Early hemodynamic changes during uncontrolled intra-abdominal bleeding

Central hemodynamics was studied in 32 pigs during the first 10 min after making a 5-mm laceration in the infrarenal aorta. Blood flow probes were placed proximally and distally to the site of the bleeding and also over the portal vein and renal artery. We found that the bleeding, which was indicated by a difference in the rate of blood flow between the two aortic probes, stopped spontaneously after about 3 min. The short-term changes in blood flow rates closely followed simple monoexponential functions with mean half-times of 34 (proximal aorta), approximately 10 (lower aorta), 27 (splanchnic) and 21 s (kidney) to reach steady-state levels amounting to 20, 20, 27 and 8% of the baseline flow rates, respectively.