Alfentanil combined with vecuronium or pancuronium: haemodynamic implications

Forty-two fit, anticholinergized patients, induced with thiopentone, received either vecuronium (V) or pancuronium (P) 0.1 mg/kg, followed by alfentanil 15 micrograms/kg. The mean heart rate in the Group V was significantly lower than that in the Group P. The difference, 10-15 bpm, appeared after alfentanil administration, and lasted for 5 min postintubation, when under N2O anaesthesia. The Group P patients maintained their arterial pressure closer to the preinduction level than did the Group V patients, but a statistically significant inter-group difference appeared only at two recording stages. Four Group V patients, contrasted to none of the Group P patients (P less than 0.05), were put in head-down tilt, or were given atropine, and/or etilephrine for an undue decrease in arterial pressure. Compared to vecuronium, pancuronium increased heart rate, and protected from arterial hypotension, when combined with low-dose alfentanil.     

Diabetic autonomic neuropathy and the haemodynamic actions of vecuronium and pancuronium during vitrectomy

In order to clarify whether autonomic neuropathy modifies the haemodynamic effects of alfentanil, vecuronium and pancuronium, twenty-seven patients with diabetes mellitus were studied at thiopentone induction, and during nitrous oxide anaesthesia for ophthalmic vitreous surgery. Heart rate was lower in the diabetic patients receiving vecuronium compared with those receiving pancuronium, but no difference was seen in arterial pressure. During and after anaesthesia induction, the profiles of heart rate and arterial pressure resembled those found in healthy controls. Even in patients with advanced autonomic neuropathy, anaesthetics may exert their inherent vagotonic or sympathkotonic actions.     

Thiopentone reduces the haemodynamic response to induction of high–dose fentanyl–pancuronium anaesthesia in coronary artery surgical patients

Thirty-three coronary artery bypass graft patients anaesthetized with high-dose fentanyl (50 micrograms/kg)-pancuronium-oxygen were divided into one control group receiving additional saline and two groups receiving additional 1 mg/kg or 2.5 mg/kg of thiopentone before laryngoscopy and intubation. During laryngoscopy and intubation, systemic arterial pressures, heart rate and rate-pressure-product remained at considerably elevated levels caused by pancuronium in the control group. Both doses of thiopentone reduced these haemodynamic values close to their initial levels. Cardiac index and left ventricular stroke work index were significantly decreased, especially by the higher thiopentone dose, as compared with the control group. However, there were no statistical differences between the haemodynamic changes produced by the two doses of thiopentone. Sedative or hypnotic supplementation of high-dose fentanyl anaesthesia seems to be necessary if pancuronium is used as a muscle relaxant. A small increment of thiopentone, 1 mg/kg, was enough to return haemodynamic parameters almost to their initial levels, whereas the effect of 2.5 mg/kg of thiopentone was unnecessarily strong.     

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.     

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.     

Reversal of profound paralysis: use of large doses of edrophonium to antagonize vecuronium and pancuronium induced neuromuscular blockade

The ability to evoke reversal of dense vecuronium- and pancuronium-induced paralysis (T1 10% of control) with edrophonium 1.0 mg.kg-1 was studied using train-of-four nerve stimulation and electromyographic monitoring. Two different end-points, train-of-four ratios of 0.5 and 0.7, were used to define "adequate reversal", and the results for both relaxants were compared. Reversal was reliable and rapid for vecuronium if either ratio was used with times of 2.8 (1.5) and 9 (3) min required to achieve ratios of 0.5 and 0.7, respectively. However, if the block was due to pancuronium, reversal was unreliable with 2 of 9 and 4 of 9 patients not achieving ratios of 0.5 and 0.7, respectively. Reversal was also markedly prolonged in this group with a mean time of 37 (23) min to achieve a ratio of 0.7, and in almost half these patients a supplementary dose of edrophonium was required.     

Dose-response to pancuronium in identical twins

The dose-response to pancuronium was determined in identical twins within an hour with the same anesthetic technique. The dose-response curves did not differ from parallelism, but one infant was more sensitive to pancuronium than the other. The recovery rates were also different. The variation in the dose response to pancuronium seems to extend to identical twins.     

