Hemodynamic responses to pancuronium and vecuronium during high-dose fentanyl anesthesia for coronary artery bypass grafting

Haemodynamic differences between pancuronium and vecuronium in an experimental pig model

OBJECTIVE

To compare baseline cardiovascular function in anesthetised pigs using either pancuronium or vecuronium as a neuromuscular blocker.

STUDY DESIGN

Retrospective, non-randomized comparison.

ANIMALS

Norwegian Land Race pigs (Sus scrofa domesticus) weighing mean 42 ± SD 3 kg.

METHODS

One hundred and sixteen animals from four different research protocols premedicated with identical doses of ketamine, diazepam, atropine and isoflurane, and anaesthetised with pentobarbital, fentanyl, midazolam and N(2)O were arranged into three uniform groups with respect to neuromuscular blocking agent: pancuronium bolus of 0.063 mg kg(-1) followed by 0.14 mg kg(-1) hour(-1) (n = 54), low-dose vecuronium 0.4 mg kg(-1) /0.2 mg kg(-1) hour(-1) (n = 29) and high-dose vecuronium 0.6 mg kg(-1) /0.3 mg kg(-1) hour(-1) (n = 33).

RESULTS

The majority of cardiovascular parameters demonstrated no significant differences between groups. For heart rate, there was an overall group difference, p = 0.036. Dromotropy was low in the pancuronium group, with an increased normalised PR-interval compared to the high-dose vecuronium group, median 0.200 interquartile range (0.190, 0.215) versus 0.182 (0.166, 0.199), p < 0.05. Left ventricular compliance was increased in pancuronium-treated animals, demonstrated as a reduction in the nonlinear end-diastolic pressure volume relationship β compared to both vecuronium groups, 0.021 (0.016, 0.025) versus 0.031 (0.025, 0.046) and 0.031 (0.022, 0.048), p < 0.05. The linear end-diastolic pressure volume relationship EDPVR(lin) was reduced as well in the pancuronium group, compared to the low-dose vecuronium group, 0.131 (0.116, 0.169) versus 0.181 (0.148, 0.247), p < 0.05.

CONCLUSIONS

There are only minor haemodynamic differences when using pancuronium compared to vecuronium in the fentanyl-pentobarbital-midazolam-N(2)O anesthetised domestic pigs. Furthermore, increasing doses of vecuronium have minimal haemodynamic effects.

CLINICAL RELEVANCE

Experimental studies in pigs using either pancuronium or vecuronium as a neuromuscular blocking agent are comparable with regard to cardiac and haemodynamic performance.

Glasgow Aneurysm Score Predicts the Outcome after Emergency Open Repair of Symptomatic, Unruptured Abdominal Aortic Aneurysms

OBJECTIVE

To determine the predictor factors of in-hospital postoperative mortality in patients presenting with symptomatic but not ruptured abdominal aortic aneurysm (AAA) at our institution.

PATIENTS AND METHODS

Forty-two patients who underwent urgent open repair for symptomatic, non-ruptured AAA were evaluated retrospectively.

RESULTS

Five patients (11.9%) died during the in-hospital stay. History of coronary artery disease (p=0.014), cerebrovascular diseases (p=0.015), renal failure according to Glasgow Aneurysm Score (GAS) criteria (p=0.001), serum creatinine concentration (p=0.026), and the GAS (p=0.008) were predictive of postoperative death. The ROC curve analysis showed that the Glasgow Aneurysm Score had an area under the curve of 0.870 (95%C.I. 0.71-1, S.E. 0.08, p=0.008), and its best cut-off value in predicting postoperative death was 90.0 (specificity 89.2%, sensitivity 80.0%). The postoperative mortality rate of patients with a Glasgow Aneurysm Score below 90 was 2.9%, whereas it was 50% for those with a score >or=90 (p=0.003, O.R. 33.0).

CONCLUSION

This study shows that the Glasgow Aneurysm Score is a good predictor of postoperative mortality and morbidity after urgent repair of symptomatic, non-ruptured AAA and can be useful in identifying those patients whose operative risk is prohibitive. Its simplicity makes it a clinically important tool, particularly, in the emergency setting. Patients having a score less than 90 can safely undergo urgent open repair. Thorough evaluation and improvement of preoperative status followed preferably by an endovascular repair is indicated for those with a score >or=90.

The use of neuromuscular blocking drugs in adult cardiac surgery: results of a national postal survey

Available data suggest that the choice of neuromuscular blocking drugs (NMBDs) can influence early clinical recovery of the fast-track cardiac surgical patient. The aim of this study was to use a survey tool to determine practice patterns of anesthesiologists for the use of NMBDs in the cardiac surgical setting. We mailed a survey to one third of the 3295 active members of the Society of Cardiovascular Anesthesiologists. A follow-up letter and survey were sent to each individual who did not respond to the initial mailing. After the second mailing, 459 surveys were returned, yielding a response rate of 43%. Pancuronium was listed as the primary NMBD used in the majority of patients undergoing cardiopulmonary bypass (69%) and off-pump (41%) procedures. Only 28% of respondents routinely used a peripheral nerve stimulator to monitor neuromuscular blockade in the operating room. Residual neuromuscular blockade was routinely reversed before tracheal extubation by only 9% of cardiac anesthesiologists. This survey demonstrates that long-acting NMBDs are often administered to fast-track cardiac patients. Peripheral nerve stimulator monitoring is rarely used in the operating room or intensive care unit, and reversal drugs (anticholinesterases) are infrequently administered in the postoperative period.

