Bispectral index monitoring during anesthesia with propofol for electroconvulsive therapy

We studied the changes in the bispectral index (BIS) of 22 patients during electroconvulsive therapy (ECT) under propofol and succinylcholine anesthesia. BIS values (mean+/-SD) were 94+/-4 before anesthesia, 51+/-15 before ECT, 49+/-20 after ECT, and 60+/-17 at complete re-awakening. The BIS values at re-awakening were significantly different from those before anesthesia (P<0.05). In conclusion, our study suggests that the BIS values following ECT might not reliably correlate with the patients' clinical level of consciousness.     

Bispectral index monitoring in sevoflurane and remifentanil anesthesia. Analysis of drugs management and immediate recovery

BACKGROUND: Recent studies have suggested that electroencephalogram bispectral index (BIS) monitoring can improve recovery after anaesthesia and save money by shortening patients postoperative stay. The aim of the study is to evaluate the management of drugs and to measure immediate recovery after anaesthesia with or without BIS monitoring. METHODS: We studied 90 patients undergoing abdominal surgery randomly allocated to one of two groups of 45 each with or without BIS monitoring. Standard monitoring (EKG, arterial oxygen saturation and non-invasive blood pressure) was applied. All groups were monitored with BIS, using electrodes (Zipprep, Aspect Medical Systems) applied to the forehead. In the group 2 the BIS value was blinded to the anaesthesiologist. The BIS value was displayed using Spacelabs Medical BIS Ultraview Monitor. After obtaining baseline values for the BIS index (group 1) and haemodynamic data (all groups) anaesthesia was induced with a bolus dose of remifentanil and TPS, and vecuronium. The anaesthesia was maintained with Remifentanil and Sevoflurane. At standard times BIS, haemodynamic and respiratory parameters were recorded. Recovery times were measured by a study coordinator. Drug consumption was calculated. RESULTS: In group 1 the consumption of Sevoflurane decreased by 40 % while the consumption of remifentanil decreased by 10 % as compared to group 2. The use of vecuronium did not change in the 2 groups. In group 1 the time elapsed from cessation of anaesthetics to orientation decreased significantly. The difference was 5 min, from 11 to 6 min. CONCLUSIONS: BIS monitoring decrease both sevoflurane and remifentanil consumption, when compared to anaesthesia without BIS, with an immediate recovery after sevoflurane and remifentanil anaesthesia.     

Bispectral index decreased to "10" during propofol anesthesia despite the appropriate serum concentration of propofol

We report a case showing a bispectral index (BIS) value "10" during anesthesia maintained with propofol. Vital signs of the patient including blood pressure and heart rate were stable and the depth of anesthesia was considered as adequate. The serum concentration of propofol measured later was 2.5 and 2.2 microg ml(-1) when BIS indicated 10 and 35, respectively. The age of patient was 81 and the BIS values in elderly might decrease in accordance with the reduction of brain function.     

EEG bispectral index monitoring in sevoflurane or propofol anaesthesia: analysis of direct costs and immediate recovery

BACKGROUND: Recent studies have suggested that electroencephalogram (EEG) bispectral index (BIS) monitoring can improve recovery after anaesthesia and save money by shortening patients' postoperative stay. We wanted to evaluate the direct costs of BIS monitoring and to measure immediate recovery after anaesthesia in patients with or without BIS monitoring. METHODS: Eighty patients undergoing gynaecological surgery were studied. At first, 40 patients were randomized to receive either propofol or sevoflurane anaesthesia. In these patients, BIS was collected but the information was not displayed. Thereafter, the anaesthesiologists were trained to follow and understand the BIS information, and 40 patients were anaesthetized with aid of the monitoring. Recovery times were measured by a study coordinator. Drug consumption was calculated. RESULTS: BIS monitoring improved the immediate recovery after propofol anaesthesia, while no differences were seen in patients receiving sevoflurane. The consumption of both propofol and sevoflurane decreased significantly (29% and 40%, respectively). BIS monitoring increased direct costs in these patients; the break-even times (704 min for propofol and 282 min for sevoflurane) were not reached. CONCLUSION: BIS monitoring decreased the consumption of both propofol and sevoflurane and hastened the immediate recovery after propofol anaesthesia. Detailed cost analysis showed that the monitoring increased direct costs of anaesthesia treatment in these patients, mainly due to the price of special EEG electrodes used for relatively short anaesthesias.     

Bispectral index monitoring during sedation with sevoflurane, midazolam, and propofol.

