been confounded and this might contribute to its underuse. This study aimed to compare the risk of serious medical events, defined as those resulting in hospitalisation or death, among patients with depression who received electroconvulsive therapy versus patients who did not receive electroconvulsive therapy.

METHODS

This was a propensity score-matched, retrospective cohort study using linked population-based administrative health data for adults admitted to designated psychiatric facilities in Ontario, Canada, for more than 3 days with depression between April 1, 2007, to Feb 28, 2017. Electroconvulsive therapy exposure was defined as one or more physician billing procedure codes during hospitalisation. The unit of analysis was individual admissions and propensity score matching was used to match each exposed admission to an unexposed admission to estimate the average treatment effect of electroconvulsive therapy among those treated. The primary outcome was serious medical events, a composite of hospitalisation for medical (ie, non-psychiatric) reasons or non-suicide death within 30 days from electroconvulsive therapy exposure or matched date in the unexposed group. Effect modification was examined using tests of interaction for three clinically relevant prespecified subgroups (sex, presence of psychotic symptoms, and illness polarity). Secondary outcomes were medical hospitalisation and non-suicide death separately, suicide death, and specific serious medical events.

FINDINGS

In propensity score matched analyses, there were 10 016 psychiatric hospitalisation records (6628 women, 3388 men) with mean age 56·6 years (SD 16·3) and no ethnicity data available. 65 818 admissions were eligible for matching and 5008 were matched (1:1) in each exposure group. In the propensity score matched cohort, the incidence of serious medical events was 0·25 per person-year in the exposed group and 0·33 per person-year in the unexposed group (cause-specific hazard ratio 0·78 [95% CI 0·61-1·00]). Suicide death as a competing risk did not alter this finding. The risk of suicide death was significantly lower in the exposed (≤5 of 5008 admissions) versus the unexposed group (11 [0·2%] of 5008 admissions; p<0·03). Bipolar depression, compared with unipolar depression, was associated with a greater reduction in the risk of serious medical events with electroconvulsive therapy. Electroconvulsive therapy was not associated with medical hospitalisation or non-suicide death separately, nor with any specific serious medical event.

INTERPRETATION

Among individuals hospitalised with depression, we found no evidence for a clinically significant increased risk for serious medical events with exposure to electroconvulsive therapy, and the risk of suicide was found to be significantly reduced, suggesting the benefits of electroconvulsive therapy for depression outcomes might outweigh its risks in this population.

FUNDING

Norris Scholars Award, Department of Psychiatry, University of Toronto; the Canadian Institutes for Health Research.

Posttraumatic stress disorder prevalence in medical populations: A systematic review and meta-analysis

OBJECTIVE

PTSD is increasingly recognized following medical traumas although is highly heterogeneous. It is difficult to judge which medical contexts have the most traumatic potential and where to concentrate further research and clinical attention for prevention, early detection and treatment. The objective of this study was to compare PTSD prevalence in different medical populations.

METHODS

A systematic review of the literature on PTSD following medical traumas was conducted as well as a meta-analysis with final pooled result and 95% confidence intervals presented. A meta-regression was used to investigate the impact of potential effect modifiers (PTSD severity, age, sex, timeline) on study effect size between prevalence studies.

RESULTS

From 3278 abstracts, the authors extracted 292 studies reporting prevalence. Using clinician-administered reports, the highest 24 month or longer PTSD prevalence was found for intraoperative awareness (18.5% [95% CI=5.1%-36.6%]) and the lowest was found for epilepsy (4.5% [95% CI=0.2%-12.6%]). In the overall effect of the meta-regression, only medical events or procedures emerged as significant (p = 0.006) CONCLUSION: This review provides clinicians with greater awareness of medical contexts most associated with PTSD, which may assist them in the decision to engage in more frequent, earlier screening and referral to mental health services.

Awareness With Paralysis in Mechanically Ventilated Patients in the Emergency Department and ICU: A Systematic Review and Meta-Analysis

OBJECTIVE

Awareness with paralysis is a devastating complication for mechanically ventilated patients and can carry long-term psychologic sequelae. Hundreds of thousands of patients require mechanical ventilation in the emergency department and ICU annually, yet awareness has only been rigorously examined in the operating room (incidence ~0.1%). This report collates the global literature regarding the incidence of awareness with paralysis outside of the operating room.

DATA SOURCES

We searched OvidMedline, Embase, Scopus, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, conference proceedings, and reference lists.

STUDY SELECTION

Randomized or nonrandomized studies (except single case studies) reporting on awareness with paralysis in the emergency department or ICU were eligible.

DATA EXTRACTION

Two independent reviewers screened abstracts for eligibility.

DATA SYNTHESIS

The search identified 4,454 potentially eligible studies. Seven studies (n = 941 patients) were included for analysis. A random effects meta-analysis of proportions along with multiple subgroup analyses was performed. Significant between-study heterogeneity in reporting of awareness with paralysis was noted, and the quality of the evidence was low. Analyses stratified by: 1) good-quality studies and 2) use of the modified Brice questionnaire to detect awareness revealed estimates of 3.4% (95% CI, 0-10.2%) and 1.9% (95% CI, 1.0-3.0%), respectively.

CONCLUSIONS

The incidence of awareness with paralysis in mechanically ventilated patients in the emergency department and ICU, as evaluated in a small number of qualifying studies from this comprehensive systematic review, appears much higher than that reported from the operating room. Given the clinical and statistical heterogeneity, caution is warranted in the interpretation of these findings. Further high-quality studies are needed to both define the true incidence and to target the prevention of awareness with paralysis in this vulnerable patient cohort.

Systematic Review: Anesthetic Protocols and Management as Confounders in Rodent Blood Oxygen Level Dependent Functional Magnetic Resonance Imaging (BOLD fMRI)-Part B: Effects of Anesthetic Agents, Doses and Timing

Simple Summary

To understand brain function in rats and mice functional magnetic resonance imaging of the brain is used. With this type of “brain scan” regional changes in blood flow and oxygen consumption are measured as an indirect surrogate for activity of brain regions. Animals are often anesthetized for the experiments to prevent stress and blurred images due to movement. However, anesthesia may alter the measurements, as blood flow within the brain is differently affected by different anesthetics, and anesthetics also directly affect brain function. Consequently, results obtained under one anesthetic protocol may not be comparable with those obtained under another, and/or not representative for awake animals and humans. We have systematically searched the existing literature for studies analyzing the effects of different anesthesia methods or studies that compared anesthetized and awake animals. Most studies reported that anesthetic agents, doses and timing had an effect on functional magnetic resonance imaging results. To obtain results which promote our understanding of brain function, it is therefore essential that a standard for anesthetic protocols for functional magnetic resonance is defined and their impact is well characterized.

