Neuroprotective effect of bispectral index-guided fast-track anesthesia using sevoflurane combined with dexmedetomidine for intracranial aneurysm embolization

Dexmedetomidine has sedative, anxiolytic, analgesic, anti-sympathetic, and anti-shivering effects. Dexmedetomidine might be effective in combination with sevoflurane for anesthesia, but prospective randomized controlled clinical trials with which to verify this hypothesis are lacking. In total, 120 patients who underwent embolization of an intracranial aneurysm were recruited from Anhui Provincial Hospital and Renmin Hospital of Wuhan University of China and randomly allocated to two groups. After intraoperative administration of 2% to 3% sevoflurane inhalation, one group of patients received pump-controlled intravenous injection of 1.0 ~tg/kg dexmedetomidine for 15 minutes followed by maintenance with 0.3 ~tg/kg/h until the end of surgery; the other group of patients only underwent pump-controlled infusion of saline. Bispectral index monitoring revealed that dexmedetomidine-assisted anesthesia can shorten the recovery time of spon- taneous breathing, time to eye opening, and time to laryngeal mask removal. Before anesthetic induction and immediately after laryngeal mask airway removal, the glucose and lactate levels were low, the S100~ and neuron-specific enolase levels were low, the perioperative blood pressure and heart rate were stable, and postoperative delirium was minimal. These findings indicate that dexmedetomidine can effectively assist sevoflurane for anesthesia during surgical embolization of intracranial aneurysms, shorten the time to consciousness and extubation, reduce the stress response and energy metabolism, stabilize hemodynamic parameters, and reduce adverse reactions, thereby reducing the damage to the central nervous system. This trial was registered at the Chinese Clinical Trial Registry （http：//www.chictr.org. cn/） （registration number： ChiCTR-IPR- 16008113）.

Bispectral index in predicting the prognosis of patients with coma in intensive care unit

BACKGROUND: The bispectral(BIS) index is a processed electroencephalogram(EEG) parameter with extensive validation and demonstrated clinical utility. The study aimed to investigate the correlation between the BIS index and the prognosis of patients with coma in the ICU.METHODS: A total of 208 patients with coma in the ICU were enrolled in this study. According to the BIS value, the patients were divided into four groups: group I, BIS value 0 to 20; group II, BIS value 21 to 40; group III, BIS value 41 to 60; and group IV, BIS value greater than 60. The difference in BIS values with the differences in prognosis of patients with coma was compared between the four groups, and the prognosis of patients with coma was stratified into consciousness, coma, vegetative state, and brain death. Subsequently, the best cut-off score of BIS values calculated for determining the correlation between BIS value and mental state was proposed.RESULTS: There are no significant differences in the age and APACHE II scores between the four groups(P>0.05). An inverse correlation was observed between BIS value and mental state(r= –0.749, P=0.00). According to the ROC curve, as BIS value was greater than 42.5, there were higher sensitivity and specificity in conscious-coma patients.CONCLUSION: BIS value is correlated with the prognosis of patients with coma in ICU, and BIS value can be a useful marker for estimating the prognosis of comatose patients.

Bispectral index monitoring as an adjunct to nurse-administered combined sedation during endoscopic retrograde cholangiopancreatography

AIM:To determine whether bispectral index (BIS) monitoring is useful for propofol administration for deep sedation during endoscopic retrograde cholangiopancreatography (ERCP). METHODS:Fifty-nine consecutive patients with a variety of reasons for ERCP who underwent the procedure at least twice between 1 July 2010 and 30 November 2010. This was a randomized cross-over study, in which each patient underwent ERCP twice, once with BIS monitoring and once with control monitoring. Whether BIS monitoring was done during the first or second ERCP procedure was random. Patients were intermittently administered a mixed regimen including midazolam, pethidine, and propofol by trained nurses. The nurse used a routine practice to monitor sedation using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale or the BIS monitoring. The total amount of midazolam and propofol used and serious side effects were compared between the BIS and control groups. RESULTS:The mean total propofol dose administered was 53.1 ± 32.2 mg in the BIS group and 54.9 ± 30.8 mg in the control group (P = 0.673). The individual propofol dose received per minute during the ERCP procedure was 2.90 ± 1.83 mg/min in the BIS group and 3.44 ± 2.04 mg in the control group (P = 0.103). The median value of the MOAA/S score during the maintenance phase of sedation was comparable for the two groups. The mean BIS values throughout the procedure (from insertion to removal of the endoscope) were 76.5 ± 8.7 for all 59 patients in using the BIS monitor. No significant differences in the frequency of < 80% oxygen saturation, hypotension (< 80 mmHg), or bradycardia (< 50 beats/min) were observed between the two study groups. Four cases of poor cooperation occurred, in which the procedure should be stopped to add the propofol dose. After adding the propofol, the procedure could be conducted successfully (one case in the BIS group, three cases in the control group). The endoscopist rated patient sedation as excellent for all patients in both groups. All patients in both groups rated their level of satisfaction as high (no discomfort). During the post-procedural follow-up in the recovery area, no cases of clinically significant hypoxic episodes were recorded in either group. No other postoperative side effects related to sedation were observed in either group. CONCLUSION:BIS monitoring trend to slighlty reduce the mean propofol dose. Nurse-administered propofol sedation under the supervision of a gastroenterologist may be considered an alternative under anesthesiologist.

