舒芬太尼对老年患者诱导期丙泊酚抑制气管插管反应半数有效血浆浓度的影响

目的 探讨不同靶浓度的舒芬太尼复合丙泊酚靶控输注(targeted-controlled infusion,TCI)抑制气管插管反应的丙泊酚半数有效血浆浓度(the median effective plasma concentration,Cp50).方法 研究对象为94例择期全麻拟行气管插管手术患者,ASA Ⅰ～Ⅲ级,年龄在60岁～79岁.根据年龄段和舒芬太尼靶浓度的不同按随机数字表法分为4组,A组为60岁～69岁、0.2 μg/L;B组为60岁～69岁、0.3 μg/L;C组为70岁～79岁、0.2 μg/L;D组为70岁～79岁、0.3 μg/L.试验以效应室浓度TCI舒芬太尼,待舒芬太尼血浆浓度与效应室浓度平衡后,以血浆靶浓度TCI丙泊酚,意识消失后给予0.2 mg/kg的顺阿曲库铵,待丙泊酚的血浆浓度和效应室浓度平衡且静注顺阿曲库铵达3 min后行气管插管.丙泊酚的血浆靶浓度按序贯法确定.结果 A组患者有效抑制气管插管反应的丙泊酚的Cp50为3.60 mg/L,95％可信区间(confidence interval,CI)为3.44 mgl～3.76 mg/L;B组患者Cp50为2.03 mg/L,95％CI为1.88 mg/L～2.20 mg/L;C组患者Cp50为2.70 mg/L,95％CI为2.56 mg/L～2.84 mg/L;D组患者Cp50为1.97 mg/L,95％CI为1.81 mg/L～2.12 mg/L.结论 随着舒芬太尼的效应室靶浓度的增加以及年龄的增加,丙泊酚的Cp50明显降低.     

复合丙泊酚时瑞芬太尼抑制妇科腹腔镜手术患者气腹反应的半数有效血浆靶浓度

目的确定复合丙泊酚时瑞芬太尼抑制妇科腹腔镜手术患者气腹反应的半数有效血浆靶浓度(median effective plasma concentration,Cp50)。方法择期拟行妇科腹腔镜手术患者22例,年龄20～60岁,BMI 18～30kg/m2,ASAⅠ或Ⅱ级。麻醉诱导采用靶控输注(TCI)瑞芬太尼和丙泊酚,对应血浆靶浓度(Cp)分别为5ng/ml和4μg/ml,静脉注射罗库溴铵0.6mg/kg。气管插管后稳定3min,调整瑞芬太尼Cp,第1例患者为6ng/ml,待效应室靶浓度与Cp平衡后建立气腹。发生气腹反应时,下一例采用高一级浓度,否则采用低一级浓度,浓度梯度的比值为1.2。发生气腹反应的标准:建立气腹后3min内HR增快和/或MAP升高幅度超过基础值的20%。计算复合丙泊酚时瑞芬太尼抑制妇科腹腔镜手术患者气腹反应的Cp50及其95%CI。结果复合丙泊酚时瑞芬太尼抑制妇科腹腔镜手术患者气腹反应的Cp50及其95%CI为4.58(4.14～5.08)ng/ml。结论复合丙泊酚时瑞芬太尼抑制妇科腹腔镜手术患者气腹反应的Cp50为4.58ng/ml。     

