尼卡地平对维库溴铵和阿曲库铵肌松时效的影响

目的探讨尼卡地平对维库溴铵、阿曲库铵肌松时效的影响.方法40例ASAⅠ～Ⅱ级择期手术的全麻患者,随机分为四组,每组10例.四组病人均行健忘镇痛慢诱导气管内插管.吸入5096N2O-氧混合气,静注芬太尼、羟丁酸钠维持麻醉.Ⅰ组静注维库溴铵0.1mg@kg-1(2×ED95);Ⅲ组静注阿曲库铵0.5mg@kg-1(2×ED95);收缩压超过基础值30%时,Ⅱ组和Ⅳ组均给予尼卡地平20μg@kg-1,1min后分别静注与Ⅰ组、Ⅲ组同等剂量的维库溴铵或阿曲库铵.用Biometer加速度仪监测肌松情况.结果Ⅰ组、Ⅱ组维库溴铵起效时间分别为(2.6±0.2)min和(2.0±0.2)min,Ⅲ组、Ⅳ组阿曲库铵起效时间分别为(3.1±0.7)min和(2.3±0.5)min,Ⅱ组和Ⅳ组均明显缩短(P＜0.05);Ⅱ组临床作用时间较Ⅰ组延长(P＜0.05);Ⅳ组T190%恢复时间及恢复指数较Ⅲ组延长(P＜0.05);Ⅱ组无反应期、T150%恢复时间、9096恢复时间及恢复指数,均长于Ⅰ组;Ⅳ组无反应期、临床作用时间及T15096恢复时间均长于Ⅲ组,但无统计学意义).结论尼卡地平能缩短维库溴铵、阿曲库铵的起效时间,延长维库溴铵、阿曲库铵的临床作用和恢复时间.     

罗库溴铵和维库溴铵在终末期肾衰竭病人临床药效的比较

目的　比较罗库溴铵和维库溴铵在终末期肾衰竭病人中的肌松效应。方法　 2 5例ASAⅢ级行肾移植术病人随机分为罗库溴铵组 (R组 ,15例 )和维库溴铵组 (V组 ,10例 )。麻醉诱导后分别给予 2×ED95剂量的罗库溴铵 (0 6mg/kg)或维库溴铵 (0 1mg/kg)。术中当T1恢复至 2 5 %时 ,追加 0 5×ED95剂量的罗库溴铵 (0 15mg/kg)或维库溴铵 (0 0 2 5mg/kg)。末次剂量后 ,使肌张力自然恢复或给予新斯的明拮抗。结果　初量罗库溴铵的起效时间为 (1 98± 0 4 7)min ,明显短于维库溴铵的 (3 2 5±0 82 )min。初量和追加量的罗库溴铵的肌松维持时间分别为 (4 6 87± 14 6 0 )min和 (34 86± 15 5 7)min,与维库溴铵相似。两组应用拮抗药后 ,恢复指数均显著缩短。结论　对于终末期肾衰竭病人 ,罗库溴铵的起效快于维库溴铵 ,肌松作用维持时间和恢复指数与维库溴铵相似。     

异氟醚对新斯的明拮抗维库溴铵肌松作用的影响

目的：研究一定浓度的异氟醚对新斯的明拮抗维库溴铵肌松作用的影响。方法：30例病人随机分为三组（各10例）：（1）丙泊酚静脉麻醉组,即对照组（P组）。（2）观察组。以异氟醚维持麻醉,再分为两组;术中呼气未异氟醚浓度均为1MAC,临近手术结束用新斯的明拮抗时,呼气末异氟醚浓度分别为1MAC（1M组（）和0．3MAC（0．3M组）,术中各组均连续输注维库溴铵,术毕以新斯的明0．035mg/kg拮抗并记录以下数据;维库溴铵输注速率,从拮抗开始到T1恢复到90％,TOF恢复到0．7和0．9的时间拮抗后15分钟时的T1,TOF比值,结果：1M组和0．3M组维库溴铵输注速率较P组降低IP＜0．05）,新斯的明拮抗后,0．3M组和1M组T1恢复到90％,TOF恢复到0．7和0．9的时间较P组延长（P＜0．05和P＜0．01）,1M组TOF恢复到0．9的时间较0＝3M组延长（P＜0．05）,在新斯的明拮抗后15分钟,0．3M组和1M组的T1和TOF比值均低于P组（P＜0．05）,1M组的TOF比值低于0．3M组（P＜0．05）,结论：呼气未浓度为1MAC和0．3MAC的异氟醚均能影响新斯的明对维库溴铵肌松作用的拮抗。     