Comparison of 1.5% lidocaine and 0.5% ropivacaine epidural anesthesia combined with propofol general anesthesia guided by bispectral index

Objective： To compare the effects of epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine on propofol requirements, the time to loss of consciousness （LOC）, effect-site propofol concentrations, and the hemodynamic variables during induction of general anesthesia guided by bispectral index （BIS） were studied. Methods： Forty-five patients were divided into three groups to receive epidurally administered saline （Group S）, 1.5% （w/w） lidocaine （Group L）, or 0,5% （w/w） ropivacaine （Group R） Propofol infusion was started to produce blood concentration of 4 lag/ml. Once the BIS value reached 40-50, endotracheal intubation was facilitated by 0.1 mg/kg vecuronium. Measurements included the time to LOC, effect-site propofol concentrations, total propofol dose, mean arterial blood pressure （MABP）, and heart rate （HR） at different study time points. Results： During induction of anesthesia, both Groups L and R were similar for the time to LOC, effect-site propofol concentrations, total propofol dose, MABP, HR, and BIS. The total doses of propofol administered until 1 min post-intubation were significantly less in patients of Groups R and L compared with Group S. MABP and HR were significantly lower following propofol induction compared with baseline values in the three groups, or MABP was significantly increased following intubation as compared with that prior to intubation in Group S but not in Groups R and L while HR was significantly increased following intubation in the three groups. Conclusion： Epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine has similar effects on the time to LOC, effect-site propofol concentrations, total propofol dose, and the hemodynamic variables during induction of general anesthesia.

Efficacy of Bispectral index-monitored closed-loop targeted-controlled infusion of propofol for laparoscopic radical operation for gastric cancer

Objective:To discuss the efficacy of Bispectral index (BIS)-monitored closed-loop targeted-controlled infusion of propofol for laparoscopic radical operation for gastric cancer.Methods:A total of 106 patients with primary gastric cancer who underwent laparoscopic radical operation for gastric cancer in our hospital between August 2015 and February 2018 were chosen as the research subjects and divided into the control group (n=53) and the observation group (n=53) according to the different anesthesia methods. Control group of patients received BIS-monitored manually adjusted targeted-controlled infusion concentration of propofol, and observation group of patients received BIS-monitored closed-loop targeted-controlled infusion of propofol. The differences in hemodynamic index levels as well as serum contents of inflammatory factors and stress hormones were compared between the two groups of patients before anesthesia (T0), 30 min after surgery started (T1) and 30 min before surgery ended (T2).Results:At T0, the differences in hemodynamic index levels as well as serum contents of inflammatory factors and stress hormones were not statistically significant between the two groups. At T1 and T2, hemodynamic indexes MAP and HR levels of observation group were lower than those of control group at the corresponding time points;serum inflammatory factors sICAM-1, IL-1β, IL-8 and TNF-α contents were lower than those of control group at the corresponding time points;serum stress hormones Cor, T4 and glucagon contents were lower than those of control group at the corresponding time points.Conclusion: BIS-monitored closed-loop targeted-controlled infusion of propofol can effectively stabilize the intraoperative hemodynamics and inhibit the systemic inflammatory stress response in patients with laparoscopic radical operation for gastric cancer.