BACKGROUND: Bispectral Index (BIS) has been used to measure sedation depth. Ideally, to guide anesthetic management, range of BIS scores at different sedation levels should not overlap, and BIS should be independent of drug used. This study assessed ability of BIS to predict sedation depth between sevoflurane, propofol, and midazolam. Quality of recovery was also compared. METHODS: Patients undergoing surgery with local or regional anesthesia and sedation were randomized to sevoflurane (n = 23), midazolam (n = 21), or propofol (n = 22). Sedation was titrated to Observers's Assessment of Alertness-Sedation score of 3 (responds slowly to voice). BIS and Observers's Assessment of Alertness-Sedation were measured every 5 min. BIS prediction probability (PK) was compared between drugs. Recovery was assessed by BIS and Digit Symbol Substitution and memory tests. RESULTS: Bispectral Index of responders to voice was significantly different from nonresponders (86 +/- 10 vs. 74 +/- 14, mean +/- SD; P < 0.001) However, wide variability and overlap in BIS were observed (25th-75th percentile, responders vs. non-responders: 79-96 vs. 65-83). BIS of responders was different for sevoflurane versus propofol and midazolam. BIS was a better predictor of propofol sedation than sevoflurane or midazolam (PK = 0.87 +/- 0.11, 0.76 +/- 0.01, and 0.69 +/- 0.02, respectively; P < 0.05). At 10 min after the procedure, 76, 48, and 24% of sevoflurane, propofol, midazolam patients, respectively, returned to baseline Digit Symbol Substitution scores (P < 0.05). Excitement-disinhibition occurred in 70, 36, and 5% of sevoflurane, propofol, and midazolam patients, respectively (P < 0.05). CONCLUSION: Individual BIS scores demonstrate significant variability, making it difficult to predict sedation depth. The relation between BIS and sedation depth may not be independent of anesthetic agent. Quality of recovery was similar between drugs, but excitement occurred frequently with sevoflurane.     

Bispectral index and regional cerebral oxygen saturation during propofol/N2O anesthesia

PURPOSE: A study was undertaken to compare the influence of midazolam, isoflurane, and aminophylline (which may antagonize anesthetic action) on bispectral index (BIS) and regional cerebral oxygen saturation (rSO(2)) during propofol/N(2)O anesthesia, and to test the hypothesis that the drug-induced changes in BIS values are accompanied by a change in rSO(2). METHODS: General anesthesia was administered to 36 patients with a continuous infusion of propofol to maintain a BIS value of 40 +/- 5. After baseline recordings, patients were randomly assigned to receive either midazolam, isoflurane, or aminophylline. Bispectral index values, rSO(2) using near-infrared spectroscopy, and hemodynamic parameters were recorded for 60 min. RESULTS: Midazolam (0.05 mg x kg(-1)) significantly decreased the BIS from 47.8 +/- 5.4 to 35.0 +/- 4.5 at five minutes after injection (P < 0.001 vs control) during propofol anesthesia, whereas the rSO(2) was unchanged. Similarly, isoflurane (1.1% end-tidal) decreased the BIS from 42.5 +/- 7.5 to 27.8 +/- 6.9 (P < 0.001) without affecting rSO(2). In contrast, aminophylline (3 mg.kg(-1)) was associated with an increase in BIS from 41.6 +/- 2.1 to 48.3 +/- 9.2 at five minutes after injection (P < 0.05) without affecting rSO(2). CONCLUSIONS: Midazolam or isoflurane-induced decreases in the BIS during propofol anesthesia were not accompanied by a decrease in rSO(2). Aminophylline significantly increased the BIS score during propofol anesthesia, suggesting that aminophylline can antagonize, at least in part, the sedative actions of propofol.     

Bispectral index-guided desflurane and propofol anesthesia in ambulatory arthroscopy: comparison of recovery and discharge profiles

In this prospective, randomized study we compared the recovery profiles of bispectral index (BIS)-guided anesthesia regimens with desflurane or propofol in ambulatory arthroscopy. Fifty ASA I–II adult patients who underwent knee arthroscopy were randomized to receive desflurane (D) or propofol (P) infusion accompanied by remifentanil and nitrous oxide during maintenance, titrated to maintain a bispectral index value between 50 and 60. Initial awakening, fast-track eligibility, and home readiness as well as intraoperative hemodynamics, were compared. The groups did not differ with respect to demographics, duration of operation, or intraoperative vital signs. Although the times for initial awakening parameters were shorter in group D, the differences between the groups were not significant. The time needed for the White fast-track score to reach 12 was shorter in group P than group D (9 ± 3.5 min vs 12.5 ± 5.3 min). However, home readiness did not differ significantly between the groups. Desflurane is an alternative to propofol for BIS-guided ambulatory anesthesia. Using desflurane in combination with opioid analgesics blunted its rapid emergence characteristics, and the higher frequency of emetic symptoms with desflurane diminished the success of its fast-track eligibility.     

