March 1st, 2017
Listening to Bowel Sounds: An Outdated Practice?
Alexandra Godfrey, BSc PT, MS PA-C
Medical programs teach us that listening to bowel sounds is an essential part of the physical examination of the abdomen, especially when the differential includes ileus, small bowel obstruction, diarrhea or constipation. Woe betide the student who fails to auscultate the abdomen of patients with these presentations. Yet firstly there’s little supporting evidence for this maneuver, and secondly there’s a lack of consensus about correct technique. Despite these issues, bowel sounds are claimed to help us develop our differential and cinch our diagnosis. The relationship between bowel sounds and pathology is not evidence based. It appears to be more a reflection of tradition and anecdotal evidence.
The noises produced by the movement of gas and fluids during peristalsis are bowel sounds. The technique learned depends on the school, the clinical gut of faculty and staff, and the physical exam text chosen. Some educators teach students that listening in one area is enough whereas others teach them to listen in all four quadrants. Bates’ recommends listening in only one spot, Mosby’s in all four quadrants, and DeGowin’s suggests listening in all four quadrants and the midline. Given that borborygmi may disseminate across the entire abdomen, and what you hear in one quadrant may reflect another part of the abdomen, the precise placement of your stethoscope seems irrelevant.
Also controversial is the duration of auscultation. Educators (and texts) teach students to listen for bowel sounds for anything from 30 seconds to 7 minutes. In reality, a healthy person may have no sounds for several minutes but then later have up to 30 a minute. Bowel sounds may cycle with peak-to-peak periods over 50-60 minutes. This means that any analysis less than that time will be inadequate.1 Additionally, some intestinal contractions are silent, so we cannot presume that a quiet bowel is a motionless bowel.
This complexity is further compounded by order of operations. Schools in the United States teach students to listen prior to palpation whereas schools elsewhere teach students to auscultate after palpation. I was taught to listen in each quadrant for up to 30 seconds or until bowel sounds were heard. This was done prior to palpation. Reversing the procedure was considered unacceptable. The thinking here is that palpation might disturb the intestines, trigger peristalsis, and thus alter the physical exam. My question is — so what?
There’s little evidence to suggest that borborygmi triggered by palpation are any more or less pathological than those that are not. I also suspect that patients might push on their own bellies before a clinician ever enters the room or even in their presence to illustrate their pain: it hurts here!
In researching this issue lately, as I folded page corners of great medical tomes and drew boxes around pertinent information, I felt that I might do just as well turning those pages into something tangible, relevant and concrete; something akin to the Japanese art of origami – a model of bird’s beak esophagus perhaps.
A friend and colleague of mine who trained as a surgeon in South Africa in the 1970’s described to me his memories of learning the nuances of borborygmi. Back then, this was their art.
“When I trained, and did a lot of intestinal surgery, borborygmi really meant being able to hear loud bowel sounds without a stethoscope. We learned to listen for those differences that depict ileus from mechanical intestinal obstruction, an important distinction since the mechanical obstruction often needed an urgent operation while ileus did not; we learned to distinguish propulsive sounds from ‘tinkling,’ non-propulsive ones. I got quite good at that as a chief registrar in Johannesburg. My teachers and the master clinicians who taught me, translated bowel sounds into action. Propulsion — operate! Tinkling — don’t operate!”
The most common and urgent reason to listen to bowel sounds is small bowel obstruction (SBO). The instruction is that bowel sounds will be hyperactive or absent in the setting of SBO. This is the time when the diligent clinician should wield their scope, placing the diaphragm below the diaphragm. However, in a recent study, 53 doctors used a Littman’s electronic stethoscope to assess the bowel sounds of patients with and without SBO. The median frequency with which doctors classified borborygmi as abnormal did not differ significantly between patients with and without bowel obstruction (26% vs. 23%, P=0.08). The study concluded that auscultation of the abdomen provided little help when making clinical decisions regarding management.2
A study published in The Journal of Surgical Education in 2010 came to similar conclusions. They found that “listeners frequently arrive at the incorrect diagnosis.” Listeners were unable to accurately characterise bowel sounds as normal, SBO or ileus. They also noted no difference in accuracy between surgical and internal medicine residents. They concluded that listening to bowel sounds is not a clinically useful part of the physical exam.3
Another reason to listen to bowel sounds is ileus. A study in 2012 examined the utility of listening to bowel sounds as a method of determining the end of post-operative ileus. This study determined that there was no association between the finding of bowel sounds and the return of bowel activity. This research concludes that routine assessment of bowel sounds for resolution of ileus is according to an outdated and unnecessary procedure.4 Undeniably, patients with ileus and SBO often do have abnormal bowel sounds, but it appears that listening for them has little utility in clinical practice today.