Comparison of Entropy vs. Bispectral Index Anesthetic Depth Monitoring during Isoflurane Anesthesia in Living Donor Liver Transplantation: Observational Study

Liver transplantation (LT) recipients are known to require less anesthetic agents. Providing minimally required anesthetics while avoiding awareness is especially important in LT recipients because it would help manage perioperative hemodynamic instability with less vasopressor and fast track recovery. This study aims to compare state entropy (SE) against bispectral index (BIS) during isoflurane anesthesia in LT. We adjusted anesthesia to BIS values 40 - 60, and compared it with concomitant SE values. BIS, SE values, and anesthetic requirements according to liver failure severity, etiology and LT stages were analyzed. For BIS-SE differences, SE value that is different from the concomitant BIS by more than 15 was defined as a significant disagreement. Mann Whitney, Kruskal Wallis test and a Poisson exact test were used for analysis. The BIS-SE pair sets of 2895 from 38 patients were analyzed. BIS, SE values and anesthetic requirements were significantly lower in MELD ≥ 20 (p < 0.001 in all) and in alcoholic etiology (p < 0.001 in all). For BIS-SE differences, 320 disagreement data pairs were seen at a rate of 1.33 times/hr (95% CI = [1.19, 1.48], p < 0.001). A significant disagreement was delineated in MELD score ≥ 20 (3.04 times/hr, CI = [2.64, 3.49], p < 0.001), alcoholic etiology (3.19 times/hr, [2.67, 3.78], p < 0.001) and postreperfusion stage (1.63 times/hr, [1.43, 1.85], p < 0.001). In these significant BIS-SE differences, 95.9% (307/320 disagreement data pairs) showed higher BIS than SE. In conclusion, in high MELD and alcoholic etiology, anesthetic requirements were significantly less, and BIS and SE showed great discrepancy with lower SE values. Therefore, when SE monitoring is used during LT, anesthesiologists may need to consider that in high MELD and alcoholic etiology, SE tends to show lower values than the concomitant BIS values that are within optimal anesthetic depth ranges.

The Bispectral Index Interest during General Anesthesia at the University Hospital of Parakou (Republic of Benin) in 2019

Background: The bispectral index (BIS) derived from the electroencephalogram is an additional means of monitoring the depth of narcosis. Objective: To compare the monitoring of the depth of narcosis by the BIS associated with clinical data versus standard monitoring at the University Hospital of Parakou in Benin in 2019. Methods: This was an observational study for descriptive and analytical purposes with prospective data collection, carried out in general surgery and intensive care unit for 4 months. The inclusion criteria were: an age ≥ 18 years, an ASA score ≤ 3, surgery under general anesthesia and informed consent of the patient. Two groups were formed: non-BIS group monitored by clinical parameters (PA, FC, FR, EtCO2, and SpO2) only and BIS group monitored by bispectral index in addition to clinical parameters. Patients were seen 48 hours after the procedure. Results: 36 patients were collected. The mean age was 40.63 ± 16.77 years with a sex ratio of 3. ASA 1 patients represented 86.11% of the sample and ASA2 patients 13.89%. The average doses of Propofol were not significantly reduced in the BIS group (p = 0.555). On the other hand, the period of intraoperative recovery (p-value = 0.007) and the NVPO (p = 0.043;OR = 0.10;95% CI [0.01 - 0.97]) were significantly reduced by the use of BIS. One case of intraoperative memorization (2.78%) was however found in the BIS group. Conclusion: The bispectral index makes it possible to significantly reduce the risk of intraoperative awakening and PONV, and not significantly reduce the consumption of Propofol.

Comparison of Correlation Dimension and Fractal Dimension in Estimating BIS index

This paper compares the correlation dimension (D2) and Higuchi fractal dimension (HFD) approaches in estimating BIS index based on of electroencephalogram (EEG). The single-channel EEG data was captured in both ICU and operating room and different anesthetic drugs, including propofol and isoflurane were used. For better analysis, application of adaptive segmentation on EEG signal for estimating BIS index is evaluated and compared to fixed segmentation. Prediction probability (PK) is used as a measure of correlation between the predictors and BIS index to evaluate the proposed methods. The results show the ability of these algorithms (specifically HFD algorithm) in predicting BIS index. Also, evolving fixed and adaptive windowing methods for segmentation of EEG reveals no meaningful difference in estimating BIS index.

