Bowel Sounds Are Not Associated With Flatus, Bowel Movement, or Tolerance of Oral Intake in Patients After Major Abdominal Surgery.

Background: Auscultation for bowel sounds has been advocated by some clinicians as a method to determine the resolution of postoperative ileus.
Objective: Our primary aim was to prospectively evaluate the relationships between bowel sounds and the ability to tolerate oral intake in patients after major abdominal surgery. Secondarily we aimed to evaluate relationships among bowel sounds, flatus and bowel movement, and oral intake.
Design: This was a prospective, blinded observational study.
Settings: The study was conducted at Western Pennsylvania Hospital.
Patients: A total of 124 adult patients undergoing major abdominal surgery were included.
Main Outcome Measures: Data were collected by medical students blinded to the purpose of the study for 10 days postoperatively or until discharge, including the presence of bowel sounds (auscultation for 1 minute), flatus, bowel movement, and tolerance of oral intake (defined as ingestion of ≥1000 mL/24 h and each subsequent day without vomiting). Associations between paired variables were determined using ϕ coefficient testing.
Results: The study population consisted of 51 men and 73 women, with a mean age of 64 years (range, 20-92 y). The majority of patients (78/124 (63%)) underwent colorectal resection. The median length of hospital was 6 days. Bowel sounds were not associated with flatus, bowel movement, or tolerance of oral intake throughout the study period. The positive predictive value of bowel sounds in predicting flatus and bowel movement was low in the early postoperative period and remained <25% in predicting tolerance of oral intake throughout the study period. The analysis was repeated, including only those patients undergoing colorectal procedures, and was essentially unchanged. Flatus correlated with bowel movement in the first 6 days postoperation, but neither flatus nor bowel movement was associated with tolerance of oral intake.
Limitations: The rate of tolerance of oral intake was relatively modest throughout the study period.
Conclusions: Bowel sounds are not associated with flatus, bowel movement, or tolerance of oral intake after major abdominal surgery.