腹腔镜结直肠手术中滴定靶控输注麻醉的应用

目的探讨以脑电双频指数（B1S）和收缩压为滴定目标、以丙泊酚复合瑞芬太尼滴定靶控输注静脉麻醉对腹腔镜结直肠手术中麻醉用药量和麻醉深度的影响。方法选择60例择期腹腔镜结直肠手术患者为研究对象,采用丙泊酚复合瑞芬太尼滴定靶控输注静脉麻醉,以BIS维持40～60、收缩压波动不超过基础值的20％为目标,滴定调节两种药物的血浆靶浓度,当BIS与收缩压的变化趋势出现矛盾时首先调节SBP。记录不同时间点的BIS、血压及麻醉药血浆靶控浓度等。结果麻醉诱导后血压基本平稳,BIS维持在60以内,其中在人工气腹建立后和Trendelenburg体位期间,BIS低至35。40之间：整个麻醉过程中患者均无术中知晓。麻醉期间存在手术刺激时,丙泊酚和瑞芬太尼血浆靶浓度的95％C1分别为2．55～2．65mg／L和4．09～4．26μg／L,其中丙泊酚的血浆靶浓度所推荐剂量。结论在腹腔镜结直肠手术中,以BIS结合收缩压为目标进行丙泊酚复合瑞芬太尼滴定靶控输注静脉麻醉,可维持有的麻醉深度,并减少麻醉药的用量。     

An Investigation of Learning during Propofol Sedation and Anesthesia Using the Process Dissociation Procedure

Background: Many studies have shown that patients may remember words learned during apparently adequate anesthesia. Performance on memory tests may be influenced by explicit and implicit memory. We used the process dissociation procedure to estimate implicit and explicit memory for words presented during sedation or anesthesia.

Methods: We investigated intraoperative learning in 72 women undergoing pervaginal oocyte collection during propofol and alfentanil infusion. One word list was played once before infusion, another was played 10 times during surgery. Venous blood was taken for propofol assay at the end of the intraoperative list. Behavioral measures of anesthetic depth (eyelash reflex, hand squeeze response to command) were recorded and used to adjust the dose of anesthetic where clinically appropriate. On recovery, memory was assessed using an auditory word stem completion test with inclusion and exclusion instructions.

Results: The mean blood propofol concentration was 2.5 [mu]g/ml (median, 2.3 [mu]g/ml; range, 0.7-6.1 [mu]g/ml). Mean alfentanil dose was 2.1 mg (median, 2.0 mg; range, 1.2-3.4 mg). Comparison of target and distractor hits in the inclusion condition showed memory for preoperative words only. However, the process dissociation procedure estimates showed explicit (mean, 0.18;P < 0.001) and implicit (mean, 0.05;P < 0.05) memory for the preoperative words, and a small amount of explicit memory for the intraoperative words (mean, 0.06; 95% confidence interval, 0.01-0.10). Memory performance did not differ between the 17 patients who consistently responded to command and eyelash reflex and the 32 patients who remained unresponsive. Blood propofol concentration and alfentanil dose did not correlate with memory for the intraoperative list.     

An investigation of learning during propofol sedation and anesthesia using the process dissociation procedure

BACKGROUND: Many studies have shown that patients may remember words learned during apparently adequate anesthesia. Performance on memory tests may be influenced by explicit and implicit memory. We used the process dissociation procedure to estimate implicit and explicit memory for words presented during sedation or anesthesia. METHODS: We investigated intraoperative learning in 72 women undergoing pervaginal oocyte collection during propofol and alfentanil infusion. One word list was played once before infusion, another was played 10 times during surgery. Venous blood was taken for propofol assay at the end of the intraoperative list. Behavioral measures of anesthetic depth (eyelash reflex, hand squeeze response to command) were recorded and used to adjust the dose of anesthetic where clinically appropriate. On recovery, memory was assessed using an auditory word stem completion test with inclusion and exclusion instructions. RESULTS: The mean blood propofol concentration was 2.5 microg/ml (median, 2.3 microg/ml; range, 0.7-6.1 microg/ml). Mean alfentanil dose was 2.1 mg (median, 2.0 mg; range, 1.2-3.4 mg). Comparison of target and distractor hits in the inclusion condition showed memory for preoperative words only. However, the process dissociation procedure estimates showed explicit (mean, 0.18; P < 0.001) and implicit (mean, 0.05; P < 0.05) memory for the preoperative words, and a small amount of explicit memory for the intraoperative words (mean, 0.06; 95% confidence interval, 0.01-0.10). Memory performance did not differ between the 17 patients who consistently responded to command and eyelash reflex and the 32 patients who remained unresponsive. Blood propofol concentration and alfentanil dose did not correlate with memory for the intraoperative list. CONCLUSIONS: There was no unprompted recall of surgery, but the process dissociation procedure showed memory for words presented during surgery. This memory was apparently explicit but did not correlate with the measures of depth of anesthesia used.     