脑电双频指数监测下腋路臂丛神经阻滞复合全身麻醉在肩关节镜手术中的应用效果

目的:探究脑电双频指数(BIS)监测下腋路臂丛神经阻滞复合全身麻醉在肩关节镜手术中的应用效果。方法:选择2020年1月—2023年1月在宁夏医科大学总医院、吴忠市人民医院进行肩关节镜手术的患者86例,应用随机数字表法将其分为对照组(采用BIS监测下锁骨上入路臂丛神经阻滞复合全身麻醉)及观察组(采用BIS监测下腋路臂丛神经阻滞复合全身麻醉),各43例。对比两组不同时刻[麻醉前(T_(0))、气管插管即刻(T_(1))、切皮时(T_(2))、拔管时(T_(3))]心率(HR)、平均动脉压(MAP)、BIS值;对比两组麻醉苏醒后及术后2、12 h疼痛评分[视觉模拟评分法(VAS)]、肌力评分;对比两组术中舒芬太尼用量;对比两组不良反应发生率。结果:T_(0)时,两组HR、MAP比较,差异均无统计学意义(P>0.05);T_(1)、T_(2)、T_(3)时,观察组HR、MAP均低于对照组,差异均有统计学意义(P<0.05);T_(0)、T_(1)、T_(2)时,两组BIS比较,差异均无统计学意义(P>0.05);观察组T_(3)时BIS高于对照组,差异有统计学意义(P<0.05)。观察组麻醉苏醒后及术后6、12 h的VAS评分均低于对照组,肌力评分均高于对照组,差异均有统计学意义(P<0.05)。两组不良反应发生率比较,差异无统计意义(P>0.05)。结论:BIS监测下腋路臂丛神经阻滞复合全身麻醉在肩关节镜手术中的麻醉效果显著,可稳定血流动力学,患者术后疼痛程度较轻,对肌力影响较小,安全性较高。

rSO2-BIS监测在儿童肱骨髁上骨折手术中的应用研究

目的 探讨局部脑氧饱和度(regional cerebral oxygen saturation,rSO2)-脑电双频指数(bispectral index,BIS)监测麻醉方式在儿童肱骨髁上骨折手术中的应用。方法 选取江西省儿童医院骨科2020年1月至2022年12月收治的60例肱骨髁上骨折手术患儿,按随机数字表法分为对照组和观察组,每组30例。观察组患儿麻醉后给予rSO2-BIS监测,对照组患儿给予常规麻醉管理。结果 观察组患儿的丙泊酚中/长链脂肪乳和瑞芬太尼注射液用量明显少于对照组(P<0.05);患儿苏醒时各时间点的心率、血氧饱和度及平均动脉压比较,差异无统计学意义(P>0.05);术后镇痛药补救率低于对照组,拔管时间短于对照组(P<0.05);术后不良反应发生率及不良行为率低于对照组(P<0.001)。多因素分析结果发现丙泊酚中/长链脂肪乳和瑞芬太尼注射液的用量是诱发患儿术后出现不良反应和不良行为的独立危险因素,rSO2-BIS监测是减少患儿术后出现不良行为和不良反应的关键因素(P<0.05)。结论 儿童肱骨髁上骨折术中采用rSO2-BIS监测可降低手术患儿术后不良行为和不良反应的发生率,进而改善术后疗效。

瑞马唑仑联合不同剂量丙泊酚对腹腔镜下全子宫切除术患者麻醉诱导镇静及不良反应的影响

目的探究瑞马唑仑联合不同剂量丙泊酚对腹腔镜下全子宫切除术患者麻醉诱导镇静及不良反应的影响。方法选取2021年4月至2023年8月行腹腔镜下全子宫切除术患者96例,采用随机数字表法分为A、B组各48例,患者均采用瑞马唑仑联合丙泊酚进行麻醉诱导,其中A组丙泊酚剂量为0.5 mg/kg,B组丙泊酚剂量为1.0 mg/kg。比较2组围术期指标、麻醉诱导情况,麻醉诱导开始时(T0)、机械通气前即刻(T1)及机械通气3 min(T2)时血流动力学指标及术中术后不良反应发生情况。结果2组手术时间、术中出血量、补液量比较差异均无统计学意义(P>0.05)。B组麻醉诱导时间短于A组,丙泊酚补救患者少于A组(P<0.05,P<001)。2组T0~T2时心率(HR)、平均动脉压(MAP)、脑电双频指数(BIS)均呈下降趋势(P<0.05),但2组同一时间点HR、MAP、BIS比较无明显差异(P>0.05)。B组总不良反应发生率为60.42%高于A组的25.00%(P<001)。结论瑞马唑仑联合小剂量丙泊酚在腹腔镜下全子宫切除术中可发挥较好的镇静作用和血流动力学稳定作用,丙泊酚剂量为1.0 mg/kg时镇静作用更佳,但不良反应发生率较高。

