Preoperative recognition of intestinal strangulation obstruction. Prospective evaluation of diagnostic capability.

Early recognition of intestinal strangulation in patients with small bowel obstruction is essential to allow safe nonoperative management of selected patients. We prospectively evaluated preoperative diagnostic parameters as well as the preoperative judgement of the senior attending surgeon for the determination of the presence or absence of intestinal strangulation in 51 consecutive patients who were about to undergo laparotomy for complete mechanical small bowel obstruction. Strangulation was present in 21 (42 percent) of the 51 patients. No preoperative clinical parameter, including the presence of continuous abdominal pain, fever, peritoneal signs, leukocytosis, or acidosis, or a combination thereof proved to be sensitive, specific, and predictive for strangulation. Moreover, the senior surgeon's experienced clinical judgement detected strangulation in only 10 of 21 patients with strangulation preoperatively (sensitivity, 48 percent). Indeed, only 1 of these 10 patients had an early, reversible lesion, whereas 9 had advanced, irreversible infarction. Only 25 of 36 preoperative assessments of simple obstruction proved correct (predictive value of an assessment of no strangulation, 69 percent). Overall, the preoperative assessment was correct in only 35 of the 51 patients (efficiency, 70 percent). These data show that in patients with complete mechanical small bowel obstruction, the preoperative diagnosis of strangulation cannot be made or excluded reliably by any known clinical parameter, combination of parameters, or by experienced clinical judgement. Nonoperative management of complete intestinal obstruction is therefore undertaken at a calculated risk (31 +/- 51 percent in the present series) of delaying definitive treatment of intestinal ischemia.