The influence of atropine dose on recovery from vecuronium-induced neuromuscular blockade.

To determine whether the dose of atropine affects the rate of neostigmine-induced recovery from vecuronium-induced neuromuscular blockade, the authors monitored isometric adductor pollicis mechanical activity in 36 anesthetized (thiopental, fentanyl, nitrous oxide) adult patients (ASA physical status 1 or 2). Once surgery was completed and twitch height had spontaneously regained 25% of its initial value, the patients were randomly allocated into three groups (A10, A15, A20; n = 12 in each group) according to the dose of atropine (10, 15, or 20 micrograms/kg) that was mixed with 40 micrograms/kg neostigmine. Twitch height, train-of-four, and 50- and 100-Hz tetanic fade were recorded for 15 min after the administration of the reversal agents. No significant differences were found among the three groups in the final twitch height (95% +/- 2%), train-of-four (87% +/- 1%, 88% +/- 2%, 89% +/- 1%), and 50-Hz tetanic fade (90% +/- 1%, 94% +/- 1%, 93% +/- 1%) (mean +/- SEM). Fifteen minutes after reversal, fade in response to 100-Hz tetanus was statistically greater in the A10 group than in the two other groups (70% +/- 3% of control versus 84% +/- 4% and 81% +/- 2%) (mean +/- SEM, P less than 0.05). The present results demonstrate that larger doses of atropine facilitate neostigmine's reversal of vecuronium neuromuscular blockade. The clinical implications of the differences observed in this study remain to be determined.     

The effects of nimodipine on vecuronium-induced neuromuscular blockade

Nimodipine, a calcium channel blocking drug, is used in the treatment of cerebral arterial spasm after subarachnoid haemorrhage due to bleeding from an intracranial aneurysm. The purpose of this study was to evaluate the effects of nimodipine on neuromuscular blockade after vecuronium had been given to facilitate tracheal intubation and maintenance of muscle paralysis in patients undergoing clipping of intracranial aneurysm. Twenty patients were divided into two groups: a control group (n = 10) who received no calcium channel blocking drug, and a nimodipine group (n = 10) consisting of patients treated with nimodipine at clinically used doses of 0.03 mg kg(-1) h(-1) pre- and perioperatively. Anaesthesia was induced with atropine 10 microg kg(-1), dehydrobenzperidol 5 mg, fentanyl 5 microg kg(-1), thiopental 5 mg kg(-1) and maintained with a mixture of N2O and isoflurane (0.5-1% inspired concentration) in O2, and additional doses of fentanyl 2.5 microg kg(-1). Neuromuscular responses were monitored by acceleromyograpy. The first twitch of the train-of-four response (T1) was considered as twitch height. After a stabilization period, an intubating dose of vecuronium 0.1 mg kg(-1) was administered. The onset of action, the time of first appearance of T1 and clinical duration of action were recorded. Then, maintenance doses of vecuronium 0.03 mg kg(-1) were administered twice more when T1 had recovered to 25% of control twitch height. The study ended when the recordings of the 3rd 25% T1 recovery had been obtained. There were no statistical differences in the onset time (120+/-44 s in the control group, 141+/-33 s in the nimodipine group), in the first appearance time of T1 (28+/-6 min in the control group, 30+/-8 min in the nimodipine group), and in the times for 25% recovery in T1 (41+/-11, 32+/-2, 40+/-13 min in the control group, respectively, and 44+/-16, 36+/-15, 38+/-15 min in nimodipine group, respectively) between the groups studied. The time between the injection of the intubating dose of vecuronium and the third recovery of T1-25% of control was not significantly different between the control group (113+/-34 min) and the nimodipine group (117+/-42 min). This study indicates that nimodipine does not have any significant effect on the time course of action of vecuronium including the onset time and its clinical duration of action after the initial and the two maintenance doses in these patients.     