Absence of implicit and explicit memory during propofol/remifentanil anaesthesia

BACKGROUND AND OBJECTIVE: High doses of opioid associated with low doses of hypnotic is a popular anaesthetic technique since the use of remifentanil has become widespread. This type of anaesthesia could result in a higher incidence of implicit memory. METHODS: Ten patients were anaesthetised with a target-controlled infusion of remifentanil (target concentration of 8 ng mL(-1)) combined with a target-controlled infusion of propofol with progressive stepwise increases until loss of consciousness was reached. A tape containing 20 words was then played to the patients. Bispectral index (BIS, Aspect Medical Systems, Newton, MA, USA) was continuously monitored during the whole study period. Implicit and explicit memories were tested between 2 and 4 h after recovery. RESULTS: Loss of consciousness was obtained with a mean calculated propofol plasma concentration of 1.3 +/- 0.4 microg mL(-1). At this low hypnotic concentration no implicit or explicit memory was found in the three postoperative memory tests. Median (range) BIS value during word presentation was 93 (80-98). CONCLUSIONS: In our group of young American Society of Anesthesiologists (ASA) I/II patients, no explicit or implicit memory was found when the calculated concentration of propofol combined with a high concentration of remifentanil was maintained at the level associated with loss of consciousness with high BIS values.     

不同镇静程度下健康志愿者事件相关电位与意识和记忆的关系

目的探讨不同镇静程度下事件相关电位(ERPs)与意识和记忆的关系。方法 10名志愿者加入本研究。采用异丙酚静脉靶控输注,记录不同镇静清醒(OAA/S)评分、ERPs各波(N1、P3) 波幅及潜伏期、无创血压、心电图、脉搏血氧饱和度。于OAA/S评分3分、2分时给志愿者听学习表内容。志愿者清醒后4 h进行记忆测试。采用加工分离程序(PDP)分离内隐记忆和外显记忆。计算学习表、干扰表包含测验和排除测验的测试成绩,计算外显记忆、内隐记忆成绩。结果与基础值比较, OAA/S评分3分时,N1潜伏期延长,波幅降低;P3波幅降低,潜伏期延长(P<0．05或0．01);OAA/S评分为2分时,N1潜伏期延长,波幅降低,P3消失;OAA/S评分3分时存在外显记忆和内隐记忆;评分2 分时,意识和外显记忆一同消失,内隐记忆存在。与OAA/S评分3分比较,2分时内隐记忆成绩下降 (P<0．01)。P3波幅与外显记忆成绩呈正相关(n=10,P<0．05或0．01)。结论 P3可作为判断镇静状态下意识和外显记忆存在或消失的指标,但不能反映内隐记忆的存在与否。     

The contribution of remifentanil to middle latency auditory evoked potentials during induction of propofol anesthesia

There is a debate regarding whether opioids, as a component of general anesthesia, are adequately reflected in the assessment of anesthesia based on derivatives of the electroencephalogram. To test the hypothesis of a possible quantitative contribution of remifentanil on middle latency auditory evoked potentials, we studied its interaction with propofol anesthesia in 45 unpremedicated male patients undergoing elective lower limb orthopedic surgery. They were allocated randomly to three groups. The first two groups received remifentanil either with a high (8 ng mL(-1)) or a low (3 ng mL(-1) target concentration using target-controlled infusion (TCI). The third group received spinal anesthesia instead of remifentanil. Anesthesia was induced by a stepwise increase in propofol concentration using TCI. The auditory evoked potential index (AEPex) and calculated propofol effect site concentrations were determined at loss of consciousness and the reaction to laryngeal mask airway insertion was noted. The propofol infusion was then converted to a closed-loop TCI using an AEPex value of 40 as the target. We found no significant contribution of remifentanil alone on the auditory evoked response, whereas increasing concentrations of remifentanil led to a significant decrease of the calculated propofol effect site concentrations (P = 0.023) necessary for unconsciousness. Prediction probability for AEPex was inversely related to the remifentanil concentration and was best for the control group, which received propofol alone. These results support previous findings of a quantitative interaction between remifentanil and propofol for loss of consciousness but question the specific contribution of remifentanil to auditory evoked potentials.     

Anesthetic management of a case of craniotomy using TCI of remifentanil with intraoperative monitoring of motor evoked potential

We experienced anesthetic management using target-controlled infusion (TCI) of remifentanil for craniotomy in which monitoring of motor evoked potential (MEP) was performed. Anesthesia was induced and maintained by TCI of propofol and remifentanil. Vecuronium bromide was not administered except for facilitating tracheal intubation. Target effect-site concentrations (ESCs) of remifentanil during intubation, exposure, dura incision, microsurgery and closure were 6, 10, 8, 5 and 8 ng x ml(-1), respectively. Myogenic MEP was sufficiently elicited throughout the microsurgery without patient's body movement. Extubation was completed 10 min after the end of surgery with administration of remifentanil continued at a target ESC of 2 ng ml(-1) after surgery. Emergence from anesthesia was good without complaint of pain or respiratory disorder or new neurological deficit. It has been reported that remifentanil is suitable because of its wide dosage window with respect to recording MEP. ESC of remifentanil was fixed during continuous infusion, but its absolute value varies depending on lean body mass and/or age. The use of TCI enabled easy elimination of the above effects, adjustment of ESC to the expected value and maintenance of ESC of remifentanil at a constant level. TCI of remifentanil might be suitable for anesthesia with monitoring of MEP.     

