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Hemodynamic responses to pancuronium and vecuronium during high-dose fentanyl anesthesia for coronary artery bypass
R Paulissian1, M Mahdi, N J Joseph
1Department of Anesthesiology, Illinois Masonic Medical Center, Chicago 60657.
Insights
Pancuronium, unlike vecuronium, increased myocardial ischemia during high-dose fentanyl anesthesia for coronary artery bypass grafting (CABG) surgery. Vecuronium showed fewer ischemic changes but caused bradycardia in patients on beta-blockers.
Area of Science:
- Cardiology
- Anesthesiology
- Pharmacology
Background:
- High-dose fentanyl anesthesia is used for coronary artery bypass grafting (CABG).
- Pancuronium and vecuronium are neuromuscular blocking agents used in anesthesia.
- The hemodynamic and electrocardiographic (ECG) effects of these agents require careful evaluation in CABG patients.
Purpose of the Study:
- To compare the hemodynamic and ECG effects of pancuronium and vecuronium.
- To assess the incidence of myocardial ischemia associated with each muscle relaxant.
- To evaluate the safety profile of pancuronium versus vecuronium in high-dose fentanyl anesthesia for CABG.
Main Methods:
- A comparative study involving 48 patients undergoing elective CABG.
- Patients received high-dose fentanyl anesthesia and either pancuronium or vecuronium.
- Hemodynamic data and ECG tracings were collected at multiple time points before and after surgical interventions.
Main Results:
- Pancuronium group (n=26) showed increased heart rate, cardiac index, and rate-pressure product, with 42.3% experiencing ischemic ECG changes.
- Vecuronium group (n=22) had no significant increases in hemodynamic parameters, a decrease in cardiac index, and only 5.6% showed ischemic ECG changes.
- Four patients in the vecuronium group on beta-blockers developed hypotension and bradycardia.
Conclusions:
- High-dose fentanyl-pancuronium anesthesia is associated with a higher incidence of myocardial ischemia.
- Vecuronium is associated with fewer myocardial ischemic changes compared to pancuronium.
- Caution is advised with vecuronium in patients on beta-blockers due to potential bradycardia and hypotension.
Abstract:
The hemodynamic and electrocardiographic (ECG) effects of pancuronium and vecuronium were compared during high-dose fentanyl anesthesia for coronary artery bypass grafting (CABG) surgery. Forty-eight morphine-scopolamine premedicated patients scheduled for elective CABG were anesthetized with fentanyl (100 micrograms/kg) in divided doses, and either of two muscle relaxants, pancuronium (n = 26; 0.10 mg/kg) or vecuronium (n = 22; 0.09 mg/kg). Hemodynamic data, blood gas samples, and ECG tracings were obtained at the following intervals: (1) control; (2) prior to intubation; (3) 1 minute after intubation; (4) prior to sternotomy; and (5) 1 minute after sternotomy. In the pancuronium group, heart rate (HR), cardiac index (CI), and rate-pressure product (RPP) were increased after induction of anesthesia and following intubation. Eleven patients (42.3%) displayed ischemic ST segment changes. Four patients in this group developed tachycardia and hypertension to an extent requiring pharmacological intervention. Vecuronium-treated patients displayed no increases in HR, MAP, and RPP, and a decrease in CI. Only one patient (5.6%) developed evidence of ischemic ECG changes. Four patients in the vecuronium group, all receiving preoperative beta-blocker therapy, became hypotensive and bradycardic after the induction of anesthesia. The present investigation confirms the increased incidence of myocardial ischemia during high-dose fentanyl-pancuronium anesthesia. Although vecuronium was associated with fewer myocardial ischemic changes, the occurrence of bradycardia and hypotension in some patients receiving preoperative beta-adrenergic blocking drugs remains a concern.