Monitoring of vecuronium-induced neuromuscular blockade during one-lung ventilation

Purpose  We investigated the monitoring of neuromuscular blockade caused by vecuronium in patients receiving one-lung ventilation (OLV) anesthesia for lung surgery. Methods  Eighteen adult patients requiring OLV for lung surgery (OLV group) and 18 undergoing two-lung ventilation (TLV) for colon surgery (control group) were enrolled in this study. In the two groups, anesthesia was maintained with sevoflurane, fentanyl, and epidural lidocaine. Time from vecuronium 0.1 mg·kg⁻¹ to the onset of neuromuscular blockade; times to the return of T1, T2, T3, or T4 (the first, second, third, or fourth response of the train-of-four [TOF]); and recovery of T1/control or TOF ratio (T4/T1) were compared between the two groups. Results  Time to the onset of neuromuscular blockade in the OLV group was similar to that in the control group (289 ± 74 vs 270 ± 85 s [mean ± SD]; P = 0.482). Times from vecuronium to the return of T1, T2, T3, or T4 in the OLV group did not significantly differ from those in the control group (21.9 ± 7.0 vs 25.8 ± 6.7 min for T1; P = 0.099). T1/control in the OLV group was significantly higher than that in the control group 50-120 min after vecuronium (P < 0.05). The TOF ratio did not differ significantly between the two groups. Conclusion  During OLV for lung surgery, recovery of T1/control is accelerated in anesthetized patients receiving vecuronium.     

Influence of epidural lidocaine injection on vecuronium-induced neuromuscular blockade

BACKGROUND: We investigated vecuronium-induced neuromuscular blockade in patients with continuous epidural lidocaine injection and those without epidural lidocaine. METHODS: Lower thoracic epidural injection of lidocaine was commenced at a rate of 2-3 mg x kg(-1) x h(-1) following its bolus injection (1.5-2 mg x kg(-1)) only in epidural group. Neuromuscular function was monitored by acceleromyographic train-of-four (TOF) responses of the adductor pollicis muscle to ulnar nerve stimulation after induction of general anesthesia. RESULTS: Neuromuscular block was obtained by vecuronium 0.1 mg x kg(-1) as an intubating dose and was maintained 5-10% of baseline first twitch (T 1) of TOF responses by continuous vecuronium administration. The maximum depression of T 1 response and onset time obtained by vecuronium 0.1 mg x kg(-1) were not different between the groups, but mean clinical duration from administration of the first dose to T 1 recovery to 5% of baseline was significantly prolonged in group with epidural lidocaine (49.5 min), compared to that without lidocaine (32.3 min). Furthermore, maintenance dose of vecuronium obtained in the group with epidural lidocaine (0.034 mg x kg(-1) x h(-1)) was significantly smaller than that in the group without lidocaine (0.060 mg x kg(-1) x h(-1)). CONCLUSIONS: Based on our results, we conclude that lidocaine injected continuously into the epidural space potentiates vecuronium-induced neuromuscular block.     

The effects of nicardipine and verapamil on the recovery time of vecuronium-induced neuromuscular blockade]

The present study investigated the effects of intravenous therapeutic dose of either nicardipine or verapamil on the recovery from transient neuromuscular blockade produced by vecuronium in 21 adult patients scheduled for elective surgery. Neuromuscular function was evaluated by single twitch height (T1), an amplitude of activity of the ulnar nerve being evoked by an electrical stimulation (0.2 msec, 0.1 Hz) under N2O/O2 and halothane anesthesia. The patients given vecuronium were randomly assigned to one of 3 groups: a control group who received no Ca entry blocker, nicardipine group and verapamil group. Nicardipine (30 mcg.kg-1) or verapamil (50 mcg.kg-1) was injected when T1 reached to 10% of the control twitch height. The recovery time of vecuronium (the time between 25% and 75% recovery) was not different significantly among the control (9.4 +/- 3.7 min), nicardipine (8.5 +/- 3.1 min) and verapamil (9.8 +/- 4.3 min) groups. We conclude that a therapeutic dose of either nicardipine or verapamil could be safely given intravenously to the patients under vecuronium-induced neuromuscular blockade.     