脑电双频谱指数监测提高麻醉管理及全麻苏醒质量Meta分析研究

目的 评价脑电双频谱指数（BIS）监测是否改善麻醉管理和麻醉苏醒质量。方法按照制定的检索策略检索Pubmed和Medline—CDRom数据库（1990年1月至2004年1月），随后按照一定的入选原则找出符合要求的文献。按已制定的研究评价标准进行筛选，共10篇文献纳入最终的Meta分析。结果 BIS监测在镇痛药用量一致的情况下可减少催眠药物的用量。吸入麻醉中BIS监测可减少吸入麻醉药用量，但肌松药用量增加。BIS组病人睁眼时间、言语指令反应恢复时间、拔管时间、定向力恢复时间均缩短。BIS监测对术后恶心呕吐及术后疼痛的发生率没有影响。BIS监测减少术中知晓与术后记忆发生的证据尚不足。结论 BIS监测能减少全身麻醉中药物用量并提高麻醉苏醒质量。     

The effect of encephalogram bispectral index monitoring during total intravenous anesthesia with propofol in outpatient surgery]

OBJECTIVE: To assess the effect of monitoring the encephalogram bispectral index (BIS) during outpatient surgery. Outcome measures were amount of propofol administered, awakening and discharge. MATERIAL AND METHODS: Forty consecutive outpatient surgery patients were studied. The patients gave informed consent and received general intravenous anesthesia with propofol administered through a laryngeal mask using a computerized system (Diprifusor(R)). Two groups were formed: in group A, BIS was monitored, although the information was hidden from the anesthesiologists, who used the usual signs (loss of blinking reflex, pupil size and hemodynamic response) to guide anesthesia; in group B the anesthesiologists used BIS monitoring to guide propofol administration. Measurements were blood pressure, heart rate and BIS at six times during the procedure (T1-T6). Other data recorded were age, weight, height, propofol consumption in relation to weight and duration of procedure, consumption of rocuronium and alfentanil, duration of propofol infusion, time from withdrawal of propofol until eye opening, duration of stay in the post-anesthesia intensive care unit and time until total recovery. A questionnaire assessed the presence of intraoperative awareness and degree of satisfaction. The data were analyzed by Student's t and a chi square tests, with statistical significance at p < 0.05. RESULTS: Demographic variables (age, weight and height) were similar, as were duration of propofol infusion, total dose of alfentanil and rocuronium, evolution of blood pressure and heart rate. Statistically significant differences in BIS were observed at two times, T4 and T5; total propofol administered was 32.6% lower in group B; and time until eye opening was significantly shorter in group B. No significant differences were observed for time until full recovery. No instances of intraoperative awareness were reported and satisfaction was high in both groups. CONCLUSION: BIS monitoring allows for propofol titration that leads to a mean reduction of 32.6% in consumption, shortening the time until eye opening without causing intraoperative awareness or reducing patient satisfaction.     

脑电双频指数在全凭静脉麻醉中的作用

目的 评价脑电双频指数(BIS)监测对全凭静脉麻醉用药及苏醒质量的影响.方法 鼻内窥镜手术全凭静脉麻醉患者66例随机均分为BIS组(Ⅰ组)和常规组(Ⅱ组),均采用丙泊酚联合雷米芬太尼双通道靶控输注.记录术中麻醉药用量、睁眼时间、拔管时间、语言指令反应恢复时间、定向力恢复时间及术中知晓发生率.结果 Ⅰ组丙泊酚用量显著少于Ⅱ组(P<0.05),而且其睁眼时间、拔管时间、语言指令反应恢复时间、定向力恢复时间均明显短于Ⅱ组(P<0.05).两组均无术中知晓发生.结论 BIS监测可减少全凭静脉麻醉丙泊酚用量并改善麻醉苏醒质量.     

