Hemoperitoneum: Abdominal Blood, Endogenous Carbon Monoxide and Hemostasis

Blunt abdominal trauma can cause peritoneal bleeding which is associated with patient instability. Extra‐vascular blood can degrade to release heme, which is ‐in turn‐ metabolized to form carbon monoxide (CO). This CO exerts biological effects, and has been shown to promote platelet disaggregation in isolated incubated platelets. We wanted to determine if abdominal blood increases CO excretion to interfere with platelet aggregation and/or clotting mechanisms. For this purpose male Lewis rats were administered whole blood IP (30% calculated blood volume) or the plasma fraction alone as a control (N=12 each). Two days after formation of the experimental hemoperitoneum, rats injected with whole blood displayed 70% higher CO excretion over plasma controls. Animals with whole blood hemoperitonium also displayed prolonged activated clotting time (20%), and decreased amplitude of both collagen and thrombin activated platelet aggregation (−30 and −40%, respectively). The findings suggest that hemoperitoneum drives CO formation to interfere with hemostatic processes, and promote bleeding. Supported by grants Department of Army #W81XWH‐07‐1‐0717 (RAJ and RMS), AHA 0865241F (FKJ) and NIH HL064577 (RAJ).