心脏手术使用潘库溴铵或罗库溴铵术后的残余肌松作用

非心脏手术中使用潘库溴铵或氯筒箭毒碱术后约有25％～40％病人显示残余的肌松作用(TOF比值<0.7)。如果改用阿曲库铵、维库溴铵或米库氯铵(美维松)则残余肌松的发生率低于10％。作者为使心脏术后病人能及早拔除气管导管,缩短机械通气时间和自主呼吸能提前恢复,特研究对比术中使用潘库溴铵或罗库溴铵(rocuronium)术后残余肌松作用的情况。     

丙泊酚与芬太尼静脉全麻下老年人持续输注国产维库溴铵及阿曲库铵肌松作用的比较

目的 比较静脉全麻下老年人持续输注国产维库溴铵及阿曲库铵的肌松作用.方法 观察在全麻下行腹部外科手术患者30例,ASA Ⅰ或Ⅱ级,年龄65～86岁,随机均分为维库溴铵组(Ⅰ组)和阿曲库铵组(Ⅱ组).使用TOF-watch SX肌松监测仪监测尺神经-拇内收肌传递功能.术中调整维库溴铵和阿曲库铵输注速度,使T1维持在参照值的10%,观察并记录两组输注速度的变化,两组恢复指数(T25-75)以及T1从10%恢复至TOFR-0.9的时间.结果 Ⅰ组在持续输注90 min时,输注速度下降60%,此后基本维持这一水平,Ⅱ组持续输注150 min后仅下降23%,两组患者T25-75 Ⅰ组为(24.8±4.2)min,Ⅱ组为(20.2±3.7)min,T10至TOFR=0.9 Ⅰ组为(37,5±4.5)min,Ⅱ组为(29.2±5.2)min(P＜0.05).结论 与维库溴铵比较,阿曲库铵较适用于老年人全麻下持续输注维持肌松,其具有输注速率稳定,肌松恢复迅速等优点.     

潘库溴铵与维库溴铵,阿曲库铵合用的实验研究

目的：将结构相近的潘库溴铵与维库溴铵和结构不同的潘库溴铵与阿曲库铵合用，比较其作用效果以判别相互作用的类型。方法：以刺激电极和力－位移换能器监测兔胫前肌的阻滞程度。选１５只新西兰白兔通过累积给药法求得兔三种药物的ＥＤ５０值。再将２０只新西兰白兔随机分为４组，分别采用潘库溴铵与维库溴铵、阿曲库铵合用、按不同顺序给药的方法。每种肌松药剂量为１／２×ＥＤ５０。结果：潘库溴铵与阿曲库铵合用，Ｔ１抑制９２％～９７％，明显高于５０％（Ｐ＜０．０１），提示有协同作用；而潘库溴铵与维库溴铵合用，Ｔ１仅抑制３９％～５２％。结论：非去极化肌松药间之相互作用与药物结构相关。     