Abstract

In rodent models the use of functional magnetic resonance imaging (fMRI) under anesthesia is common. The anesthetic protocol might influence fMRI readouts either directly or via changes in physiological parameters. As long as those factors cannot be objectively quantified, the scientific validity of fMRI in rodents is impaired. In the present systematic review, literature analyzing in rats and mice the influence of anesthesia regimes and concurrent physiological functions on blood oxygen level dependent (BOLD) fMRI results was investigated. Studies from four databases that were searched were selected following pre-defined criteria. Two separate articles publish the results; the herewith presented article includes the analyses of 83 studies. Most studies found differences in BOLD fMRI readouts with different anesthesia drugs and dose rates, time points of imaging or when awake status was compared to anesthetized animals. To obtain scientifically valid, reproducible results from rodent fMRI studies, stable levels of anesthesia with agents suitable for the model under investigation as well as known and objectively quantifiable effects on readouts are, thus, mandatory. Further studies should establish dose ranges for standardized anesthetic protocols and determine time windows for imaging during which influence of anesthesia on readout is objectively quantifiable.

Subjective experience, cognitive functioning and trauma level of patients undergoing awake craniotomy due to brain tumor - Preliminary study

BACKUP AND OBJECTIVE

Awake craniotomy (AC) for brain tumors, when the patient is conscious during the operation, allows to reduce the risk of motor disability and aphasia, however, it may be a source of extreme stress. The aim of our study was to examine the patients' subjective experience of the surgery including the level of psychological trauma and cognitive functioning.

METHOD

Eighteen patients operated due to brain tumor were enrolled in this study. The Essener Trauma-Inventory Questionnaire and the Addenbrooke's Cognitive Examination (ACE III) were administrated. The patients' experience with awake craniotomy was evaluated with a qualitative descriptive survey.

RESULTS

All patients remembered the intraoperative neuropsychological examination and several sensations like: drilling, cold, head clamp fixation or having eyes covered. In most of the patients the postoperative psychological trauma experience did not reach the clinical level. The ACE III postoperative scores revealed partial cognitive deficits with the lowest scores in memory and word fluency domains. Slight amnestic aphasia was observed postoperatively only in two patients.

CONCLUSIONS

Awake craniotomy for resection of brain tumors is well-tolerated by patients and does not cause significant psychological trauma. Nonetheless, anxiety about the procedure warrants further study and individualized neuropsychological care is needed for the emotional preparation of the patient.

Awareness and bispectral index (BIS) monitoring in mechanically ventilated patients in the emergency department and intensive care unit: a systematic review protocol

INTRODUCTION

Accidental awareness with recall is one of the most feared complications for patients undergoing general anaesthesia and can lead to post-traumatic stress disorder in up to 70% of patients experiencing it. To reduce the incidence of awareness with recall, the bispectral index monitor is recommended for patients receiving total intravenous anaesthetics, especially those receiving neuromuscular blockers. While extensive investigation into awareness and bispectral index monitoring has occurred for operating room patients, this has not extended to other clinical arenas where sedated and mechanically ventilated patients are cared for, namely the intensive care unit and emergency department. The purpose of this systematic review is to assess the world's literature to determine the incidence of awareness with paralysis in mechanically ventilated patients and the impact of bispectral index monitoring for reducing this complication.

METHODS AND ANALYSIS

Randomised trials and non-randomised studies are eligible for inclusion. With aid from a medical librarian, an electronic search will include Ovid Medline, Embase.com, Scopus, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials. To find data published in abstract form, literature from professional society conferences (2010-2019) will be manually searched. Two authors will independently review search results and consensus will be reached with assistance from a third author, as needed. Heterogeneity and publication bias will be assessed and reported. If possible and appropriate, a meta-analysis of the data will be conducted for quantitative data analysis.

ETHICS AND DISSEMINATION

The proposed systematic review does not require ethical approval, as it is conducted at the study level and does not involve individual patient-level data. Results will be disseminated by data sharing via academically established means, presentation at local and national scientific meetings and publication as a peer-reviewed manuscript.

PROSPERO REGISTRATION NUMBER

The protocol has been submitted to International Prospective Register of Systematic Reviews and is awaiting registration.

Awareness during emergence from anesthesia: Features and future research directions

The anesthesia awareness with recall (AAWR) phenomenon represents a complication of general anesthesia consisting of memorization of intraoperative events reported by the patient immediately after the end of surgery or at a variable distance from it. Approximately 20% of AAWR cases occur during emergence from anesthesia. Clinically, these unexpected experiences are often associated with distress especially due to a sense of paralysis. Indeed, although AAWR at the emergence has multiple causes, in the majority of cases the complication develops when the anesthesia plan is too early lightened at the end of anesthesia and there is a lack of use, or misuse, of neuromuscular monitoring with improper management of the neuromuscular block. Because the distress caused by the sense of paralysis represents an important predictor for the development of severe psychological complications, the knowledge of the phenomenon, and the possible strategies for its prophylaxis are aspects of considerable importance. Nevertheless, a limited percentage of episodes of AAWR cannot be prevented. This paradox holds also during the emergence phase of anesthesia which represents a very complex neurophysiological process with many aspects yet to be clarified.

