Proceedings

The Immediate Hemodynamic and Metabolic Effects of Bolus Injections of Pharmacologic Agents During Cardiopulmonary Bypass

¹ Perfusion Services, Emory University Clinic and Hospitals, Atlanta, Georgia
² Division of Cardiothoracic Anesthesia, Department of Anesthesia, Emory University, Atlanta, Georgia

^* Direct correspondence to Jeffrey B. Riley, 2459 Big Creek Terrace, Stone Mountain, GA 30087.

Abstract

The cardiovascular and arterial reservoir level responses to injections of phenylephrine (1.2 micrograms/kilogram (ugm/kg)), chlorpromazine (.01 milligram/kilogram (mg/kg)), phentolamine (.01 mg/kg), pancuronium (.045 mg/kg), diazepam (.11 mg/kg), fentanyl citrate (5.2 ugm/kg) and morphine sulfate (.12 mg/kg) into the defoamer of a bubble oxygenator were observed.

The arteriolar geometric component (GC) was isolated by dividing the systemic vascular resistance (SVR) by the blood viscosity estimated with hematocrit and temperature. The patient’s venous capacitance change was measured by observing the change in the oxygenator arterial reservoir volume (RV). Direct measurement of arterial and venous oxygen saturation, blood flow, and hemoglobin concentration were employed to calculate the patient’s actual oxygen transfer (VO₂). The percent of ideal VO₂ (%VO₂,i) then was calculated by dividing the actual VO₂ by the VO₂ expected for the patient’s age, body surface area and temperature. Percent change from baseline value in the three indices was reported for three consecutive forty second intervals. Average baseline SVR index, cardiac index, temperature, drug amount and number of circulations are reported in a two-minute graphic profile.

Phenylephrine decreased % VO₂,i and increased R V, while chlorpromazine, diazepam, and fentanyl citrate increased % VO₂,i and decreased RV to varying degrees. Pancuronium and morphine sulfate did not affect GC. However, they caused transient increases in % VO₂,i. Phentolamine concurrently decreased % VO₂,i and GC.

The hemodynamic-oxygen consumption profile is a useful clinical tool in determining adequacy of the total body O₂ delivery in patients of extreme weight and body surface area or in patients receiving vasoactive drugs during cardiopulmonary bypass (CPB).