Abstract
When are bowel sounds most reliable in the diagnosis of small bowel obstruction?
Author(s): Ms Jennifer Struble,Dr Michael A J Moser,Dr Michael A J MoserBackground: A recent study by our group found that only 42% of recorded small bowel obstruction (SBO) bowel sounds were correctly identified by test physicians. Sound analysis revealed that some of the bowel sounds were very typical, while others were atypical, and hence rarely identified as SBO. The purpose of our study was to determine if ‘typical’ sounds are more commonly found in certain settings such as early versus late, or proximal versus distal, SBO.
Methods: Healthy volunteers (n = 10) or patients with radiological or laparotomy confirmed small bowel obstruction (n = 19) were enrolled as study subjects. Unselected recordings of bowel sounds from each subject were obtained using an electronic stethoscope. Twenty study physicians were then individually presented with 36 consecutive sound recordings and were asked whether each sound clip represented small bowel obstruction or normal subjects.
Results: Test physicians scored an average of 45% (16.2/36) correct answers. Intra-observer agreement, however, was excellent (85%, kappa = 0.696), suggesting that the recordings were of good quality and the test physicians were consistent. Intra-patient agreement was poor (59.29%, kappa = 0.117), suggesting that a patients’ bowel sounds vary considerably even between recordings taken even just minutes apart. Listening for a full minute, as opposed to 30 seconds made no difference, and no difference was seen in correct answers whether the obstruction was proximal or distal, or early or late. Conclusion: In conclusion, the auscultation of bowel sounds does not appear to be reliable in diagnosing SBO. Nor does it appear that ‘typical’ sounds are more common in certain settings such as early versus late, or proximal versus distal, SBO. Our study suggests that the reason may be that sounds, made by the obstructed bowels, vary greatly from one moment to the next.