I am a keen supporter of the history and physical exam. I advocate for the use of hands, ears and eyes. However, clinicians must be progressive, embracing new modalities and letting go of less reliable methods. For example, teaching bedside ultrasound for the diagnosis of SBO might be a better use of time. A recent systematic review and meta-analysis of the diagnostic modalities used to identify SBO found ultrasound to be superior to all other modalities.5
It is unlikely that medical, nursing and physician assistant programs will stop teaching students to listen for borborygmi any time soon. I hope though that the lack of both evidence and standardisation will at least encourage students, educators and clinicians to question the efficacy and utility of this maneuver. No one should fault the clinicians of earlier times; they lacked the technology and data we have today. Some might consider auscultating for bowel sounds as another part of our arsenal for deployment, rather like Homans’s sign for deep vein thrombosis: something to pull out of our medical tool bag when diagnostic resources are scarce – when our scope is all we have. That said, given the lack of consensus and supporting evidence, I believe patients might benefit more from the ancient art of origami than borborygmi. At least the former might soothe the patient.
1) McGee, S, Evidence-Based Physical Diagnosis, 3rd Edition. Philadelphia, PA: Elsevier-Saunders; 2012
2) Breum BM, Rud B, Kirkegaard T, Nordentoft T. Accuracy of abdominal auscultation for bowel obstruction. World Journal of Gastroenterology : WJG. 2015;21(34):10018-10024. doi:10.3748/wjg.v21.i34.10018.
3) Felder S, Margel D, Murrell Z , Fleshner P. Usefulness of Bowel Sound Auscultation: A Prospective Evaluation. Journal of Surgical Education, 2014-09-01, Volume 71, Issue 5, Pages 768-773.
4) Massey R. Return of bowel sounds indicating an end of postoperative ileus: is it time to cease this long-standing nursing tradition? Medsurg Nursing, 2012-05, Volume 21, Issue 3, Page 146 -150
5) Taylor N, Lalani M. Adult Small Bowel Obstruction. Journal of the Society of Academic Emergency Medicine,5) 2013-06-12, Volume 20, Issue 6, Pages 527-544
It is unfortunate that more and more of the physical exam is being discarded as irrelevant, unnecessary, or potentially misleading.
In addition to the above controversy about listening for bowel sounds, “Choosing Wisely” now counsels us to skip the bimanual pelvic exam when performing routine PAP smears. “Too many false positives” we are told.
It is certainly the case that there is a wide range of normal (and abnormal) in physical findings. Nevertheless, what is left unexplained by those who advise us to eliminate parts of the routine exam (unless “an abnormality is suspected”) is how examiners are to develop and maintain their skills in performing the exam without actually doing it over and over again.
I have been a physician for nearly 40 years now. Each time I do a physical exam I add the findings to my mental “library” of findings–a practice that assists me the next time I perform the exam and interpret my findings. I suspect this practice is common.
Consider the low “yield” of lung and heart auscultation on a routine office visit for hypertension. Should we abandon these parts of the exam as well?
I AM VERY PROUD THAT YOU WROTE THIS AND ARE THINKING LIKE A SCIENTIST. TRYING TO MOVE MEDICINE FORWARD FOR US ALL. NOT SURE I AGREE, BUT I GRADUATED PA SCHOOL IN 1975, SO IT TAKES ME LONGER TO BREAK HABITS….
In addition to my first comment (above), let me simply point out that the practice of medicine has never been an exact science.
It behooves us as healing professionals to be both scientists and humanists. Touching the patient during the physical exam has both diagnostic and therapeutic potential.
I totally agree Frank. I am a strong supporter of the physical exam, just not this particular part of it. We can touch the patient, learn from our senses, be humanistic, practice the art and be precise. I think that is achievable.
Not an “outdated practice” but an outdated skill.
Scientifically speaking –
1. Even if bowel auscultation adds “minimal” to the physical examination n- it probably adds “SOMETHING” (like that one piece in a 1000 piece jigsaw puzzle.
2. Four references on this topic is NOT a body of evidence, a “consensus” or persuasive to me.
3. One needs to assess the SKILL in assessing bowel sounds – like the skill of diastolic murmurs etc. . .without this factor we know the results will not be statistically significant.
4. Listening to bowel sounds gives additional time to think about the patient, quietly, and to meditate on the problem (a known factor that increases diagnostic validity).
5. If listening to bowel sounds is completely useless for abdominal assessment – it may still be HIGHLY useful for enhancing patient compliance, engagement, satisfaction, and empathy resulting in a better overall positive outcome (consider research showing “patient navigators/supports” who DID NOTHING for the patient were able to increase satisfaction and reduce length of stay and readmission rates.).
I would continue to apply the microscope of scientific analysis to clinical lore, scientifically.
1) it adds something, of course. Everything we do adds depth and dimension.
2) This space doesn’t provide for multiple references. But if you want me to send you them, I am happy to oblige.
3) This is true. The skill of the provider matters. However, the studies I looked at suggested even those well practiced at the art did no better than those who weren’t. The data is there to support this.