Awareness during general anesthesia despite simultaneous bispectral index and end-tidal anesthetic gas concentration monitoring

Awareness during general anesthesia occurs in approximately 0.1–0.2% of cases; nevertheless, particular attention is required because it can lead to critical complications including insomnia, depression, anxiety, and post-traumatic stress disorder. To prevent these complications, bispectral index (BIS) and end-tidal anesthetic gas (ETAG) concentration monitoring are commonly used to examine patient consciousness during surgery. In the present case, an 80-year-old man was scheduled for total gastrectomy. Anesthesia was maintained using desflurane 4.0–5.0% vol, oxygen, and nitrous oxide. The authors simultaneously monitored BIS, which was maintained between 37 and 43, and ETAG, which was maintained between 0.9 and 1.2 minimum alveolar concentration (MAC). After the operation, however, the authors were surprised to learn that the patient complained of awareness during anesthesia. Although BIS and ETAG concentration monitoring are useful in preventing awareness during anesthesia, they cannot be completely trusted. Even though BIS was maintained at approximately 40 and ETAG at 0.7–1.3 MAC, awareness during anesthesia occurred.

The triple variable index combines information generated over time from common monitoring variables to identify patients expressing distinct patterns of intraoperative physiology

Background

Mean arterial pressure (MAP), bispectral index (BIS), and minimum alveolar concentration (MAC) represent valuable, yet dynamic intraoperative monitoring variables. They provide information related to poor outcomes when considered together, however their collective behavior across time has not been characterized.

Methods

We have developed the Triple Variable Index (TVI), a composite variable representing the sum of z-scores from MAP, BIS, and MAC values that occur together during surgery. We generated a TVI expression profile, defined as the sequential TVI values expressed across time, for each surgery where concurrent MAP, BIS, and MAC monitoring occurred in an adult patient (≥18 years) at the University of Pittsburgh Medical Center between January and July 2014 (n = 5296). Patterns of TVI expression were identified using k-means clustering and compared across numerous patient, procedure, and outcome characteristics. TVI and the triple low state were compared as prediction models for 30-day postoperative mortality.

Results

The median frequency MAP, BIS, and MAC were recorded was one measurement every 3, 5, and 5 min. Three expression patterns were identified: elevated, mixed, and depressed. The elevated pattern displayed the highest average MAP, BIS, and MAC values (86.5 mmHg, 45.3, and 0.98, respectively), while the depressed pattern displayed the lowest values (76.6 mmHg, 38.0, 0.66). Patterns (elevated, mixed, depressed) were distinct across the following characteristics: average patient age (52, 53, 54 years), American Society of Anesthesiologists Physical Status 4 (6.7, 16.1, 27.3%) and 5 (0.1, 0.6, 1.6%) categories, cardiac (2.2, 6.5, 16.1%) and emergent (5.8, 10.5, 12.8%) surgery, cardiopulmonary bypass use (0.3, 2.6, 9.8%), intraoperative medication administration including etomidate (3.0, 7.3, 12.6%), hydromorphone (47.6, 26.3, 25.2%), ketamine (11.2, 4.6, 3.0%), dexmedetomidine (18.4, 16.6, 13.6%), phenylephrine (74.0, 74.8, 83.0), epinephrine (2.0, 6.0, 18.0%), norepinephrine (2.4, 7.5, 21.2%), vasopressin (3.4, 7.6, 21.0%), succinylcholine (74.0, 69.0, 61.9%), intraoperative hypotension (28.8, 33.0, 52.3%) and the triple low state (9.4, 30.3, 80.0%) exposure, and 30-day postoperative mortality (0.8, 2.7, 5.6%). TVI was a better predictor of patients that died or survived in the 30 days following surgery compared to cumulative triple low state exposure (AUC 0.68 versus 0.62, p < 0.05).

Conclusions

Surgeries that share similar patterns of TVI expression display distinct patient, procedure, and outcome characteristics.

Electronic supplementary material

The online version of this article (10.1186/s12874-019-0660-9) contains supplementary material, which is available to authorized users.

Accidental awareness during general anaesthesia - a narrative review

Unintended accidental awareness during general anaesthesia represents failure of successful anaesthesia, and so has been the subject of numerous studies during the past decades. As return to consciousness is both difficult to describe and identify, the reported incidence rates vary widely. Similarly, a wide range of techniques have been employed to identify cases of accidental awareness. Studies which have used the isolated forearm technique to identify responsiveness to command during intended anaesthesia have shown remarkably high incidences of awareness. For example, the ConsCIOUS-1 study showed an incidence of responsiveness around the time of laryngoscopy of 1:25. On the other hand, the 5th Royal College of Anaesthetists National Audit Project, which reported the largest ever cohort of patients who had experienced accidental awareness, used a system to identify patients who spontaneously self-reported accidental awareness. In this latter study, the incidence of accidental awareness was 1:19,600. In the recently published SNAP-1 observational study, in which structured postoperative interviews were performed, the incidence was 1:800. In almost all reported cases of intra-operative responsiveness, there was no subsequent explicit recall of intra-operative events. To date, there is no evidence that this occurrence has any psychological consequences. Among patients who experience accidental awareness and can later remember details of their experience, the consequences are better known. In particular, when awareness occurs in a patient who has been given neuromuscular blocking agents, it may result in serious sequelae such as symptoms of post-traumatic stress disorder and a permanent aversion to surgery and anaesthesia, and is feared by patients and anaesthetists. In this article, the published literature on the incidence, consequences and management of accidental awareness under general anaesthesia with subsequent recall will be reviewed.

Non-instrumental clinical monitoring does not guarantee an adequate course of general anesthesia. A prospective clinical study

BACKGROUND

Clinical monitoring is the most common method of adjusting the appropriate level of general anesthesia. However, episodes of intraoperative awareness (AWR) are still reported, suggesting that clinical observations may not be sufficient in some cases. The objective of this study was to compare the efficacy of clinical and instrumental neuromonitoring with auditory evoked potentials (AEP) in an intraoperative analysis of the proper level of general anesthesia.

METHODS

Patients scheduled for elective surgery were randomly divided into two groups. Subjects in the first group underwent intravenous, in the second group volatile anesthesia. The adequacy of anesthesia was analyzed using clinical parameters. All the participants were instrumentally monitored with the autoregressive AEP index (AAI). After the anesthesia, patients filled out a questionnaire on possible AWR.

RESULTS

Data of 208 patients (87 in the first, and 121 in the second group) were analyzed. Before surgery there were no changes in AAI values between groups (80 vs. 78, P=0.5192). The mean values of clinical parameters changed, but five minutes after the nociceptive stimuli. The mean values of AAI at analyzed time points were specific for general anesthesia. In patients under intravenous anesthesia, we found more episodes of too low (46/608 vs.15/847, P<0.000) anesthesia. One case of AWR was found in the TIVA group.