Pretreatment with lidocaine accelerates onset of vecuronium-induced neuromuscular blockade

The purpose of this study was to investigate the effect of pre-treatment with lidocaine on the onset of vecuronium-induced neuromuscular block in a randomized, double-blinded trial. Thirty-one patients were randomly allocated to one of two groups according to the agents administrated 3 min prior to vecuronium injection; Group C, normal saline 0.75 ml.kg-1 and Group L, 2% lidocaine 1.5 mg.kg-1. Anesthesia was induced with propofol 1.5 mg.kg-1 followed by continuous infusion at 8 mg.kg-1.hr-1. Neuromuscular blockade was evaluated with accelerometry, which measured a train-of-four (TOF) pattern of abductor policies muscle. The disappearance of the first response in TOF was regarded as onset of neuromuscular block. Changes in systolic and diastolic arterial pressure (SBP, DBP) and heart rate (HR) were measured before and after tracheal intubation. Times to onset of neuromuscular blockade induced by vecuronium in Group L and Group C were 115 +/- 20 sec and 174 +/- 45 sec, respectively. After tracheal intubation, SBP, DBP and HR in both groups increased compared with those before tracheal intubation, but the changes were not significant. Changes in SBP, DBP and HR did not differ between Group L and Group C. The mechanisms by which lidocaine reduced the time to onset of neuromuscular block caused by vecuronium could not be clarified from our study, but this may be related to pre- and post-junctional effects of lidocaine at neuromuscular junction. In conclusion, administration of lidocaine prior to tracheal intubation reduces the time to onset of neuromuscular block caused by vecuronium, but does not attenuate changes in blood pressure and heart rate caused by tracheal intubation.     

Effect of volatile anesthetics on vecuronium-induced neuromuscular blockade in children

We studied 60 children undergoing elective surgery to evaluate the effect of interactions between vecuronium and isoflurane or halothane on the potency and duration of neuromuscular blockade, as measured by electromyography. Vecuronium was first administered by a logarithm-based cumulative method (14, 22, 35, 56, 89 micrograms/kg) in 10 children anesthetized with thiopental (5 mg/kg), alfentanil (15 micrograms/kg first dose, then 10 micrograms/kg), and N2O/O2 (60:40) until a 95% +/- 2% twitch depression (ED95) was obtained. Thirty children given the same balanced anesthesia were then randomly assigned to three groups (n = 10 in each) to receive a single ED20 (21 micrograms/kg), ED50 (33 micrograms/kg), or ED80 (47 micrograms/kg) intravenous bolus of vecuronium calculated from the mean regression line of twitch responses of the first 10 children. In the second part of the study, 20 children were anesthetized with isoflurane (1.2%) or halothane (0.7%) and compared with the previous 10 children anesthetized with alfentanil-N2O. Potency of vecuronium determined by single-bolus or logarithm-based cumulative techniques was not significantly different. Isoflurane and halothane significantly decreased ED50 (22.3 +/- 1.6 and 25.4 +/- 1.4 micrograms/kg, respectively; mean +/- SE) and ED95 (41.5 +/- 3.3 and 46.7 +/- 3.2 micrograms/kg, respectively) compared with alfentanil-N2O (ED50: 32.8 +/- 0.8 micrograms/kg, ED95: 70.5 +/- 2.6 micrograms/kg). Recovery rate from vecuronium-induced neuromuscular blockade was significantly longer with isoflurane than with alfentanil-N2O or halothane. We conclude that in children single-bolus and logarithm-based cumulative techniques give similar potency estimates for vecuronium. Isoflurane and halothane increase by similar amounts the neuromuscular potency of vecuronium.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of acutely administered phenytoin on vecuronium-induced neuromuscular blockade

Phenytoin was administered intravenously in a dose of 10 mg kg to a group of patients in whom steady state neuromuscular blockade had been established with an infusion of vecuronium. A control group of patients were given 0.9% saline instead of phenytoin. Administration of phenytoin produced significant augmentation of neuromuscular blockade (p less than 0.001). The possible mechanism of this effect is discussed.     

Can early administration of neostigmine, in single or repeated doses, alter the course of neuromuscular recovery from a vecuronium-induced neuromuscular blockade?

