Acupressure for prevention of pre-operative anxiety: a prospective, randomised, placebo controlled study

Pre-operative anxiety is associated with many unwanted effects such as increased analgesic and anaesthetic requirement, postoperative pain and prolonged hospital stay. In the present study, we investigated the effects of acupressure on pre-operative anxiety and bispectral index (BIS) values. Seventy-six adults, ASA grade I and II, undergoing elective surgery, were randomly assigned to two equal groups. Group 1 (control) received acupressure at an inappropriate site and group 2 (acupressure) received acupressure at extra 1 point. The study was conducted during the pre-operative period and the duration of the study was 40 min (acupressure was applied for 10 min and thereafter patients were observed for another 30 min). Anxiety was recorded on a visual stress scale (VSS) at the start of the study and thereafter at 10 and 40 min. BIS was recorded at 0, 2, 5, 10, 12, 15, 30 and 40 min. The VSS decreased in both groups following pressure application for 10 min: median VSS (interquartile range) were 5 (1) vs. 8 (1) in the acupressure and 7 (0) vs. 8 (1) in the control groups (p < 0.001). Both pre-operative anxiety and BIS decreased significantly during acupressure application at extra 1 point (p < 0.001). Acupressure is effective in decreasing both pre-operative anxiety and BIS; however, these effects are not sustained 30 min following release of acupressure. Further studies are needed to elucidate the duration for which acupressure is effective.     

The influence of acupressure on the monitoring of acoustic evoked potentials in unsedated adult volunteers

Approaches for monitoring depth of anesthesia can be influenced by things other than anesthetics. In this study, we evaluated the influence of acupressure on the A-line autoregressive index (AAI) and on stress levels in unsedated volunteers. Fifteen unsedated adult volunteers received pressure on the acupuncture Extra 1 point (EP) and on a control point for 10 min on different days. AAI was recorded 5 min before, during, and 5 min after the interventions. Before and after the procedures, the volunteers quantified their level of stress by means of a visual analog stress scale (VSS; 0-100). Corresponding data were compared by Wilcoxon's signed rank test (Bonferroni correction, P < 0.05). Data are median (range). AAI decreased from 73 (40-99) to 53 (33-94) after 10 min of pressure on EP (P = 0.0044). Five minutes after release of pressure there was no difference compared with initial values. There was a statistically significant difference between VSS before and after pressure on EP (36 [7-67] to 15 [0-44]; P = 0.0066), but not on control point. In conclusion, there was a wide range of AAI values in awake volunteers. The AAI was influenced by acupressure performed on the EP in unsedated adult volunteers. Acupressure on this point significantly reduced stress levels.     

Effect of aminophylline on bispectral index

BACKGROUND: The aim of the present study was to investigate the effects of aminophylline on BIS as well as clinical recovery in patients anesthetized with sevoflurane. METHODS: Sixty patients with status of ASA I-II scheduled for elective surgery were enrolled in this study. Anesthesia was induced by 2 mg kg(-1) of propofol and 0.5 mg kg(-1) of atracurium, maintained with 1:1 ratio of oxygen and nitrous oxide and 2-2.5% sevoflurane, keeping BIS values at 50 +/- 5. During the last 30 min of the operation no muscle relaxant was given and anesthesia was continued without decreasing anesthetic concentration. After sevoflurane discontinuation, saline was given to Group P, and 5 mg kg(-1) of aminophylline was given to Group A. Bispectral index values, heart rate, blood pressure and oxygen saturation were determined in all the patients before and every min after injection of the test drug for 15 min. The following variables were measured in both groups: eye opening, extubation time, response to command, Aldrete scores, and performing three simple arithmetic calculations. RESULTS: Between groups there was no statistically significant difference in mean arterial blood pressure, SpO2 and anesthesia time. Heart rate was found to be statistically higher (P < 0.001) at 2 to 6 min in Group A when compared with group P. Eye opening, verbal response, extubation and arithmetic calculation times were significantly shorter (P < 0.001) in Group A. Bispectral index scores were significantly higher in Group A at 1 to 12 min after aminophylline injection when compared with placebo (P < 0.001). Conclusion: Recovery from sevoflurane anesthesia and BIS scores are improved in early period when aminophylline is given at emerging from anesthesia.     

