Effects of depth of neuromuscular blockade on the BIS-guided propofol requirement: A randomized controlled trial.

BACKGROUND: Deep neuromuscular blockade is considered beneficial for improving the surgical space condition during laparoscopic surgery. Adequacy of the surgical space condition may affect the anesthetists' decision regarding titration of depth of anesthesia. We investigated whether deep neuromuscular blockade reduces the propofol requirement under bispectral index monitoring compared to moderate neuromuscular blockade. METHODS: Adult patients undergoing elective laparoscopic colorectal surgery were randomly allocated to a moderate or deep group. A train-of-four count of 1-2 in the moderate group, and a post-tetanic count of 1-2 in the deep group, were maintained by continuous infusion of rocuronium. The induction and maintenance of anesthesia were achieved by target-controlled infusion of propofol and remifentanil. The dose of propofol was adjusted to maintain the bispectral index in the range of 40-50. The remifentanil dose was titrated to maintain the systolic blood pressure to within 20% of the ward values. RESULTS: A total of 82 patients were included in the analyses. The mean±SD dose of propofol was 7.54 ±â€Š1.66 and 7.42 ±â€Š1.01 mg·kg-1·h-1 in the moderate and deep groups, respectively (P = .104). The mean±SD dose of remifentanil was 4.84 ±â€Š1.74 and 4.79 ±â€Š1.77 µg kg-1 h-1 in the moderate and deep groups, respectively (P = .688). In comparison to the moderate group, the deep group showed significantly lower rates of intraoperative patient movement (42.9% vs 22.5%, respectively, P = .050) and additional neuromuscular blocking agent administration (76% vs 53%, respectively, P = .007). Postoperative complications, including pulmonary complications, wound problems and reoperation, were not different between the two groups. CONCLUSION: Deep neuromuscular blockade did not reduce the bispectral index-guided propofol requirement compared to moderate neuromuscular blockade during laparoscopic colon surgery, despite reducing movement of the patient and the requirement for a rescue neuromuscular blocking agent. TRIAL REGISTRATION: Clinicaltrials.gov (NCT03890406).

Color density spectral array for early evaluation of prognosis of patients with coma in pediatric intensive care unit.

The aim of this study was to assess the bedside brain function monitoring of color density spectral array (CDSA) for early prognostic evaluation of coma patients in pediatric intensive care unit (PICU).Forty-two consecutive pediatric coma patients were enrolled. The individual conscious state was evaluated according to the Glasgow coma scale (GCS). CDSA parameters including CDSA pattern (CDSAP), sleep-wake cycle (SWC), sleep stage (SS), and drug-induced fast wave activity (DIFWA) were recorded. Three months later, prognosis was evaluated according to pediatric cerebral performance category (PCPC) score, based on which the patients were divided into FP-group (favorable prognosis) and PP-group (poor prognosis).The changeable type of CDSAP, appearance of SWC, SS, and DIFWA were significantly correlated with favorable prognosis. Both GCS and SWC were significantly correlated with the prognosis. However, there was substantial overlap in GCS between FP-group and PP-group. Although the absence of SWC was statistically an independent risk factor for poor prognosis but with a high false positive rate (0.143), a linear logistic regression showed the odds ratio of GCS for predicting prognosis was 0.93 (95% confidence interval: 0.48-1.80; P = .83) and that of SWC was 0.12 (95% confidence interval: 0.03-0.47; P = .03). Furthermore, the absence of SWC was correlated with poor prognosis in nonintracranial infection patients.Our study found that several CDSA factors are associated with prognosis of coma patients in PICU. SWC may be a potential indicator for evaluating the prognosis of coma patients in PICU.

Triple-low Alerts Do Not Reduce Mortality: A Real-time Randomized Trial.

