Role of hypotension in altering blood coagulability after endotoxin

¹ Department of Medicine and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland

Because hypotension, regardless of etiology, profoundly influences blood coagulation, the role of hypotension in altering blood coagulability after endotoxin was investigated. By means of femoral artery catheterization, serial whole blood clotting times were determined in siliconized tubes at 37 C and correlated with mean arterial blood pressures in 1-kg albino rabbits. After duplicate base-line determinations, 200 µg/kg E. coli endotoxin was injected intravenously into nine animals; this quantity of endotoxin was the largest dose not lethal to normal rabbits of the strain employed. Nine control animals received isotonic saline. Blood from the endotoxin-treated group exhibited some accelerated coagulability between 1–2 hr after endotoxin injection and became significantly hypercoagulable (P < 0.05) during the 3rd and 4th hr. The observed hypercoagulability could not be correlated with the hypotensive arterial blood pressure levels, the mean coefficient of correlation being –0.18. These data suggest that endotoxin-induced hypercoagulability in the rabbit results from specific reactions that are mediated by mechanisms distinct from those known to operate during the hypotensive state per se.