The document discusses bowel sounds, including their source, techniques for auscultation, and clinical significance. Some key points: - Bowel sounds are produced by normal peristaltic activity in the small intestine moving intestinal contents. - When auscultating, the diaphragm of the stethoscope should be used with the patient in a supine position. Sites of auscultation include all four abdominal quadrants. - The minimum time to auscultate before concluding no sounds is present is debated, with recommendations ranging from 30 seconds to 5 minutes. - Normal bowel sounds have a frequency of 2-4 per minute, gurgling/clicking quality,

1. Bowel Sounds
Jibran Mohsin
Resident, Surgical Unit I
SIMS/Services Hospital, Lahore

2. QUERIES
1. Source of bowel sounds
2. Position of patient
3. Part of stethoscope to be used?
4. Site of auscultation
5. Minimum amount of time to auscultate before concluding that no bowel sounds are present?
6. Normal frequency
7. Sequence
8. How to hold stethoscope?
9. Features of normal bowel sounds
10. Hypoactive bowel sounds
11. Hyperactive bowel sounds
12. Clinical significance of bowel sounds

3. 1. Source of bowel sounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Tonic contractions
Propulsive movements
Anti-peristaltic movements

4. 1. Source of bowel sounds
Movementsofthesmall
intestine Pendular movements
Mixing contractions
(segmentation contractions)
Tonic contractions
Propulsive movements
Anti-peristaltic movements
Bowel Sounds/noises are produces due to normal
peristaltic activity of small gut/bowel causing movement
of its contents (containing mixture of fluid and gas)

5. 1. Source of bowel sounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Tonic contractions
Propulsive movements
Anti-peristaltic movements
• Waves of contraction moving in downward direction
along gut;
• Seen as side to side movement during surgery
• Rhythmic lengthening and shortening of gut loops;
• myogenic origin;
• serve to reassume gut loops within limited space of
abdominal cavity

6. 1. Source of bowel soundsMovementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Tonic contractions
Propulsive movements
Anti-peristaltic movements
• 12 per minute (duodenum and proximal jejunum) and 8-9 per minute (terminal ileum)
• Help in mixing intestinal contents with digestive juices
• Also increase vascular and lymphatic flow, aids in absorption
• Decrease the transit time, further favors digestion and absorption

7. 1. Source of bowel sounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Tonic contractions
Propulsive movements
Anti-peristaltic movements
• Involves relatively larger segments of
intestine with intermediate zones of
relaxation (large segments of intestine are
isolated from each other)
• Serve to increase transit time to allow
digestion and absorption

8. 1. Source of bowel soundsMovementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Tonic contractions
Propulsive movements
Anti-peristaltic movements
1. Peristalsis in the small intestine
• Occur irregularly and don’t travel along whole of intestine (unlike
esophageal and gastric peristalsis); i.e. can occur in any part of small
intestine
• Produced in response to stretch (myenteric reflex)
• 1st moves in both directions but immediately its travel upwards is
inhibited;
• Serve to propel chyme towards distal end/anus at velocity of 0.5 to 2
cm/sec (faster in proximal intestine and slower in terminal intestine)
• Very weak and usually die out after travelling only 3-5cm, very rarely >
10 cm. (net movement along small gut normally average only 1
cm/min; i.e. 3-5 hours needed for passage of chyme from pylorus to
ileocecal valve).

9. 1. Source of bowel sounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Tonic contractions
Propulsive movements
Anti-peristaltic movements
2. Propulsive effect of segmentation movements:
• Also travel 1 cm or so in anal direction and during that
time help propel the food down the intestine.
3. Peristaltic Rush (Rush Peristalsis):
• Contrary to normally weak small bowel peristalsis,
intense irritation of intestinal mucosa, as occurs in some
severe cases of infectious diarrhea (intestinal obstruction
proximal to lesion), can cause both powerful and rapid
peristalsis
• 2-25 cm/min (average 10 cm/min)
• Travel long distances in small gut within minutes,
sweeping the contents of intestine into the colon and
thereby relieving the small intestine of irritative chyme
and excessive distension.

