Recovery from neuromuscular blockade: residual curarisation following atracurium or vecuronium by bolus dosing or infusions

We conducted a survey of the incidence of Postoperative Residual Curarisation (PORC) in two groups of patients following the use of atracurium or vecuronium. In the first group (B) the neuromuscular blocking drugs were administered by bolus dosing, and in the second group (I) by continuous infusion. On arrival in the recovery room, neuromuscular function was assessed both by compound evoked electromyogram (EMG) in a train of four pattern and also clinically, by the ability to sustain a headlift for >5 seconds, and to cough. Results were obtained from 150 patients (100 in group B and 50 in group I). The incidence of PORC, as defined by a train of four ratio of <0.7, on arrival in the recovery room was 12% in group B, and 24% in group I. Clinical criteria of adequate neuromuscular reversal revealed different results, with the majority of patients being unable to perform either clinical test on arrival in recovery. Those patients in whom a peripheral nerve stimulator was used intra-operatively did not have a reduced incidence of PORC. We have demonstrated that PORC is still a common occurrence even with intermediate duration of action neuromuscular blocking drugs.     

Train–of–four fade during onset of neuromuscular block with nondepolarising neuromuscular blocking agents

Fade in the train-of-four (TOF) responses during onset of neuromuscular block was studied following administration of atracurium (225 or 450 micrograms/kg), vecuronium (40 or 80 micrograms/kg), pancuronium (60 or 120 micrograms/kg) and tubocurarine (450 micrograms/kg). TOF ratios were measured at approximate heights of T1 (first response in the TOF) of 75, 50 and 25%. Fade in TOF increased as the height of T1 decreased, with maximum fade being observed at T1 of 25%. The greatest difference between relaxants was observed at T1 of 25%, vecuronium showing the least fade and pancuronium, atracurium and tubocurarine showing increasing fade, in that order. The difference between atracurium and tubocurarine or between vecuronium and pancuronium was not significant, but the degree of TOF fade was significantly greater with atracurium and tubocurarine in comparison to vecuronium or pancuronium.     

Neuromuscular monitoring and postoperative residual curarisation: a meta-analysis

We conducted a meta-analysis to examine the effect of intraoperativemonitoring of neuromuscular function on the incidence of postoperativeresidual curarisation (PORC). PORC has been considered presentwhen a patient has a train-of-four (TOF) ratio of < 0.7 or< 0.9. We analysed data from 24 trials (3375 patients) thatwere published between 1979 and 2005. We excluded data on mivacuriumfrom this meta-analysis because only three studies had examinedthe incidence of PORC associated with its use. Long- and intermediate-actingneuromuscular blocking drugs had been given to 662 and 2713patients, respectively. Neuromuscular function was monitoredin 823 patients (24.4%). A simple peripheral nerve stimulatorwas used in 543 patients, and an objective monitor was usedin 280. The incidence of PORC was found to be significantlylower after the use of intermediate neuromuscular blocking drugs.We could not demonstrate that the use of an intraoperative neuromuscularfunction monitor decreased the incidence of PORC.     

Neostigmine and edrophonium as antagonists of atracurium and pancuronium

Edrophonium 0.5 mg/kg or neostigmine 0.04 mg/kg were administered to two groups of 30 patients each for antagonism of atracurium- or pancuronium-induced neuromuscular block at 25% single twitch recovery. Neuromuscular block was studied using both single twitch and train-of-four (TOF) nerve stimulation. The times to 100% single twitch recovery were significantly more rapid for patients receiving edrophonium (P less than 0.01) in both groups (atracurium and pancuronium); the TOF ratios were similar for atracurium, but for pancuronium they were greater after neostigmine than after edrophonium, and only at 25 min were these ratios similar. It is concluded that edrophonium in a dose of 0.5 mg/kg antagonizes neuromuscular blockade induced by atracurium, as does neostigmine in a dose of 0.04 mg/kg, but the former does not consistently antagonize neuromuscular blockade induced by pancuronium even at 25% of single twitch recovery.     

Dose-response studies of atracurium, vecuronium and pancuronium in the elderly

Dose-response curves were constructed for atracurium, vecuronium and pancuronium in elderly subjects in order to assess potency of these relaxants. The results were compared to data previously obtained for adult subjects using the same method. A single-dose method of potency determination was used in both studies. The results indicate no significant difference in the potency of these relaxants between elderly and adult subjects; the ED95S were 249 and 226 micrograms/kg for atracurium, 43.1 and 39.6 micrograms/kg for vecuronium and 65.9 and 60 micrograms/kg for pancuronium respectively in the elderly and the adults.     