Target-controlled infusion anesthesia with propofol and remifentanil compared with manually controlled infusion anesthesia in mastoidectomy surgeries

Target-controlled infusion (TCI) system is increasingly used in anesthesia to control the concentration of selected drugs in the plasma or at the site of drug effect (effect-site). The performance of propofol TCI delivery when combined with remifentanil in patients undergoing elective surgeries has been investigated. Our aim in this study was to assess the anesthesia profile of the propofol and remifentanil target controlled infusion (TCI) anesthesia as compared to the manually controlled infusion (MCI), in mastoidectomy surgery, where a bloodless field is of utmost importance to the surgeon. Sixty patients, aged 18-60 years ASA I-II enrolled in the study, were divided into two equal groups. Group MCI received propofol and remifentanil by conventional-dose-weight infusion method, and Group TCI received propofol 4 microg/ml and remifentanil 4 ng/ml as effect-site target concentration. The hemodynamic variability, recovery profile, postoperative nausea and vomiting (PONV), surgeons satisfaction were assessed. Results were analyzed by SPSS version 11.5. The two groups were comparable with respect to age, ASA class, sex, weight, basal vital signs, operation time. The blood pressure and pulse were above desired levels in some data points in the MCI Group (P < or = 0.05). The PACU stay time to reach Aldret score of 10 was longer in the MCI Group (42.54 +/- 8 vs 59.01 +/- 6 min) (P < or = 0.05). The PONV was more common in the MCI Group (P < or = 0.05). Surgeon's satisfaction of the surgical field showed no significant differences except when described as "good", more common in the TCI Group. TCI is capable to induce and maintain anesthesia as well as MCI. In some stages of anesthesia, the TCI control of vital signs are better than the MCI. In some stages of anesthesia, the TCI control of vital signs are beter than the MCI. Recovery profile and complication rate and surgeon's satisfactions are more acceptable in the TCI than in the MCI Group.     

靶控输注瑞芬太尼和异丙酚麻醉诱导时镇静催眠效应的相互作用

目的 探讨靶控输注(TCI)瑞芬太尼和异丙酚麻醉诱导时镇静催眠效应的相互作用.方法 择期全麻手术患者32例,ASAⅠ或Ⅱ级,年龄22～63岁,体重指数18～25 kg/m2.采用TCI异丙酚和瑞芬太尼诱导麻醉,随机分为4组(n=8):Ⅰ组单纯TCI异丙酚,Ⅱ组～Ⅳ组TCI瑞芬太尼,血浆靶浓度分别为2、4、6 ng/ml,当瑞芬太尼血浆靶浓度与效应室浓度达平衡时开始TCI异丙酚,异丙酚初始血浆靶浓度均为0.5μg/ml,当异丙酚血浆靶浓度与效应室浓度达平衡时以0.5μg/ml的浓度梯度递增诱导至患者意识消失.每隔3min观察睫毛反射和意识状态,同时抽取桡动脉血样6ml,分别采用反相高效液相色谱法和高效液相色谱-紫外法测定异丙酚和瑞芬太尼血药浓度.采用药效学相互作用模型公式和等辐射法分析两者镇静催眠效应的相互作用.结果 与Ⅰ组比较,Ⅱ组～Ⅳ组睫毛反射消失和意识消失时异丙酚血药浓度降低,而Ⅱ组～Ⅳ组随瑞芬太尼血药浓度升高,异丙酚血药浓度依次降低(P<0.05).睫毛反射消失和意识消失时,异丙酚和瑞芬太尼血药浓度用药效学相互作用模型曲线拟合均优于直线回归(P<0.05).拟合出睫毛反射消失时EC50,prop=2.77μg/ml、EC50,rem=26.67 ng/ml,其等辐射法公式EC prop/2.77+Ecrem/26.67=0.69;意识消失时EC50,prop=3.76μg/ml、EC50,rem=31.56 ng/ml,其等辐射法公式Ecprop/3.76+Ecrem/31.56=0.65.结论 麻醉诱导期间,TCI瑞芬太尼(血浆靶浓度2～6ng/ml)和异丙酚在镇静催眠效应上呈协同作用.     