不同剂量瑞马唑仑麻醉诱导对瑞芬太尼抑制气管插管反应的半数有效血浆靶浓度的影响

目的 探讨麻醉诱导时不同剂量瑞马唑仑对瑞芬太尼抑制气管插管反应半数有效血浆靶浓度(Cp₅₀)的影响。方法 选择择期行气管插管全身麻醉手术患者79例,男14例,女65例,年龄18～60岁,BMI 18～30 kg/m²,ASAⅠ或Ⅱ级。采用随机数字法将患者分为三组：瑞马唑仑0.2 mg/kg(R1组)、0.3 mg/kg(R2组)和0.4 mg/kg(R3组)。根据分组分别静脉注射瑞马唑仑0.2、0.3、0.4 mg/kg进行麻醉诱导,待患者MOAA/S评分为0分时,将瑞芬太尼进行靶控输注(TCI)给药,3 min后行气管插管术。瑞芬太尼血浆靶浓度由序贯法确定,初始剂量为3.0 ng/ml,剂量梯度为0.2 ng/ml,并根据插管反应确定下一例患者瑞芬太尼剂量。记录入室后安静状态下、麻醉诱导后、气管插管后的HR、MAP、BIS。记录意识消失时间。采用Probit法计算Cp₅₀及95%可信区间(CI)。结果与入室后安静状态下比较,麻醉诱导后R1组HR明显增快、BIS明显降低(P<0.05),R2、R3组HR明显增快,M...     

纤维支气管镜检查术中瑞芬太尼复合不同靶浓度丙泊酚的应用

目的 比较纤维支气管镜检查术瑞芬太尼靶控输注复合不同靶浓度丙泊酚靶控输注麻醉效果.方法 行纤维支气管镜检查患者150例.ASA Ⅰ或Ⅱ级,年龄18～60岁,性别不限,按照数字随机分为三组,P5.0组、P5.5组和P6.0组.采用瑞芬太尼复合丙泊酚行全凭静脉麻醉,瑞芬太尼效应室靶浓度3.0 ng/ml靶控输注,丙泊酚效应室靶浓度5.0、5.5、6.0 μg/ml靶控输注,两者效应室靶浓度达到目标浓度时开始检查,检查结束停止用药.检查期间采用高频喷射通气供氧,频率150次/分,推动压力0.2 MPa,I:E为1:1.5.记录麻醉诱导前(T0)、麻醉诱导后1 min(T1)、纤维支气管镜至鼻道(T2)、至声门(T3)、至隆突(T4)、至主支气管(T5)、至叶支气管(T6)、灌洗活检(T7)、术毕(T8)、患者睁眼(T9)和清醒(T10)时的MAP、HR、SpO2、NT值.记录麻醉诱导时间(从用药到检查开始)、检查持续时间、呛咳情况、患者睁眼和苏醒时间.记录利多卡因表面麻醉、麻黄碱静注、尼卡地平及艾司洛尔静注的例数.在T0、T8、T10三个时点分别抽取患者的动脉血行血气分析,记录PO2和PCO2值.结果 三组MAP、HR、SpO2波动均在正常范围内.P6.0组的麻醉诱导时间、睁眼时间和苏醒时间明显高于P5.0组和P6.5组(P＜0.05).P5.5组和P6.0组麻醉效果明显好于P5.0组(P＜0.05).P5.5组术者的满意度明显高于P5.0组和P6.0组(P＜0.05).三组患者舒适度差异无统计学意义.P5.5组不良反应发生例数明显少于P5.0组和P6.0组(P＜0.05).三组均未出现SpO2＜85%或心律失常的不良反应.三组间PO2和PCO2差异无统计学意义.结论 丙泊酚效应室靶浓度5.5 μg/ml复合瑞芬太尼效应室靶浓度3.0 ng/ml靶控输注,行纤维支气管镜检查麻醉术麻醉效果最好.     

不同效应室浓度瑞芬太尼靶控输注时气管插管诱发病人的心血管反应

瑞芬太尼起效迅速、作用持续时间短、消除快,主要由血液和组织中非特异性酯酶水解代谢,不受肝肾功能的影响; 其时量相关半衰期短,适用于靶控输注(TCI),是新型的阿片类镇痛药。瑞芬太尼单次注射可抑制气管插管时病人的心血管反应,而TCI可避免其单次静脉注射引起血液动力学变     