10. 1. Source of bowel sounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Tonic contractions
Propulsive movements
Anti-peristaltic movements
• Resembles peristalsis in every aspect but
moves in opposite direction ie. Orally
• Normally occur in 2nd and 3rd parts of
duodenum; causing regurgitation of its
contents into stomach lowering of acidity of
gastric contents
• Also occur in terminal ileum: prevents rapid
entry of ileal contents into cecum, thus
favoring intestinal absorption.

11. 2. Position of Patient
• Lying on back/Supine

12. 3. Part of stethoscope to be used?
Part of stethoscope used: Diaphragm is used Bell is used
Reference: Macleod’s Clinical examination,12th
edition, pg. 204
SRB’s clinical methods in
surgery, 1st edition, pg. 469-470

13. 4. Site of auscultation?
1st school of thought 2nd school of thought
listening in one site on the abdomen until bowel sounds are
heard, don’t move it from site to site,
right to umbilicus(umbilical region)
Close to ileocecal junction
in all 4 quadrants
Rationale Because sounds are easily transmitted throughout the
abdomen, auscultating in one place is sufficient
if an abnormality is fond in the first
area
References Bickley and Szilagyi, 2009
Kahan et al, 2009
Macleod’s Clinical examination,12th edition, pg. 204
SRB’s clinical methods in surgery, 1st edition, pg. 469-470
Bedside techniques: Methods of clinical examination,3rd
edition, pg. 164
Hutchisons clinical methods, 22nd edition, pg. 132
Rushforth 2009
Seidel et al 2006

14. 4. Site of auscultation?

15. 4. Site of auscultation?

16. 4. Site of auscultation?

17. 5. Minimum amount of time to auscultate before
concluding that no bowel sounds are present?
Interpretation Studies
Varied from 30 seconds to Epstein, 2008
7 minutes Cox and Steggall, 2009
Many authors advised to auscultate for at
least 5 minutes if no sounds heard
initially
Smith, 1987;
McConnell, 1994;
Kirton, 1997;
Mehta, 2003;
Estes, 2006;
Seidel et al, 2006;
Jarvis, 2008

18. 5. Minimum amount of time to auscultate before
concluding that no bowel sounds are present?
Interpretation References
Several minutes Bedside techniques: Methods of clinical examination,3rd
edition, pg. 164;
Hutchisons clinical methods, 22nd edition, pg. 132
Up to 2 minutes Macleod’s Clinical examination,12th edition, pg. 204
30 seconds Browse’s introduction to the symptoms and signs of surgical
disease, 4th edition, pg. 390-391

19. 5. Minimum amount of time to auscultate before
concluding that no bowel sounds are present?

20. 5. Minimum amount of time to auscultate before
concluding that no bowel sounds are present?

21. 5. Minimum amount of time to auscultate before
concluding that no bowel sounds are present?

22. 6. Normal frequency
Interpretation References
2-4 in number/minute SRB’s clinical methods in surgery, 1st edition, pg. 469-470
Every 5-10 seconds, but frequency varies Macleod’s Clinical examination,12th edition, pg. 204
Bedside techniques: Methods of clinical examination,3rd edition,
pg. 164;
Every few seconds Browse’s introduction to the symptoms and signs of surgical
disease, 4th edition, pg. 390-391

23. 6. Normal frequency

24. 6. Normal frequency

25. 6. Normal frequency

26. 7. Sequence
1st School of thought 2nd school of thought
Auscultation performed immediately after inspection, before
touching the patient
Traditional sequence of inspection,
palpation, percussion and
auscultation.
Rationale Palpation can stimulate peristalsis, causing subsequent
bowel sounds that may not have been there otherwise.
(Use of light palpation to stimulate peristalsis if no sounds
were heard)

27. 7. Sequence

28. 7. Sequence

29. 7. Sequence

30. 8. How to hold the stethoscope?
• not putting pressure on the diaphragm otherwise peristalsis could be
stimulated and thereby mask the true auscultation findings.

