The pathophysiology of septic shock: comparison of systemic hemodynamical responses in the rat following a sonicated, heat-killed, and live E coli injection.

Abstract

Systemic hemodynamical responses in anesthetized rats subjected to a bolus IV injection of sonicated (50 watts, 3 min), heat-killed (100 degrees C, 15 min), or live E coli suspension (12-15 X 10(8) E coli organisms in 0.5 ml saline per kg body wt) were continuously monitored for 6 h. A transpulmonary thermodilution method was used for measurement of cardiac output. After injection of sonicated E coli suspension, there was a triphasic hemodynamical response: 1) a hypodynamic state immediately following treatment, 2) a recovery phase, and 3) a profound, progressive hypodynamic state in the late phase. In contrast, heat-killed E coli suspension induced a biphasic response: 1) an insignificant hyperdynamic state in the early phase, and 2) a progressive hypodynamic state in the late phase. An injection of live E coli suspension resulted in a biphasic response: 1) a hyperdynamic state in the early phase, and 2) a progressive hypodynamic state in the late phase.