CONCLUSIONS

AAI index is good indicator of patients' level of consciousness during general anesthesia. Standard clinical monitoring provides appropriate level of the procedure. However, it is insufficient during TIVA and does not prevent episodes of AWR.

Effects of remifentanil and dexmedetomidine on the mother's awareness and neonatal Apgar scores in caesarean section under general anaesthesia

Objective

This study aimed to compare the effects of remifentanil and dexmedetomidine on awareness during the induction of general anaesthesia.

Material and Methods

Ninety patients scheduled for elective caesarean section under general anaesthesia were included and randomly divided into three anaesthesia groups: 2 mg/kg propofol (control group); 2 mg/kg propofol and 1 µg/kg dexmedetomidine (dexmedetomidine group); and 2 mg/kg propofol and 1 µg/kg remifentanil (remifentanil group). All patients received routine monitoring, and Apgar scores at 1 and 5 minutes were recorded. The bispectral index and the isolated forearm technique were used to determine the depth of anaesthesia.

Results

Bispectral index values at skin and uterine incisions and at delivery were similar among the groups. The number of patients who responded positively to the isolated arm technique during the induction period was also similar. One-minute Apgar scores in the control group were significantly lower and 5-minute Apgar scores significantly higher than those in the other groups.

Conclusion

The effects of remifentanil and dexmedetomidine added to propofol on maternal awareness, neonatal Apgar scores, and bispectral index values were similar compared with propofol alone. However, it was observed that remifentanil controlled the haemodynamic responses to sympathetic stimuli in a better manner than dexmedetomidine.

Nitrous oxide-based vs. nitrous oxide-free general anaesthesia and accidental awareness in surgical patients: an abridged Cochrane systematic review

Accidental awareness during general anaesthesia can arise from a failure to deliver sufficient anaesthetic agent, or from a patient's resistance to an expected sufficient dose of such an agent. Awareness is 'explicit' if the patient is subsequently able to recall the event. We conducted a systematic review into the effect of nitrous oxide used as part of a general anaesthetic on the risk of accidental awareness in people over the age of five years undergoing general anaesthesia for surgery. We included 15 randomised controlled trials, 14 of which, representing a total of 3439 participants, were included in our primary analysis of the frequency of accidental awareness events. The awareness incidence rate was rare within these studies, and all were considered underpowered with respect to this outcome. The risk of bias across all studies was judged to be high, and 76% of studies failed adequately to conceal participant allocation. We considered the available evidence to be of very poor quality. There were a total of three accidental awareness events reported in two studies, one of which reported that the awareness was the result of a kink in a propofol intravenous line. There were insufficient data to conduct a meta- or sub-group analysis and there was insufficient evidence to draw outcome-related conclusions. We can, however, recommend that future studies focus on potentially high-risk groups such as obstetric or cardiac surgery patients, or those receiving neuromuscular blocking drugs or total intravenous anaesthesia.

Intraoperative Awareness and Recall: A Comparative Study of Dexmedetomidine and Propofol in Cardiac Surgery

Background Awareness during general anesthesia is undesired and unanticipated patient wakefulness during surgery or recall of intraoperative events. Incidence of awareness in patients undergoing cardiac surgery is significantly higher than the overall incidence of 1% during general surgery. Awareness during cardiac surgery can be prevented by a number of methods. One such method is the supplemental, intraoperative use of sedative agents. Propofol, a bisubstituted phenol, is an intravenous general anesthetic that has been shown to reduce the incidence of awareness. Dexmedetomidine-an alpha₂-adrenergic agonist with anxiolytic, opioid, and general anesthetic-sparing properties-is being considered for maintaining intraoperative depth of anesthesia. The purpose of this study was to evaluate the effect of dexmedetomidine on depth of anesthesia and to compare it with the effect of propofol in cardiac surgery. Methods This was a prospective, randomized, double-blind study conducted in a tertiary-care hospital. Sixty patients with American Society of Anesthesiologists (ASA) physical status I-III planned for elective open heart surgery were randomized into two groups of 30 patients each. Each patient of the dexmedetomidine group received an initial loading dose of dexmedetomidine at 1 mcg kg^-1 over 10 minutes followed by infusion at the rate of 0.2-0.6 mcg kg^-1 hr^-1. Patients of the propofol group received propofol infusion at the rate of 0.25^-1 mg kg^-1 hr^-1. An identical technique-of standard general anesthesia and routine physiological monitoring-was used in both groups. Bispectral scores were recorded at predetermined intervals during surgery and the target bispectral index (BIS) was kept at 50±10. The patients were assessed for awareness and recall 24 hours after tracheal extubation using the Brice Questionnaire. Results Intraoperative BIS scores remained within the target range in both groups; however, the BIS scores showed variable trends between the groups and were significantly lower in the dexmedetomidine group (p < 0.001). None of the patients in either group had recall of intraoperative events. Conclusion Administration of dexmedetomidine was as effective in reducing awareness and recall in cardiac surgery compared to propofol. Thus, dexmedetomidine can be used as an alternative sedative agent to prevent awareness and recall in cardiac surgery.

Monitoring the end-tidal concentration of sevoflurane for preventing awareness during anesthesia (MEETS-PANDA): A prospective clinical trial

OBJECTIVE

It was hypothesized that monitoring end-tidal sevoflurane (ETS) during endoscopic surgery could reduce the incidence of intraoperative awareness in patients undergoing general anesthesia. Herein, the incidence of intraoperative awareness and other correlative factors was recorded and compared.

METHODS

Two thousand five hundred ASA I-III patients aged 18-80 years who underwent general anesthesia were randomly divided into 2 groups (n = 1250): routine care group (R) and ETS concentration group (E). ETS concentration was monitored in group E and maintained at a sevoflurane minimum alveolar concentration (MAC) of 0.7-1.3; group R was monitored using routine care, and the sevoflurane was maintained. Patients were assessed for intraoperative awareness with a questionnaire on their explicit memory 24-48 h after surgery.

