Accuracy of routine postoperative swallow study in predicting leak or obstruction after gastric bypass.

Background: Many bariatric surgeons use a routine postoperative day 1 swallow study after Roux-en-Y gastric bypass to rule out leak or obstruction. The authors' practice adheres to this dictum, but the aim of this study was to determine how accurate this testing is in properly predicting complications.

Methods: A retrospective chart review of all patients undergoing gastric bypass in the past 5 years (2008-2012) was performed; the results of their swallow study was examined and compared with their actual clinical outcome within 30 days of operation.

Results: The records of 501 patients were reviewed, and there were 15 leaks and 29 obstructions for a total prevalence rate of 9%. When the swallow study was negative, 33 complications were missed and 433 reports were correct. When the swallow study was positive, only 11 complications were correctly identified and 24 of the reports were false positive. The sensitivity of the test was only 25%. The positive predictive value was only 31%. The result of the swallow study was incorrect 12% of the time.

Conclusion: Routine postoperative swallow study after gastric bypass was a poor method of accurately detecting clinically significant obstruction or leak. This test may be unnecessary for all patients and might best be used when clinically indicated.