Objective The aim of this study was to evaluate the optimal time for decompression in a 24-hour lasting porcine model.Methods After baseline data were recorded,24 pigs were randomly allocated into three groups as follows:one SAP-alone group,and two SAP + ACS groups (decompression at 6 and 12 hours,respectively).We used a N2 pneumoperitoneum to increase the intra-abdominal pressure to 25 mmHg and retrograde intra-ductal infusion of sodium taurocholate to induce severe acute pancreatitis (SAP).Systemic hemodynamic profiles,urine output,systemic oxygenation,and serum biochemical parameters of the animals were obtained.Results After induction of ACS,the hemodynamics and oxygenation of the study animals deteriorated significantly.The survival time of the 12-hour group was significantly shortened (P =0.008 vs.6 hours).Early decompression (6 h) restored systemic hemodynamics,oxygenation,organ function,and inflammatory intensity to a level comparable to that of the SAP-alone group.In contrast,animals in 12-hour group developed more severe hemodynamic suppression,oxygenation and organ dysfunction and inflammatory process.For instance,the cardiac output levels in the three groups were 2.70 ±0.50 for the SAP group,2.75 ±0.48 for the 6 hour-group and 2.19 ±0.43 for the 12 hour-group.Conclusion Early decompression could significantly reduce the mortality in a porcine model of SAP incorporating ACS,and also improve systemic hemodynamics,organ function and inflammatory intensity.