The authors sought to determine whether neostigmine, given at a time when no response to peripheral nerve stimulation could be elicited, hastened recovery from a vecuronium-induced neuromuscular blockade (NMB). The effect of neostigmine (70 micrograms/kg) in antagonizing a profound (no-twitch) vecuronium-induced (0.1 mg/kg) NMB in 40 healthy patients was studied. Patients were randomly assigned to one of four groups specifying the sequence of neostigmine administration. Fifteen minutes after the administration of vecuronium, when there was no detectable twitch response, each patient received either neostigmine (70 micrograms/kg) with glycopyrrolate (15 micrograms/kg) or an equivalent volume of normal saline (placebo). When T1 (the first response in the train-of-four [TOF] sequence) recovered to 10% of control, patients again received either neostigmine with glycopyrrolate in the same doses as before or the placebo. The following variables were measured: times from vecuronium injection until T1 recovered to 10% (t [10]) and 90% (t [90]) of control, and time until the TOF ratio was equal to 75% (t [TOF75]). Mean values of t (90) and t (TOF75) were shorter (54.7-75.2 min and 60.4-79.5 min, respectively) for the three groups who received neostigmine as compared with patients who received two doses of placebo (104.3 and 122.6 min, respectively). There were no differences in the t (90) and t (TOF75) values among the three groups who received neostigmine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidurally administered mepivacaine delays recovery of train-of-four ratio from vecuronium-induced neuromuscular block

BACKGROUND: The aim of this study was to examine the efficacy of epidurally administered mepivacaine on recovery from vecuronium-induced neuromuscular block. METHODS: Eighty patients were randomly assigned to one of two study groups. They were either given epidurally a bolus of 0.15 ml kg(-1) of mepivacaine 2%, followed by repetitive injections of 0.1 ml kg(-1) h(-1) throughout the study, or were not given epidurally. General anaesthesia was induced and maintained with fentanyl, propofol and nitrous oxide. Neuromuscular block was induced with vecuronium 0.1 mg kg(-1) and monitored using acceleromyographic train-of-four (TOF) at the adductor pollicis. Patients in each treatment group were randomized to receive neostigmine 0.04 mg kg(-1) at 25% recovery of the first twitch of TOF or to recover spontaneously to a TOF ratio of 0.9. The effect of epidural mepivacaine on speed of spontaneous and facilitated recovery of neuromuscular function was evaluated. RESULTS: The time from administration of vecuronium to spontaneous recovery to a TOF ratio of 0.9 was significantly longer in the epidural mepivacaine group [105.4 (14.2) min] as compared with the control group [78.5 (9.1) min, P < 0.01]. Neostigmine administered at 25% of control in T1 shortened recovery from neuromuscular block, however the time required for facilitated recovery to a TOF ratio of 0.9 in the epidural group was significantly longer than that in the control group [7.6 (1.6) min vs 5.8 (2.1) min, P < 0.01]. CONCLUSIONS: In clinical anaesthesia, it should be recognized that epidurally administered mepivacaine delays considerably the TOF recovery from neuromuscular block.     

体温对国产维库溴铵体内清除过程的影响

目的：观察病人体温对国产维库溴铵体内清除过程的影响。方法：选择ASA分级I－Ⅱ级行择期手术患者68例病人随机分为两组：I组为保温组（36例），Ⅱ组为未保温组（32例）。用加速度仪监测神经肌肉传导功能，观察两组病人体温与国产维库溴铵作用高峰时间、临床作用时间、体内作用时间、恢复时间值的差别，并对病人体温与肌松药体内清除各时相值进行单因素相关分析。结果：与I组比较，Ⅱ组的病人体温明显降低，肌松药总用量明显减少，肌松药的高峰时间、临床作用时间、体内作用时间、恢复时间均明显延长（P＜0．05）。病人体温与肌松药高峰时间、临床作用时间、体内作用时间、恢复时间值间有明显的相关性，相关系数分别为－0．62、－0．73、－0．67、－0．71，P均＜0．01。结论：低体温影响国产维库溴铵的体内清除过程，延长其作用时间。     