脑电双频谱指数监测下布托啡诺复合丙泊酚对老年人超声支气管镜检查的影响

目的探讨脑电双频谱指数监测下布托啡诺复合丙泊酚对老年人超声支气管镜检查的影响。方法选择2022年6月至2023年4月期间于本院明确诊断的实施无痛超声支气管镜检查的老年患者180例作为研究对象,随机分为Ⅰ组(单纯丙泊酚组)、Ⅱ组(舒芬太尼复合丙泊酚组)和Ⅲ组(布托啡诺复合丙泊酚组),每组各60例。比较各组麻醉前后血流动力学指标、麻醉、镇痛、镇静效果及不良反应。结果Ⅲ组镜入喉腔和镜检结束时平均动脉压(MAP)和心率(HR)、丙泊酚用量、麻醉起效时间、镜检时间、苏醒时间及不良反应发生率均低于Ⅰ、Ⅱ组,镜入喉腔和镜检结束时SpO_(2)及Ramsay评分高于Ⅰ、Ⅱ组(P<0.05)。结论布托啡诺复合丙泊酚诱导血流动力学指标稳定,能够提升患者舒适度,具有较好的麻醉、镇痛及镇静效果,且术后不良反应更少,更适用于老年超声支气管镜的检查。

BIS指导下丙泊酚联合瑞芬太尼靶控输注对老年髋关节置换患者术中丙泊酚用量和术后谵妄发生率的影响

目的:探讨脑电双频指数(BIS)指导下丙泊酚联合瑞芬太尼靶控输注(TCI)对老年髋关节置换患者术中丙泊酚用量和术后谵妄发生率的影响。方法:回顾性分析老年髋部骨折患者的病例资料,依据患者接受的麻醉方式不同分为两组,即接受BIS指导下丙泊酚联合瑞芬太尼TCI麻醉的髋关节置换患者纳入观察组,接受BIS指导下丙泊酚联合瑞芬太尼持续静脉泵入的同类患者纳入对照组,建立二元Logistics回归分析,构建倾向性评分匹配模型分析得出观察组获取56例病例资料,对照组获取49例病例资料,组间差异无统计学意义(P>0.05)。观察两组不同时间点[入室后(T_(0))、麻醉后(T_(1))、骨水泥后(T_(2))、术毕(T_(3))、出室后(T_(4))、术后3h(T_(5))及术后5h(T_(6))时刻]的平均动脉压(MAP)、心率(HR)、手术一般情况、丙泊酚用量、BIS值维持情况,对比两组不同时间点(术前及术后1h、6h、1d、3d、7d时刻)谵妄评分[谵妄量表分析系统(CAM-CR)],记录两组术后谵妄发生率,比较两组不同时间点(术前及术后1d)的血糖(Glu)及血浆肾上腺素(E)、皮质醇(Cor)水平变化。结果:观察组在T_(1)时刻MAP值相比T_(0)时刻有显著性降低(P<0.05),两组均在T_(2)时刻MAP值相比T_(0)时刻有显著性降低(P<0.05),其中对照组在T_(5)、T_(6)及T_(7)时刻HR值相比T_(4)时刻出现显著性降低(P<0.05);两组手术时间、麻醉时间及术中出血量对比均差异无统计学意义(P>0.05),观察组丙泊酚用量显著少于对照组(P<0.05),观察组BIS值目标范围维持时间比显著高于对照组(P<0.05),观察组苏醒时间、气管拔管时间及定向力恢复时间显著短于对照组(P<0.05);术后1h、6h、1d、3d、7d,两组CAM-CR评分可见先升高后降低,均显著高于术前(P<0.05),观察组术后1h、6h、1d、3d的CAM-CR评分均显著低于对照组(P<0.05),两组术后7d的上述评分较术前和组间同时间点对比均差异无统计学意义(P>0.05);观察组的术后谵妄发生率为5.36%,显著低于对照组的18.37%(P<0.05);术后1d,两组Glu及血浆E、Cor水平相比术前出现显著性升高(P<0.05),但观察组显著低于对照组(P<0.05)。结论:BIS指导下丙泊酚联合瑞芬太尼TCI应用于老年髋关节置换患者术中能稳定血流动力学,改善围手术期指标,并减少丙泊酚用量,改善BIS值维持情况,并促进患者麻醉恢复,减少术后谵妄发生风险,同时能减轻机体应激反应。

