In the SICU, bladder pressure was measured everaday to reflect intraabdominal pressure. And patients received CT examination at day 1, day 3, day 5 and every eusing week, other than additional illness-required CT. The measurement of colonic or cecum diameter, and assessment of intestional eddema, ischemia and perforation were performed by two trained fellows to record the recovery time. Criteria for colonic recovery were as follows: 1.enteral nutrition reached or surpass 50% of targeted needs more than 3 days; 2. Restoration of normal aerofluxus and defecation; 3. Significant improvent of colonic distension or colonic wall was shown on abdominal CT (colonic diameter < 6 cm or cecum diameter < 9 cm).