A new model for the study of the abdominal compartment syndrome in rats

The purpose of the present study was to develop of a rodent model of abdominal compartment syndrome (ACS), which allows detailed analysis of intra-abdominal hypertension (IAH)- and decompression-associated reperfusion injury.

In 20 anesthetized and ventilated Sprague-Dawley rats an IAH of 20 mmHg was induced for 3 h by intraperitoneal infusion of gelatin polysuccinate. After decompression, an additional 3-h period of reperfusion was studied. Sham-operated animals, undergoing identical procedures without IAH induction, served as controls. Controlled hyperventilation and intravenous fluid substitution were adapted to keep PCO(2) <60 mmHg and mean arterial pressure (MAP) >100 mmHg.

IAH of 20 mmHg could successfully be maintained for the entire 3-h period. MAP was not affected during IAH, however, decreased upon decompression despite forced fluid resuscitation. CVP was markedly elevated during IAH, but returned to baseline after decompression. Of interest, the IAH-induced reduction of PaO(2) did not recover to baseline after decompression, indicating a persistent deterioration of gas exchange. In contrast, IAH-associated elevation of PaCO(2) normalized during reperfusion. IAH was further accompanied by metabolic acidosis, which persisted after decompression, indicating reperfusion injury. IAH was further associated with a significant increase of serum potassium, lactate, AST, LDH, bilirubin, urea, and creatinine as well as creatine kinase (CK) and CK-MB. Histomorphological analysis revealed parenchymal injury in liver, lung, intestine, and myocardium.

We established an easily reproducible ACS model in the rat, demonstrating hemodynamic deteriorations and organ dysfunctions similar as known from patients with IAH. Decompression did not restore functional deteriorations, indicating persistent post-ACS reperfusion injury. The model may be suitable to study mechanisms and novel treatment strategies in ACS.