舒芬太尼抑制老年患者McGrath视频喉镜下气管插管反应的半数有效浓度

目的 测定舒芬太尼抑制老年患者McGrath视频喉镜气管插管反应的半数有效浓度(median effectiveconcentration,EC50).方法 选择全身麻醉下气管插管行外科手术的老年患者29例,年龄66岁～75岁.患者入室建立静脉通路后给予咪达唑仑0.02 mg/kg.诱导同时以效应室靶浓度(target effect-site concentration,Ce)靶控输注(target-controlled infusion,TCI)丙泊酚和舒芬太尼,丙泊酚的初始Ce为1.5 mg/L,2 min后调至2.5 mg/L;舒芬太尼的Ce浓度为0.3 μg/L.当镇静/警醒评分≤2时,给予罗库溴铵0.6 mg/kg.待舒芬太尼Ce与血浆浓度(plasma concentration,Cp)平衡后McGrath视频喉镜下气管插管.观察患者的气管插管反应,若插管反应呈阳性,按序贯法依次升高下一例舒芬太尼的Ce,若插管反应呈阴性,则降低下一例舒芬太尼的Ce,各相邻浓度间比例为1.2.结果 舒芬太尼TCI抑制老年患者McGrath视频喉镜下气管插管反应的EC50为0.194 μg/L,95％置信区间(confidence interval,cI)为0.174 μg/L～0.212 μg/L(P＜0.01).麻醉诱导过程中舒芬太尼的平均用量为(0.211±0.039) μg/kg(P＜0.01).结论 丙泊酚Ce为2.5 mg/L时,舒芬太尼抑制50％老年患者McGrath视频喉镜下气管插管反应的Ce为0.194 μg/L.     

舒芬太尼抑制双腔气管插管心血管反应的半数有效效应室浓度

目的通过序贯法测定咪达唑仑复合丙泊酚靶控输注下舒芬太尼在双腔气管插管中抑制心血管反应的半数有效效应室浓度(EC50)。方法选择全身麻醉下行左侧双腔气管插管的胸科非心脏手术患者,诱导时舒芬太尼目标靶控效应室浓度根据序贯法原则设定,当出现6个交叉点时终止试验。双腔气管插管心血管反应阳性的标准:在双腔气管插管5min内患者HR或MAP升高超过基础值的20%。结果实际21例患者纳入统计。舒芬太尼抑制双腔气管插管心血管反应的EC50:Dixon-Mood法计算为0.34ng/ml(95%CI:0.33~0.36ng/ml);Probit回归模型测得为0.34ng/ml(95%CI:0.31~0.37ng/ml)。结论咪达唑仑复合丙泊酚靶控输注下,舒芬太尼抑制双腔气管插管心血管反应的EC50为0.34ng/ml。     

七氟醚诱导无肌松下舒芬太尼抑制气管插管反应的浓度

目的 测定七氟醚诱导无肌松条件下舒芬太尼抑制气管插管反应的效应室靶浓度(EC50和EC95).方法 选择27例ASA Ⅰ或Ⅱ级择期全麻手术患者,吸入8%七氟醚诱导同时靶控输注(TCI)舒芬太尼,舒芬太尼靶浓度按改良序贯法增加或减少0.02 ng/ml.患者意识消失后七氟醚浓度降至5%,待舒芬太尼的血浆浓度和效应室浓度平衡1 min后行气管插管.用概率单位回归法计算出舒芬太尼抑制气管插管反应的EC50、EC95及相应的95%可信区间(CI).结果 舒芬太尼抑制气管插管反应的EC50为0.325 ng/ml,95%CI为0.307～0.342 ng/ml;EC95为0.363 ng/ml,95%CI为0.344～0.498 ng/ml.结论 七氟醚诱导时无肌松条件下舒芬太尼抑制气管插管反应的EC50和EC95为0.325 ng/ml和0.363 ng/ml.     

