Abstracts of papers presented at the annual meeting,

Abstract

Avoidance of increasing afterload is important during anaesthesia for cardiac surgery. We studied the haemodynamic consequence of deliberate vasodilation during sternotomy in nine patients (mean age 57 -+ 12 years, mean left ventricular ejection fraction 0.51 +-0.09) undergoing valvular replacement. Nicergoline, a new ergol derivative, produces vasodilation (alpha blocking effect), bradycardia (central effect) and has no effect on myocardial metabolism) It was given as a continuous infusion, started after induction, at a rate of 0.8 mg. kg-t/hour.This group was compared to a control group of 12 patients (mean age 60 +-13 years; mean left ventricular ejection fraction 0.51 -+ 0.1) undergoing valvular replacement (seven patients) coronary artery bypass graft (four patients) or aneurysmectomy (one patient). Premedication was pentobarbitone sodium 60-120 mg PR., with intramuscular promethazine I mg. kg -I and meperidine 1 rag. kg -I. Anaesthesia was neurolepanalgesia with droperidol 100 mg and fentanyl 2 mg in 500 ml D5W infused during 15 minutes of induction at 5 mg. kg-t/hr and then maintained at 2 mg. kg-I/hr during sternotomy. Flunitrazepam 0.25 to 0.5 mg and paneuroniurn bromide 0.08 mg-kg -l were given at induction. Measurements were made before and after stcrnotomy in the two groups of patients.In the control group, sternotomy did result in an increased rate-pressure product (p < 0.01), while cardiac index and systemic vascular resistance remained unchanged. In the nieergoline group, increase in rate pressure product was not significant. Cardiac index increased significantly (p < 0.05) as systemic vascular resistance decreased; volume needed to maintain adequate filling pressure was higher in this group (p < 0.05) as was the weight gain during operation (p < 0.05) and postoperative bleeding. This may be related to nicergoline platelet anti-aggregation properties.Our study suggests that deliberate vasodilation such as produced with nicergoline may yield to increased vasoplegia, bleeding and weight gain during operation despite decrease in MVO2 and aftedoad. Intravenous nitroglycerin (NG) is used in coronary patients during anaesthesia to reduce blood pressure (BP) and rate-pressure-product (RPP). It is given orally or intravenously to awake patients for angina. Does the awake patient with cerebration and an active autonomic system react to NG differently than an anaesthetized patient?We studied seven patients having coronary grafts, both awake, sedated and, later, after sternotomy with hypertension. With a radial needle and two thermodiluuon catheters (pulmonary artery and coronary sinus) we determined total coronary sinus flow (CSF), cardiac index (CI), vascular resistance (SVR), total coronary sinus flow (CSF), myocardian oxygen consumption (MVO2) and lactate extraction. Studies were done before and after NG 100 ug/min with mean doses of 1.04 mg given in 10.6 minutes awake and 1.2 mg given in 8.2 minutes after sternotomy.These male patients had a mean age of 57.4 years and mean surface area of 1.95 m 2. Mean...