Dexmedetomidine infusion during caesarean section under general anaesthesia: Evaluation of maternal awareness using BIS,maternal and neonatal outcomes

Study objectives

The present study investigated the effect of dexmedetomidine infusion on bispectral index and hemodynamic values for patients undergoing cesarean section under general anesthesia as well as the postoperative maternal and fetal outcomes.

Effects of acupressure, manual acupuncture and Laserneedle acupuncture on EEG bispectral index and spectral edge frequency in healthy volunteers

BACKGROUND AND OBJECTIVE: The main purpose of this study was to investigate the effects of sensory (acupressure and acupuncture) and optical stimulation (Laserneedle acupuncture) on electroencephalographic bispectral index, spectral edge frequency and a verbal sedation score. METHODS: Twenty-five healthy volunteers (mean age +/- SD: 25.5 +/- 4.0yr) were investigated during the awake state. The acupuncture point Yintang and a placebo control point were stimulated. The study was performed as a randomized, controlled and partly blinded cross-over trial. RESULTS: Bispectral index and spectral edge frequency values both decreased significantly (P < 0.001) during acupressure on Yintang to values of 62.9 (minimum 35) +/- 13.9 bispectral index and to 13.3 (minimum 2.9) +/- 8.1 Hz (spectral edge frequency right) and 13.8 (minimum 2.7) +/- 7.3 Hz (spectral edge frequency left), respectively. Bispectral index was also significantly (P < 0.05) affected by Laserneedle acupuncture and acupressure on the control point but the changes were not clinically relevant, 95.4 +/- 4 and 94.2 +/- 4.8, respectively. All interventions significantly (Yintang: P < 0.001; control point: P < 0.012) reduced verbal sedation score. CONCLUSIONS: The study highlights the electroencephalographic similarities of acupressure induced sedation and general anaesthesia as assessed by bispectral index and spectral edge frequency.     

Ephedrine,but not phenylephrine,increases bispectral index values during combined general and epidural anesthesia

Ephedrine and phenylephrine are used to treat hypotension during combined general and epidural anesthesia, and they may change anesthetic depth. In the current study, we evaluated the effects of ephedrine versus phenylephrine on bispectral index (BIS) during combined general and epidural anesthesia. After injection of ropivacaine through the epidural catheter, general anesthesia was induced with propofol and vecuronium, and was maintained with 0.75% sevoflurane. Approximately 10 min after the intubation, BIS was recorded as a baseline value. Patients with decreases in arterial blood pressure <30% of the preanesthetic values were defined as control group (n = 9). Patients who had to be treated for larger decreases in arterial blood pressure were randomly assigned to receive ephedrine 0.1 mg/kg (n = 17) or phenylephrine 2 micro g/kg (n = 17). BIS values were recorded at 1-min intervals for 10 min. BIS in the ephedrine group was significantly larger from 7 to 10 min than that in the control and phenylephrine groups (P < 0.05). Seven patients in the ephedrine group had BIS >60, whereas no patient in the control and phenylephrine groups had BIS >60 (P < 0.005). Ephedrine, but not phenylephrine, increased BIS during general anesthesia combined with epidural anesthesia.     

Physostigmine does not antagonize sevoflurane anesthesia assessed by bispectral index or enhances recovery

In this double-blinded study, we investigated the effect of physostigmine on sevoflurane anesthesia and recovery. Forty female patients scheduled for breast biopsy were randomly assigned to receive either physostigmine 2 mg IV or an equal volume of normal saline after skin closure. Anesthesia was induced and maintained with sevoflurane in oxygen. After skin closure, a steady state of 0.6% inspired and end-tidal sevoflurane concentration was obtained, heart rate, blood pressure, and Bispectral index (BIS) baseline values were recorded, and physostigmine or normal saline was administered. Hemodynamics and BIS values were also recorded 5, 8, and 10 min after treatments. Anesthesia was discontinued, and orientation, sedation, sitting ability, and "picking up matches" scores were recorded immediately after extubation and 15 and 30 min later. No differences were found between the two groups in BIS (69, 70, 70, and 71 in the Physostigmine group versus 70, 74, 75, and 76 in the Control group) or blood pressure. Only heart rate was increased 8 min after physostigmine (P < 0.05 versus the control). Scores assessing early recovery were similar in the two groups at all time points. We conclude that physostigmine does not change BIS or enhance recovery after sevoflurane anesthesia. IMPLICATIONS: This double-blinded, randomized study investigated the impact of physostigmine of BIS values during 0.6% sevoflurane anesthesia as well as in the postoperative recovery, when sevoflurane is administered as a sole anesthetic. Physostigmine has no effect on BIS values or on the tests assessing recovery.     

