Comparison of the Use of a Propofol Infusion in Cardiac Surgical Patients with Normal and Low Cardiac Output States

Abstract

Objectives: This study compared the hemodynamic effects of a propofol infusion with fentanyl analgesia in patients undergoing cardiac surgery with normal and low cardiac output states. Low cardiac output was defined as a cardiac index less than 2.5 L/min/m2 with a minimum pulmonary capillary wedge pressure of 7 mmHg. Design: A prospective and open study. Setting: A single center cardiothoracic unit within a teaching hospital. Participants: Patients were assigned to group P, poor cardiac output or group N, normal cardiac output, after thermodilution pulmonary artery catheter assessments. Interventions: Both groups received a propofol infusion, 8 mg/kg/hr, until induction of anesthesia, followed by 4 mg/kg/hr until the intensive care unit. Fentanyl, 15 μg/kg, and pancuronium, 0.15 mg/kg, were administered after induction. The lungs were ventilated with oxygen. Measurements and Main Results: Hemodynamic assessments were repeated at intervals until cardiopulmonary bypass. Changes within and between groups were compared using t tests on percentage change from baseline. Group N had significantly greater decreases in cardiac index, stroke volume, and left ventricular stroke work index than group P. There were comparable decreases in mean arterial pressure on induction of anesthesia, 14% and 8% in group N and group P, respectively. In both groups, right ventricular ejection fraction was unchanged. Conclusions: The use of a propofol infusion for induction and maintenance of anesthesia in patients with low cardiac output states undergoing cardiac surgery is not contraindicated.