脑电双频指数监测下的浅镇静技术在20例牙科焦虑症患者下颌阻生齿拔除中的应用

目的:探讨浅镇静技术在焦虑患者阻生牙拔除术中的应用。方法:对20例下颌阻生牙焦虑患者行丙泊酚静脉输入,在患者脑电双频指数(bispectral index,BIS)达到80~85时拔除阻生牙,术中监测患者心率(heart rate,HR)、平均动脉压(mean arterial pressure,MAP)、呼吸频率及血氧饱和度等,术后指导患者记录视觉模拟评分法(visual analogue scale,VAS)评分及询问患者顺行遗忘情况,采用SPSS 20.0软件包对数据进行数据统计,配对t检验比较术中生理指标与入室时的差异性,采用描述性分析法分析患者术中疼痛情况。结果:所有患者均顺利完成手术,未出现明显不良反应,术中HR、MAP、呼吸频率及血氧饱和度均未出现异常,患者术后VAS评分为1~3分,对手术开始、黏膜切开及牙钻声音顺行遗忘,即焦虑得到缓解。结论:针对牙科焦虑症患者下颌阻生牙的拔除,丙泊酚静脉浅镇静技术(BIS=80~85)即可达到较为满意的效果,减轻患者焦虑,提高舒适度。

Application value of dexmedetomidine in anesthesia for elderly patients undergoing radical colon cancer surgery

BACKGROUND Colon cancer presents a substantial risk to the well-being of elderly people worldwide.With advancements in medical technology,surgical treatment has become the primary approach for managing colon cancer patients.However,due to age-related physiological changes,especially a decline in cognitive function,older patients are more susceptible to the effects of surgery and anesthesia,increasing the relative risk of postoperative cognitive dysfunction(POCD).There-fore,in the surgical treatment of elderly patients with colon cancer,it is of pa-ramount importance to select an appropriate anesthetic approach to reduce the occurrence of POCD,protect brain function,and improve surgical success rates.METHODS One hundred and seventeen patients with colon cancer who underwent elective surgery under general anesthesia were selected and divided into two groups:A and B.Group A received Dex before anesthesia induction,and B group received an equivalent amount of normal saline.Changes in the mini-mental state exami-nation,regional cerebral oxygen saturation(rSO2),bispectral index,glucose uptake rate(GluER),lactate production rate(LacPR),serum S100βand neuron-specific enolase(NSE),POCD,and adverse anesthesia reactions were compared between the two groups.RESULTS Surgical duration,duration of anesthesia,and intraoperative blood loss were comparable between the two groups(P>0.05).The overall dosage of anesthetic drugs used in group A,including propofol and remifentanil,was significantly lower than that used in group B(P<0.05).Group A exhibited higher rSO2 values at the time of endotracheal intubation,30 min after the start of surgery,and immediately after extubation,higher GluER values and lower LacPR values at the time of endotra-cheal intubation,30 min after the start of surgery,immediately after extubation,and 5 min after extubation(P<0.05).Group A exhibited lower levels of serum S100βand NSE 24 h postoperatively and a lower incidence of cognitive dysfunction on the 1st and 5th postoperative days(P<0.05).CONCLUSION The use of Dex in elderly patients undergoing radical colon cancer surgery helps maintain rSO2 Levels and reduce cerebral metabolic levels and the incidence of anesthesia-and surgery-induced cognitive dysfunction.

Bispectral index monitoring prevent awareness during total intravenous anesthesia： a prospective, randomized, double-blinded, multi-center controlled trial

Background Awareness is a serious complication of general anesthesia. In China, the incidence of intraoperative awareness was 1% in patients undergoing total intravenous anesthesia （TIVA）. In this study, we compared the incidence of awareness between Bispectral index （BIS）-guided and routine TIVA protocol and evaluated the effect of BIS on preventing awareness. Methods A prospective, randomized, double-blinded, multicenter controlled trial was performed. Patients （〉18 years of age） undergoing TIVA were randomly divided into BIS-guided group （Group A, BIS was monitored and recommended to maintain between 40-60） and control group （Group B, BIS was monitored but the screen was covered）. The intraoperative BIS values were downloaded and the BIS trends of confirmed awareness cases were analyzed to determine whether light anesthesia existed. Results Of the total 5228 patients, 2919 patients were assigned to Group A and 2309 to Group B. Four cases of confirmed awareness （0.14%） were reported in the BIS-guided group and 15 （0.65%） in the control group （P=-0.002, OR=0.21, 95% confidence intervals： 0.07-0.63）. The incidence of possible awareness （0.14% vs. 0.26%, P=0.485） and dreaming （3.1% vs. 3.1%, P=0.986） was comparable between BIS-guided group and the control group. Among the 19 confirmed awareness cases, intraoperative BIS trends of six cases were downloaded and identified. Five of them showed signs of light anesthesia as BIS 〉60 and lasted 19-106 minutes, whereas one case had a stable BIS trend and the values were within 60 during the operation. Another five awareness cases were reviewed for anesthesia procedures, of which improper light anesthesia were confirmed. Conclusions BIS-guided TIVA （BIS was recommended to maintain between 40-60） decreased the risk of awareness compared with routine TIVA. The main reason for awareness was light anesthesia.