Propofol and remifentanil pharmacodynamic interaction during orthopedic surgical procedures as measured by effects on bispectral index

STUDY OBJECTIVE: To identify and quantify the interaction between propofol and remifentanil during surgical procedures with a bispectral index (BIS) of 50 that was chosen as a continuous surrogate measure for "adequate depth" of anesthesia. DESIGN: Prospective, open-label study. SETTING: Department of orthopedics of a university hospital. PATIENTS: 20 patients undergoing orthopedic surgery. INTERVENTIONS: Anesthesia was induced and maintained with propofol and remifentanil, both administered by target-controlled infusion (TCI). Initial target concentrations of propofol (1.5-8 microg/mL) and remifentanil (2-15 ng/mL) were chosen and alternated in order to maintain the BIS between 45 and 55. If constant target concentrations had been maintained for 20 minutes and the BIS did not depart from the desired range, blood samples were taken to determine propofol concentrations, and the BIS value was recorded. Isobolographic interaction models were fitted to the infusion rates of remifentanil and propofol, predicted target concentrations of both drugs, and measured propofol concentrations versus predicted remifentanil concentrations. MAIN RESULTS: The isobole for the interaction of propofol and remifentanil in the concentration range investigated (propofol 1.5-8 microg/mL and remifentanil 1-30 ng/mL) is a concave up hyperbola ((0.15. C(prop))(3.13). C(rem) = 1) with C(prop) = propofol plasma concentration [microg/mL] and C(rem) = remifentanil blood concentration [ng/mL]). Use of predicted (=TCI target) concentrations or the respective infusion rates did not alter the general shape of the interaction isobole.Conclusions: The interaction between propofol and remifentanil for maintenance of a BIS value between 45 and 55 during surgery is synergistic. This finding applies regardless of whether measured concentrations (for propofol), predicted concentrations of the infusion device, or infusion rates are used as model input. Notably, the interaction isobole of the (clinically readily available) infusion rates provides a useful dosing recommendation for the coadministration of propofol and remifentanil during maintenance of anesthesia.     

靶控输注异丙酚复合瑞芬太尼麻醉用于重症肌无力患者胸腺切除术的效果

目的 探讨靶控输注异丙酚复合瑞芬太尼用于重症肌无力患者胸腺切除术的效果.方法 择期拟行胸腺切除术的重症肌无力患者45例,ASA分级Ⅰ或Ⅱ级,年龄16～64岁,体重45～95 kg.麻醉诱导:靶控输注异丙酚(血浆靶浓度4μg/ml)和瑞芬太尼(效应室靶浓度4 ng/ml),2%利多卡因2～3 ml行气管内表面麻醉后行气管插管,机械通气.麻醉维持:靶控输注异丙酚,血浆靶浓度3～5 μg/ml;靶控输注瑞芬太尼,效应室靶浓度3～6 ng/ml.术毕前30 min,静脉注射舒芬太尼0.15μg/kg进行镇痛.记录首次气管插管的成功情况、切皮时患者体动反应情况、苏醒时间、拔除气管导管时间、术毕拔除气管导管情况及心血管事件的发生情况.结果 所有患者均顺利完成气管插管,首次气管插管成功率100%.切皮时无一例患者发生体动反应;苏醒时间1.0～3.2 min;拔除气管导管时间2.6～7.0 min;术毕拔除气管导管率100%.麻醉诱导期间有3例患者发生心动过缓,4例患者发生低血压,对症处理后均恢复正常;术中有3例患者发生心动过缓,对症处理后恢复正常.结论 靶控输注异丙酚复合瑞芬太尼麻醉可安全有效地用于重症肌无力患者胸腺切除手术.     

Continuous infusion of remifentanil and target-controlled infusion of propofol for patients undergoing cardiac surgery: a new approach for scheduled early extubation

OBJECTIVE: To assess hemodynamic stability, postoperative pain management, and the control and timing of early extubation of a total intravenous anesthetic technique using propofol target-controlled infusion (TCI) and remifentanil in cardiac surgery. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Fifty patients scheduled for elective cardiac surgery. INTERVENTIONS: Premedication consisted of oral midazolam, 0.1 mg/kg. Anesthesia was induced with propofol TCI at a target concentration of 1.5 to 2 microg/mL; remifentanil, 1 microg/kg; and rocuronium. Anesthesia was maintained with propofol at the same target concentration and remifentanil titrated between 0.25 and 1 microg/kg/min. Thirty minutes before the end of surgery, a 0.1-mg/kg bolus of morphine was administered intravenously. Postoperative sedation was achieved by maintaining the propofol infusion until the patient was deemed ready for extubation. Postoperative pain relief was evaluated using a visual analog scale. The intervals between arrival in the intensive care unit, spontaneous ventilation, and extubation were recorded. MEASUREMENTS AND MAIN RESULTS: Included in this study were 36 men and 14 women (American Society of Anesthesiologist = III; New York Heart Association = II) scheduled for cardiac surgery. All patients remained hemodynamically stable throughout the perioperative period. Thirty-seven patients were successfully extubated during the first 4 postoperative hours. Spontaneous breathing was achieved at a mean interval of 15+/-5 minutes after propofol discontinuation. The mean interval to extubation was 163+/-45 minutes after arrival in the intensive care unit. Extubation was performed 48+/-12 minutes after patients were considered ready to awaken. During spontaneous ventilation, 36 patients received additional boluses of morphine (mean, 2.5+/-1 mg). Subsequently, all patients achieved a visual analog scale less than 40 mm. CONCLUSION: The combination of remifentanil and propofol TCI resulted in hemodynamic stability and good postoperative analgesia. This technique allows physicians to schedule the time of extubation in patients undergoing cardiac anesthesia.     