BACKGROUND: Triple-low events (mean arterial pressure less than 75 mmHg, Bispectral Index less than 45, and minimum alveolar fraction less than 0.8) are associated with mortality but may not be causal. This study tested the hypothesis that providing triple-low alerts to clinicians reduces 90-day mortality. METHODS: Adults having noncardiac surgery with volatile anesthesia and Bispectral Index monitoring were electronically screened for triple-low events. Patients having triple-low events were randomized in real time, with clinicians either receiving an alert, "consider hemodynamic support," or not. Patients were blinded to treatment. Helpful responses to triple-low events were defined by administration of a vasopressor within 5 min or a 20% reduction in end-tidal volatile anesthetic concentration within 15 min. RESULTS: Of the qualifying patients, 7,569 of 36,670 (20%) had triple-low events and were randomized. All 7,569 were included in the primary analysis. Ninety-day mortality was 8.3% in the alert group and 7.3% in the nonalert group. The hazard ratio (95% CI) for alert versus nonalert was 1.14 (0.96, 1.35); P = 0.12, crossing a prespecified futility boundary. Clinical responses were helpful in about half the patients in each group, with 51% of alert patients and 47% of nonalert patients receiving vasopressors or having anesthetics lowered after start of triple low (P < 0.001). There was no relationship between the response to triple-low events and adjusted 90-day mortality. CONCLUSIONS: Real-time alerts to triple-low events did not lead to a reduction in 90-day mortality, and there were fewer responses to alerts than expected. However, similar mortality with and without responses suggests that there is no strong relationship between responses to triple-low events and mortality.

Detection of seizure patterns with multichannel amplitude-integrated EEG and the color density spectral array in the adult neurology intensive care unit.

This study's purpose was to determine the sensitivity, false-positive and false-negative of seizure detection in adult intensive care by amplitude-integrated electroencephalography (aEEG) and color density spectral array (CDSA).30 continuous electroencephalogram (EEG) recordings were randomly performed in 3 digital EEG-recording machines, 3 specialized neurophysiologists participated in this study, underwent 4 hours of training of CDSA and aEEG, marked any epochs suspected to be seizures without access to the raw EEG. The results will be compared and analyzed with continuous EEG reading to consider sensitivity, positive or negative rate.The recordings in this study, comprised 720 hours of EEG containing a total of 435 seizures. The median sensitivity for seizure identification was 80% of CDSA and 81.3% of aEEG, Median false-positive was 4 per 24 hours of CDSA, and 2 per 24 hours of aEEG display, Median false-negative was 4 per 24 hours of CDSA, and 4 per 24 hours of aEEG display. The time spent in identification of seizures by CDSA and aEEG was much time-saving than continuous EEG-reading.In this study, both CDSA and aEEG have a higher sensitivity but lower false-positive or missed rate in the interpretation of seizure identification in adult NICU.

Use of the critical-care pain observation tool and the bispectral index for the detection of pain in brain-injured patients undergoing mechanical ventilation: A STROBE-compliant observational study.

The assessment of pain in patients with brain injury is challenging due to impaired ability to communicate. We aimed to test the reliability and validity of the critical-care pain observation tool (CPOT) and the bispectral index (BIS) for pain detection in critically brain-injured patients.This prospective observational study was conducted in a neurosurgical intensive care unit in a University-Affiliated Hospital. Adult brain-injured patients undergoing mechanical ventilation were enrolled. Nociceptive (endotracheal suctioning) and non-nociceptive (gentle touching) procedures were performed in a random crossover fashion. Before and immediately after the procedure, CPOT was evaluated by 2 residents and 2 chief nurses, and BIS was documented. The ability to self-report pain was also assessed. The inter-observer reliability of CPOT was analyzed. The criterion and discriminant validities of the CPOT and the BIS were tested.During the study, we enrolled 400 brain-injured patients. The ability to self-report pain was maintained in 214 (54%) and 218 (55%) patients during suctioning and gentle touching, respectively. The intraclass correlation coefficients (95% confidence interval) for inter-observer reliability of CPOT ranged from 0.86 (0.83-0.89) to 0.93 (0.91-0.94). Using self-reported pain as the reference, the area under the receiver operating characteristic curve (95% confidence interval) was 0.84 (0.80-0.88) for CPOT and 0.76 (0.72-0.81) for BIS. When the 2 instruments were combined as either CPOT ≥2 or BIS ≥88 after the procedure, the sensitivity and specificity were 0.90 (0.85-0.93) and 0.59 (0.52-0.66), respectively; and when the 2 instruments were combined as both CPOT ≥2 and BIS ≥88, the sensitivity and specificity were 0.62 (0.55-0.68) and 0.89 (0.83-0.93). Both CPOT and BIS increased significantly after suctioning (all P < .001) but remained unchanged after gentle touching (P ranging from .06 to .14).Our criterion and discriminant validity results supported the use of CPOT and BIS to detect pain in critically brain-injured patients. Combining use of CPOT and BIS in different ways might provide comprehensive pain assessment for different purposes.

Feasibility of continuous sedation monitoring in critically ill intensive care unit patients using the NeuroSENSE WAVCNS index.