BIS指导下七氟烷吸入在小儿腹腔镜疝囊高位结扎术中的应用价值

目的:探讨脑电双频指数(BIS)指导下七氟烷吸入麻醉在小儿腹腔镜疝囊高位结扎术中的应用的临床价值。方法:选取2020年6月~2022年10月九江市第一人民医院拟实施七氟烷吸入麻醉下腹腔镜疝囊高位结扎术的小儿120例,采用随机数字表法分为BIS组60例(BIS术中维持在40~50)、对照组60例(由麻醉师根据患儿情况调节麻醉药物使用);对比BIS组和对照组患儿不同时间的心率(HR)、平动动脉压(MAP)、血氧饱和度(SpO_(2))及BIS组和对照组患儿的意识消失时间、喉罩置入时间、拔除喉罩时间、苏醒时间、麻醉复苏室(PACU)停留时间、七氟烷使用量、不良反应情况。结果:经重复测量的方差分析法分析,BIS组和对照组的HR、MAP组间差异具有统计学意义(P<0.05),BIS组的HR、MAP测定值波动较对照组小;BIS组和对照组的SpO_(2)测定值差异无统计学意义(P>0.05);BIS组和对照组的意识消失时间、喉罩置入时间组间差异无统计学意义(P>0.05),BIS组的苏醒时间、拔除喉罩时间、PACU停留时间、七氟烷使用量测定值低于对照组,差异有统计学意义(P<0.05);BIS组患者的不良反应发生率(6.67%)明显低于对照组(20.00%),差异有统计学意义(P<0.05)。结论:BIS指导下七氟烷吸入麻醉在小儿腹腔镜疝囊高位结扎术中的应用可减小七氟烷用量、更好的维持术中血流动力学的稳定。

Comparison of the ability of wavelet index and bispectral index for reflecting regain of consciousness in patients undergone surgery

Background Wavelet index （WLI） is a new parameter for monitoring depth of anesthesia based on Wavelet analysis. We observed the change of WLI and bispectral index （BIS） in patients regain of consciousness （ROC） in the absence of frontalis electromyographic （EMG） interference. The aim of this study was to compare the ability of WLI and BIS for reflecting ROC in patients undergone surgery. Methods Twelve patients who were scheduled for maxillofacial surgeries were enrolled in the study. BIS and WLI values were monitored continually. After being given midazolam and remifentanil, patients were asked to squeeze the investigator＇s hand ever 30 seconds. Patients were continuously given propofol until loss of consciousness （LOC1）. Tunstalrs isolated forearm technique was used to test the surgical consciousness in patients. After total muscle relaxation endotracheal intubations were performed, and the patients were connected to a ventilator. Then, propofol was withdrawn until the patients showed regain of consciousness （ROC1） and an awareness reaction. After the command test, patients were readministered with propofol until loss of consciousness （LOC2）. After surgery, all of the sedatives were withdrawn, and the patients were let to regain consciousness （ROC2）, Results The BIS values of twelve patients at ROC1 after using muscle relaxant were much lower than those at LOC1 and ROC2 without using muscle relaxant, showing statistical significance （P 〈0.05）. Meanwhile, the WLI values of twelve patients at ROC1 after using muscle relaxant were much higher than those at LOC1 and equal to ROC2 without using muscle relaxant, showing statistical significances （P 〈0.05） between ROC1 and LOCI. Conclusions This study showed that under muscle relaxation or facial paralysis, when there is no EMG signal, BIS can not accurately reflect regain of consciousness in surgical patients, but WLI can reflect it accurately. So WLI may have advantages for reflecting state of consciousness in surgical patients.