A comparison of target- and manually controlled infusion propofol and etomidate/desflurane anesthesia in elderly patients undergoing hip fracture surgery

Elderly patients have a higher risk of developing adverse drug reactions during anesthesia, especially anesthesia affecting cardiovascular performance. In this prospective randomized study we compared quality of induction, hemodynamics, and recovery in elderly patients scheduled for hip fracture surgery and receiving either etomidate/desflurane (ETO/DES) or target-controlled (TCI) or manually controlled (MAN) propofol infusion for anesthesia. Sixteen patients were anesthetized with ETO (0.4 mg/kg) followed by DES titrated from an initial end-tidal concentration of 2.5%. Eighteen patients received propofol TCI at an initial plasma concentration of 1 microg/mL and titrated upwards by 0.5-microg/mL steps. Fifteen patients received a bolus induction of propofol 1 mg/kg over 60 s followed by an infusion initially set at 5 mg . kg(-1) . h(-1). All received a bolus (20 microg/kg) followed by an infusion of 0.4 microg . kg(-1) . min(-1) alfentanil. According to hemodynamics, concentrations of DES or propofol (TCI group) and propofol infusion rate (MAN group) were respectively adjusted by a step of 20% and 50%. In the TCI and ETO/DES groups, the time spent at a mean arterial blood pressure within 15% and 30% of baseline values was more than 60% and 80% of anesthesia time, whereas in the MAN group it was <30% and 60%, respectively. In the MAN group more anesthetic drug adjustments were recorded (6.4 +/- 2.8 versus 2.5 +/- 1.2 [ETO/DES] and 2.6 +/- 1 [TCI]). TCI improves the time course of propofol's hemodynamic effects in elderly patients.     

Total intravenous anesthesia for intraoperative monitoring of the motor pathways: an integral view combining clinical and experimental data

OBJECT: Monitoring of descending corticospinal pathways by using motor evoked potentials (MEPs) has proven to be useful in preventing permanent neurological deficits during cranial and spinal procedures. Difficulties in interpretation of intraoperative changes in potentials may largely be attributed to the effects of anesthesia. Development of suitable intravenous anesthesia protocols specifically tailored for MEP monitoring, including plasma level target-controlled infusion (TCI), requires precise knowledge of the specific neurophysiological properties of the various agents. METHODS: The effects of alfentanil, sufentanil, fentanyl, remifentanil, thiopental, midazolam, etomidate, ketamine, and propofol on neurogenic and myogenic MEPs were evaluated in an integral study combining clinical data obtained in 40 patients and experimental investigations conducted in 140 animals. The dose-dependent modulation of MEPs after electrical and magnetoelectrical stimulation of the motor cortex was recorded from peripheral muscles and the spinal cord. The results were as follows: opioids, propofol, and thiopental suppressed myogenic, but not neurogenic MEPs in a dose-dependent fashion; remifentanil exerted the least suppressive effects. Etomidate and midazolam did not suppress myogenic MEP, even at plasma concentrations sufficient for anesthesia. Ketamine induced moderate reduction of compound muscle action potential amplitudes only at high doses. Remifentanil and propofol administered via TCI systems allowed recording of myogenic potentials within a defined target plasma concentration range. CONCLUSIONS: Development of standardized total intravenous anesthesia/TCI protocols by using anesthetic agents such as propofol, remifentanil, ketamine, and midazolam, which have favorable pharmacokinetic and neurophysiological properties, will enhance the quality of intraoperative MEPs and promote the use of MEP monitoring as a useful tool to reduce surgery-related morbidity.     