Sedation in the intensive care unit (ICU) is challenging, as both over- and under-sedation are detrimental. Current methods of assessment, such as the Richmond Agitation Sedation Scale (RASS), are measured intermittently and rely on patients' behavioral response to stimulation, which may interrupt sleep/rest. A non-stimulating method for continuous sedation monitoring may be beneficial and allow more frequent assessment. Processed electroencephalography (EEG) monitors have not been routinely adopted in the ICU. The aim of this observational study was to assess the feasibility of using the NeuroSENSE™ monitor for EEG-based continuous sedation assessment. With ethical approval, ICU patients on continuous propofol sedation were recruited. Depth-of-hypnosis index (WAVCNS) values were obtained from the NeuroSENSE. Bedside nurses, blinded to the NeuroSENSE, performed regular RASS assessments and maintained the sedation regimen as per standard of care. Participants were monitored throughout the duration of their propofol infusion, up to 24 h. Fifteen patients, with median [interquartile range] age of 57 [52-62.5] years were each monitored for a duration of 9.0 [5.7-20.1] h. Valid WAVCNS values were obtained for 89% [66-99] of monitoring time and were widely distributed within and between individuals, with 6% [1-31] spent < 40 (very deep), and 3% [1-15] spent > 90 (awake). Significant EEG suppression was detected in 3/15 (20%) participants. Observed RASS matched RASS goals in 36/89 (40%) assessments. The WAVCNS variability, and incidence of EEG suppression, highlight the limitations of using RASS as a standalone sedation measure, and suggests potential benefit of adjunct continuous brain monitoring.

Role of bispectral index monitoring and burst suppression in prognostication following out-of-hospital cardiac arrest: a systematic review protocol.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is associated with significant mortality or may have a poor neurological outcome. Various community-training programmes have improved practices like bystander cardiopulmonary resuscitation (CPR) and early defibrillation using automated external defibrillator (AED). Post-resuscitation care has also changed significantly in the millennium. Interventions like targeted temperature management (TTM), avoidance of hyperoxia and emergency cardiac catheterisation have given patients a chance of a better neurological outcome. Despite these timely interventions, it is still very difficult to predict neurological outcome. The European Resuscitation Council and European Society of Intensive Care Medicine (ERC-ESICM) published guidance in 2015 with a strong recommendation to delay prognostication for at least 72 h and with an emphasis to adapt a multimodal approach, which includes neurological examination, biomarkers, electroencephalogram (EEG) and radiological tests. These interventions not only have cost attached to them, but the unpredictability has a significant emotional impact on family members. Bispectral index (BIS) monitoring device acts on the principle of EEG and converts the waveform into an absolute number and also measures the burst suppression. We hypothesize that patients who have a low BIS value and high burst suppression within 24 h of presentation will have a poor neurological outcome. The primary objective of this review is to look at BIS monitor as a tool, which could help bring forward the timing of prognostication. METHODS: Electronic databases will be systematically searched for randomised controlled trials and prospective or retrospective cohort studies with no language restrictions. The search will be supplemented with grey literature searches of thesis, dissertations and hand searching of relevant journals. Two independent reviewers will screen, select and perform analysis according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) method. The selected studies will be analysed using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system. Meta-analysis will be performed if suitable. DISCUSSION: This review will synthesize the evidence on the use of BIS monitors within 24 h of achieving return of spontaneous circulation (ROSC) and may help in early prognostication. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD 42016050224 .

Effectiveness of an Electronic Alert for Hypotension and Low Bispectral Index on 90-day Postoperative Mortality: A Prospective, Randomized Trial.

BACKGROUND: We tested the hypothesis that an electronic alert for a "double low" of mean arterial pressure less than 75 mmHg and a bispectral index less than 45 reduces the primary outcome of 90-day mortality. METHODS: Adults having noncardiac surgery were randomized to receive either intraoperative alerts for double-low events or no alerts. Anesthesiologists were not blinded and not required to alter care based upon the alerts. The primary outcome was all-cause 90-day mortality. RESULTS: Patients (20,239) were randomized over 33 months, and 19,092 were analyzed. After adjusting for age, comorbidities, and perioperative factors, patients with more than 60 min of cumulative double-low time were twice as likely to die (hazard ratio, 1.99; 95% CI, 1.2 to 3.2; P = 0.005). The median number of double-low minutes (quartiles) was only slightly lower in the alert arm: 10 (2 to 30) versus 12 (2 to 34) min. Ninety-day mortality was 135 (1.4%) in the alert arm and 123 (1.3%) in the control arm. The difference in percent mortality was 0.18% (99% CI, -0.25 to 0.61). CONCLUSIONS: Ninety-day mortality was not significantly lower in patients cared for by anesthesiologists who received automated alerts to double-low states. Prolonged cumulative double-low conditions were strongly associated with mortality.

