RIGHT VENTRICULAR PUMP DYSFUNCTION WITH ACUTE EXPERIMENTAL SEPTIC SHOCK

Right ventricular (RV) function has been poorly characterized at the onset of acute bacterial septic shock. Using a volumetric thermodilution catheter, previously validated in our laboratory, we serially measured RV function in a porcine model of acute septic shock. Six pigs (21.3 ± 0.9 kg) were instrumented and Pseudomonas aeruginosa (3.4 × 108 cfu/ml, 0.3 ml/20 kg/min) was infused. RV ejection fraction, RV volumes, cardiac output, arterial pressure, central venous pressure, and pulmonary arterial pressure were measured at baseline and at 30, 60, 120, and 240 min after starting the bacterial infusion. RV ejection fraction and stroke volume were decreased at 30 min compared to baseline (21 ± 5 vs 43 ± 5% and 14 ± 3 vs 23 ± 3 ml, respectively; P < 0.05) and remained depressed throughout the experiment. Mean arterial pressure was significantly reduced at 60, 120, and 240 min compared to baseline (P < 0.05). There was a significant increase in pulmonary vascular resistance (1771 ± 493 vs 301 ± 99 dyn-sec-cm-5 at 30 min; P < 0.05) and RV stroke work (5.7 ± 1.1 vs 2.3 ± 0.3 gm-m/beat at 30 min; P < 0.05) while no significant change in RV endiastolic volume or central venous pressure was observed. Thus, a decrease in RV pump performance was associated with an increase in afterload and no change in preload. These results suggest that severe RV pump dysfunction occurs early in acute septic shock. This was manifested by significant reductions in RV ejection fraction and increased in stroke work. This study demonstrated that thermodilution methods can successfully be used to follow changes in RV performance in the setting of acute septic shock. Serial measurements of RV function may be useful for assessing RV failure during clinical septic shock. © 1991.