The haemodynamic effects of rocuronium and vecuronium are different under balanced anaesthesia

Background: Rocuronium has been reported to have minimal haemodynamic effects. However, this conclusion has been drawn primarily from investigations conducted under narcotic-based anaesthesia. This study was designed to evaluate the cardiovascular effects of rocuronium under isoflurane/N20/fentanyl anaesthesia and to compare rocuronium's haemodynamic effects to those of vecuronium and pancuronium.
Methods: Anaesthesia was induced with fentanyl 2 μg/kg, thiopentone 4 mg/kg, and suxamethonium 0.5 mg/kg in 75 ASA I or II patients. After tracheal intubation, anaesthesia was maintained with isoflurane 0.5% and N₂0 50% in oxygen. Five min after intubation (baseline), patients randomly received either vecuronium 100 μg/kg, rocuronium 600 μg/kg, rocuronium 900 μg/kg, rocuronium 1200 μg/kg, or pancuronium 140 μg/kg. One min after administration of muscle relaxant, mean arterial pressure (MAP) and heart rate (HR) were recorded and were subsequently measured at 1-min intervals for the next 4 min.
Results: HR decreased significantly ( P <0.05) at all times compared to baseline in patients receiving vecuronium. HR significantly ( P < 0.05) increased in those receiving rocuronium 1200 μg/kg or pancuronium. Patients who received vecuronium had a sigruficant ( P < 0.05) decrease in MAP at all times compared to baseline. Comparing results between groups, patients who received rocuronium or pancuronium had significantly ( P < 0.05) higher MAP compared to those administered vecuronium.
Conclusion: The haemodynamic effects of rocuronium and vecuronium are different under balanced anaesthesia. Rocuronium may attenuate the fall in MAP that often occurs under balanced anaesthesia without surgical stimulation.     

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.     

The influence of pancuronium and vecuronium combined with balanced anaesthesia on haemodynamics and myocardial oxygen balance

The effects of the non-depolarizing muscle relaxants pancuronium (Pancuronium) and vecuronium (Norcuron) (0.1 mg/kg) on myocardial blood flow, myocardial oxygen consumption, myocardial lactate balance, cardiovascular dynamics and electrocardiogram were studied in two groups of eight patients undergoing coronary artery bypass surgery. After induction of anaesthesia with 0.015-0.02 mg/kg flunitrazepam, isoflurane (0.5 vol%) and N2O/O2 (l/l), neuromuscular blockade was induced with pancuronium or vecuronium (0.1 mg/kg) combined with a single dose of 0.005 mg/kg fentanyl. Haemodynamic measurements were performed and the electrocardiogram was recorded before anaesthesia, in steady-state anaesthesia, after relaxation with pancuronium or vecuronium combined with fentanyl, and after intubation. The haemodynamic data consisted of heart rate, cardiac index, stroke volume index, mean arterial pressure, total peripheral resistance, pulmonary arterial pressure, pulmonary capillary wedge pressure, right atrial pressure, myocardial blood flow, coronary vascular resistance, myocardial oxygen consumption, coronary aterio-mixed venous content difference, myocardial lactate extraction and rate pressure product. In the vecuronium group, heart rate decreased significantly more (21%) than in the pancuronium group (9%). Therefore myocardial oxygen consumption (48% resp. 35%) and coronary blood flow (31% resp. 18%) decreased more in the vecuronium than in the pancuronium group. The higher metabolic demand in the pancuronium group induced a significantly lower coronary vascular resistance, because the decrease in coronary perfusion pressure was similar in both groups. None of the other haemodynamic parameters differed significantly in either patient group. We did not observe ST-segment depressions or elevations in the ECG, increases in PCWP or myocardial lactate production. Therefore extended myocardial ischaemia can be excluded in our patients who received pancuronium or vecuronium for neuromuscular blockade.     