Neostigmine after spontaneous recovery from neuromuscular blockade

The effect of neostigmine on neuromuscular function was examined after spontaneous recovery from an atracurium-induced neuromuscular blockade, which reached a train-of-four ratio of either 0.5 or 0.9. Two doses of neostigmine 2.5 mg were given 5 minutes apart. Neuromuscular recovery was assessed with train-of-four and tetanic stimuli. The first dose of neostigmine antagonised the neuromuscular blockade. The second dose diminished tetanic height and increased tetanic fade. The train-of-four measured mechanically was adversely affected to a small degree, but when measured with the electromyograph no significant change occurred. Neostigmine may adversely affect neuromuscular function after spontaneous recovery from a non-depolarising block. This is unlikely with a single modest dose and any effects are probably short-lived.     

Duration of vecuronium-induced neuromuscular blockade predicted by dose and onset time

We investigated the adequacy of using dose and onset time as variables to predict the duration of action of vecuronium in patients. The onset time until 95% twitch depression and the duration until 25% twitch recovery were measured for doses ranging from 0.1 to 0.3 mg kg^-1. Statistical analyses were performed by simple and multiple regressions. The duration of action was better predicted by dose (r² = 0.61) than by onset time (r² = 0.51). However, the predictability was significantly improved by a multiple regression model of the variables, and the explanatory power was largest when using the square root of duration as the dependent variable (r² = 0.69). We conclude that the duration of neuromuscular blockade after vecuronium can be predicted more accurately by the combined use of dose and onset time than by dose alone.     

Comparison of evoked electromyography and mechanical activity during vecuronium-induced neuromuscular blockade

The relationship of compound electromyography to mechanical myography was investigated in 20 patients given vecuronium in a dose of 0.1 mg kg-1. Mechanical response was affected less quickly and recovered faster than the electrical response. Although there was a good correlation between the two throughout the study, a shift towards mechanical responses was observed in all cases for the onset of blockade and recovery from blockade. Moreover, during recovery the mechanical responses became greater than the control value in all patients. This was also reflected in the statistically significant difference (P less than 0.05) of the regression lines relating tension and electromyography (TI as well as train-of-four ratio) between onset of, and recovery from, neuromuscular block.     

The influence of 0.5 % isoflurane on a vecuronium-induced neuromuscular blockade

The influence of adding 0.5% isoflurane to a narcotic-based anaesthesia on the duration of effect and recovery time after repetitive administration of vecuronium was studied in ten healthy patients. The twitch response in the adductor pollicis muscle was recorded after supramaximal train-of-four (TOF) stimulation of the ulnar nerve at the wrist. Prior to endotracheal intubation a bolus dose of vecuronium (0.08 mg/kg b.w.) was given. During surgery repeated injections of vecuronium (0.02 mg/kg b.w.) were administered at a TOF ratio of 0.25. Hand-skin temperature, systolic blood pressure, end-tidal CO2 and isoflurane concentrations were continuously monitored. Before and after 90 min administration of isoflurane, the duration of effect was 21 +/- 4 and 24 +/- 5 min (mean +/- s.d., P less than 0.05) respectively. Corresponding recovery times were 270 +/- 60 and 280 +/- 70 s (n.s.). Skin temperature remained unchanged and systolic blood pressure showed only minor variations. The addition of 0.5% isoflurane to a narcotic-based anaesthesia causes a moderate increase in duration of effect but no change in recovery time from a repetitive vecuronium-induced neuromuscular blockade of 0.02 mg/kg.     

Comparative effects of desflurane and isoflurane on vecuronium-induced neuromuscular blockade.