麻醉诱导时靶控输注丙泊酚抑制插入喉罩反应的半数有效浓度

目的全身麻醉诱导时靶控输注(TCI)丙泊酚抑制插入喉罩反应的血浆半数有效浓度(EC50)。方法择期手术需插入喉罩患者25例,麻醉诱导时丙泊酚的初始靶浓度为4.0μg/ml,依次降低丙泊酚靶浓度,各相邻比率为1∶1。以出现插喉罩阳性反应的上一级为入选本研究的第1例,共20例患者纳入本研究统计分析。按Dixon′s序贯法调节丙泊酚的血浆靶控浓度:如果出现插喉罩阳性反应,则使用上一级浓度;如果阴性反应,则使用下一级浓度。结果插入喉罩时TCI丙泊酚的EC50为2.43μg/ml,95%可信区间为2.05～2.89μg/ml。结论设定合适的浓度,靶控输注丙泊酚插入喉罩的麻醉方法是安全有效的,可减少麻醉诱导引起的不良反应,降低麻醉的风险。     

丙泊酚复合瑞芬太尼抑制人工流产扩宫时体动反应25例的研究

目的:研究丙泊酚复合瑞芬太尼抑制人工流产扩张宫颈时体动反应的半数有效效应室靶浓度.方法:25例拟实施人工流产术患者,经静脉靶控输注瑞芬太尼复合丙泊酚,丙泊酚维持效应室靶控浓度5.4 μg/mL,瑞芬太尼效应室靶控浓度从0.7 μg/L开始,相邻靶浓度比值为1.2.结果:25例患者镇静深度满意,术中无知晓;当瑞芬太尼效应室靶控浓度升高到2.51 μg/L时,出现第1例无体动反应.其中2例出现呼吸抑制,3例出现血压下降超过基础值的30%,2例出现心率减慢.结论:瑞芬太尼复合效应室靶浓度为5.4 μg/mL丙泊酚时,抑制人工流产患者扩宫时体动反应的EC50为2.17 μg/L,95%可信区间为1.92～2.45 μg/L.     

不同剂量瑞芬太尼复合异丙酚的气管插管条件及血流动力学的变化

喉镜置入和气管插管常可引起心动过速、高血压、心律失常、血浆儿茶酚胺浓度升高及敏感患者的心肌缺血、动脉瘤破裂等，可能导致对机体的损伤。采用静脉注射阿片类药物可以抑制机体的应激反应。异丙酚是一种起效快的新型麻醉药，广泛应用于麻醉诱导和麻醉维持。瑞芬太尼具有理想的阿片类受体激动剂特性和独特的药理学特点，现已广泛应用于临床麻醉诱导和维持。异丙酚复合瑞芬太尼用于麻醉诱导，既能使麻醉达到一定深度，又能减轻气管插管的心血管反应。本研究以血压、心率及患者的反应作为观察指标，旨在观察不同剂量瑞芬太尼复合异丙酚麻醉诱导后气管插管条件及血流动力学的变化，为临床合理应用瑞芬太尼提供参考。     

Assessment of tracheal intubation in children after induction with propofol and different doses of remifentanil

Tracheal intubating conditions were assessed in 112 children after induction of anaesthesia with propofol and remifentanil 1.0, 2.0 or 3.0 micro g.kg-1. Subjects in a control group were given propofol and mivacurium 0.2 mg.kg-1. Haemodynamic and respiratory parameters were recorded. Plasma catecholamine levels were measured in a subgroup of 40 children. Intubating conditions were acceptable in 14/28 (50%), 18/26 (69%) and 22/27 (82%) in those subjects given remifentanil 1.0, 2.0 or 3.0 micro g.kg-1, respectively, and in 27/28 (96%) of the control group. Intubating conditions in subjects given remifentanil 3.0 micro g.kg-1 were better than in those given remifentanil 1.0 micro g.kg-1 (p < 0.05). There were no significant differences in intubating conditions between those given remifentanil 3.0 micro g.kg-1 and the control group. Systolic blood pressure and heart rate increased in response to tracheal intubation in subjects given remifentanil 1.0 micro g.kg-1 and in the control group (p < 0.05). Time to resumption of spontaneous respiration was prolonged in subjects given remifentanil 3.0 micro g.kg-1 (p < 0.001). In conclusion, remifentanil 2 micro g.kg-1 provides acceptable intubating conditions and haemodynamic stability without prolonging the return of spontaneous respiration.     