顺式阿屈库铵与维库溴铵诱导期药效学研究

目的对比观察顺式阿屈库铵与维库溴铵单次静注的药效学及对循环系统的影响。方法择期行声带息肉摘除术ASAI-II级病人30例,随机分为2组,分别以顺式阿屈库铵0.15mg/kg(C组)与维库溴铵0.1mg/kg(V组)为肌松剂静注诱导,观察记录诱导期间患者血压、心率变化,应用肌松监测仪记录各组起效时间、最大阻滞程度、T1恢复到25%、75%、90%的时间及气管插管条件。结果2组患者诱导后血压、心率变化与临床常规诱导相似,组间对比无明显差异。肌松起效时间分别为5.2±1.9(C组)与3.1±0.8(V组),差别具有显著性(P0.05)。最大阻滞程度、T1恢复到25%、75%、90%的时间及气管插管条件无统计学差异。结论顺式阿屈库铵与维库溴铵在药效学及对循环系统的影响相似。     

新斯的明拮抗小儿和成年患者维库溴铵的残余肌松作用

目的 观察麻醉恢复期新斯的明拮抗小儿和成年全麻患者维库溴铵的残余肌松作用的剂量反应和安全性.方法 全麻下择期手术的小儿和成年患者各50例,维库溴铵首剂0.1 mg/kg,术中必要时追加0.05 mg/kg.采用加速度肌松监测仪监测四个成串反应的比值(train-of-four ratio,TOFR).当TOFR恢复至0.55时,小儿和成年患者分别随机分为5个亚组,分别给予新斯的明10、20、30、50 μg/kg及阿托品5、10、15、25μg/kg,对照组静脉注射生理盐水2 ml.观察TOFR恢复至0.7、0.9、1.0的时间及术后6、24 h恶心呕吐的发生情况.结果 新斯的明明显加快TOFR的恢复(P＜0.05),其中30μg/kg～50μg/kg效果均更明显(P＜0.05).小儿和成年患者新斯的明拮抗维库溴铵残余肌松作用的剂量反应曲线的差异无统计学意义(P＞0.05),拮抗5min时,小儿和成年患者新斯的明的ED95分别为(6.4±10.5)μg/kg和(2.7±19.2)μg/kg.术后6、24 h恶心呕吐情况的差异无统计学意义(P＞0.05).结论 在TOFR恢复至0.55时,小儿和成年患者新斯的明拮抗维库溴铵的残余肌松作用的效果无统计学差异,推荐使用小剂量的新斯的明进行拮抗,剂量不宜超过30μg/kg.     

维库溴铵靶控输注与间断单次静注肌松效应的对比

目的 探讨维库溴铵靶控输注的肌松效应。方法 选取40例择期全麻手术的病人,随机分为对照组和靶控组各20例,设定肌松水平为T_l/T_e=25％。对照组当T_l/T_e恢复至25％时静脉推注维库溴铵负荷剂量的1/4;靶控组则启动维库溴铵动态靶控和反馈程序,反馈指标为T_1T_e>25%。结果 肌松平均水平对照组为(14.0±2.2)％,靶控组为(22.9±1.8)％;肌松水平的平均偏移对照组为(-0.4±0.1)%,靶控组为(-0.1±0.1)%,两者差异有非常显著性(P<0.01)。恢复指数、维持肌松水平期间用药量和总药量两组差异无显著性。结论 维库溴铵靶控输注能达到设定肌松水平并维持该肌松水平的恒定,肌松的稳定性明显优于传统给药方式;靶控输注对维库溴铵恢复时间和用药量没有影响。     