RESULTS

A total of 2532 patients were selected, and 86 patients were excluded. As for the groups, 1219 patients were assigned to group E, and 1227 patients were assigned to group R. As for intraoperative awareness, group E had 2 patients, and group R had 14. Compared with group R, the incidence of intraoperative awareness in group E was significantly lower (p = 0.003); the time-averaged ETS concentration and sevoflurane dosage were lower in group E (p < 0.05); and no significant changes were found in tracheal extubation time, intravenous general anesthetic dosage, or postoperative complication incidence in either group (p > 0.05). The incidence of intraoperative awareness was higher in women than men in group R (p < 0.05).

CONCLUSION

Using ETS-guided anesthesia and maintaining the sevoflurane concentration (0.7-1.3 MAC) can decrease the incidence of patient awareness during endoscopic surgery.

Novel Methods for Measuring Depth of Anesthesia by Quantifying Dominant Information Flow in Multichannel EEGs

In this paper, we propose novel methods for measuring depth of anesthesia (DOA) by quantifying dominant information flow in multichannel EEGs. Conventional methods mainly use few EEG channels independently and most of multichannel EEG based studies are limited to specific regions of the brain. Therefore the function of the cerebral cortex over wide brain regions is hardly reflected in DOA measurement. Here, DOA is measured by the quantification of dominant information flow obtained from principle bipartition. Three bipartitioning methods are used to detect the dominant information flow in entire EEG channels and the dominant information flow is quantified by calculating information entropy. High correlation between the proposed measures and the plasma concentration of propofol is confirmed from the experimental results of clinical data in 39 subjects. To illustrate the performance of the proposed methods more easily we present the results for multichannel EEG on a two-dimensional (2D) brain map.

Spectral Gini Index for Quantifying the Depth of Consciousness

We propose indices that describe the depth of consciousness (DOC) based on electroencephalograms (EEGs) acquired during anesthesia. The spectral Gini index (SpG) is a novel index utilizing the inequality in the powers of the EEG spectral components; a similar index is the binarized spectral Gini index (BSpG), which has low computational complexity. A set of EEG data from 15 subjects was obtained during the induction and recovery periods of general anesthesia with propofol. The efficacy of the indices as indicators of the DOC was demonstrated by examining Spearman's correlation coefficients between the indices and the effect-site concentration of propofol. A higher correlation was observed for SpG and BSpG (0.633 and 0.770, resp., p < 0.001) compared to the conventional indices. These results show that the proposed indices can achieve a reliable quantification of the DOC with simplified calculations.

Anaesthetic interventions for prevention of awareness during surgery

BACKGROUND

General anaesthesia is usually associated with unconsciousness. 'Awareness' is when patients have postoperative recall of events or experiences during surgery. 'Wakefulness' is when patients become conscious during surgery, but have no postoperative recollection of the period of consciousness.

OBJECTIVES

To evaluate the efficacy of two types of anaesthetic interventions in reducing clinically significant awareness:- anaesthetic drug regimens; and- intraoperative anaesthetic depth monitors.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, ISSUE 4 2016); PubMed from 1950 to April 2016; MEDLINE from 1950 to April 2016; and Embase from 1980 to April 2016. We contacted experts to identify additional studies. We performed a handsearch of the citations in the review. We did not search trial registries.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of either anaesthetic regimens or anaesthetic depth monitors. We excluded volunteer studies, studies of patients prior to skin incision, intensive care unit studies, and studies that only randomized different word presentations for memory tests (not anaesthetic interventions).Anaesthetic drug regimens included studies of induction or maintenance, or both. Anaesthetic depth monitors included the Bispectral Index monitor, M-Entropy, Narcotrend monitor, cerebral function monitor, cerebral state monitor, patient state index, and lower oesophageal contractility monitor. The use of anaesthetic depth monitors allows the titration of anaesthetic drugs to maintain unconsciousness.

DATA COLLECTION AND ANALYSIS

At least two authors independently scanned abstracts, extracted data from the studies, and evaluated studies for risk of bias. We made attempts to contact all authors for additional clarification. We performed meta-analysis statistics in packages of the R language.

MAIN RESULTS

We included 160 studies with 54,109 enrolled participants; 53,713 participants started the studies and 50,034 completed the studies or data analysis (or both). We could not use 115 RCTs in meta-analytic comparisons because they had zero awareness events. We did not merge 27 of the remaining 45 studies because they had excessive clinical and methodological heterogeneity. We pooled the remaining 18 eligible RCTs in meta-analysis. There are 10 studies awaiting classification which we will process when we update the review.The meta-analyses included 18 trials with 36,034 participants. In the analysis of anaesthetic depth monitoring (either Bispectral Index or M-entropy) versus standard clinical and electronic monitoring, there were nine trials with 34,744 participants. The overall event rate was 0.5%. The effect favoured neither anaesthetic depth monitoring nor standard clinical and electronic monitoring, with little precision in the odds ratio (OR) estimate (OR 0.98, 95% confidence interval (CI) 0.59 to 1.62).In a five-study subset of Bispectral Index monitoring versus standard clinical and electronic monitoring, with 34,181 participants, 503 participants gave awareness reports to a blinded, expert panel who adjudicated or judged the outcome for each patient after reviewing the questionnaires: no awareness, possible awareness, or definite awareness. Experts judged 351 patient awareness reports to have no awareness, 87 to have possible awareness, and 65 to have definite awareness. The effect size favoured neither Bispectral Index monitoring nor standard clinical and electronic monitoring, with little precision in the OR estimate for the combination of definite and possible awareness (OR 0.96, 95% CI 0.35 to 2.65). The effect size favoured Bispectral Index monitoring for definite awareness, but with little precision in the OR estimate (OR 0.60, 95% CI 0.13 to 2.75).We performed three smaller meta-analyses of anaesthetic drugs. There were nine studies with 1290 participants. Wakefulness was reduced by ketamine and etomidate compared to thiopental. Wakefulness was more frequent than awareness. Benzodiazepines reduces awareness compared to thiopental, ketamine, and placebo., Also, higher doses of inhaled anaesthetics versus lower doses reduced the risk of awareness.We graded the quality of the evidence as low or very low in the 'Summary of findings' tables for the five comparisons.Most of the secondary outcomes in this review were not reported in the included RCTs.

