Enhancement of a small bowel obstruction model using the gastrografin® challenge test

Based on a previous published data on small bowel obstruction (SBO), a management model for predicting the need for exploration has been adopted in our institution. In our model, patients presenting with three criteria-the history of obstipation, the presence of mesenteric edema, and the lack of small bowel fecalization on computed tomography (CT)-undergo exploration. Patients with two or less features were managed nonoperatively. An alternative tool for predicting need for operative intervention is Gastrografin (GG) challenge test.

We hypothesized that the GG challenge test, when used in combination with our prior model, will decrease the rate of explorations in patients not meeting the criteria for immediate operation.

An approval from IRB was obtained to review patients admitted with a diagnosis of SBO from November 2010 to September 2011. All patients presenting with signs of ischemia, patients with all three model criteria defined previously, and those who had an abdominal operation within 6 weeks of diagnosis were excluded. All patients had an abdominal/pelvic CT and GG challenge at the time of diagnosis. Patients were compared to historic controls managed without the GG challenge (from July to December 2009). Successful GG challenge was defined as the presence of contrast in the colon after a follow-up film or a bowel movement. Data were presented as medians or percentages; significance was considered at p < 0.05.

One hundred and twenty-five patients with a diagnosis of small bowel obstruction were identified wherein 47 % were males. Fifty-three received a GG challenge (study), and 72 did not have a GG challenge (historic). There was no difference in age (70 vs 65 years), history of prior SBO (51 vs 49 %), history of diabetes mellitus (21 vs 18 %), history of malignancy (32 vs 39 %), or cardiac disease (30 vs 39 %). Both groups had similar number of previous abdominal operations (two vs two). The presence of mesenteric edema (68 vs 75 %), the lack of small bowel fecalization (47 vs 46 %), and a history of obstipation (25 vs 24 %) were similar in both groups. Patients in the study group had a lesser rate of abdominal exploration (25 vs 42 %, p = 0.05) and fewer complications (13 vs 31 %, p = 0.02) compared to the historic control group. There was equivalent incidence of ischemic bowel (4 vs 7 %), duration of hospital stay (4 vs 7 days), duration from admission to operation (2 vs 3 days), and mortality (8 vs 6 %); 44 patients had a successful GG challenge with nine failures. There was a greater rate of exploration in patients with a failed challenge compared to those with a successful challenge (89 vs 11 %, p < 0.01).

The use of the GG challenge enhanced the SBO prediction model by decreasing the need for exploration in patients not meeting the criteria for immediate operation. Patients who failed the GG challenge test were much more likely to undergo an exploration.