Target-controlled infusion for remifentanil in vascular patients improves hemodynamics and decreases remifentanil requirement

Remifentanil is a potent ultra-short-acting opioid, which permits rapid emergence. However, remifentanil is expensive and may have detrimental effects on hemodynamics in case of overdose. Target-controlled infusion (TCI) permits adapting infusion to pharmacokinetic models. In this prospective randomized study, we compared intra- and postoperative hemodynamics, remifentanil requirement during anesthesia, and postoperative morphine requirement in patients scheduled for carotid surgery, and receiving either continuous IV weight-adjusted infusion of remifentanil (RIVA) or TCI for remifentanil (TCIR). Forty-six patients were enrolled in this study: all were anesthetized by using TCI for propofol. Twenty-three received RIVA (0.5 micro g. kg(-1) x min(-1)) for the induction of anesthesia and endotracheal intubation, with the infusion rate decreased to 0.25 micro g x kg(-1) x min(-1) after intubation, then adapted by step of 0.05 micro g x kg(-1) x min(-1) according to hemodynamics. Twenty-three patients received TCIR (Minto model, Rugloop), with an effect-site concentration at 4 ng/mL during induction, then adapted by step of 1 ng/mL according to hemodynamics. All patients received atracurium and a 50% mixture of N(2)O/O(2). Hemodynamic variables were recorded each minute. The number and duration of hemodynamic events were collected, and total doses of anesthetics (remifentanil and propofol) and vasoactive drugs were noted in both groups of patients. Data were analyzed by using unpaired t-tests. RIVA was significantly associated with more frequent episodes of intraoperative hypotension (16 versus 6, P < 0.001) and more frequent episodes of postoperative hypertension and/or tachycardia requiring more frequent administration of beta-adrenergic blockers (16 vs 10, P < 0.04) in comparison with TCIR. The need for morphine titration was not significantly different between groups. TCIR led to a significantly smaller requirement of remifentanil (700 +/- 290 versus 1390 +/- 555 micro g, P < 0.001) without difference in propofol requirement. This prospective randomized study demonstrated that, during carotid endarterectomy, in comparison with patients receiving remifentanil using continuous RIVA, TCI results in less hypotensive episodes during the induction of anesthesia, in fewer episodes of tachycardia and/or hypertension and a smaller beta-adrenergic blocker requirement during recovery, and a decrease in remifentanil requirement. Recommendations to prefer TCI for remifentanil administration during carotid endarterectomy may be justified. IMPLICATIONS: Remifentanil for intraoperative analgesia in carotid artery surgery is associated with a better stability in perioperative hemodynamics when administered in target-controlled infusion compared with continuous weight-adjusted infusion. This may be related to a smaller requirement of this drug when using target-controlled infusion, as well as a smooth mode of administration.     

The effect of remifentanil on the bispectral index change and hemodynamic responses after orotracheal intubation

In order to examine whether changes in the bispectral index (BIS) may be an adequate monitor for the analgesic component of anesthesia, we evaluated the effect of remifentanil on the BIS change and hemodynamic responses to laryngoscopy and tracheal intubation. Fifty ASA physical status I patients were randomly assigned, in a double-blinded fashion, to one of five groups (n = 10/group) according to the remifentanil target effect compartment site concentration (0, 2, 4, 8, or 16 ng/mL). The target-controlled infusion (TCI) of remifentanil was initiated 3 min after the TCI of propofol that was maintained at the effect-site concentration of 4 microg/mL throughout the study. After the loss of consciousness and before the administration of vecuronium 0.1 mg/kg, a tourniquet was applied to one arm and inflated above the systolic blood pressure in order to detect any gross movement within the first minute after tracheal intubation, which was performed 3 min after remifentanil TCI began. A BIS value was generated every 10 s. Arterial blood pressure and heart rate (HR) were measured every minute, noninvasively. Measures of mean arterial pressure (MAP), HR, and BIS were obtained before the induction, before the start of remifentanil TCI, before laryngoscopy, and 5 min after intubation. The relationships between remifentanil effect-site concentrations and BIS change or hemodynamic responses (changes in MAP and HR) to intubation were determined by logarithmic regression. BIS values were not affected by remifentanil before laryngoscopy. During this period, MAP and HR decreased significantly (P < 0.01) in the remifentanil 8 and 16 ng/mL groups. Changes in BIS, MAP, and HR were negatively correlated with remifentanil effect-site concentration (P < 0.0001). The number of movers in the remifentanil 0-, 2-, 4-, 8-, and 16-ng/mL groups was, respectively, 10, 9, 7, 1, and 0. Hypotensive episodes (MAP < 60 mm Hg) were noted in 1, 2, and 5 patients in the remifentanil 4-, 8-, and 16-ng/mL groups, respectively. We conclude that the addition of remifentanil to propofol affects BIS only when a painful stimulus is applied. Moreover, remifentanil attenuated or abolished increases in BIS and MAP after tracheal intubation in a comparable dose-dependent fashion. IMPLICATIONS: Bispectral index change is as sensitive as hemodynamic responses after a painful stimulus for detecting deficits in the analgesic component of anesthesia. It may, therefore, be a useful monitor of the depth of anesthesia in patients who are incapable of HR and MAP responses to noxious stimuli because of medications or cardiovascular disease.     