AUTHORS' CONCLUSIONS

Anaesthetic depth monitors may have similar effects to standard clinical and electrical monitoring on the risk of awareness during surgery. In older studies comparing anaesthetics in a smaller portion of the patient sample, wakefulness occurred more frequently than awareness. Use of etomidate and ketamine lowered the risk of wakefulness compared to thiopental. Benzodiazepines compared to thiopental and ketamine, or higher doses of inhaled anaesthetics versus lower doses, reduced the risk of awareness.

BIS Monitoring: Awareness and Catastrophic Events

The bispectral index is an electroencephalogram-based monitoring tool to help anesthesiologists determine depth of anesthesia. The bispectral index indicates both the potential for awareness and of relative hypnotic overdose, but it does not predict movement or hemodynamic responses to stimulation, and it cannot predict the exact moment consciousness returns. The bispectral index has been assessed for its relationship to awareness, and bispectral index monitoring appears to be generally associated with a low incidence of awareness. The bispectral index has also has been noted to detect periods of cerebral ischemia. It is also being used in intensive care units to help quantify the level of sedation in patients and as an outcome predictor in patients with brain injuries. Low values of the bispectral index often occur during catastrophic, ischemic, events but the use of this technology for the routine monitoring of such events is unproven.

Nitrous oxide-based versus nitrous oxide-free general anaesthesia and accidental awareness during general anaesthesia in surgical patients

BACKGROUND

Accidental awareness during general anaesthesia (AAGA) is when a patient unintentionally becomes conscious during a procedure performed with general anaesthesia and subsequently has explicit recall of this event. Incidence estimates for AAGA vary, with the most common estimate being one to two cases per 1000 general anaesthetics. Evidence linking nitrous oxide use and an increased risk of AAGA has come from observational studies data but the literature is contradictory, with some studies finding a protective effect of nitrous oxide.

OBJECTIVES

To assess the effect of general anaesthesia including nitrous oxide on the risk of AAGA in patients aged five years and over.

SEARCH METHODS

We searched the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and trial registers ((www.clinicaltrials.gov), the WHO International Clinical Trials Registry Platform (www.who.int/ictrp/network/en/) and Current Controlled Trials (www.isrctn.com/)) for eligible studies on December 9 2015. In addition, we conducted forward and backward citation searching using key identified papers.

SELECTION CRITERIA

We considered all randomized controlled trials (RCTs), including quasi-randomized studies and cluster-randomized studies, of participants aged five years or older receiving general anaesthesia for any type of surgery.We included trials in which participants receiving general anaesthesia that included nitrous oxide for maintenance at a concentration of at least 30% were compared with participants receiving no nitrous oxide during general anaesthesia. The intervention group must have received nitrous oxide in conjunction with an additional anaesthetic. We excluded studies where the depth of anaesthesia differed between the study arms. For inclusion in the review, studies needed to state in their methods that they planned to assess AAGA. We defined this as when a patient becomes conscious during a procedure performed with general anaesthesia and subsequently has explicit recall of this event.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane to identify studies. We extracted data and conducted 'Risk of bias' assessment using the Covidence database.

MAIN RESULTS

We included 15 studies. The total number of participants included in the analyses was 3520. Most studies were small with fewer than 120 participants, although two larger studies with 2012 and 671 participants were included. There was considerable variation in many of the study characteristics, including the anaesthetics used. The concentrations of nitrous oxide varied between 50% and 70%, and half of the studies used clinical signs and haemodynamic changes to monitor depth of anaesthesia.As it was not possible to blind the anaesthetist to the anaesthetic used, we rated all studies at high risk of performance bias and we therefore downgraded the quality of evidence by one level for risk of bias using the GRADE approach. Other types of bias were generally low, or were rated unclear due to missing information.No studies were designed to measure AAGA as the primary outcome, and were therefore statistically underpowered to answer this review question. Despite the inclusion of 3520 participants, only three awareness events were reported by two studies. In one study the event was due to technical failure. Due to the rarity of the events, we did not consider it appropriate to pool the data, and we therefore downgraded the quality of evidence by a further level for imprecision using GRADE.

AUTHORS' CONCLUSIONS

It is not possible to draw any conclusions from this review. The included studies were mainly small (fewer than 120 participants) and there were limited estimates of effect, with only two studies reporting any events. We cannot therefore determine whether the use of nitrous oxide in general anaesthesia increases, decreases or has no effect on the risk of accidental awareness.

Monitoring the Depth of General Anaesthesia with Bis Monitor in the Course of Surgical Procedure in Children Shortens the Period of Recovery from General Anaesthesia

Monitoring the depth of general anaesthesia (GA) enables the anaesthetist to reach the optimal depth of GA, and thus prevent the occurrence of too deep or too shallow anaesthesia, together with all associated consequences. Anaesthesia, which is too shallow, increases the risk of perioperative awareness. In adult patients, the incidence of perioperative awareness is 0.1-0.2 % for the total number of GA procedures, in paediatric population, the clinical studies present the incidence of up to 5 % (1973), 0.8 % (2005) for the total number of GA procedures. Perioperative awareness is a serious complication, with possible psychological consequences for the patients, including post-traumatic stress disorder.

BIS monitoring is one of the possibilities how to assess the depth of GA. This technique is based on the assessment of EEG curve, when individual parameters of the EEG signal are, using mathematical methods, transformed into a dimensionless number, so-called bispectral index (BIS), the value of which is expressed on the scale from 0 to 100, and which reflects the depth of general anaesthesia.

This prospective randomized clinical trial has proven, on a group of 101 children that the use of BIS monitor in the course of GA shortens the period of recovery from general anaesthesia, however, it does not decrease the consumption of inhalation anaesthetics when compared to GA performed without BIS monitoring. The results of the study confirmed the importance of monitoring the depth of GA in patients with intravenous administration of Propofol. The authors have observed an inverse linear relation between the values of BIS and MAC (minimum alveolar concentration).

Patient perspectives on intraoperative awareness with explicit recall: report from a North American anaesthesia awareness registry

BACKGROUND

Awareness during general anaesthesia is a source of concern for patients and anaesthetists, with potential for psychological and medicolegal sequelae. We used a registry to evaluate unintended awareness from the patient's perspective with an emphasis on their experiences and healthcare provider responses.