The effect of age on the dose of remifentanil for tracheal intubation in infants and children

Introduction: This study aimed to determine the age‐specific bolus dose of remifentanil (ED₅₀) to facilitate tracheal intubation without the use of neuromuscular blocking agents. Methods: ASA 1–2 subjects were recruited into three groups of 0–3 months (group I), 4–12 months (group II), and 1–3 years (group III) of age. A sequential up‐and‐down design determined the remifentanil bolus dose, which was initially started at 3 mcg·kg^?1 and adjusted in 1 mcg·kg^?1 increments (range 1–6 mcg·kg^?1). Following pretreatment with glycopyrrolate 10 μg·kg^?1 and an induction dose of propofol 5 mg·kg^?1, remifentanil was administered with a blinded study investigator commencing tracheal intubation after 60 s. After tracheal intubation, the time to return of spontaneous ventilation was measured. Logistic regression was used to predict the ED₅₀ and ED₉₅ of remifentanil. Results: Sixty‐four subjects were recruited. Tracheal intubation was successful at first attempt in over 90% of subjects in each age group. Satisfactory intubating conditions were achieved in 85%, 63%, and 75% of subjects in groups I, II, and III, respectively. The logistic regression results for ED₅₀ (95% CI) were 3.1 (2.5–3.8), 3.7 (2.0–5.4), and 3.0 (2.1–3.9) mcg·kg^?1, and ED₉₅ (95% CI) were 5.0 (3.0–7.0), 9.4 (1.5–17.4), and 5.6 (2.9–8.4) mcg·kg^?1 in groups I, II, and III, respectively. Infants aged 4–12 months (group II) showed a marked variability in dose response; however, the mean ED₅₀ and ED₉₅ were not different to groups I and III. Older children had a longer duration of apnea than infants, 331 vs 180 s (P < 0.05). Discussion: The ED₅₀ of remifentanil for tracheal intubation was higher in all age groups than previously reported. Ideal intubating conditions were achieved in 50% of subjects with remifentanil doses of 3.1–3.7 mcg·kg^?1. Higher doses will be required for higher success rates and with anticholinergic pretreatment, doses of up to 6 mcg·kg^?1 were tolerated, without adverse effects, in two patients. Further investigation of the variability in dose response in infants and assessment of the safety this technique is warranted.     

Tracheal intubation without neuromuscular blockade in children: a comparison of propofol combined either with alfentanil or remifentanil

Forty healthy children, aged between two and 12 years of age undergoing elective surgery where the anaesthetic technique involved tracheal intubation followed by spontaneous ventilation were studied. Induction of anaesthesia was with either alfentanil 15 μg·kg^?1 or remifentanil 1 μg·kg^?1 followed by propofol 4 mg·kg^?1 to which lignocaine 0.2 mg·kg^?1 had been added. Intubating conditions were graded on a four point scale for ease of laryngoscopy, vocal cord position, degree of coughing, jaw relaxation and limb movement. All children were successfully intubated at the first attempt. There were no significant differences in the assessments of intubating conditions between the two groups. Arterial blood pressure and heart changes were similar in the two groups with both alfentanil and remifentanil attenuating the haemodynamic response to tracheal intubation. The time taken to resumption of spontaneous ventilation was similar in both groups.     

Propofol and remifentanil for intubation without muscle relaxant: the effect of the order of injection

BACKGROUND: Common practice in intubation without muscle relaxant is to inject the opioid drug prior to the hypnotic drug. Because remifentanil reaches adequate cerebral concentration more rapidly than does propofol, we tested the hypothesis that injection of remifentanil after propofol might lead to better intubating conditions. METHODS: Thirty ASA I-II patients scheduled for elective surgery and with no anticipated difficult intubation were enrolled in the study. Five minutes after midazolam 30 microg kg(-1), patients were randomized into two groups: group PR received propofol 2.5 mg kg(-1) followed by remifentanil 1 microg kg(-1), and group RP received remifentanil 1 microg kg(-1) followed by propofol 2.5 mg kg(-1). Intubating conditions were compared using a well-validated score, and continuous arterial pressure was recorded non-invasively. RESULTS: Compared with group RP, intubating conditions were significantly better in group PR. The mean arterial pressure decrease was more pronounced in group RP. CONCLUSIONS: We therefore conclude that in premedicated healthy patients with no anticipated risk of difficult intubation, intubating and haemodynamic conditions are better when remifentanil is injected after propofol.     