七氟醚对不同性别患者罗库溴铵肌松作用的影响

目的 比较罗库溴铵肌松效应的性别差异和七氟醚对不同性别患者罗库溴铵肌松增效作用.方法 择期手术患者120例(男:女为1:1),年龄20～60岁.ASA Ⅰ或Ⅱ级,按性别随机分为丙泊酚组和七氟醚组:女性丙泊酚组(PF组).男性丙泊酚组(PM组),女性七氟醚组(SF组),男性七氟醚组(SM组),每组30例.所有患者静脉注射咪达唑仑、芬太尼和丙泊酚行麻醉诱导,意识消失后,置入喉罩,接麻醉机辅助通气并启动肌松监测.丙泊酚组静脉输注丙泊酚维持麻醉,设定血浆靶控浓度2～6 μg/ml,输注丙泊酚5 min后静脉注射罗库溴铵0.6 mg/kg,七氟醚组在呼气末七氟醚浓度稳定于1 MAC 5 min后静脉注射罗库溴铵0.6 mg/kg.记录肌松起效时间、完全肌松时间、T1恢复到25%和TOF恢复到25%的时间.结果 PM组较PF组起效时间长,完全肌松时间、T1恢复到25%和TOF恢复到25%的时间缩短(P＜0.05).SF组TOF恢复到25%的时间较PF组延长(P＜0.05),SM组较PM组起效时间缩短,完全肌松时间、T1恢复到25%和TOF恢复到25%的时间均延长(P＜0.05).SM组T1恢复到25%和TOF恢复到z5%的时间较SF组延长(P＜0.05).结论 女性罗库溴铵起效更快,作用时间长;而七氟醚对男性罗库溴铵的增效作用优于女性.     

Precurarization with Vecuronium and Pancuronium in Awake, Healthy Volunteers: The Influence on Neuromuscular Transmission and Pulmonary Function

The influence of pretreatment with pancuronium and vecuronium on the neuromuscular transmission was compared in 24 healthy, awake, non-premedicated volunteers using train-of-four (TOF) nerve stimulation and measurement of respiratory frequency, vital capacity, inspiratory force and peak expiratory flow (PEF). The subjects were randomly allocated to one of three groups. Each subject received one dose of pancuronium and one dose of vecuronium: Group I pancuronium 0.01 mg/kg and vecuronium 0.005 mg/kg; Group II pancuronium 0.01 mg/kg and vecuronium 0.01 mg/kg and Group III pancuronium 0.01 mg/kg and vecuronium 0.015 mg/kg intravenously. The median TOF ratio decreased significantly in Groups I and II following both pancuronium and vecuronium. The TOF ratio following vecuronium in Group II was significantly lower compared to the TOF ratio following vecuronium in Group I. Only PEF decreased significantly in Group I following pancuronium and in Group II following both pancuronium and vecuronium. There was no significant difference between Group I and Group II regarding the number of subjects with signs or symptoms of partial neuromuscular blockade. Following vecuronium 0.005 mg/kg, one subject was unable to swallow and the twitch height decreased to 0.25. In Group II one subject was unable to lift her head and had difficulty in swallowing following pancuronium 0.01 mg/kg. Only four subjects entered Group III because of an unacceptably high frequency of signs and symptoms of partial neuromuscular blockade and a decrease in median TOF ratio to 0.64 following vecuronium. The subjects felt it difficult to swallow, and one subject could just sustain head lift for 10 s following vecuronium 0.015 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of residual curarization using low-current stimulation

The present study employed train-of-four (TOF) stimulation at a current of 20 mA to assess the incidence and degree of residual neuromuscular blockade in 64 randomly selected Post Anesthesia Care Unit (PACU) patients. Group C (Control, n = 10) had received anaesthesia without nondepolarizing muscle relaxant; Group V (n = 25) had received vecuronium; and Group P (n = 29) had received pancuronium. At the end of surgery, each patient had been considered by his anaesthetist to have adequate neuromuscular function on the basis of clinical signs and tactile or visual evaluation of responses to TOF stimulation. However, upon testing in the PACU 15 min later, 45% (13 of 29) of Group P patients and 8% (2 of 25) of Group V patients had a TOF ration less than 0.70. This study indicates that residual curarization may be commonly encountered following long-acting relaxants despite qualitative intraoperative TOF monitoring. The present incidence, detected at a current of 20 mA, is consistent with previous reports which employed supramaximal TOF stimulation. We conclude that despite intraoperative monitoring, residual curarization following long-acting nondepolarizing agents is common and that it may be detected with TOF at a low stimulating current (20 mA).     

Early and late reversal of rocuronium and vecuronium with neostigmine in adults and children.