Hemodynamic effects of atracurium, vecuronium and pancuronium during sufentanil anesthesia for coronary artery bypass

A study was undertaken to evaluate the cardiovascular effects of sufentanil, in combination with three different muscle relaxants, used as sole anesthetic with 100% O2 in 30 patients undergoing elective coronary artery vein graft surgery. Patients were randomly allocated to receive pancuronium (P), vecuronium (V) or atracurium (A) for muscle relaxation. All patients received 15 micrograms/kg sufentanil at induction followed by 5-10 micrograms/kg sufentanil prior to sternotomy. At the 95% level of significance no statistical difference was found for any of the measured and derived cardiovascular parameters between groups P, V and A, except for a decreased systolic blood pressure in the atracurium group after induction. Sufentanil in combination with pancuronium or vecuronium provided stable hemodynamic conditions throughout anesthesia. Atracurium was less satisfactory. We conclude that there is no advantage to be gained, in the presence of beta blockade, from the use of the new generation muscle relaxants as compared to pancuronium during high-dose sufentanil anesthesia for coronary artery vein grafting.     

An evaluation of Org NC 45 (vecuronium) in paediatric anaesthesia

Vecuronium (Org NC 45) was evaluated as a neuromuscular blocking agent in children and compared with pancuronium in a double-blind study. Satisfactory intubating conditions were present 90 seconds after 0.1 mg/kg of either drug. The onset of complete block was quicker after vecuronium but the greatest difference was found in the duration to 25% recovery which was significantly shorter with vecuronium (20 min) compared with pancuronium (48 min). The use of vecuronium was associated with cardiovascular stability and no clinical evidence of histamine release. Antagonism of the block was readily achieved with neostigmine.     

Economy in the use of muscle relaxants Vecuronium after pancuronium

Vecuronium is an intermediate duration, non-depolarising muscle relaxant. When used during prolonged procedures, it may be given by intermittent injection, by continuous infusion or by a single very large dose at the start of anaesthesia. It may also be used to maintain relaxation after the initial use of a long-acting agent, such as pancuronium. This study demonstrates that the effect of a dose of vecuronium used in this fashion is increased when interaction with pancuronium takes place. The clinical and theoretical implications of this observation are discussed.     

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.     

Hemodynamic effects of vecuronium in patients with coronary artery disease

The hemodynamic effects of vecuronium 0.2 mg/kg were investigated in 11 patients with coronary artery disease. Vecuronium, at a dose double the ED90, produced 90% neuromuscular block in a mean time of 163 +/- 7 s, and was not associated with any significant hemodynamic changes. The results suggest that vecuronium can safely be used in cardiac patients.     

Muscle relaxants change myocardial metabolism in patients with ischemic heart disease during high-dose fentanyl anesthesia

Although not unanimously accepted, high-dose fentanyl anesthesia has been associated with hemodynamic stability and little derangement of myocardial oxygen balance. This apparent inconsistency inspired us to investigate the effects on cardiac function and myocardial metabolism of stepwise increasing doses of fentanyl, accumulating to 15, 30, and 50 micrograms.kg-1, with the least possible interference from other drugs. Subjects were unpremedicated patients with ischemic cardiac disease scheduled for coronary artery bypass grafting or major vascular surgery. In an initial study employing succinylcholine for muscle relaxation, we found that heart rate (HR), coronary sinus blood flow (CSF) and coronary vascular resistance (CVR) remained unchanged, while systemic arterial pressure (SBP), rate-pressure product (RPP), coronary perfusion pressure (CPP) and left ventricular work (LVW) decreased. Myocardial uptake of oxygen (MVO2) and free fatty acids (FFA) both decreased in a dose-dependent manner. Arterial lactate concentration and myocardial lactate uptake both increased. These findings opposed the postinduction myocardial ischemia noted by some other investigators. In most of these studies pancuronium bromide had been used for muscle relaxation. Since the latter agent has been claimed to increase cardiac work, a second group of correspondingly diseased patients was studied in which succinylcholine was replaced by pancuronium bromide. In this group HR, RPP, CSF and MVO2 all increased at the lowest dose of fentanyl and HR additionally also at 30 micrograms.kg-1. The cardiac index was higher in the pancuronium group at the lowest and middle dose steps of fentanyl. Lactate uptake decreased with higher doses of fentanyl and relative myocardial lactate extraction declined.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.