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.     

Out-patient laparoscopy in general anaesthesia with alfentanil and atracurium A comparison with fentanyl and pancuronium

The effects of the new intravenous anaesthetic drugs alfentanil (50 micrograms/kg) and atracurium (0.5 mg/kg) on per- and post-operative function in out-patients clinics were compared with fentanyl (5 micrograms/kg) and pancuronium (0.07 mg/kg). Sixty-two healthy female patients submitted for out-patient sterilization by laparoscopy participated in the study. Thirty patients receiving alfentanil and atracurium (the AA-group) had significantly less pain during analgetic injection, less coughing during intubation, and faster and more pronounced muscle relaxation during induction of anaesthesia, compared with 32 patients receiving fentanyl and pancuronium (the FP-group). The AA-group had less adrenocortical stress-response judged by systolic blood pressure and pulse rate during anaesthesia. Reversal of anaesthesia and neuromuscular blockade were performed without differences in awakening parameters between the two groups. The AA-group had a significantly better score on P-deletion test 45 min after reversal of anaesthesia, a better street fitness score in the afternoon after the procedure and a better day-life function score at home in the evening. There was no difference between the groups in postoperative complaints and in function after the day of operation.     

Duration of action of vecuronium in infants and children anaesthetized without potent inhalation agents

The duration of effects of vecuronium has previously been studied in paediatric patients only during inhalation anaesthesia. We therefore studied the age-related differences in duration of action after administration of 0.1 mg kg-1 of vecuronium in 66% N2O in O2, fentanyl anaesthesia without inhalation agents. Forty-nine children (2 wk-14 yr, ASA 1-2) were selected for study and divided into four groups according to age. Evoked EMG monitor (Relaxograph, Datex, Finland) was calibrated with hypothenar muscle recording. The completely restored first twitch (T1) level was used as reference for recovery calculations. In infants (age less than 1 yr) the onset time (68 s) was only 0.6-0.8 times that of older patients (P less than 0.01). In infants the duration of surgical relaxation to T1 10% (42 min) and the recovery index (21 min) were 1.7-2.9 times longer than in older patients (P less than 0.01). It took 55 min from the beginning of recovery to full restoration of T1 in infants, compared with 20-24 min in 3-15-year-old children. Interestingly, the younger the child, the more rapidly train-of-four ratio recovered compared with T1 (P less than 0.01). Because of the age-dependent prolongation of vecuronium relaxation and spontaneous recovery in small children, the level of relaxation should be monitored also in clinical practice.     

Cardiovascular effects of vecuronium, atracurium, pancuronium, metocurine and RGH-420 1 in dogs

The effect on the cardiovascular haemodynamic status of five neuromuscular blocking drugs, RGH-4201, vecuronium, atracurium, pancuronium and metocurine, was studied in five conditioned foxhounds anaesthetised with fentanyl. Changes in heart rate, mean arterial blood pressure, central venous pressure, mean pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac output were recorded at 2, 5, 10, 20 and 30 min after administration of the drugs. From these, stroke volume, systemic vascular resistance and pulmonary vascular resistance were calculated. Administration of RGH-4201 was followed by a pronounced increase in heart rate, accompanied by an increase in cardiac output and a decrease in systemic and pulmonary vascular resistance. Metocurine and pancuronium resulted in a decrease of right and left filling pressures and systemic-/pulmonary vascular resistance. Changes after atracurium, vecuronium and metocurine were minimal. It is concluded that RGH-4201 causes major alterations in the cardiovascular haemodynamic status in dogs anaesthetised with fentanyl when compared to vecuronium, atracurium, metocurine and pancuronium. With respect to cardiovascular stability, atracurium and vecuronium offer advantages.     