4) you can use this skill to take time to think about the patient if you wish but that isn’t how it is taught or what we are suggesting to the patient. This makes it a performance and everything thing we do the patient makes them vulnerable.
5) Yes you can check more boxes for listening to bowel sounds. The patient may feel you paid them more attention. I would suggest though there are other ways we can be attentive to our patients. With our ears plugged with a stethoscope we are providing perhaps more of a barrier ? I prefer to think we can enhance empathy by being present. In other ways.
Thank you for your thoughtful comments
My thought was, what difference does it make if you are using a stethoscope or a bedside ultrasound? At least with the ultrasound you can explain to the patient what you are seeing or not seeing and show them simultaneously. I’d be happier if I could see what the provider was doing and seeing, rather than just relying on their interpretation of some sounds or lack thereof.
I think I agree with your considerations. Even if I’m young I feel the time I take to listen to bowel movement with a stethoscope to be always useful. Not only cause it pushes me to use my senses at their best, sometimes in kind of a musical way, and not only cause it gives me the time to compose the puzzle I created with every single clue I gathered from the examination. I find bowel movements assesment to be useful to understand the nature of constipation, for example. Will we miss, for example, rare but interesting findings like bruits? The more we can understand with our senses, the less we’ll be slave of advanced, expensive and not always available diagnostic techniques..
Over dependence on investigations and discarding clinical methods is not just a co incidence. I am afraid it is also driven by billing practices if unethical physicians of first world nations. A day will comw when a client gets a routine PET- MRI as it suits yhe institution to embellish the bill, pun intended.
If, at least for a single patient, listening to bowel sounds helped making differentials, deciding amongst treatment options or ultimately saving his life, listening to bowel signs is worth a lifetime of practicing.
That’s how medicine works. It’s not human body engineering. It’s medicine. You can’t put that to cold percentages and efficacy measurements. That can’t be oversimplified.
Plus, considering that physical examination has virtually no complications, a physician should always do what he thinks is worthy to tend to the patients’ needs.
It’s not surprising that American medicine is so expensive and at the same time so judicially demanding.
I agree with you Karine: it isn’t human body engineering. There are many dimensions to medical practice. It is indeed an art. I am exploring one aspect of the exam. This does not extend to the entire exam nor to the entire encounter. Certainly, we can say that the simple laying on of hands, paying attention to the patient, taking time to be present is a very valuable part of our practice.
As surgeon and after touching “a few” bellys…. This part of the physical exam is totally worthless. It hasnt change a single decision in years.
Interesting article! And don’t get me wrong, i’m all about moving forward in the incredible art of medicine and specially semiology. But as it happends more to offen in the late years that these are just TRENDS! and only keeping us away more and more from the patient bedside to sit infront of a screen.
Besides when you are in the bush hundreds of miles away from even a regular set of x-rays or eco (humanitarian worker for 5 years now), the clinical skills and the most important part is between the eartips.
No to trends, more anamnesis and clinical skills.
Cheers, from Angola.
Thank you for this. I’m quoting you in a remediation paper for nursing school when my instructor failed me on a focused abdominal assessment. Everything else during the assessment was fine except the auscultation. Patient had a triple A and an ileus following the repair. I couldn’t hear anything so I said I would listen again later instead of replying with the usual answer of 5 minutes in each quadrant. Unsatisfactory response I guess. The number of studies out there contradicting this outdated practice is astounding and yet instructors (even the younger ones!) still cling to it in spite of evidence contradicting it.
Durup-Dickenson, M., MD, & Kirk Christensen, M., MD. (2013). Abdominal auscultation does not provide clear clinical diagnoses. Danish Medical Journal, 60(5). Retrieved March 10, 2017.
Here are three other sources I used questioning the use of auscultation in the abdominal assessment:
Madsen, D., BSN, RN, Sebolt, T., BSN, RN, Cullen, L., MA, RN, Folkedahl, B., BSN, RN, COCN, CWCN, Mueller, T., MSN, RN, CCRN, Richardson, C., BSN, RN, & Titler, M., PhD, RN, FAAN. (2005). Listening to Bowel Sounds: An Evidence-Based Practice Project. AJN, American Journal of Nursing, 105(12), 40-49. doi:10.1097/00000446-200512000-00029
Massey, R. L., PhD, RN, NEA-BC. (2012). Return of Bowel Sounds Indicating An End of Postoperative Ileus: Is it Time to Cease this Long-Standing Nursing Tradition? Medsurg Nursing, 21(3), 146-150. Retrieved March 10, 2017.
Thank you for these references Rachel. There’s quite a lot in nursing education and literature about this practice, but it seems such tests are hard wired into our DNA as we go through training.
Of course the issue isn’t whether abdominal auscultation can provide a “clear clinical diagnosis”–it can’t any more than any other isolated portion of the physical exam. The issue is really whether abdominal auscultation can contribute to the totality of the patient’s care.