脑电双频指数-靶控输注注射泵闭环丙泊酚靶控输注应用于妇科腹腔镜手术的安全效益研究

目的 观察BIS-靶控输注(target controlled infusion,TCI)注射泵闭环丙泊酚TCI对妇科腔镜手术患者丙泊酚的节约效应及血流动力学的影响. 方法 纳入ASA分级Ⅰ、Ⅱ级择期行妇科腔镜手术的患者40例,采用计算机随机数字表分组分为闭环组和开环组,每组20例.闭环组采用BIS监测闭环丙泊酚TCI维持全身麻醉,开环组采用BIS监测下人工调整丙泊酚TCI血浆效应浓度2～5 mg/L维持全身麻醉,BIS目标值50±5;瑞芬太尼血浆效应浓度4μg/L TCI.记录两组在入室后5 min(T0)、诱导后气管插管前(T1)、插管后1 min(T2)、插管后5 min(T3)、手术切皮时(T4)、切皮后30 min(T5)、缝皮(T6)、手术结束(T7)、意识恢复(T8)、拔管即刻(T9)及拔管后5 min(T10)等时点MAP、HR、BIS值的变化,同时记录两组患者诱导及维持丙泊酚用药量、苏醒时间及进入PACU时的疼痛数字评分(numerical rating scale,NRS)及Ramsay镇静评分. 结果 术中维持丙泊酚剂量闭环组[(6.2±1.4) mg· kg-1·h-1]较开环组[(6.9±1.0)mg·kg-1·h-1]降低了10％,两组各时点MAP、HR、BIS差异无统计学意义(P＞0.05),闭环组切皮时MAP、HR、BIS波动明显小于开环组(P＜0.05).两组患者苏醒时间、NRS及Ramsay镇静评分差异无统计学意义(P＞0.05). 结论 BIS-TCI注射泵闭环丙泊酚TCI与常规BIS监测下开环丙泊酚TCI可同样安全地应用于临床,可对患者个体化合理给予全身麻醉药物,并可部分降低术中丙泊酚使用剂量,降低麻醉后手术前的循环波动.同时,避免麻醉医师手动调控TCI靶控血浆浓度,极大地降低了麻醉医师的工作量,并使围麻醉期更加平稳安全.     

Validation of the bispectral index monitor for measuring the depth of sedation in children

The Bispectral Index (BIS) is an empirically calibrated number derived from adult electroencephalograph data that correlates with the depth of sedation in adults. We tested the hypothesis that the BIS score is a valid measure of the depth of pediatric sedation in a study designed to avoid limitations of a previously published report. BIS values from 96 healthy ASA physical status I-II children aged 1-12 yr undergoing sedation were continually recorded and electronically transferred to a computer. Two independent observers blinded as to BIS score evaluated sedation using the Observer's Assessment of Alertness/Sedation (OAA/S) and the University of Michigan Sedation Scale (UMSS) at 3-5 min intervals. There was a significant correlation between BIS and UMSS and between BIS and OAA/S by both the Spearman's rank correlation test and by prediction probability (P < 0.001). In children <6 yr, there was a significant correlation between BIS and the clinical sedation scores for subgroups undergoing invasive and noninvasive procedures (P < 0.001). There was also good agreement between the 2 independent observers who assessed clinical sedation scores (kappa = 0.51, P < 0.001). We conclude that the BIS monitor is a quantitative, nondisruptive and easy to use depth of sedation monitor in children.     

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.     