We investigated the influence of the timing of neostigmine administration on recovery from rocuronium or vecuronium neuromuscular blockade. Eighty adults and 80 children were randomized to receive 0.45 mg/kg rocuronium or 0.075 mg/kg vecuronium during propofol/fentanyl/N2O anesthesia. Neuromuscular blockade was monitored by train-of-four (TOF) stimulation and adductor pollicis electromyography. Further randomization was made to control (no neostigmine) or reversal with 0.07 mg/kg neostigmine/0.01 mg/kg glycopyrrolate given 5 min after relaxant, or first twitch (T1) recovery of 1%, 10%, or 25%. Another eight adults and eight children received 1.5 mg/kg succinylcholine. At each age, spontaneous recovery of T1 and TOF was similar after rocuronium and vecuronium administration but was more rapid in children (P < 0.05). Spontaneous recovery to TOF0.7 after rocuronium and vecuronium administration in adults was 45.7 +/- 11.5 min and 52.5 +/- 15.6 min; in children, it was 28.8 +/- 7.8 min and 34.6 +/- 9.0 min. Neostigmine accelerated recovery in all reversal groups (P < 0.05) by approximately 40%, but the times from relaxant administration to TOF0.7 were similar and independent of the timing of neostigmine administration. Recovery to T1 90% after succinylcholine was similar in adults (9.4 +/- 5.0 min) and children (8.4 +/- 1.1 min) and was shorter than recovery to TOF0.7 in any reversal group after rocuronium or vecuronium administration. Recovery from rocuronium and vecuronium blockade after neostigmine administration was more rapid in children than in adults. Return of neuromuscular function after reversal was not influenced by the timing of neostigmine administration. These results suggest that reversal of intense rocuronium or vecuronium neuromuscular blockade need not be delayed until return of appreciable neuromuscular function has been demonstrated. Implications: These results suggest that reversal of intense rocuronium or vecuronium neuromuscular blockade need not be delayed until return of appreciable neuromuscular function has been demonstrated. Although spontaneous and neostigmine-assisted recovery is more rapid in children than in adults, in neither is return of function as rapid as after succinylcholine administration.     

Recovery of neuromuscular function after cardiac surgery: pancuronium versus rocuronium

The use of pancuronium in fast-track cardiac surgical patients may be associated with delays in clinical recovery. Our objective in this study was to evaluate the incidence and severity of residual neuromuscular blockade after cardiac surgery in patients randomized to receive either pancuronium (0.08-0.1 mg/kg) or rocuronium (0.6-0.8 mg/kg). Eighty-two patients undergoing cardiopulmonary bypass were randomized to a pancuronium (n = 41) or rocuronium (n = 41) group. Intraoperative and postoperative management was standardized. In the intensive care unit, train-of-four (TOF) ratios were measured each hour until weaning off ventilatory support was initiated. Neuromuscular blockade was not reversed. After tracheal extubation, patients were examined for signs and symptoms of residual paresis. When weaning of ventilatory support was initiated, significant neuromuscular blockade was present in the pancuronium subjects (TOF ratio: median, 0.14; range, 0.00-1.11) compared with the rocuronium subjects (TOF ratio: median, 0.99; range, 0.87-1.21) (P < 0.05). Patients in the rocuronium group were more likely to be free of signs and symptoms of residual paresis than patients in the pancuronium group. Our findings suggest that the use of longer-acting muscle relaxants in cardiac surgical patients is associated not only with impaired neuromuscular recovery, but also with signs and symptoms of residual muscle weakness in the early postoperative period. IMPLICATIONS: The use of long-acting muscle relaxants in fast-track cardiac surgical patients is associated with significant residual neuromuscular block in the intensive care unit, including signs and symptoms of residual paresis.     

Does perioperative tactile evaluation of the train-of-four response influence the frequency of postoperative residual neuromuscular blockade?