IMPLICATIONS

This postal survey of cardiac anesthesiologists demonstrates that long-acting muscle relaxants are frequently administered to fast-track cardiac surgical patients. Neuromuscular blockade is rarely monitored or reversed in this patient population.

Rocuronium versus vecuronium during fentanyl induction in patients undergoing coronary artery surgery

OBJECTIVE

To evaluate the neuromuscular, ventilatory, and cardiovascular effects of rocuronium and vecuronium.

DESIGN

Randomized, prospective, blinded study.

SETTING

Tertiary care teaching center, single institution.

PARTICIPANTS

Patients undergoing elective coronary artery bypass graft procedure.

INTERVENTIONS

Patients received rocuronium, 1.0 mg/kg (n = 17), or vecuronium, 0.15 mg/kg (n = 15), during fentanyl induction of anesthesia.

MEASUREMENTS AND MAIN RESULTS

Measures consisted of time to visual loss of orbicularis oculi twitches in response to facial nerve stimulation, ease of mask ventilation, hemodynamics, need for vasoactive drugs, and tracheal intubating conditions. Median time to twitch loss was faster (p < 0.05) after rocuronium (60 s) than after vecuronium (>84 s). Within 45 seconds, only 3 of 17 patients in the rocuronium group had moderate-to-severe difficulty with mask ventilation versus 12 of 15 patients in the vecuronium group (p < 0.05). Tracheal intubating conditions were excellent in all patients after rocuronium. In the vecuronium group, intubating conditions were excellent in 46%, good in 27%, and poor in 27% (p < 0.05 vrocuronium). Patients receiving vecuronium were more likely to require ephedrine and phenylephrine for hypotension (10/15 patients v 5/17 patients for rocuronium, p < 0.05). There were no clinically important differences in hemodynamic variables, oxygen metabolism, or myocardial ischemia between groups.

CONCLUSION

During narcotic induction of anesthesia, rocuronium was associated with lower requirement for vasopressors, faster onset of neuromuscular blockade, and better conditions for mask ventilation and tracheal intubation compared with vecuronium.

Haemodynamic effects of high-dose vecuronium compared with pancuronium in beta-blocked patients with coronary artery disease during fentanyl-diazepam-nitrous oxide anaesthesia

BACKGROUND

Different combinations of neuromuscular blockers and opioids have been used in patients with angina pectoris to provide cardiovascular stability and reduce risk of myocardial ischaemia during anaesthesia.

METHODS

We have compared the haemodynamic effects of high-dose vecuronium (0.3 mg kg-1) with those of a standard dose of pancuronium (0.1 mg kg-1) in patients scheduled for coronary artery bypass grafting during fentanyl-diazepam-nitrous oxide anaesthesia. All patients were receiving beta-adrenergic blocking agents. The given doses of vecuronium and pancuronium are equieffective with respect to duration of neuromuscular blockade.

RESULTS

During a 25-min experimental period following the administration of the randomly selected drug, no significant changes in the haemodynamic parameters were observed in the vecuronium group. The administration of pancuronium, however, resulted in a significant mean increase in heart rate (20%), rate-pressure product (23%) and cardiac index (21%). Following endotracheal intubation in the pancuronium group, we observed an additional significant increase in mean arterial pressure and rate-pressure product.

CONCLUSION

High-dose administration of vecuronium has minimal haemodynamic effects and may thus offer a better alternative than pancuronium for long-lasting neuromuscular blockade in patients with coronary artery disease during fentanyl-diazepam-nitrous oxide anaesthesia.

High-dose vecuronium neuromuscular block: a comparison of arrhythmias and onset of block during sufentanil anaesthesia

This study compared the heamodynamic effects of sufentanil with those observed following concomitant sufentanil and high-dose vecuronium administration to determine whether vecuronium induces bradyarrhythmias. Sixty coronary artery bypass patients were stratified into beta blocker (n = 30) or non-beta blocker (n = 30) groups and following induction with sufentanil (9 +/- 3 micrograms.kg-1) and midazolam (0.07 +/- 0.04 mg.kg-1), received either succinylcholine 1 mg.kg-1 (SxCh), vecuronium 0.3 mg.kg-1 (Vec 0.3), or vecuronium 0.5 mg.kg-1 (Vec 0.5). Using a Holter ECG monitor, bradyarrhythmias were classified as mild (HR 46-50), moderate (HR 40-45) or severe (HR < 40). In the pre-induction period, there were no differences in the incidence of mild, moderate or severe bradyarrhythmias among the SxCh, Vec 0.3 or Vec 0.5 groups, in either the beta blocker or non-beta blocker groups. Following induction, there were similar reductions in mean heart rate and mean arterial pressure in all three muscle relaxant groups in both the beta and the non-beta blocker groups; however, there was no difference in the incidence of mild, moderate or severe bradyarrhythmias among the SxCh, Vec 0.3 or Vec 0.5 groups. The Vec 0.5 beta blocker group had a higher incidence of mild bradyarrhythmias (32 +/- 36%) than the Vec 0.5 non-beta blocker group (2 +/- 3%, P = 0.017). Using EMG recording, the onset time of maximal neuromuscular block for the Vec 0.3 group (108 +/- 17 sec) was longer (P < 0.05) than the SxCh (76 +/- 21 sec) and Vec 0.5 (82 +/- 13 sec) groups, which were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

[General anesthesia in a patient with catecholaminergic polymorph ventricular tachycardia]

A patient suffering from a catecholaminergic polymorph ventricular tachycardia treated with nadolol was scheduled for dental extractions under general anaesthesia. During induction, whereas the basal heart rate was at 30-35 b.min-1, occurred an episode of bidirectional ventricular tachycardia probably induced by the administration of pancuronium.