HOLLYWOOD, FLA – The radiopaque contrast agent Gastrografin accurately diagnosed the majority of small bowel obstructions, allowing surgeons to identify which patients needed emergent surgery and which could be managed conservatively.
When instilled via nasogastric tube, the diatrizoate solution had a 92% positive predictive value for adhesive small bowel obstruction,, said at the annual scientific assembly of the Eastern Association for the Surgery of Trauma.
Dr. Zielinski of the Mayo Clinic, Rochester, Minn., examined the diagnostic accuracy of the Gastrografin challenge, a small bowel obstruction diagnosis and treatment protocol he developed at the center. The challenge begins with 2 hours of nasogastric suctioning. Patients then receive 100 mL Gastrografin mixed with 50 mL water via the nasogastric tube. The tube is clamped for 8 hours, and then patients have an abdominal x-ray. If the contrast material appears in the colon, or if the patient has a bowel movement in the interim, then the challenge is passed, the tube can be removed, and diet advanced.
If there is no contrast in the colon, or if the patient has no bowel movement, then the surgeon assumes the obstruction remains, and exploratory surgery proceeds.
Dr. Zielinski’s study comprised 316 patients with a suspected adhesive small bowel obstruction. Of these, 173 were managed with the Gastrografin challenge; they were compared to 143 patients who were managed without the contrast agent.
Patients were a mean of 58 years. There were no significant differences in the rate of prior abdominal operations; duration of obstipation; or small bowel feces sign.
The comparator group was managed by a clinical algorithm in which any patient with initial signs of ischemia underwent exploratory surgery, and those without signs of ischemia were managed symptomatically. Patients in the Gastrografin arm who passed the trial were similarly managed, while those who failed it underwent exploratory surgery.
Among those who had the challenge, 130 (75%) passed. Gastrografin had a high diagnostic accuracy for small bowel obstruction, with 87% sensitivity, 71% specificity; and 92% positive predictive value. The negative predictive value was not as good, at 59%.
The Gastrografin protocol was associated with significantly fewer exploratory surgeries (21% vs. 44%), and significantly fewer small bowel resections (7% vs. 21%). That advantage was maintained even among patients in both groups who underwent exploratory surgery, with an ultimate resection rate of 34% vs. 49%. The length of stay was also significantly less in the Gastrografin group, 4 vs. 5 days).
There was no difference in the overall complication rate (12.5% vs. 18%). Complications included acute kidney injury (6% vs. 9%); pneumonia (4% vs. 5%), organ space infection (1% vs. 4%), surgical site infection (3.5% vs. 5%), and anastomotic leak (2% each group).
The rate of missed small bowel strangulation was significantly lower among the Gastrografin group as well (0.6% vs. 7.7%). There were no cases of Gastrografin pneumonitis.
Dr. Zielinski had no financial disclosures.