Bispectral Index Monitoring in Patients Undergoing Open Heart Surgery.

INTRODUCTION: To obtain the optimal anesthesia depth is not easy in cardiovascular surgery patients where the haemodynamic reserve is limited, due to reasons such as not being able to give the desired dose of anesthetic agent, or the change in the pharmacokinetics of the agent in the heart-lung machine. This study was planned to assess the contribution of bispectral index (BIS) monitoring in the depth of anesthesia. METHODS: The patients were divided into 2 groups, and BIS monitoring was used for each patient. Group 1 (G1 n=35): keeping the BIS monitor screen open, the anesthesia need was set. Group 2 (G2 n=35): BIS monitor was tied to the patient and the monitor screen was closed in such a way that the anaesthesist couldn't see the BIS value. When the recording time came, the data on the monitor was recorded. The need for the anesthetic agent was set according to the parameters such as haemodynamics or follow up of pupils, instead of BIS value, by titrating the anesthetic infusion doses. RESULTS: BIS values were similar in both groups before the induction, BIS values in both groups showed a decrease, showing no significant statistical difference (P>0.05). One patient in each group said that he dreamt, and one patient in G2 said that he had heard a noise and felt that he was taken from one place to another. CONCLUSION: The management should be done with clinical evaluation, haemodynamics and other monitorization methods and BIS monitoring findings together.

Bispectral index monitoring in patients undergoing open heart surgery

Abstract Introduction: To obtain the optimal anesthesia depth is not easy in cardiovascular surgery patients where the haemodynamic reserve is limited, due to reasons such as not being able to give the desired dose of anesthetic agent, or the change in the pharmacokinetics of the agent in the heart-lung machine. This study was planned to assess the contribution of bispectral index (BIS) monitoring in the depth of anesthesia. Methods: The patients were divided into 2 groups, and BIS monitoring was used for each patient. Group 1 (G1 n=35): keeping the BIS monitor screen open, the anesthesia need was set. Group 2 (G2 n=35): BIS monitor was tied to the patient and the monitor screen was closed in such a way that the anaesthesist couldn't see the BIS value. When the recording time came, the data on the monitor was recorded. The need for the anesthetic agent was set according to the parameters such as haemodynamics or follow up of pupils, instead of BIS value, by titrating the anesthetic infusion doses. Results: BIS values were similar in both groups before the induction, BIS values in both groups showed a decrease, showing no significant statistical difference (P>0.05). One patient in each group said that he dreamt, and one patient in G2 said that he had heard a noise and felt that he was taken from one place to another. Conclusion: The management should be done with clinical evaluation, haemodynamics and other monitorization methods and BIS monitoring findings together.

The relationship between the Bispectral Index (BIS) and the Observer Alertness of Sedation Scale (OASS) scores during propofol sedation with and without ketamine: a randomized, double blinded, placebo controlled clinical trial.

Prior studies have examined the static effect of intravenous ketamine on the BIS Index for sedation but it remains unknown if the BIS Index is a reliable method to track sedation levels in the presence of ketamine. The major objective of the current investigation was to compare the BIS Vista Index ability to track varying depths of sedation as determined by OASS scores in a standardized anesthetic regimen with and without ketamine. The study was a randomized, double blinded clinical trial. Patients undergoing breast surgery under sedation with propofol were randomized to receive ketamine (1.5 µg kg min(-1)) or saline. Infusion data was used to estimate propofol plasma concentrations (Cp). The main outcome of interest was the correlation between the BIS Vista Index with the OASS score. Twenty subjects were recruited and fifteen completed the study. Four hundred fifty-five paired data points were included in the analysis. Model performance (Nagelkerke R(2)) of the multinomial logistic regression model was 0.57 with the c-statistic of 0.87 (95 % CI 0.82-0.91). Compared to awake the odds ratio for BIS values predicting moderate sedation in the saline/propofol group 1.19 (95 % CI 1.12-1.25) but only 1.06 (95 % CI 1.02-1.1) in the ketamine/propofol group (P = 0.001). There was no difference in the odds for BIS values to predict deep sedation between groups (P = 0.14). The BIS monitor can be used to monitor sedation level even when ketamine is used with propofol as part of the sedation regimen. However, ketamine reduces the value of the BIS in predicting moderate sedation levels.