STUDY OBJECTIVE: To evaluate the neuromuscular effects of a nondepolarizing muscle relaxant (vecuronium) during anesthesia with equipotent concentrations of either desflurane or isoflurane. DESIGN: Randomized open study comparing effects of desflurane and isoflurane on vecuronium-induced neuromuscular blockade. SETTING: University-affiliated medical center. PATIENTS: Forty-five healthy adults undergoing elective surgical procedures randomly assigned to receive either desflurane, nitrous oxide (N2O), and vecuronium or isoflurane, N2O, and vecuronium for maintenance of general anesthesia. INTERVENTIONS: Following a standardized induction sequence, patients receiving either desflurane and N2O or isoflurane and N2O were administered bolus doses of vecuronium equal to 0.01, 0.02, or 0.03 mg/kg intravenously (IV) during the maintenance period. Neuromuscular transmission was measured using a Relaxograph monitor. MEASUREMENTS AND MAIN RESULTS: Vecuronium produced similar depression of neuromuscular function at equipotent (50% of the minimum alveolar concentration) end-tidal concentrations of isoflurane 0.6% and desflurane 3.0%. Following administration of vecuronium 0.01 to 0.03 mg/kg IV, onset times (3.4 +/- 0.4 minutes to 3.2 +/- 0.4 minutes and 3.2 +/- 0.5 minutes to 3.0 +/- 0.6 minutes), maximum T1 twitch depression (80% +/- 10% to 95% +/- 9% and 81% +/- 9% to 97% +/- 10%), clinical duration of blockade (12 +/- 5 minutes to 20 +/- 8 minutes and 10 +/- 5 minutes to 19 +/- 17 minutes), and T1 recovery times (10 +/- 3 minutes to 12 +/- 6 minutes and 10 +/- 3 minutes to 12 +/- 4 minutes) were similar in the isoflurane and desflurane treatment groups, respectively (means +/- SD). CONCLUSION: Vecuronium has similar neuromuscular effects when administered in the presence of desflurane 3% and isoflurane 0.6%.     

Does intravenous infusion of nitroglycerin potentiate pancuronium- and vecuronium-induced neuromuscular blockade?

The dose requirement for 95% depression of twitch tension and the time course of the neuromuscular blocking effects of the ED95 of pancuronium bromide and vecuronium bromide were studied during intravenous infusion of glucose, 5%, and nitroglycerin, 1 microgram X kg-1 X min-1, in 20 cats anesthetized with pentobarbital. Nitroglycerin administered continuously starting 1 hr before the administration of the ED95 and maintained during at least five maintenance doses of either pancuronium or vecuronium did not significantly potentiate the action of the neuromuscular blocking drugs, nor did it alter their time course of action. A tendency for a decrease (statistically not significant) rather than an increase in the duration of action of maintenance doses of both pancuronium and vecuronium was apparent during the treatment with nitroglycerin. These findings indicate a lack of interaction between pancuronium or vecuronium and nitroglycerin, provided that moderate doses are used.     

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.     

Effect of low-dose infusion of prostaglandin E1 on vecuronium-induced neuromuscular blockade

The effect of low-dose (20 ng·kg⁻¹·min⁻¹) infusion of prostaglandin E₁ (PGE₁) on vecuronium-induced neuromuscular blockade was studied. The study population consisted of 24 elderly patients (65–75 years old) and 24 younger adult patients (25–56 years old). They were randomly assigned to the control and PGE₁ groups. The steady-state dose requirement (SSDR) of vecuronium was derived from ondemand infusion of the drug which produced a stable twitch height of 20% of its baseline reading, and recovery time after steady-state infusion was defined as the time for recovery from twitch height from 25% to 75%. The patients in the PGE₁ group received an infusion of PGE₁ 20 ng·kg⁻¹·min⁻¹, while those in the control group received an infusion of normal saline. The SSDR (23.2±9.1 and 34.2±5.9 μg·kg⁻¹. hr⁻¹, respectively;P=0.02) was significantly less and the recovery time (35.0±9.5 and 19.9±4.2 min, respectively;P=0.01) was significantly longer in the elderly than in the younger patients. However, low-dose infusion of PGE₁ significantly increased the SSDR (23.2±9.1 to 37.4±3.7 μg· kg⁻¹·hr⁻¹;P=0.01) and shortened the recovery time (35.0±9.5 to 23.5±4.0 min;P=0.02) in elderly patients. We concluded that low-dose infusion of PGE₁ is effective in preventing the prolonged action of vecuronium in elderly patients.