Can we improve the assessment of discharge readiness?: A comparative study of observational and objective measures of depth of sedation in children

BACKGROUND: Current recommended discharge criteria might not be rigorous enough to detect residual sedation. This study evaluated the use of the Bispectral Index (BIS monitor), the University of Michigan Sedation Scale (UMSS; i.e., 0-4 observational scale), and a Modified Maintenance of Wakefulness Test (MMWT; visual observation of the time the child is able to stay awake) in assessing return to baseline status. METHODS: Twenty-nine children sedated for echocardiographic examination were studied. Nurses administered sedatives and monitored and discharged children according to institutional guidelines. Children were monitored with the BIS(R) throughout the study. Trained observers assigned UMSS scores every 10-15 min until revised discharge criteria were met (i.e., UMSS score of 0 or 1, MMWT duration >/= 20 min). The MMWT value was recorded at each observation following the procedure. Subsequently, blinded observers recorded average BIS values for the 5 min before each UMSS observation. RESULTS: There were moderate correlations between the BIS, MMWT, and UMSS scores (r = 0.68-0.78; P < 0.01). Revised criteria correctly identified children who were awake and alert (BIS value >/= 90) in 88% of the cases. Only 55% of the children had returned to baseline BIS values when discharged by the nurse, compared with 92% when revised criteria were met (P < 0.05). It took longer to meet revised criteria compared with standard criteria (75.3 +/- 76.2 min vs. 16.4 +/- 13.1 min; P = 0.001). CONCLUSIONS: The incorporation of specific, objective discharge criteria (i.e., UMSS score of 0 or 1, MMWT duration >/= 20 min) may ensure a status closer to baseline (BIS value >/= 90) compared with nursing judgment using standard criteria. However, such assurance may delay the discharge of sedated children.     

Anesthetic considerations for magnetic seizure therapy: a novel therapy for severe depression

Electroconvulsive therapy (ECT) is a highly effective treatment for severe depression. However, its use is associated with significant posttreatment cognitive impairment. Magnetic seizure therapy (MST) was developed as an alternative therapy that could reduce postseizure side effects through the induction of more "focal" seizure activity. Using an open-parallel study design, we compared 20 case-matched patients undergoing a series of either ECT or MST procedures with respect to their anesthetic, muscle relaxant, and cardiovascular drug requirements, effects on cardiovascular and electroencephalographic bispectral index (BIS) values, and early recovery times. We found that MST was associated with a reduced time to orientation (4 +/- 1 versus 18 +/- 5 min; P < 0.01) compared with ECT. To minimize residual muscle paralysis after MST, a reduction in the succinylcholine dosage (38 +/- 17 versus 97 +/- 2 mg; P < 0.01) was required. The BIS values were higher before, and lower immediately after, the stimulus was applied in the MST (versus ECT) group. The Hamilton depression rating scale score was significantly reduced from the baseline value in both treatment groups; however, the posttreatment score was lower after the series of ECT treatments (6 +/- 6 versus 14 +/- 10; P < 0.05). We conclude that MST was associated with a decreased requirement for muscle relaxants, reduced variability in the BIS values after seizure induction, and a more rapid recovery of cognitive function compared with ECT. Further studies are required to evaluate the antidepressant efficacy of MST versus ECT when they are administered at comparable levels of cerebral stimulation.     

Acupressure for postoperative nausea and vomiting in gynaecological patients receiving patient-controlled analgesia

BACKGROUND AND OBJECTIVES: To evaluate the effectiveness of acupressure in preventing nausea and vomiting in patients undergoing gynaecological operations and receiving a patient-controlled analgesia device. METHODS: Patients aged between 40 and 65 yr were included. Exclusion criteria were obesity, diabetes mellitus, and history of motion sickness, postoperative nausea and vomiting, or smoking. Patients were randomized into one of two groups, acupressure and control. In the acupressure group, acupressure bands were placed on both wrists with the plastic bead positioned at the P6 point. In controls, beads were placed at a non-acupoint site. All patients received a standard general anaesthetic. Postoperatively, patients were connected to a patient-controlled analgesia device with morphine (loading dose 5 mg, background infusion 1 mg h-1, bolus dose 1 mg and lock-out time 10 min). Pain and sedation scores, respiratory rate, heart rate, arterial pressure and oxygen saturation were recorded for 24 h. Metoclopramide 10 mg was administered intravenously as a rescue antiemetic. RESULTS: Fifty patients received acupressure and 50 were controls. In the acupressure group, 33% of patients had nausea compared with 63% controls. The cumulative incidence of vomiting at 24 h was 25% with acupressure and 61% in controls. The incidence of nausea, vomiting and antiemetic use was significantly lower with acupressure. CONCLUSIONS: Acupressure at the P6 meridian point is an effective alternative for the prevention of nausea and vomiting in patients receiving patient-controlled analgesia with morphine after gynaecological surgery.     