Comparison of C50 for Propofol-remifentanil Target-controlled Infusion and Bispectral Index at Loss of Consciousness and Response to Painful Stimulus in Elderly and Young Patients

Background：In this prospective randomized study,we compared the predicted blood and effect-site C50 for propofol and remifentanil target-controlled infusion （TCI） and the bispectral index （BIS） values at loss of consciousness （LOC） and response to a standard noxious painful stimulus （LOS） in elderly and young patients,respectively.We hypothesized that the elderly patients will require lower target concentration of both propofol and remifentanil at above two clinical end-points.Methods：There were 80 American Society of Anesthesiologists （ASA） physical status Ⅰ Ⅱ unpremedicated patients enrolled in this study,they were divided into elderly group （age ≥65 years,n =40） and young group （aged 18-54 years,n =40）.Propofol was initially given to a predicted blood concentration of 1.2 μg/ml and thereafter increased by 0.3 μg/ml every 30 s until Observer＇s Assessment of Alertness and Sedation score was 1.The propofol level was kept constant,and remifentanil was given to provide a predict blood concentration of 2.0 ng/ml,and then increased by 0.3 ng/ml every 30 s until loss of response to a tetanic stimulus.BIS （version 3.22,BIS Quattro sensor） was also recorded.Results：In elderly group,the propofol effect-site C50 at LOC of was 1.5 （1.4-1.6） μg/ml,was significantly lower than that of young group,which was 2.2 （2.1-2.3） μg/ml,the remifentanil effect-site C50 at LOS was 3.5 （3.3-3.7） ng/ml in elderly patients,was similar with 3.7 （3.6-3.8） ng/ml in young patients.Fifty percent of patients lost consciousness at a BIS value of 57.3 （56.4-58.1）,was similar with that of young group,which was 55.2 （54.0-56.3）.Conclusion：In elderly patients,the predicted blood and effect-site concentrations of propofol at LOC were lower than that of young patients.At same sedation status,predicted blood and effect-site concentrations of remifentanil required at LOS were similar in elderly and young patients.BIS were not affected by age.Low-propofol/high-opioid may be optional TCI strategy for elderly patients.

Changes in the Bispectral Index in Response to Loss of Consciousness and No Somatic Movement to Nociceptive Stimuli in Elderly Patients

Background： Bispectral index （BIS） is considered very useful to guide anesthesia care in elderly patients, but its use is controversial for the evaluation of the adequacy of analgesia.This study compared the BIS changes in response to loss of consciousness （LOC） and loss of somatic response （LOS） to nociceptive stimuli between elderly and young patients receiving intravenous target-controlled infusion （TCI） of propofol and remifentanil.Methods： This study was performed on 52 elderly patients （aged 65-78 years） and 52 young patients （aged 25-58 years）, American Society of Anesthesiologists physical status Ⅰ or Ⅱ.Anesthesia was induced with propofol administered by TCI.A standardized noxious electrical stimulus （transcutaneous electrical nerve stimulation, [TENS]） was applied （50 Hz, 80 mA, 0.25 ms pulses for 4 s） to the ulnar nerve at increasing remifentanil predicted effective-site concentration （Ce） until patients lost somatic response to TENS.Changes in awake, prestimulus, poststimulus BIS, heart rate, mean arterial pressure, pulse oxygen saturation, predicted plasma concentration, Ce of propofol, and remifentanil at both LOC and LOS clinical points were investigated.Results： BISLOC in elderly group was higher than that in young patient group （65.4 ＆#177; 9.7 vs.57.6 ＆#177; 12.3） （t =21.58, P 〈 0.0001） after TCI propofol, and the propofol Ce at LOC was 1.6 ＆#177; 0.3 μg/ml in elderly patients, which was significantly lower than that in young patients （2.3 ＆#177; 0.5 μg/ml） （t =7.474, P 〈 0.0001）.As nociceptive stimulation induced BIS to increase, the mean of BIS maximum values after TENS was significantly higher than that before TENS in both age groups （t =8.902 and t =8.019, P 〈 0.0001）.With increasing Ce of remifentanil until patients lost somatic response to TENS, BISLOS was the same as the BISLOC in elderly patients （65.6 ＆#177; 10.7 vs.65.4 ＆#177; 9.7）, and there were no marked differences between elderly and young patient groups in BISawake, BISLOS, and Ce of remifentanil required for LOS.Conclusion： In elderly patients, BIS can be used as an indicator for hypnotic-analgesic balance and be helpful to guide the optimal administration of propofol and remifentanil individually.