不同剂量舒芬太尼对老年患者气管插管心血管反应的影响

目的观察不同剂量舒芬太尼对老年患者气管插管时心血管反应的影响,探讨其减轻老年患者气管插管心血管反应的适宜剂量。方法拟行择期结、直肠癌腹腔镜手术;老年患者90例,随机分为舒芬太尼0．1μg／kg组（S1组）,舒芬太尼0．2μg／kg组（S2组）,舒芬太尼0．3μg／kg组（S3组）,每组各30例。监测患者人室静卧后5min（T0,基础值）、插管前1min（T1）、插管后1min（T2）、3min（T3）、5min（T4）各时点患者的收缩压（SBP）、舒张压（DBP）、心率（HR）,并在以上各时点抽取上肢静脉血,以高效液相色谱法测定血浆去甲肾上腺素（NE）和肾上腺素（N）水平。结果S1组患者气管插管后血流动力学及血浆去甲肾上腺素（NE）和肾上腺素（N）浓度与插管前比较明显增高,呈一过性;S2组患者患者气管插管后血流动力学及血浆去甲肾上腺素（NE）和。肾上腺素（N）浓度与插管前比较,轻度增高;S3组患者患者气管插管后血流动力学及血浆去甲肾上腺素（NE）和肾上腺素（N）浓度与插管前比较无明显变化。结论气管插管前静脉注射舒芬太尼0．3μg／kg能减轻气管插管引起的应激反应,用于老年患者可能有利于减少气管插管引起的心脑血管意外的发生。     

Assessment of tracheal intubating conditions in children using remifentanil and propofol without muscle relaxant

BACKGROUND: Tracheal intubation in children can be achieved by deep inhalational anaesthesia or an intravenous anaesthetic and a muscle relaxant, suxamethonium being widely used despite several side-effects. Studies have shown that oral intubation can be facilitated safely and effectively in children after induction of anaesthesia with propofol and alfentanil without a muscle relaxant. Remifentanil is a new, ultra-short acting, selective mu-receptor agonist that is 20-30 times more potent than alfentanil. This clinical study was designed to assess whether combination of propofol and remifentanil could be used without a muscle relaxant to facilitate tracheal intubation in children. METHODS: Forty children (5-10 years) admitted for adenotonsillectomy were randomly allocated to one of two groups to receive remifentanil 2 microg.kg(-1) (Gp I) or remifentanil 3 microg.kg(-1) (Gp II) before the induction of anaesthesia with i.v. propofol 3 mg.kg(-1). No neuromuscular blocking agent was administered. Intubating conditions were assessed using a four-point scoring system based on ease of laryngoscopy, jaw relaxation, position of vocal cords, degree of coughing and limb movement. Mean arterial pressure (MAP) and heart rate (HR) measured noninvasively before induction of anaesthesia to 5 min after intubation (seven time points). RESULTS: Tracheal intubation was successful in all patients without requiring neuromuscular blocking agent. Intubating conditions were clinically acceptable in 10 of 20 patients (50%) in Gp I compared with 18 of 20 patients (90%) in Gp II (P < 0.05). MAP and HR decreased in both groups after induction of anaesthesia (P < 0.01). Both HR and MAP were significantly lower in Gp II compared with Gp I after tracheal intubation (P < 0.01). No patient in the present study developed bradycardia or hypotension. CONCLUSIONS: We conclude that remifentanil (3 microg.kg(-1)), administered before propofol (3 mg.kg(-1)) provides acceptable tracheal intubating conditions in children, and completely inhibited the increase in HR and MAP associated with intubation.     