Can We Improve the Assessment of Discharge Readiness?: A Comparative Study of Observational and Objective Measures of Depth of Sedation in Children

Background: Current recommended discharge criteria might not be rigorous enough to detect residual sedation. This study evaluated the use of the Bispectral Index (BIS(R) monitor), the University of Michigan Sedation Scale (UMSS; i.e., 0-4 observational scale), and a Modified Maintenance of Wakefulness Test (MMWT; visual observation of the time the child is able to stay awake) in assessing return to baseline status.

Methods: Twenty-nine children sedated for echocardiographic examination were studied. Nurses administered sedatives and monitored and discharged children according to institutional guidelines. Children were monitored with the BIS(R) throughout the study. Trained observers assigned UMSS scores every 10-15 min until revised discharge criteria were met (i.e., UMSS score of 0 or 1, MMWT duration >= 20 min). The MMWT value was recorded at each observation following the procedure. Subsequently, blinded observers recorded average BIS values for the 5 min before each UMSS observation.

Results: There were moderate correlations between the BIS, MMWT, and UMSS scores (r = 0.68-0.78; P < 0.01). Revised criteria correctly identified children who were awake and alert (BIS value >= 90) in 88% of the cases. Only 55% of the children had returned to baseline BIS values when discharged by the nurse, compared with 92% when revised criteria were met (P < 0.05). It took longer to meet revised criteria compared with standard criteria (75.3 +/- 76.2 min vs. 16.4 +/- 13.1 min; P = 0.001).     

Comparative effects of ketamine on Bispectral Index and spectral entropy of the electroencephalogram under sevoflurane anaesthesia

Background. The Bispectral Index (BIS) and spectral entropyof the electroencephalogram can be used to assess the depthof hypnosis. Ketamine is known to increase BIS in anaesthetizedpatients and may confound that index as a guide to steer administrationof hypnotics. We compared the effects of ketamine on BIS, responseentropy (RE) and state entropy (SE) during surgery under sevofluraneanaesthesia. Methods. Twenty-two women undergoing gynaecological surgerywere enrolled in this double-blind, randomized study. Anaesthesiawas induced i.v. and maintained with sevoflurane. Under stablesurgical and anaesthetic conditions, patients were assignedto receive either a bolus of ketamine 0.5 mg kg^–1 or thesame volume of saline. Blood pressure, heart rate, BIS, RE andSE were measured every 2.5 min from 10 min before (baseline)until 15 min after ketamine or saline administration. The maximumrelative increase in BIS, RE and SE compared with baseline wascalculated for each patient. Values are mean (SD). Results. Baseline values were BIS 33 (4), RE 31 (5), SE 30 (5)for the ketamine patients and BIS 35 (3), RE 33 (5) and SE 32(6) for the patients receiving saline. BIS, RE and SE increasedsignificantly from 5 min (BIS) and 2.5 min (RE and SE) afterketamine administration, peaking at 46 (8) (BIS), 52 (12) (RE)and 50 (12) (SE) respectively. The maximum relative increasein RE [42.2 (10.4%)] and SE [41.6 (10.9)%] was higher than thatof BIS [29.4 (10.4%)]. Blood pressure, heart rate and RE–SEgradient did not change in either group. Conclusions. Ketamine administered under sevoflurane anaesthesiacauses a significant increase in BIS, RE and SE without modificationof the RE–SE gradient. This increase is paradoxical inthat it is associated with a deepening level of hypnosis.     

