A clinically applicable exsanguination shock model in swine.

In order to evaluate treatments of the rapid exsanguination seen in the majority of civilian trauma or combat fatalities, we designed a rapid exsanguination, conscious, unheparinized 100% fatal porcine hemorrhage model. Immature female swine were bled 60% of their estimated blood volume 5 days after placement of a bleeding catheter. The change in arterial base excess concentration (BE) and hematocrit (Hct) was followed after hemorrhage. Variables were bleeding time (120, 60, 30, and 15 min) and catheter placement (carotid, 7 cases; and distal aorta, 24 cases). The Hcts before hemorrhage were similar in both groups. The time for removal of 60% EBV for routine mortality was longer with the carotid (60 min) versus the distal aorta (15 min) catheter group. At autopsy the carotid catheters partially obstructed the orifice of the opposite carotid. In the aortic group, a rate of hemorrhage of 2.65 +/- 0.97 ml/kg/min was required to provide the ischemia necessary for 100% mortality. The BE after hemorrhage was significantly different in survivors versus nonsurvivors. A carotid artery catheter that extends into the porcine brachiocephalic artery appears to cause artifactual mortality by interfering with blood flow to the opposite carotid. A conscious, unheparinized, and reliably fatal exsanguination model has been standardized. The animal must sustain a 60% EBV loss from the distal aorta in 15 min.