Assessment of Bowel Sounds


Published: 10 September 2016

Most nurses carry out a cursory listen for bowel sounds, but you may not realise how variable and important these sounds can actually be.

As with most things learned at university, it is easy to forget the particulars once you are working on a nursing floor. Instead of really focusing on the sounds, you may simply write down what you think you hear.

This can be a problem because changes in bowel sounds may indicate problems with the patient long before other signs emerge. For instance, the absence of bowel sounds after surgery can indicate an ileus before the patient starts vomiting or complaining of abdominal pain.

For this reason, it is important to go over bowel sounds once more, pay closer attention to them, and not use them merely as a stepping stool to the next level of assessment. After reading this article, you may like to also review your knowledge of assessing constipation.

The Abdomen

The abdomen can be divided into four quadrants. Although another system divides it into nine sections, the most common way to think of the abdomen is by drawing a line down the midline over the umbilicus and another across the abdomen bisecting it at the same point. This will give you the standard right upper quadrant, right lower quadrant, left upper quadrant and left lower quadrant. You should know the structures within each area to help determine what the bowel sounds mean.

In the right upper quadrant, you will find the lower margin of the liver, the gallbladder, part of the large intestine and a few loops of the small intestine. The right lower quadrant contains the appendix, the connection between the large and small intestines and loops of bowel. The left upper quadrant contains the lower margin of the spleen, part of the pancreas and some of the stomach and duodenum. The left lower quadrant contains bowel loops and the descending colon. Knowing the structures under your stethoscope will help you determine the nature of the bowel sounds.

bowel sounds abdomen diagram
A diagram outlining the four quadrants of the abdomen. RUQ: right upper quadrant; RLQ: right lower quadrant; LUQ: left upper quadrant; LLQ: left lower quadrant.

What Bowel Sounds to Listen for

Although you can listen for vascular sounds over the abdomen, such as abdominal aortic bruits, most of the time you are listening for the sounds of the bowels themselves. As peristalsis moves the chyme along the bowel tract, grumbling noises are heard, indicating that the bowels are active. You should listen over all four quadrants, not simply in one place. In fact, several areas per quadrant would be ideal, especially in patients who have gastrointestinal (GI) issues.

The first item to listen for is the presence of bowel sounds. To chart an assessment finding of no bowel sounds, you need to listen over the quadrant for at least five minutes. You should also do your auscultation before palpation and percussion to avoid influencing bowel sounds. In most cases, bowel sounds are present, but you need to categorise them. You should listen for the intensity of the sound – whether it is soft or strong. You should also listen for frequency. Hypoactive bowel sounds could indicate a problem, so if you are having trouble hearing them, this is significant.

Hyperactive bowel sounds, on the other hand, may indicate stomach upset, cramping and anything that is increasing peristalsis. The location and pitch of the sounds are important as well. Hypoactive bowel sounds in the right upper quadrant could indicate a bowel obstruction there. The pitch is important, too, as it can indicate the strength of the peristalsis and point to a problem.

What Findings Mean

Auscultating bowel sounds can allow you to pinpoint areas where an obstruction may have occurred. Finding no bowel sounds can mean an ileus or obstruction above that area of the intestine. Hypoactive bowel sounds are considered as one every three to five minutes, and this can indicate diarrhoea, anxiety or gastroenteritis. Hyperactive bowel sounds are often found before a blockage. It is quite common to find one quadrant with hyperactive bowel sounds and one with none or hypoactive ones. This is because the intestine is attempting to clear the blockage with increased peristalsis.

You may also hear high-pitched sounds and rushing noises. Again, this is a sign that the intestine is attempting to deal with a blockage. It is important to chart the location, quality, intensity and frequency of bowel sounds to document the GI system completely. Most nurses default to bowel sounds active in all four quadrants, but you need to be aware that this may not always be the case. A harried and hurried nurse may perform a quick assessment, but bowel sounds are a great indicator of the overall health of the patient. You need to listen for more than a few seconds and in several places to fully assess your client’s GI function.