EUROPEAN JOURNAL OF SURGERY

Objective: To investigate the effect of increased intra-abdominal pressure followed by abdominal deflation on small intestine with or without previous intestinal ischaemia. Design: Randomised experimental study. Setting: University hospital, Turkey. Animals: 78 male New Zealand white rabbits. Interventions: Experiment 1: 30 rabbits (10 in each group) were subjected to intra-abdominal pressure of 0 mmHg. (controls), 15 mmHg or 25 mmHg for 60 minutes. Experiment 2: 48 rabbits were divided into four groups (n = 12 in each). The first comprised sham-operated controls. In the other 3, the superior mesenteric artery was occluded for 60 minutes. Reperfusion was started and maintained under intra-abdominal pressure of 0 mmHg. 15 mmHg, or 25 mmHg for one hour. Intestinal specimens were obtained five and 60 minutes after abdominal deflation in the pressure groups and at identical times in the other groups in both experiments. Main outcome measures: Intestinal malondialdehyde concentration, wet:dry intestinal weight ratio, and mucosal injury score under light microscopy. Results: In experiment I the malondialdehyde concentration. wet:dry weight ratio. and mucosal injury scores were higher in the 25 mmHg group than in the other groups, in both specimens. Theme was a significant increase in malondialdehyde concentration in the 15 mmHg group in only the 5-minute specimen, In experiment 2, except for the wet:dry weight ratio in the 5-minute specimen in the 15 mmHg group, there were significant increases in malondialdehyde concentration, wet:dry weight ratio, and mucosal injury score in all groups except controls in both specimens. Malondialdehyde concentration and wet:dry weight ratio were higher in the 25 mmHg group than in the 0 mmHg group in the 60-minute specimen, and higher than the 15 mmHg group in both specimens. Wet:dry weight ratio was less in the 15 mmHg group than the 0 mmHg group in both specimens. Mucosal injury score was higher in the 25 mmHg group than the other groups in both specimens. Conclusion: Increased intra-abdominal pressure for 60 minutes followed by abdominal deflation led to an ischaemia-reperfusion-like injury in normal small intestine in rabbits. and added to reperfusion injury in the ischaemic small intestine at an intra-abdominal pressure of 25 mmHg