Acupressure and preoperative parental anxiety: a pilot study

In this randomized sham-controlled study we examined the anxiolytic and sedative effects of acupressure on parents in the preoperative holding area before their children's surgery. Sixty-one parents received acupressure either at the Yintang point (midpoint between the two eyebrows) or at a sham point. Anxiety (as measured by the Stait-Trait Anxiety Inventory), arterial blood pressure, and heart rate were assessed before and after the intervention and a Bispectral Index monitor was used to continuously monitor hypnotic sedation levels. Repeated-measures analysis of variance showed that parents in the acupressure group reported significantly less anxiety at 20 min post-intervention as compared with parents in the sham group (37 +/- 10 versus 45 +/- 13, P = 0.03). Bispectral Index values, heart rate, and arterial blood pressure, however, did not differ between the two study groups (P = not significant). We conclude that acupressure at the Yintang point may be used as a treatment for parental preoperative anxiety. Future studies are needed to quantify the magnitude and duration of the anxiolytic effect.     

右美托咪定预注对瓣膜置换术患者麻醉诱导期血流动力学和脑电双频指数的影响

目的观察新型肾上腺素受体激动剂右美托咪定（dexmedetomi（iine,Dex）预注对瓣膜置换术患者麻醉诱导期血流动力学和脑电双频指数（bispectralindex,BIS）值的影响。方法选择择期瓣膜置换术患者30例,采用随机数字表法分为两组：Dex组（D组）和对照组（C组）,每组15例。D组于麻醉诱导前静脉微量泵预注用生理盐水稀释成50ml的Dex（浓度为4mg／L）0．5μg／kg,输注时间为10min,C组以同样方式输注等体积生理盐水。均以依托咪脂、芬太尼、哌库溴铵、咪达唑仑复合诱导麻醉。记录入室后输注Dex前即刻基础值（T1）、输注Dex后5min（T2）、输注Dex后10min麻醉诱导前时刻（T3）、麻醉诱导后1min（T4）、麻醉诱导后3min（T5）、插管前OPN（T6）、插管即刻（T7）、插管后1min（T8）、插管后3min（Tq）、插管后5min（T10）各时点的心率（heartrate,HR）、有创血压值（artefial blood pressure,ABP）[收缩压（systolic blood pressure,SBP）、舒张压（diastolic blood pressure,DBP）、平均动脉压mean artery pressure,MAP）]和BIS变化。结果全麻诱导前,与T1（92．6±2．5）比较,D组BIS在T2（73．2±1．9）、T3（70．1±2．3）时显著下降（P〈0．05或P〈0．01）,C组没有明显变化;全麻诱导期,与T3比较,两组BIS明显下降;气管插管期间,与T6比较,C组在T7时BIS（34．8±2．2）显著增高（P〈0．05或P〈0．01）,而D组BIS无明显变化。与C组比较,D组BIS在T2～T5、T7明显降低（P〈0．05或P〈0．01）。全麻诱导前,与T1比较,D组在T2、T3时ABP略有增高,HR显著降低（P〈0．05或P〈0．01）;全麻诱导期,与T1比较,两组ABP、HR均下降;气管插管期间,与T6比较,D组DBP、MAP、HR在T7、T8略有升高,T9、T10无明显变化（P〉0．05）,C组ABP、HR在B～T10显著增高（P〈0．05或P〈0．01）。与C组比较,D组SBP、MAP在T4-T10和DBP在T3-T10显著增高、HR在T2～T10显著降低（P〈0．05或P〈0．01）。结论静脉预注Dex能明显加深麻醉,BIS降低,减少瓣膜置换术患者气管内插管期心血管反应,血流动力学更加平稳,适合在临床中应用。     

The effect of desflurane and sevoflurane on cerebral oximetry under steady-state conditions

