A Novel Physiologic Model for the Study of Abdominal Compartment Syndrome (ACS)

Background: Current abdominal compartment syndrome (ACS) models rely on intraperitoneal instillation of fluid, air, and other space-occupying substances. Although this allows for the study of the effects of increased abdominal pressure, it poorly mimics its pathogenesis. We have developed the first reported large animal model of ACS incorporating hemorrhagic shock/resuscitation. Methods: Hemorrhagic shock was induced and maintained ( 1 hour) in 12 Yorkshire swine by bleeding to a mean arterial pressure ( MAP) of 50 mm Hg. The collected blood plus two additional volumes of crystalloid was then reinfused. Mesenteric venous hypertension was induced by tightening a previously placed portal vein snare in a nonocclusive manner to mimic the effects of abdominal packing. Crystalloids were infused to maintain MAP. Hemodynamic measurements, abdominal pressure, peak inspiratory pressures, urine output, and blood chemistries were measured sequentially. Animals were studied for 36 hours after decompression. Results: ACS (intra-abdominal pressure of >= 20 mm Hg with new organ dysfunction) developed in all animals. There were significant increases in peak inspiratory pressure, central venous pressure, and pulmonary artery pressure and decreases in MAP upon development of ACS. Urine output was significantly decreased before decompression. Mean blood lactate decreased and base excess increased significantly after decompression. Conclusions: We have created the first reported physiologic animal ACS model incorporating hemorrhagic shock/resuscitation and the effects of damage control surgery.