The authors conducted a randomized controlled clinical trial to evaluate the usefulness of perioperative manual evaluation of the response to train-of-four (TOF) nerve stimulation. A total of 80 patients were divided into four groups of 20 each. For two groups (one given vecuronium and one pancuronium), the anesthetists assessed the degree of neuromuscular blockade during operation and during recovery from neuromuscular blockade by manual evaluation of the response to TOF nerve stimulation. In the other two groups, one of which received vecuronium and the other pancuronium, the anesthetists evaluated the degree of neuromuscular blockade solely by clinical criteria. The use of a nerve stimulator was found to have no effect on the dose of relaxant given during anesthesia, on the need for supplementary doses of anticholinesterase in the recovery room, on the time from end of surgery to end of anesthesia, or on the incidence of postoperative residual neuromuscular blockade evaluated clinically. The median (and range of) TOF ratios recorded in the recovery room were 0.75 (0.33-0.96) and 0.79 (0.10-0.97) in the vecuronium groups monitored with and without a nerve stimulator, respectively. These ratios were significantly higher than those found in the pancuronium groups, which wre 0.66 (0.06-0.90) and 0.63 (0.29-0.95), respectively. However, no difference was found between the vecuronium and pancuronium groups in the number of patients showing clinical signs of residual neuromuscular blockade, as evaluated by the 5-s head-lift test.(ABSTRACT TRUNCATED AT 250 WORDS)     

Spontaneous recovery of residual neuromuscular blockade after atracurium or vecuronium during isoflurane anaesthesia

With atracurium and vecuronium, spontaneous recovery of residual neuromuscular blockade monitored electromyographically during 0.5% isoflurane anaesthesia was studied in 60 patients undergoing plastic surgery. After thiopentone, in random order, either atracurium 0.5 mg kg-1 or vecuronium 0.1 mg kg-1 was administered and isoflurane added to N2O and O2 mixture. Following spontaneous recovery of both the single twitch amplitude (T1) to 75% of the control value and the train-of-four ratio (TOF ratio) to 75%, incremental doses of the relaxant were given to maintain the T1 at less than 10%. Before the end of surgery, the blockade was again permitted to recover spontaneously. During the initial spontaneous recovery, the mean recovery time of T1 from 25% to 75% (the recovery index) with atracurium was longer (P less than 0.001) than that with vecuronium (13.2 min and 10.1 min, respectively) but, during the second recovery, the mean recovery index was shorter (P less than 0.05) with atracurium than with vecuronium (16.1 min and 19.8 min, respectively). The recovery time from T1 75% to TOF ratio 75%, indicating the recovery rate of residual neuromuscular blockade, with atracurium was about 15 min after both the initial and the second recoveries. With vecuronium, the respective recovery times were significantly (P less than 0.001) longer (25.6 min and 38.5 min, respectively). It is concluded that with vecuronium there is slower spontaneous recovery of residual neuromuscular blockade than with atracurium.     

Perioperative train-of-four monitoring and residual curarization

It has beert suggested thai perioperative train-of-four (TOF) monitoring does not reduce the incidence of postoperative residual curarization (PORC). The purpose of this study was to examine whether the use of tactile assessment of the response of the adductor pollicis to supramaximal TOF stimulation of the ulnar nerve at. the wrist during anaesthesia affected the incidence of PORC. Thirty-nine ASA I or II surgical patients were studied during thiopentone/fentanyl N₂O/enflurane anaesthesia. Pancuronium (70–100 μg · kg^?1) was used to facilitate tracheal intubation and additional pancuronium increments used to maintain surgical relaxation. The requirement for incremental doses of pancuronium and adequacy of recovery following reversal were assessed according to random allocation, either with (Group A; n = 20) or without (Group B; n = 19) access to TOF monitoring. Patients in the two groups received neostigmine in similar doses (Group A: 53 μg · kg^?1 (5.9); Group B: 55 μg · kg^?1 (5.4)). On arrival of the patient to the recovery area, neuromuscular function was assessed electromyographically (using the Datex NMT 221 to measure TOF ratio) and clinically. The incidence of PORC (TOF ratio < 70%) was greater in Group B (47%) than in Group A (15%) (P = 0.029). We conclude that the use of perioperative TOF monitoring decreases the incidence of pancuronium-induced PORC.     

