HEMODYNAMIC CONSEQUENCES OF ENDOTOXEMIA IN SHEEP

  • 1 January 1981
    • journal article
    • research article
    • Vol. 8  (5) , 551-561
Abstract
Sheep were given 0.75 mg/kg of Escherichia coli endotoxin i.v. The induced sepsis produced a triphasic response. Phase 1 occurs during the 1st h after endotoxin administration and is characterized by a decreased cardiac output, lymph to plasma protein ratio and neutrophil count; an increased hematocrit, total plasma protein concentration, lymph flow and pulmonary artery pressure were also seen. During phase 2 these variables return toward their baseline values. Phase 3 begins 2.5 h after the administration of endotoxin and shows many of the same changes that were observed in phase 1. Also during the late phase, the plasma protein concentration and lymphocyte count were reduced and the lymph to plasma protein ratio was increased. An early fall in cardiac output apparently occurs as a consequence of hypovolemia. The decreased volume is the result of fluid movement from the vascular compartment to the interstitial space consequent to a microvascular pressure increase. Since the changes occur coincidentally with a drop in neutrophil count, these cells may bear some causal relationship to the response. The late fall in cardiac output in phase 3, also the result of a diminished vascular volume, occurs secondarily to extravascular fluid movement seemingly as a consequence of both an elevated microvascular pressure and an increased permeability to protein. The latter may be causally related to a fall in lymphocytes.