Computerized analysis of bowel sounds in normal and small bowel obstructed rats

Small bowel obstruction (SBO) is a common surgical emergency which may be mimicked by ileus or other nonsurgical conditions. The aims of this work is to delineate gastrointestinal sound (GIS) correlates in a rat model. Seven rats were studied in paired SBO and control states. Computerized analysis of GIS was performed under continuous IV sedation. After adaptive filtering, every GIS event was isolated and analyzed for duration and dominant frequency. It was found that long duration sounds (greater than 100 ms) occurred in each of the obstructed, but in none of the nonobstructed cases (p=0.02). The overall mean event duration and dominant frequency in SBO compared to control states was both significantly longer and lower (22.42.6 vs 7.0±2.6 ms, p=0.001 for duration; and 296±34 vs 427±33, p=0.001 for frequency). Besides these mean differences, there was also a clear evolution with time in GIS characteristics, with lengthening of the duration (+0.56 ms/min, p=0.001) and lowering of the dominant frequency (−3.3 Hz/min, p=0.01). It is concluded that GIS analysis may prove useful in the noninvasive, rapid, and accurate diagnosis of SBO.