How useful are bowel sounds in assessing the abdomen?

The purpose of our study is to determine the accuracy of bowel sounds in the diagnosis of ileus and bowel obstruction.

Healthy volunteers (n = 10) and patients with radiologically or laparotomy confirmed small bowel obstruction (n = 9) and ileus (n = 7) were enrolled. Two 30-second recordings from each subject were obtained using an electronic stethoscope. Study physicians (n = 20) were then presented with 43 recordings in blinded fashion and were asked whether each was from a normal subject or from a subject with bowel obstruction or ileus.

Physicians arrived at the correct diagnosis a median of 30 times out of 43 (69.8%). Intra-observer variation (κ = 0.72, agreement 81.3%) and intra-subject variation (κ = 0.63, agreement 78.7%) were very good. Bowel sounds from subjects with ileus and normal bowel sounds were correctly identified most of the time (84.5 and 78.1%, respectively). Bowel sounds from patients with obstruction were correctly identified only 42.1% of the time, but if a physician believed he or she was hearing a bowel obstruction, this had a strong positive predictive value (PPV, 72.7%).

Our results suggest that the auscultation of bowel sounds is useful, especially in detecting ileus. The diagnosis of obstruction had a high PPV.