Residual neuromuscular block is a risk factor for postoperative pulmonary complications A prospective, randomised, and blinded study of postoperative pulmonary complications after atracurium, vecuronium and pancuronium

Background: After anaesthesia involving pancuronium a high incidence of both residual neuromuscular block and postoperative pulmonary complications (POPC) has been reported. The aim of this study was to compare the incidence of POPC following the use of pancuronium, atracurium, and vecuronium, and to examine the effect of residual neuromuscular block on the incidence of POPC.
Methods: A total of 691 adult patients undergoing abdominal, gynaecological, or orthopaedic surgery under general anaesthesia were randomised to receive either pancuronium, atracurium, or vecuronium. Perioperatively, the response to train-of-four (TOF) nerve stimulation was evaluated manually. Post-operatively, the TOF ratios were measured mechanomyograph-ically, and through a 6-day follow-up the patients were examined for pulmonary complications.
Results: The incidence of residual block, defined as a TOF ratio <0.7, was significantly higher in the pancuronium group (59/226: 26%) than in the atracurium/vecuronium groups (24/450: 5.3%). In the pancuronium group, significantly more patients with residual block developed POPC (10/59: 16.9%) as compared to patients without residual block (8/167 4.8%). In the atracurium/vecuronium groups, the incidence of POPC was not significantly different in patients with (1/24: 4.2%) or without (23/426: 5.4%) residual block. Multiple regression analysis indicated that abdominal surgery, age, long-lasting surgery, and a TOF ratio<0.7 following the use of pancuronium were potential risk factors for the development of POPC.
Conclusion: Postoperative residual block caused by pancuronium is a significant risk factor for development of POPC.     

Neuromuscular blockade can be assessed accelerographically over the vastus medialis muscle in patients positioned prone

PURPOSE: To study accelerographic monitoring of neuromuscular blockade over the vastus medialis muscle in anesthetized patients in the prone position. METHODS: Sixty adult patients were divided into four groups of 15: prone (P)-post-tetanic count (PTC), P-train-of-four (TOF), supine (S)-PTC or S-TOF group. In the P-PTC and P-TOF groups, the muscular branch of the femoral nerve was stimulated and the movement of the vastus medialis muscle was measured accelerographically. In the S-PTC and S-TOF groups, the depth of neuromuscular blockade was assessed mechanically at the thumb. After administration of vecuronium 0.1 mg.kg(-1), TOF stimuli were delivered every 20 sec in all groups. Onset of neuromuscular blockade (time from vecuronium to the minimum level of T1 (first response of TOF) was compared between the P-PTC or P-TOF group and S-PTC or S-TOF group. Recoveries of PTC and those of TOF were compared between the P-PTC and S-PTC groups and P-TOF and S-TOF groups, respectively. RESULTS: Onset of neuromuscular blockade in the P-PTC or P-TOF group was shorter than in the S-PTC or S-TOF group (132 +/- 43 vs 233 +/- 40 sec, mean +/- SD, P < 0.001). Recoveries of PTC in the P-PTC and S-PTC groups followed a similar time course. Recoveries of T1/control in the P-TOF and S-TOF groups were also comparable. In contrast, train-of-four ratio (T4/T1, TOFR) in the P-TOF group was higher than in the S-TOF group 60-120 min after vecuronium (P < 0.05). CONCLUSIONS: The degree of neuromuscular blockade can be assessed accelerographically over the vastus medialis muscle even when patients are in the prone position. When evaluated accelerographically over the vastus medialis muscle, onset of neuromuscular blockade is quicker and TOFR is higher than that assessed at the thumb.