[Waking up during general anaesthesia]. / Wakker worden tijdens de narcose.

Awareness with recall is defined as 'both conscious experience and memory of events during surgery'. Perceptions of sound, pain or paralysis and assimilation of these in the memory can lead to post-traumatic stress disorder. Prospective studies report an incidence of 0.1-1%. Risk factors include those circumstances that result in under-dosing of anaesthetic agents relative to the patient's specific requirement. A lack of reliable monitoring of depth of anaesthesia is a result of our limited knowledge of the effect of anaesthetics on consciousness and memory. No additional benefit has been shown for the use of bispectral index (BIS) monitoring compared with measuring the expired concentration of an inhaled anaesthetic agent. High-risk patients undergoing total intravenous anaesthesia may benefit from BIS for monitoring depth of anaesthesia. Further scientific investigation of the neurological processes involved in awareness with recall is required in order to develop novel monitoring techniques.

Acute alcohol intoxication and bispectral index monitoring.

BACKGROUND: Bispectral index (BIS) monitoring is commonly used to decrease the risk of awareness during anaesthesia. We aimed to determine the relationship between blood alcohol concentration and brain function (as measured by BIS) in healthy adults. METHODS: In this prospective observational study, 21 anaesthetic registrars self-regulated alcohol consumption over a 3-h period. Expired alcohol concentration (breathalyser) and BIS measurements were performed hourly for 4 h. A venous blood alcohol sample was taken at the conclusion of the study period. RESULTS: The main outcome measures were the correlation between blood alcohol and brain function as measured by BIS and the change in BIS from baseline (∆BIS) at 4 h. The median number of standard drinks consumed was 9.1 (IQR 7.7-12.3), range 5.4-17. At 4 h, there was a moderate inverse correlation between BIS and blood alcohol (r = -0.49, P = 0.029) and between ∆BIS and blood alcohol (r = -0.46, P =0.043). CONCLUSION: In healthy young adults, we found a moderate correlation between venous blood alcohol concentration and BIS. This suggests that acute alcohol consumption can decrease BIS. This information may be relevant when providing anaesthesia to intoxicated patients who require urgent or time-critical surgery, although certain limitations of this study should be kept in mind.

Predictive factors for colonoscopy complications.

OBJECTIVE: To determine factors predicting complications caused by colonoscopy. DESIGN: Prospective cohort study. SETTING: A private hospital in Hong Kong. PATIENTS: All patients undergoing colonoscopy in the Endoscopy Centre of the Hong Kong Sanatorium & Hospital from 1 June 2011 to 31 May 2012 were included. Immediate complications were those that were recorded by nurses during and up to the day after the examination, while delayed complications were gathered 30 days after the procedure by way of consented telephone interview by trained student nurses. Data were presented as frequency and percentage for categorical variables. Logistic regression was used to fit models for immediate and systemic complications with related factors. RESULTS: A total of 6196 patients (mean age, 53.7 years; standard deviation, 12.7 years; 3143 women) were enrolled and 3657 telephone interviews were completed. The incidence of immediate complications was 15.3 per 1000 procedures (95% confidence interval, 12.3-18.4); 50.5% were colonoscopy-related, including one perforation and other minor presentations. Being female (odds ratioadjusted=1.6), use of monitored anaesthetic care (odds ratioadjusted=1.8), inadequate bowel preparation (odds ratioadjusted=3.5), and incomplete colonoscopy (odds ratioadjusted=4.5) were predictors of risk for all immediate complications (all predictors had P<0.05 by logistic regression). The incidence of delayed complications was 1.6 per 1000 procedures (95% confidence interval, 0.3-3.0), which comprised five post-polypectomy bleeds and one post-polypectomy inflammation. The overall incidence of complications was 17.8 per 1000 procedures (95% confidence interval, 13.5-22.1). The incidences of complications were among the lower ranges across studies worldwide. CONCLUSION: Inadequate bowel preparation and incomplete colonoscopy were identified as factors that increased the risk for colonoscopy-related complications. Colonoscopy-related complications occurred as often as systemic complications, showing the importance of monitoring.