METHODS

English-speaking subjects self-reported explicit recall of events during anaesthesia to the Anesthesia Awareness Registry of the ASA, completed a survey, and submitted copies of medical records. Anaesthesia awareness was defined as explicit recall of events during induction or maintenance of general anaesthesia. Patient experiences, satisfaction, and desired practitioner responses to explicit recall were based on survey responses.

RESULTS

Most of the 68 respondents meeting inclusion criteria (75%) were dissatisfied with the manner in which their concerns were addressed by their healthcare providers, and many reported long-term harm. Half (51%) of respondents reported that neither the anaesthesia provider nor surgeon expressed concern about their experience. Few were offered an apology (10%) or referral for counseling (15%). Patient preferences for responses after an awareness episode included validation of their experience (37%), an explanation (28%), and discussion or follow-up to the episode (26%).

CONCLUSIONS

Data from this registry confirm the serious impact of anaesthesia awareness for some patients, and suggest that patients need more systematic responses and follow-up by healthcare providers.

The effects of bispectral index monitoring on hemodynamics and recovery profile in developmentally delayed pediatric patients undergoing dental surgery

BACKGROUND

General anesthesia is often preferred for dental surgery or rehabilitation in developmentally delayed pediatric patients. Bispectral index monitoring is used to monitor the depth of anesthesia and to ensure early recovery. However, studies on the topic in developmentally delayed pediatric patients are limited.

AIM

To evaluate the effects of Bispectral Index Scale (BIS) on hemodynamics and recovery profile in developmentally delayed pediatric patients undergoing dental surgery.

METHODS

Forty children between the ages of 6-16 years were studied in this prospective and randomized study. The children were randomized into two groups. In Group 1 (n = 20), general anesthesia was maintained with 1-2 minimum alveolar concentration (MAC) of sevoflurane in oxygen by standard practice. In Group 2 (n = 20), the depth of anesthesia was monitored by BIS. BIS values were continuously recorded from awake status to tracheal extubation. The duration of the surgical procedure, anesthesia, postanesthesia care unit (PACU) stay was noted. To evaluate recovery profile, time to spontaneous ventilation, extubation, open eyes, and PACU discharge were also noted.

RESULTS

There were significant differences between recovery times and Non-communicating Children's Pain Checklist - Postoperative Version (NCCPC-PV) scores of two groups. Time to spontaneous ventilation [Difference in means (95% CI); 3.17 (1.79-4.54) P < 0.001], extubation [Difference in means (95% CI); 3.13 (1.66-4.60) P < 0.001], open eyes [Difference in means (95% CI); 3.97 (2.34-5.59) P < 0.001], and PACU stay time [Difference in means (95% CI); 23.55 (18.08-29.01) P < 0.001] were significantly shorter in Group 2.

CONCLUSION

In conclusion, results suggest that routine BIS monitoring may be beneficial due to its favorable effects on the recovery profile in developmentally delayed pediatric patients.

Psychological sequelae of surgery in a prospective cohort of patients from three intraoperative awareness prevention trials

BACKGROUND

Elective surgery can have long-term psychological sequelae, especially for patients who experience intraoperative awareness. However, risk factors, other than awareness, for symptoms of posttraumatic stress disorder (PTSD) after surgery are poorly defined, and practical screening methods have not been applied to a broad population of surgical patients.

METHODS

The Psychological Sequelae of Surgery study was a prospective cohort study of patients previously enrolled in the United States and Canada in 3 trials for the prevention of intraoperative awareness. The 68 patients who experienced definite or possible awareness were matched with 418 patients who denied awareness based on age, sex, surgery type, and awareness risk. Participants completed the PTSD Checklist-Specific (PCL-S) and/or a modified Mini-International Neuropsychiatric Interview telephone assessment to identify symptoms of PTSD and symptom complexes consistent with a PTSD diagnosis. We then used structural equation modeling to produce a composite PTSD score and examined potential risk factors.

RESULTS

One hundred forty patients were unreachable; of those contacted, 303 (88%) participated a median of 2 years postoperatively. Forty-four of the 219 patients (20.1%) who completed the PCL-S exceeded the civilian screening cutoff score for PTSD symptoms resulting from their surgery (15 of 35 [43%] with awareness and 29 of 184 [16%] without). Nineteen patients (8.7%; 5 of 35 [14%] with awareness and 14 of 184 [7.6%] without) both exceeded the cutoff and endorsed a breadth of symptoms consistent with the Diagnostic and Statistical Manual Fourth Edition diagnosis of PTSD attributable to their surgery. Factors independently associated with PTSD symptoms were poor social support, previous PTSD symptoms, previous mental health treatment, dissociation related to surgery, perceiving that one's life was threatened during surgery, and intraoperative awareness (all P ≤ 0.017). Perioperative dissociation was identified as a potential mediator for perioperative PTSD symptoms.

CONCLUSIONS

Events in the perioperative period can precipitate psychological symptoms consistent with subsyndromal and syndromal PTSD. We not only confirmed the high rate of postoperative PTSD in awareness patients but also identified a significant rate in matched nonawareness controls. Screening surgical patients, especially those with potentially mediating risk factors such as intraoperative awareness or perioperative dissociation, for postoperative PTSD symptoms with the PCL-S is practical and could promote early referral, evaluation, and treatment.

Intraoperative awareness: controversies and non-controversies

Intraoperative awareness, with or without recall, continues to be a topic of clinical significance and neurobiological interest. In this article, we review evidence pertaining to the incidence, sequelae, and prevention of intraoperative awareness. We also assess which aspects of the complication are well understood (i.e. non-controversial) and which require further research for clarification (i.e. controversial).