We studied the effect of sevoflurane and desflurane on regional cerebral oxygenation (rSO2). Twenty-two patients undergoing abdominal hysterectomy received sevoflurane and desflurane for 15 min each and 30 min apart under steady-state conditions in a randomized, crossover manner to maintain a bispectral index (BIS) of 40-50. In another 22 patients undergoing the same anesthesia and surgery BIS was maintained at 20-30. During the 15-min administration of each anesthetic at steady-state conditions rSO2, BIS, inspired and end-tidal anesthetic concentrations, end-tidal CO2, Spo2, systolic and diastolic blood pressures, and heart rate were recorded every 3 min. The rSO2 did not differ between sevoflurane and desflurane when BIS values were maintained between 40-50 or 20-30. The MAC(BIS) values required to maintain BIS at 40-50 and at 20-30 were 1.0 versus 1.2 (P = 0.004) and 1.6 versus 1.8 (P < 0.001) for desflurane and sevoflurane respectively. Higher rSO2 values were obtained by 1.6 MAC (71 +/- 13) than by 1 MAC of desflurane (66 +/- 10; P < 0.001) and by 1.8 MAC (72 +/- 11) than by 1.2 MAC of sevoflurane (66 +/- 13; P < 0.001). In conclusion, equipotent concentrations of desflurane or sevoflurane in terms of BIS are associated with similar rSO2 values, but larger anesthetic concentrations of both anesthetics increased the rSO2 values.     

The short-acting beta1-adrenoceptor antagonists esmolol and landiolol suppress the bispectral index response to tracheal intubation during sevoflurane anesthesia

In this randomized, double-blind, controlled study, we tested the hypothesis that the short-acting beta(1)-adrenoceptor antagonists esmolol and landiolol suppress hemodynamic changes and bispectral index (BIS) increases, both of which are induced by tracheal intubation under general anesthesia with sevoflurane alone. Forty-five patients were randomly assigned to the control, esmolol, and landiolol groups (n = 15 each). Anesthesia was induced with sevoflurane in oxygen, with an end-tidal concentration maintained at 1 minimum alveolar anesthetic concentration (MAC). Infusion of saline (control group), esmolol (bolus of 1 mg/kg and then 0.25 mg x kg(-1) x min(-1); esmolol group), or landiolol (bolus of 0.125 mg/kg and then 0.04 mg x kg(-1) x min(-1); landiolol group) was started 5 min after the induction of anesthesia and was continued throughout the study. Tracheal intubation was performed 12 min after anesthesia induction. There were no differences in overall changes of mean arterial blood pressure among the three groups, whereas, at 1-5 min after tracheal intubation, heart rate increased in all groups but was significantly slower in the esmolol and landiolol groups than in the control group (P < 0.05). BIS was between 96 and 98 for all patients at baseline and decreased during the induction of anesthesia. There were no differences in BIS among the three groups before laryngoscopy (39 +/- 5, 39 +/- 5, and 38 +/- 4 in the control, esmolol, and landiolol groups, respectively). BIS increased significantly in the control group (54 +/- 10; P < 0.05) 1 min after intubation, whereas it remained unchanged in the esmolol and landiolol groups (45 +/- 10 and 41 +/- 6, respectively). In conclusion, the increase in both heart rate and BIS after tracheal intubation under 1 MAC sevoflurane anesthesia was suppressed by the concomitant administration of either esmolol or landiolol.     

The effect of music on preoperative sedation and the bispectral index

We assessed the effect of music on the level of sedation and the electroencephalograph bispectral index (BIS) during the preoperative period. Fifty-four ASA physical status I-II patients, scheduled for elective septo-rhinoplastic surgery, were included in the study. Subjects were assigned to receive either music (music group; n = 28) or no music (control group; n = 26) during the preoperative period. Sedative premedication was provided with midazolam 0.08 mg/kg IM. Observer's Assessment of Alertness/Sedation Scales (OAAS) scores and BIS values were recorded at specific time intervals. In the control group, there were more patients with an OAAS score of 1 than in the music group at 30 min after midazolam injection. In addition, there were more patients with an OAAS score of 2 in the control group than in the music group at 30-50 min. However, there were significantly more patients with an OAAS score of 3 in the music group than in the control group at 20-50 min. BIS values of the music group were also smaller than the control group at 30 and 40 min. BIS values were significantly decreased from baseline values at 10-50 min in the music group, whereas BIS values decreased at 30-50 min in the control group. In conclusion, listening to music during midazolam premedication is associated with an increase in sedation level in the preoperative period as reflected by a lower BIS value.