Prospective randomised double-blind comparative study of rocuronium and pancuronium in adult patients scheduled for elective 'fast-track' cardiac surgery involving hypothermic cardiopulmonary bypass

The majority of cardiac anaesthetists in the UK use pancuronium for fast-track cardiac surgery. We compared the duration of action of pancuronium and rocuronium in patients undergoing fast-track hypothermic cardiopulmonary bypass and cardiac surgery. We determined whether patients would have had residual neuromuscular blockade at extubation. Twenty patients were randomly allocated to receive either pancuronium 0.1 mg x kg(-1) or rocuronium 1 mg x kg(-1). Neuromuscular function was assessed by acceleromyography; spontaneous recovery was evaluated by the train-of-four ratio measured at the adductor pollicis longus muscle. Median times to recover train-of-four ratio of 0.9 were 3 h 38 min for rocuronium and 7 h 52 min for pancuronium. The median difference in recovery times was 4 h 15 min (95% CI 2 h 30 min to 6 h 20 min; p = 0.0003 by Mann-Whitney test). None of the patients in the rocuronium group and seven of 10 patients in the pancuronium group had their extubations delayed because of residual neuromuscular blockade. Unless fast-track patients have neuromuscular function assessed before extubation, pancuronium should not be used.     

Vecuronium and Atracurium in the Elderly: A Clinical Comparison with Pancuronium

The intubating conditions, time to complete block and duration of clinical relaxation were observed in a group of 101 elderly patients (aged over 65 years) following pancuronium 0.1 mg kg^-1, vecuronium 0.1 mg kg^-1 or atracurium 0.5 mg kg^-1. The intubating conditions in the three groups were similar when assessed at 2 min following relaxant administration. The time to complete block was shortest with vecuronium (4.3 min) in comparison to atracurium (5.0 min) and pancuronium (6.0 min), but the differences were not statistically significant. The duration of clinical relaxation, however, was significantly shorter with vecuronium (37 min) and atracurium (35 min) in comparison to pancuronium (99 min).     

Continuous infusions of atracurium and vecuronium,compared with intermittent boluses of pancuronium: dose requirements and reversal

This study was designed to determine the effect of prolonged infusion on the ease of reversal of atracurium and vecuronium, and whether factors which potentiate the block delayed reversal. In phase one, 40 patients were randomized (double blind) to determine the steady state conditions for atracurium and vecuronium. Fourteen atracurium patients and 17 vecuronium patients were evaluable. The unblinded second phase involved the steady state conditions using halothane or isoflurane and atracurium infusions. The infusion required for 95% twitch depression (TD95) for atracurium was 7.6 +/- 1.1 micrograms.kg-1 x min-1. The requirement for vecuronium changes with time: TD95 at 30 min was 1.01 +/- 0.16, at 60 min 0.89 +/- 0.12 and after 90 min 0.85 +/- 0.17 micrograms.kg-1 x min-1 (P < 0.05). The mean TD95 was 0.94 +/- 0.23 micrograms.kg-1 x min-1. Multivariate regression analysis of the infusion data revealed a vecuronium model predicting TD95 by the duration of infusion (P < 0.05) and weight (P = 0.05). Atracurium TD95 was predicted by age (P = 0.05). The addition of an inhalation agent to atracurium reduced the infusion rate by 2.01 +/- 0.28 micrograms.kg-1 x min-1 (P = 0.0001) for each increase in MAC. The mean reversal times for atracurium with three different anaesthetics and for vecuronium were not different. Reversal of pancuronium blockade, from less profound twitch depression (86.4 vs 95%) took twice as long as for atracurium and vecuronium for which the following predictors were identified: age, weight, duration of infusion, level of blockade, and type of anaesthetic, using a stepwise regression model.(ABSTRACT TRUNCATED AT 250 WORDS)     

Time course of action of combinations of vecuronium and pancuronium

Vecuronium 0.1 mg/kg, pancuronium 0.1 mg/kg, vecuronium 0.075 mg/kg + pancuronium 0.025 mg/kg, vecuronium + pancuronium 0.05 mg/kg each and vecuronium 0.025 mg/kg + pancuronium 0.075 mg/kg were compared with respect to time taken to onset of effect, duration of clinical relaxation and intubation conditions in five groups of 20 patients each. The time to onset and intubating conditions were similar in all the groups, indicating that the combinations have no advantage over the individual drugs. The duration of clinical relaxation was 25 minutes with vecuronium, and increased as the proportion of pancuronium in the mixture increased, being 56 minutes with pancuronium 0.1 mg/kg.     