SNAP index and Bispectral index during different states of propofol/remifentanil anaesthesia

The accuracy of the new SNAP index with the Bispectral index (BIS) to distinguish different states of propofol/remifentanil anaesthesia was compared in 19 female patients who were undergoing minor gynaecological surgery. Comparisons of the SNAP index, BIS, spectral edge frequency, mean arterial blood pressure and heart rate were performed. The ability of all parameters to distinguish between the steps of anaesthesia -awake vs. loss of response, awake vs. anaesthesia, anaesthesia vs. first reaction and anaesthesia vs. extubation - were analysed with the prediction probability. The prediction probability to differentiate between two interesting nuances of anaesthetic states -loss of response vs. first reaction - was calculated. Only the BIS showed no overlap between the investigated steps of anaesthesia. Both the SNAP index and BIS failed to differentiate the nuances of anaesthesia. The SNAP index and BIS were superior to mean arterial blood pressure and heart rate and spectral edge frequency in distinguishing between different steps of anaesthesia with propofol and remifentanil and provided useful additional information.     

Bispectral index and state entropy of the electroencephalogram during propofol anaesthesia

Editor—We read with interest the study by Bonhomme andcolleagues,¹ in which some interesting differences from ourpublished data² have emerged. We agree that Bland–Altmananalysis appears to be the right statistical test to performin an attempt to determine the degree of agreement between twomeasurement techniques. The only two studies that used the Bland–Altmananalysis to compare BIS and SE have been published by Bonhommeand our group. We found a good comparability (mean difference0.1) between the two (the upper and lower limits of agreementwere –19.9 and 19.6). Bonhomme used the same type of analysison data pairs averaged over 1 min over the entire period andreported a mean difference of 2.5 and similar upper and lowerlimits of agreement (–19.5 and 24.6). We agree that thismay be     

The effect of bispectral index monitoring on end-tidal gas concentration and recovery duration after outpatient anesthesia

We performed this study to determine whether instituting monitoring of bispectral index (BIS) throughout an entire operating room would affect end-tidal gas concentration (as a surrogate for anesthetic use) or speed of recovery after outpatient surgery. Primary caregivers (n = 69) were randomly assigned to a BIS or non-BIS Control group with cross-over at 1-mo intervals for 7 mo. Data were obtained in all outpatients except for those having head-and-neck surgery. Mean end-tidal gas concentration and total recovery duration were compared by unpaired t-test. Overall, 469 patients (80%) received propofol for induction and sevoflurane for maintenance. This homogeneous group was selected for statistical analysis. Mean end-tidal sevoflurane concentration was 13% less in the BIS group (BIS, 1.23%; Control, 1.41%; P < 0.0001); differences were most evident when anesthesia was administered by first-year trainees. Mean BIS values were 47 in the BIS-Monitored group. Total recovery was 19 min less with BIS monitoring in men (BIS group, 147 min; Controls, 166 min; P = 0.035), but not different in women. We conclude that routine application of BIS monitoring is associated with a modest reduction in end-tidal sevoflurane concentration. In men, this may correlate with a similar reduction (11%) in recovery duration.     

Bispectral index monitoring does not improve early recovery of geriatric outpatients undergoing brief surgical procedures

PURPOSE: To assess if titration of sevoflurane using the bispectral index (BIS) monitor improves the early and intermediate recovery in geriatric outpatients undergoing brief urologic procedures under general anesthesia without muscle relaxants. METHODS: After a standardized induction with propofol and fentanyl, a laryngeal mask airway was inserted and sevoflurane was administered in combination with 60% nitrous oxide in oxygen for maintenance of anesthesia in spontaneously breathing outpatients. In the Control group (n = 25), sevoflurane and fentanyl were titrated according to standard clinical practice. In the BIS-directed group (n = 25), sevoflurane was titrated to maintain a BIS value between 50 and 60, and supplemental fentanyl, 25 mug iv boluses were administered to treat tachypnea. The intraoperative anesthetic and analgesic requirements, as well as the times to eye opening, removal of the laryngeal mask airway device, response to simple commands, orientation to person and place, and postanesthesia care unit discharge eligibility (fast-track score of 14) were assessed at specific time intervals. RESULTS: The minimum alveolar concentration-hour of sevoflurane (0.25 +/- 0.15 and 0.31 +/- 0.2) and end-tidal concentrations of sevoflurane at the end of surgery (0.3 +/- 0.3 and 0.4 +/- 0.20%) did not differ significantly between the Control and BIS-directed groups, respectively. Although the percentage of patients requiring supplemental boluses of fentanyl was reduced in the BIS-directed group (16 vs 48%, P <0.05), the intraoperative BIS values and recovery times were similar in the two groups. CONCLUSION: In this non-paralyzed elderly outpatient surgery population, the use of BIS monitoring for titrating the maintenance anesthetic (sevoflurane) failed to improve the early recovery process.     