Comparative evaluation of different doses of propofol preceded by fentanyl on intubating conditions and pressor response during tracheal intubation without muscle relaxants

BACKGROUND: The aim of our study was to determine the optimal dose of propofol preceded by fentanyl for successful tracheal intubation and to see its effectiveness in blunting pressor response in children aged 3-10 years. METHODS: This prospective, double blind, randomized study was conducted on 60 ASA grade I and II children, between 3 and 10 years undergoing elective surgery who were divided into three groups of 20 each. The children received different doses of propofol (group I, 2.5 mg x kg(-1); group II, 3.0 mg x kg(-1); group III, 3.5 mg x kg(-1)) preceded by a fixed dose of fentanyl (3.0 microg x kg(-1)) 3 min earlier. The tracheal intubating conditions were graded based on scoring system devised by Helbo-Hensen et al. with Steyn modification which includes five criteria; ease of laryngoscopy, degree of coughing, position of vocal cords, jaw relaxation, and limb movement and graded on a 4-point scale. Heart rate (HR), mean arterial pressure (MAP), and oxygen saturation changes were also noted. RESULTS: Tracheal intubating conditions were acceptable in 25% of the patients in group I, while significantly higher (P < 0.001) in group II (80%) and in group III (90%). The pressor response was not effectively blunted in group I (17% increase in HR), while effectively blunted in groups II and III. A fall in cardiac output was seen in group III indicated by a decrease in MAP (16%) and HR (11%). No airway complications were noted. CONCLUSIONS: Propofol 3 mg x kg(-1) (group II) preceded by fentanyl 3 microg x kg(-1) is the optimal dose combination in our study. It provides acceptable intubating conditions in 80% patients, blunts pressor response to intubation without significant cardiovascular depression.     

Remifentanil and propofol without muscle relaxants or with different doses of rocuronium for tracheal intubation in outpatient anaesthesia

BACKGROUND: The use of muscle relaxants in outpatient anaesthesia is controversial; some authors recommend an induction regimen including propofol and opioids without muscle relaxants. This study evaluated the requirements for rocuronium after remifentanil/propofol. METHODS: We examined in four groups of ASA I-II patients (n= 30 for each) the intubating conditions three minutes after induction of anaesthesia with remifentanil 0.5 microg kg(-1) min(-1), propofol 2 mg kg(-1) without muscle relaxants or with different doses of rocuronium (0.6 mg kg(-1), 0.45 mg kg(-1), 0.3 mg kg(-1)) applying the criteria proposed by the Copenhagen Consensus Conference. In the second part of the study the time course of neuromuscular block was determined by electromyography using train-of-four (TOF) stimulation. To this end, another 60 ASA I-II patients were randomly assigned to receive remifentanil 0.5 microg kg(-1) min(-1), propofol 2 mg kg(-1) and either rocuronium 0.6 mg kg(-1), 0.45 mg kg(-1), 0.3 mg kg(-1), or 0.3 mg kg(-1) followed by neostigmine 40 microg kg(-1) and atropine 20 microg kg(-1) at a T1 recovery of 10% (n=15 for each). RESULTS: Intubating conditions were good or excellent in 30 patients after rocuronium 0.6 mg kg(-1) and in 18 patients when rocuronium was omitted (P<0.01). After 0.45 mg kg(-1) and 0.3 mg kg(-1) rocuronium the numbers were 29 and 30 patients, respectively. Reducing rocuronium from 0.6 mg kg(-1) to 0.45 mg kg(-1) or 0.3 mg kg(-1) increased the onset time from 136 (35) s to 199 (34) s and 249 (52) s (mean (SD)), (P<0.01); the clinical duration decreased from 38 (10) min to 24 (8) min and 16 (5) min, respectively (P<0.01); and the duration to a TOF-ratio of 0.8 decreased from 60 (11) min to 45 (9) min and 34 (7) min (P<0.01). After rocuronium 0.3 mg kg(-1) this time interval further decreased to 22 (3) min when neostigmine was given at a T1 of 10% (P<0.01 compared with spontaneous recovery after rocuronium 0.3 mg kg(-1)). CONCLUSION: After remifentanil/propofol intubation conditions were poor in 40% of patients without muscle relaxants; adding reduced doses of rocuronium to this regimen improved the intubation conditions significantly. In addition, reducing the initial dose of rocuronium markedly shortened its time course of action.