Evaluation of the degree of muscle blockade: a comparative study using electromyography of the muscular relaxation induced by pancuronium, atracurium and vecuronium

To compare the muscle relaxing effect of pancuronium, atracurium and vecuronium, 99 patients operated on under neuroleptanesthesia were divided in three groups depending on whether they had received, during induction, pancuronium 0.1 mg/kg, atracurium 0.5 mg/kg, or vecuronium 0.1 mg/kg. One-fourth of the initial dose was repeated if necessary. The electromyographic study of the muscle relaxing effect was carried out with stimulation of the cubital nerve with courses of supramaximal square wave electric stimuli in 'trains of four'. The time to maximal blockade (TMB), the time of clinical effectiveness (TCE), the total duration time (TDT), the time of duration of the maintenance dose (DM 25) and the recovery index (RI) were measured. TMB was 4.3 +/- 1 min for pancuronium, 3.5 +/- 0.8 min for atracurium, and 3.3 +/- 0.98 min for vecuronium. The differences between pancuronium and the other drugs were statistically significant, but they were not so between the latter two. TCE was 67.9 +/- 13.5 min for pancuronium, significantly longer than with vecuronium and atracurium (28.2 +/- 5.7 and 31.5 +/- 4.7, respectively). TDT was 126.2 +/- 19.9 min for pancuronium, 61.2 +/- 11.5 min for atracurium and 55.5 +/- 16.7 for vecuronium. The mean duration of the repeated dose was 52.7 +/- 8.4 min for pancuronium, 19.9 +/- 5 min for vecuronium and 10.9 +/- 5 min for atracurium. RI, which was similar for atracurium and vecuronium (12.7 +/- 1.7 min and 12.8 +/- 3.3 min), was longer for pancuronium (27.7 +/- 4.3 min).     

丙泊酚-七氟醚静吸复合麻醉对阿曲库铵药效学的影响

目的 观察七氟醚对阿曲库铵肌松效应的影响.方法 68例择期腹部手术的全麻患者,ASA Ⅰ或Ⅱ级,年龄18～67岁,随机均分为丙泊酚-七氟醚静吸复合麻醉组(七氟醚组)和丙泊酚静脉麻醉组(对照组).监测腩电双频指数(BIS),使用加速度肌松监测仪刺激前臂尺神经,观察拇内收肌的收缩反应,记录阿曲库铵的起效时间、无反应时间、肌松维持时间以及恢复指数等指标.结果 两组肌松起效时间、无反应时间以及T1 25%时间差异无统计学意义,但七氟醚组25%四个成串刺激比(TOFr)恢复时间、恢复指数及拔管时间均比对照组明显延长(P<0.05).结论 七氟醚麻醉能明显增强阿曲库铵的肌松效应.     

The Effects of d-Tubocurarine, Pancuronium and Atracurium on the Responses of Gastrocnemius and Soleus Muscles in the Cat

In vivo, the effects of d-tubocurarine (0.20 mg kg-1), pancuronium (0.015 mg kg-1) and atracurium (0.15 mg kg-1) on the responses of the indirectly stimulated cat gastrocnemius (fast) and soleus (slow) muscles to a twitch, train-of-four and tetanic stimuli were studied. The soleus muscle demonstrated a greater degree of fade than the gastrocnemius in response to tetanic stimuli (50 Hz). There was no difference between the responses of the two muscles to twitch or train-of-four stimuli with any of the drugs. Recovery of train-of-four ratio occurred more rapidly than did the tetanic fade ratio. At a time when train-of-four ratio exceeded 0.7, tetanic fade was still evident, especially in the soleus muscle.     

The interaction of pancuronium and vecuronium with cardiac muscarinic receptors

The interaction of vecuronium, a monoquaternary analogue of pancuronium, with the cardiac muscarinic receptors in canine hearts was investigated in vitro by [3H] QNB binding assay and compared with that of pancuronium. Both pancuronium and vecuronium, which are nicotinic antagonists of competitive types, inhibited the binding of [3H] QNB to cardiac muscarinic receptors with values of IC50 of 5.41 X 10(-7) mol/l and 3.97 X 10(-6) mol/l respectively. According to the Kd and Bmax values on the Scatchard plot, pancuronium, while not influencing the number of receptors, had a 3-fold greater inhibitory effect than vecuronium on the affinity of the muscarinic receptors. The KI values of vecuronium and pancuronium showed that pancuronium had a 7.3-fold greater affinity with the receptors than vecuronium. We concluded that vecuronium had a direct inhibitory action on the binding of [3H] QNB to the canine heart muscarinic receptors, but this action was much weaker than pancuronium.