Skin conductance monitoring compared with Bispectral Index to assess emergence from total i.v. anaesthesia using propofol and remifentanil

Background. Arousal after sevoflurane anaesthesia has been detectableby monitoring changes in skin conductance (SC) with similaraccuracy as monitoring Bispectral Index (BIS^®). As SC monitoringdetects changes in sympathetic tone, the measurements mightbe confounded by the sympatholytic properties of propofol, acomponent of total i.v. anaesthesia (TIVA). Therefore in thisstudy, monitoring of SC during emergence from TIVA was comparedwith the monitoring of BIS^®. Methods. Twenty-five patients undergoing plastic surgery wereinvestigated. The number of fluctuations of SC per second (NFSC),BIS^® and haemodynamic variables [systolic blood pressure(SBP) and heart rate (HR)] were recorded simultaneously. Theperformance of the monitoring devices in distinguishing betweenthe clinical states ‘steady-state anaesthesia’,‘first clinical reaction’ and ‘extubation’were compared using the method of prediction probability (Pk)calculation. Results. BIS^® showed the best performance in distinguishingbetween ‘steady-state anaesthesia’ and ‘firstreaction’ (Pk BIS^® 0.99 vs NFSC 0.80; P<0.01),and ‘steady-state anaesthesia’ and ‘extubation’(Pk BIS^® 1.00 vs NFSC 0.91; P<0.05); the time from firstchange of BIS^® or NFSC to a first clinical reaction wassignificantly longer for NFSC (median BIS^® 135 s vs NFSC191 s; P<0.05). BIS^® and NFSC performed better in distinguishingbetween the investigated clinical states than SBP and HR. Conclusions. In this study, BIS^® was found to predict arousalwith a higher probability but slower response times than NFSCin patients waking after TIVA.     

Duration and recovery profile of cisatracurium after succinylcholine during propofol or isoflurane anesthesia

Study Objective: To determine the duration and recovery profile of maintenance doses of cisatracurium besylate following succinylcholine, and during propofol or isoflurane anesthesia.

Design: Randomized, open-label study.

Setting: Operating suite of a university-affiliated medical center.

Patients: Forty ASA physical status I and II adult patients having elective surgery with general anesthesia lasting longer than 90 minutes.

Interventions: Following a standardized induction sequence, a baseline electromyogram (EMG) was obtained. An intubating dose of intravenous (IV) succinylcholine 1.0 mg/kg was administered. Ventilation was maintained with a face mask until the first twitch (T₁) of the evoked train-of-four (TOF) reached 10% of control when tracheal intubation was performed. Spontaneous recovery from neuromuscular blockade was allowed to occur until the first twitch returned to 25% of control. Patients then were randomized to receive cisatracurium as follows. Group 1: 0.025 mg/kg [0.5 × 95% effective dose (ED₉₅)]; Group 2: 0.05 mg/kg (ED₉₅); Group 3: 0.05 mg/kg (ED₉₅); and Group 4: 0.1 mg/kg (2×ED₉₅). Anesthesia for Groups 1 and 2 were maintained with isoflurane 1% to 2%, 66% nitrous oxide (N₂O) in oxygen (O₂), and in Groups 3 and 4, anesthesia was maintained with propofol 80 to 160 μg/kg/min, 66% N₂O in O₂. The TOF-evoked EMG was recorded at 10-second intervals. The time for the evoked EMG to spontaneously return to 25%, 50%, and 75% of the original baseline was recorded.

Measurements and Main Results: There were 10 patients in each of the four groups. The duration of action of cisatracurium 0.05 mg/kg (ED₉₅) after an intubating dose of succinylcholine is 24.5 ± 10 minutes and 21.3 ± 9 minutes during anesthesia maintained with isoflurane and propofol, respectively. Doubling the dose of cisatracurium resulted in approximately twice the duration of action (40.2 ± 7 min) during propofol anesthesia. Following a dose of cisatracurium 0.025 mg/kg (0.5×ED₉₅), the T₁ of the EMG-evoked response did not decrease below 25% in 7 of 10 patients.

Conclusion: Following succinylcholine, the duration of action of a single dose of cisatracurium 0.05 mg/kg is 20 to 25 minutes during anesthesia maintained with propofol or isoflurane. The duration and recovery profile of cisatracurium is dose dependent during propofol and isoflurane anesthetics. Cisatracurium 0.025 mg/kg is an inadequate maintenance dose following recovery from succinylcholine and it fails to provide adequate surgical relaxation.