Use of a conductance catheter to assess the effect of endotoxemia on left ventricular end-systolic pressure-volume relationships in anesthetized swine

Abstract

Effects of endotoxemia on left ventricular contractility and systemic hemodynamics were determined in pentobarbital-anesthetized swine. A multielectrode conductance (volume) catheter and a high-fidelity pressure transducer catheter were passed retrograde into the left ventricle to continuously measure pressure and volume. End-systolic pressure-volume relationships were determined during transient (8 to 10 s) caudal vena caval balloon occlusion. Lactated Ringer's solution was administered at a rate sufficient to maintain left ventricular end-diastolic pressure > or = 6 mm of Hg. Following baseline measurements, Escherichia coli endotoxin (O55-B5) was infused IV at 2.5 micrograms/kg of body weight/h for 3 hours. Left ventricular end-systolic elastance (Ees), the slope of the end-systolic pressure-volume relationship; end-systolic elastance normalized for left ventricular end-diastolic volume (Ees norm); the rate of increase of left ventricular pressure (dP/dt max); and preload recruitable stroke work (PRSW, stroke work-to-end-diastolic volume relationship) did not change in endotoxemic swine, compared with baseline measurements or with values from control (physiologic saline solution-treated) swine. Left ventricular pressures and volumes had marked pig-to-pig variability in the control and endotoxin-treated groups. Determination of Ees, Ees norm, and PRSW was further confounded by development of frequent premature ventricular contractions during caudal vena caval balloon occlusion. Endotoxin significantly (P < 0.05) decreased left ventricular end-diastolic pressure, compared with that in control swine, and significantly (P < 0.01) decreased left ventricular end-diastolic volume, compared with baseline. Endotoxin decreased cardiac index and arterial blood pressure, whereas heart rate, central venous pressure, and mean pulmonary arterial pressure increased.(ABSTRACT TRUNCATED AT 250 WORDS)