靶控输注异丙酚和瑞芬太尼静脉麻醉在隆乳手术中的应用

目的：观察异丙酚复合瑞芬太尼靶控静脉全麻（Target controlled infusion,TCI）用于门诊隆乳手术的麻醉效果。方法：ASAⅠ～Ⅱ级门诊隆乳手术患者60例,随机分为异丙酚复合瑞芬太尼靶控输注组（RP组,n=30）和氯胺酮恒速输注组（K组,n=30）。观察两组患者的术后初醒时间,准确定向时间、离院时间;术中体动程度和次数、术者评价的麻醉效果、呼吸抑制评分和HR、MAP、SpO2及术后并发症的发生情况。结果：两组患者初醒时间、准确定向时间、离院时间有明显差异,RP组明显小于K组（P〈0.05）。麻醉效果评分RP组好于P组（P〈0.05）,且其体动程度评分和次数均低于K组（P〈0.05）,两组间呼吸抑制评分无明显差异（P〉0.05）。RP组术中HR、MAP的变化较K组平稳,差异有显著性（P〈0.05）。RP组恶心、呕吐及不良记忆等术后并发症的发生也明显少于K组（P〈0.05）。结论：异丙芬复合瑞芬太尼芬TCI输注用于隆乳手术,镇静、镇痛效果好,循环更稳定,术后恢复快,不良反应少,是门诊隆乳手术理想的麻醉方法。     

手控与靶控输注瑞芬太尼用于自主呼吸患者的比较研究

背景丙泊酚和瑞芬太尼联合输注用于保留自主呼吸患者的深度镇静时常常会发生一些副反应,尤其是呼吸抑制。这些副反应的产生可能与药物的组合以及给药技术有关。靶控输注（TCI）可能会优化给药方法。因此,在这项对择期结肠镜检术患者进行的前瞻性随机双盲研究中,我们试图回答以下两个问题：第一,使用丙泊酚的同时加用瑞芬太尼是否利大于弊。第二,与手控输注相比,靶控输注瑞芬太尼是否可以减少副反应的发生。方法接受择期结肠镜检术的患者被随机分组：接爱手控持续输注瑞芬太尼细（MCI）（0．125μg·kg^-1·min^-1的速度持续输注2分钟后改为0．05μg·kg^-1·min^-1的速度持续输注）,靶控输注瑞芬太尼组（TCI）（1ng／ml）,或安慰剂组（生理盐水靶控输注或以相应的速度手控持续输注）。所有患者都接受丙泊酚靶控输注,调整靶浓度至相应水平使得患者处于深度镇静、对语言指令无反应的同时保留自主呼吸且不需要辅助通气。结果安慰剂组发生沐动、咳嗽和呃逆、暂时干扰检查操作的人数显著多于研究绍、各组间血流动力学和苏醒指标没有显著临床差异．靶控输注瑞芬太尼减少了丙泊酚的用量。使用瑞芬太尼时,靶控输注组（TCI）与手控输注组（MCI）相比,呼吸减弱和呼吸暂停的发生率明显减低（TCI：n=7,MCI：n=16,P〈0．05）.结论瑞芬太尼和丙泊酚联合应用于保留自主呼吸的深度镇静时比单独丙泊酚能提供更好的结肠镜检术条件与手控输注瑞芩太尼相比,靶控输注瑞芬太昆可以减少丙泊酚的用量并减少呼吸暂停和呼吸抑制的发生率（TCI：n=7,MCI：n=16,P〈0．05）.     

颈内动脉输注异丙酚对胶质瘤切除术患者的脑保护作用

目的 探讨颈内动脉输注异丙酚对胶质瘤切除术患者的脑保护作用.方法 择期胶质瘤切除术患者40例和立体定向胶质瘤活检术患者20例,年龄40～64岁,体重48～73 kg.采用随机数字表法,将拟行胶质瘤切除术患者随机分为2组(n=20):颈内动脉给药组(IA组)和静脉给药组(Ⅳ组).拟行立体定向胶质瘤活检术患者为对照组(C组),采用2%利多卡因15～20 ml术野局部浸润麻醉.IA组和Ⅳ组采用异丙酚-瑞芬太尼-罗库溴铵行麻醉诱导.IA组麻醉诱导后行颈内动脉穿刺置管,颈内动脉靶控输注异丙酚.两组术中调整异丙酚和瑞芬太尼靶浓度,维持BIS值40～60.间断静脉注射罗库溴铵.术中取胶质瘤组织标本,采用免疫组化法测定胶质瘤组织水通道蛋白1(AQP1)和AQP4表达.于麻醉诱导前(T1)、切皮时(T2)、术毕时(T3)、拔除气管导管时(T4)记录MAP和HR;记录手术时间、麻醉用药情况.结果 与T1时比较,Ⅳ组T2,3时MAP和HR降低(P＜0.05),IA组各时点MAP和HR比较差异无统计学意义(P＞0.05).与IA组比较,Ⅳ组MAP和HR降低(P＜0.05).与C组比较,IA组和Ⅳ组AQP1和AQP4表达下调(P＜0.05).与Ⅳ组比较,IA组异丙酚用量减少(P＜0.05),AQP1和AQP4表达、瑞芬太尼和罗库溴铵用量、手术时间比较差异无统计学意义(P＞0.05).结论 与静脉输注异丙酚相比,颈内动脉途径给药不仅可减少胶质瘤切除术患者异丙酚的用量,而且对其脑保护作用没有影响.