A influência do índice bispectral no tempo de alta hospitalar de pacientes submetidos a procedimentos oftalmológicos / The influence of the bispectral index in hospital time of patients undergoing ophthalmic procedures

Objetivo do estudo: avaliar se a titulação de drogas guiada pelo índice bispectral em pacientes submetidos à cirurgia oftalmológica ambulatorial está associada a uma redução no tempo de alta. Método: foram selecionados 111 pacientes submetidos a procedimentos oftalmológicos realizados sob sedação intravenosa associada ao bloqueio peribulbar. Ospacientes foram randomizados em dois grupos. Nos pacientes do grupo controle, o anestesista responsável administrou a sedação de acordo com parâmetros clínicos: manter o paciente entre 2 a 4 pontos na escala de sedação de Ramsay. No outro grupo, o índice bispectral foi monitorizado e a sedação foi administrada para manter os valores entre 70 e 85. Foram comparados entre os grupos os dados demográficos, a dosagem de drogas, a duração dos procedimentos, as complicações pós-operatórias e o tempo de alta. Resultados: os grupos não apresentaram diferenças estatísticas em relação aos dados demográficos, à dosagem das drogas intravenosas e à dose administrada de anestésico local. Não se observou diferença entre os grupos em relação à duração dos procedimentos e ao tempo de alta para casa. As complicações pós-operatórias detectadas foram náuseas e vômitos e dor pós-operatória, no entanto, sem diferença estatística significante entre os grupos. Conclusões: a monitorização com o índice bispectral não foi mais eficaz que à monitorização clínica, em reduzir o tempo de alta para casa de pacientes submetidos a cirurgias oftalmológicas ambulatoriais sob sedação e bloqueio peribulbar.

Study objective: assessing whether drug titration guided by the bispectral index in patients submitted to outpatient ophthalmological surgeries is associated with a decreased time of hospital discharge. Method: one hundred and eleven patients submitted to outpatient ophthalmological procedures performed under intravenous sedation associated with peribulbar block were selected for this study. Patients were randomized in two groups. In the control group, the anesthetist in charge administered sedation according to clinical parameters: maintaining the patient between 2 and 4 points in the Ramsay?s sedation scale. In the other group, the bispectral index was monitored and sedation was performed with the purpose of maintaining its values between 70 and 85. Demographic data, drug dosage, length of procedures, post-surgical complications and time of hospital discharge were compared between the two groups. Results: groups have not shown statistical differences regarding demographic data, dosage of intravenous drugs and the dosage of local anesthetic administered. No difference was observed between groups regarding the length of the procedures, and the time of hospital discharge. The post-surgical complications detected were nausea and vomiting and post-surgical pain, however, with no statistically significant difference between groups. Conclusions: bispectral index monitoring has not been more effective than clinical monitoring to reduce the time of hospital discharge of patients submitted to outpatient ophthalmological surgeries under sedation and peribulbar block.

Depth of anesthesia monitoring: a survey of attitudes and usage patterns among Australian anesthesiologists.

BACKGROUND: Utility of depth of anesthesia (DoA) monitors is contentious as evidence appears ambiguous regarding their clinical effectiveness and exact role. We conducted a survey of Australian anesthesiologists to determine their attitudes toward, and how and why they use, DoA monitors. METHODS: A random sample of 963 anesthesiologists was invited to participate in an anonymous online survey. RESULTS: The overall response rate was 30% (289 respondents). Twenty-nine percent (95% confidence interval, 24%-34%) of respondents thought DoA monitoring was indicated in all cases under relaxant general anesthesia. During total IV anesthesia with muscle relaxants, 74% of respondents (69%-79%) opined that DoA monitoring should be mandatory. DoA usage was never used by 5% of respondents (3%-8%), used in less than one-third of cases by 66% (61%-72%), and in more than one-third of cases by 29% (24%-35%). Belief in the usefulness of DoA monitoring for prevention of awareness was strongly associated with higher usage (P < 0.0001, Pearson correlation 0.32). Anesthesiologists were more influenced by higher DoA numbers than lower ones. In comparison with end-tidal anesthetic concentration monitoring, 30% (25%-35%) of respondents felt that DoA monitoring was more effective for prevention of intraoperative awareness. Thirty percent (25%-36%) of respondents reported having a previous case of awareness. CONCLUSIONS: The relatively frequent use of DoA monitoring contrasts with patterns in the UK, suggesting greater acceptance by Australian anesthesiologists. "Awareness prevention" rather than "recovery enhancement" appears to be the primary driver in DoA monitoring use in Australia. Highly variable usage patterns of DoA monitoring in the context of the current body of evidence suggest the need for greater education on the appropriate use of these monitors.