Neural correlates of successful semantic processing during propofol sedation

Sedation has a graded effect on brain responses to auditory stimuli: perceptual processing persists at sedation levels that attenuate more complex processing. We used fMRI in healthy volunteers sedated with propofol to assess changes in neural responses to spoken stimuli. Volunteers were scanned awake, sedated, and during recovery, while making perceptual or semantic decisions about nonspeech sounds or spoken words respectively. Sedation caused increased error rates and response times, and differentially affected responses to words in the left inferior frontal gyrus (LIFG) and the left inferior temporal gyrus (LITG). Activity in LIFG regions putatively associated with semantic processing, was significantly reduced by sedation despite sedated volunteers continuing to make accurate semantic decisions. Instead, LITG activity was preserved for words greater than nonspeech sounds and may therefore be associated with persistent semantic processing during the deepest levels of sedation. These results suggest functionally distinct contributions of frontal and temporal regions to semantic decision making. These results have implications for functional imaging studies of language, for understanding mechanisms of impaired speech comprehension in postoperative patients with residual levels of anesthetic, and may contribute to the development of frameworks against which EEG based monitors could be calibrated to detect awareness under anesthesia.

A decade of reversal: an analysis of 146 contradicted medical practices

OBJECTIVE

To identify medical practices that offer no net benefits.

METHODS

We reviewed all original articles published in 10 years (2001-2010) in one high-impact journal. Articles were classified on the basis of whether they addressed a medical practice, whether they tested a new or existing therapy, and whether results were positive or negative. Articles were then classified as 1 of 4 types: replacement, when a new practice surpasses standard of care; back to the drawing board, when a new practice is no better than current practice; reaffirmation, when an existing practice is found to be better than a lesser standard; and reversal, when an existing practice is found to be no better than a lesser therapy. This study was conducted from August 1, 2011, through October 31, 2012.

RESULTS

We reviewed 2044 original articles, 1344 of which concerned a medical practice. Of these, 981 articles (73.0%) examined a new medical practice, whereas 363 (27.0%) tested an established practice. A total of 947 studies (70.5%) had positive findings, whereas 397 (29.5%) reached a negative conclusion. A total of 756 articles addressing a medical practice constituted replacement, 165 were back to the drawing board, 146 were medical reversals, 138 were reaffirmations, and 139 were inconclusive. Of the 363 articles testing standard of care, 146 (40.2%) reversed that practice, whereas 138 (38.0%) reaffirmed it.

CONCLUSION

The reversal of established medical practice is common and occurs across all classes of medical practice. This investigation sheds light on low-value practices and patterns of medical research.

“Imagine your neighbor mows the lawn”: a pilot study of psychological sequelae due to awake craniotomy

Object

Although it has been reported that awake neurosurgical procedures are well tolerated, the long-term occurrence of general psychological sequelae has not yet been investigated. This study assessed the frequency and effects of psychological symptoms after an awake craniotomy on health-related quality of life (HRQOL).

Methods

Sixteen patients undergoing an awake surgery were surveyed with a self-developed questionnaire, the Posttraumatic Stress Disorder Inventory For Awake Surgery Patients, which adopts the core components of the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) posttraumatic stress disorder (PTSD) criteria. The mean time between surgery and data collection was 97.3 ± 93.2 weeks. Health-related quality of life was assessed with the 36-Item Short Form Health Survey.

Results

Forty-four percent of the patients stated that they had experienced either repetitive distressing recollections or dreams related to the awake surgery, 18.8% stated persistent avoidance of stimuli associated with the awake surgery, and symptoms of increased arousal occurred in 62.5%. Two patients presented with postoperative psychological sequelae resembling PTSD symptoms. Younger age at surgery and female sex were risk factors for symptoms of increased arousal. The experience of intense anxiety during awake surgery appears to favor the development of postsurgical PTSD symptoms, while recurrent distressing recollections particularly affect HRQOL negatively.

Conclusions

In many cases awake craniotomy is necessary to preserve language and motor function. However, in some cases awake craniotomy can lead to postoperative psychological sequelae resembling PTSD symptoms. Therefore, possible long-term effects of an awake surgery should be considered and discussed with the patient when planning this type of surgery.

Influence of esmolol on requirement of inhalational agent using entropy and assessment of its effect on immediate postoperative pain score

Background and Context:

Beta-blockers have been used for attenuation of stress response, decreasing anaesthetic requirement and augmentation of the effect of opioids during general anaesthesia.

Aims and Objectives:

The present study aims to evaluate the influence of esmolol on the requirement of an inhalational agent while monitoring the depth of anaesthesia by entropy and also its effect on immediate postoperative pain score.

Methods:

Fifty American Society of Anaesthesiologists (ASA) I and II patients, between 25 and 65 years of age who underwent lower abdominal surgeries were randomly allocated to two groups: Group E and Group S of 25 patients each. Group E received esmolol infusion while Group S received the same volume of saline infusion. Demographic data, haemodynamics, amount of isoflurane used, end-tidal isoflurane concentration, postoperative pain score and total dose of morphine consumed in immediate postoperative period of 30 min were analyzed by using appropriate statistical tests. Value of P<0.05 was considered significant and P<0.001 as highly significant.

Results:

The two groups were comparable with respect to age, weight, ASA physical status, duration of surgery and amount of isoflurane used during anaesthesia. Assessment of postoperative pain was assessed by Visual Analogue Scale (VAS) which showed significant difference at 30 min. The total dose of morphine consumption was significantly less (P<0.05) in Group E for relief of postoperative pain.

Conclusions:

We conclude that in light of depth of anaesthesia monitor esmolol has no effect on requirement of isoflurane, but it decreases the postoperative pain as well as postoperative requirement of morphine without increasing the risk of awareness.

Anesthesia awareness: narrative review of psychological sequelae, treatment, and incidence

Awareness during general anesthesia occurs when patients recall events or sensations during their surgeries, although the patients should have been unconscious at the time. Anesthesiologists are cognizant of this phenomenon, but few discussions occur outside the discipline. This narrative review summarizes the patient recollections, psychological sequelae, treatment and follow-up of psychological consequences, as well as incidence and etiology of awareness during general anesthesia. Recalled memories include noises, conversations, images, mental processes, feelings of pain and/or paralysis. Psychological consequences include anxiety, flashbacks, and posttraumatic stress disorder diagnosis. Limited discussion for therapeutic treatment after an anesthesia awareness experience exists. The incidence of anesthesia awareness ranges from 0.1 to 0.2% (e.g., 1-2/1000 patients). Increased recognition of awareness during general anesthesia within the psychological/counseling community, with additional research focusing on optimal therapeutic treatment, will improve the care of these patients.