Abstract：

Objective To investigate the cerebral protective effect of intracarotid infusion of propofol in patients undergoing resection of cerebral gliomas. Methods Sixty ASA Ⅰ- Ⅲ patients with cerebral glioma aged 40-64 yr weighing 48-73 kg were enrolled in this study. Forty patients undergoing resection of glioma under general anesthesia were randomly divided into 2 groups ( n = 20 each): intracarotid propofol group (group IA ) and intravenous propofol group (group Ⅳ). Twenty patients undergoing biopsy of glioma under local infiltration anesthesia with 2% lidocaine 15-20 md served as control group (group C). In IA and Ⅳ groups anesthesia was induced with TCI of propofol and remifentanil. Tracheal intubation was facilitated with rocuronium 0.6 mg/kg. The patients were mechanically ventilated. PErCO2 was maintained at 35-45 mm Hg. Anesthesia was maintained with TCI of propofol and remifentanil and intermittent iv boluses of rocuronium. In group IA internal carotid artery was cannulated after induction of anesthesia and propofol was administered by TCI via carotid artery while remifentanil was administered by TCI via peripheral vein. BIS was maintained at 40-60 during operation. ECG, MAP, HR, SpO2, PETCO2 and BIS were continuously monitored. MAP and HR were recorded before induction of anesthesia (T1) ,during skin incision (T2 ), at the end of operation (T3), during extubation ( T4 ). The glioma specimens were obtained for microscopic examination and determination of aquaporin 1 and aquaporin 4 ( AQP1, AQP4) expression by immunohistochemistry. Results MAP and HR were significantly decreased at T2 and T3 as compared with the baseline at T1 in group Ⅳ ( P ＜ 0.05), while there was no significant change in MAP and HR after induction of anesthesia in group IA ( P ＞ 0.05). The expression of AQP1 and AQP4 was down-regulated in IA and Ⅳ groups compared with group C (P ＜0.05). The propofol consumption during anesthesia was significantly less in group IA than in group Ⅳ (P ＜0.05). There was no significant diffe-rence in AQP1 and AQP4 expression, the amount of remifentanil and recuronium consumed and duration of operation betweenIA and Ⅳ groups ( P ＞ 0.05). Concltsion Intracarotid propofol can decrease the amount of propofol needed for maintenance of anesthesia as compared with intravenous administration and attenuate brain edema,indicating cerebral protective effect.     

Nitrous oxide prevents movement during orotracheal intubation without affecting BIS value

We sought to determine whether the addition of nitrous oxide (N(2)O) to an anesthetic with propofol and remifentanil modifies the bispectral index (BIS) during the induction of anesthesia and orotracheal intubation. Thirty ASA physical status I or II patients were randomly allocated to receive either 50% air in oxygen (control group) or 60%-70% N(2)O in oxygen (N(2)O group) that was commenced via a mask simultaneously with the induction of anesthesia. Anesthesia was performed in all the patients with IV propofol at the target effect compartment site concentration of 4 microg/mL throughout the study. A target-controlled infusion (TCI) of remifentanil was initiated 3 min after the TCI of propofol and maintained at the effect-site concentration of 4 ng/mL until the end of the study. After loss of consciousness, and before the administration of vecuronium 0.1 mg/kg, a tourniquet was applied to one arm and inflated to a value more than the systolic blood pressure. An examiner, blinded to the presence of N(2)O, sought to detect any gross movement within the first minute after tracheal intubation, which was performed 10 min after remifentanil TCI began. Inspired and expired oxygen, N(2)O, and carbon dioxide were continuously monitored. A BIS value was generated every 10 s. Arterial blood pressure and heart rate (HR) were measured noninvasively every minute. Measures of mean arterial pressure (MAP), HR, and BIS were obtained before the induction, before the start of the remifentanil TCI, before laryngoscopy, and 5 min after intubation. No significant intergroup differences were seen in BIS, HR, and MAP throughout the study. Maximum changes in BIS, HR, and MAP with intubation were significant (P < 0.01) for both groups but comparable. Six patients in the control group and none in the N(2)O group moved after intubation (P < 0.05). IMPLICATIONS: We demonstrated that 0.6 minimal alveolar concentration of nitrous oxide combined with a potent anesthetic and an opioid prevents movement after orotracheal intubation without affecting the bispectral index. This demonstrates that the bispectral index is not a useful neurophysiologic variable to monitor the level of anesthesia when nitrous oxide is added to a general anesthetic regimen using propofol and remifentanil.