31. 8. How to hold stethoscope?
• BUT no research evidence to support within the articles and
textbooks reviewed.
• Technique appears to be based on tradition, personal preference and
anecdotal teaching, resulting in dissimilar advice being given in
literature.

32. 9. Features of normal bowel sounds
(Volume/
intensity)
Pitch depends on
1. Distension of bowel
2. Proportion of gas &
fluid

33. 9. Features of normal bowel sounds
• Intermittent
• Frequency: already discussed
• Quality: Gurgling/Clicking/Rumbling
• Pitch: Low (or moderate)
• Irregular pattern
(interspersed with an occasional high-pitches noise/tinkle)

34. 9. Features of normal bowel sounds

35. 9. Features of normal bowel sounds
• Practical difficulties
• Difficult to determine whether bowel sounds are truly hypoactive or
hyperactive due to variation in normal range of frequency.
• Variation in normal volume and pitch difficult to assess.
• Variation in minimum time and site(s) required to hear bowel sounds.
• Inter-observer variation in interpretation for same patient.

36. 9. Features of normal bowel sounds
• Practical difficulties
• Failure to recognize very loud and long bowel sounds easily produced by
healthy bowel during an active stage of digestion as a normal sound.
• Borborygmus(P. borborygmi) = technical term for loud rumbling sounds
• Normal bowel sounds can be quite loud and often audible without a
stethoscope, which is not necessarily a case for concern.

37. 9. Features of normal bowel sounds
• Document abdominal auscultation findings a simply
‘ bowel sounds present’
with the assumption that they are normal sounds.

38. 10. Hypoactive bowel sounds
• Absent bowel sounds (‘Silent abdomen’) -peristalsis ceased
OR
• Diminished bowel sounds (low in frequency and volume)
Differential Diagnosis:
• Paralytic ileus(heart and breath sounds audible but no bowel sounds)
• Primary versus secondary
• Late intestinal obstruction
• Intestinal/Mesenteric ischemia
• Peritonitis
• Pancreatitis

39. 10. Hypoactive bowel sounds
• Caution:
• Late paralytic ileus:
• (short run of faint, very) high pitched tinkling sound due to spill over of contents/fluids
from one distended loop to another.
• Like ‘bell at evening pealing’
Normal bowel
sounds
heart and breath
sounds audible but
no bowel sounds
(silent abdomen)
(short run of faint,
very) high pitched
tinkling sound

40. 11. Hyperactive bowel sounds
Normal bowel sounds Hyperactive bowel sounds (‘Noisy abdomen’)
Peristalsis normal Increased (Hyperperistaltic)
Frequency Low (5-35 mins) Increased (excessive bowel sounds)
(> 5/min ; SRB clinical methods)
Pitch Low to moderate Initially high frequency(frequent) loud low pitched
gurgling/rumbling sounds (Borborygmi)
; often rising to a crescendo of high frequency high pitched
tinkling sounds
Quality Gurgling/Clicking/rumbling (Metallic) ‘Tinkling’
(Like sea water entering a large cave through a narrow entrance
or rain falling on a tin roof)
(Amphoric in nature)
Volume/intensity/
loudness
low Increased (exaggerated bowel sounds)
Pattern Irregular Rhythmic pattern with peristaltic activity*
*Presence of such sounds with patients experiences bouts of colicky abdominal pain  highly suggestive of small bowel obstruction. In between bouts of peristaltic activity
and colicky pain, bowels is quiet and no sounds on auscultation

41. 11. Hyperactive bowel sounds
• Acute (small gut) mechanical intestinal obstruction
Normal
bowel sounds
Hyperactive
Bowel sounds
Hypoactive
bowel sounds

42. 11. Hyperactive bowel sounds
• Differential Diagnosis:
• (Gastro)enteritis
• Diarrhea
• Inflammatory bowel disease
• Laxative use
• (Severe) GI bleeding
• Early acute(small gut) mechanical intestinal obstruction (distension)
• Carcinoid Syndrome
• Small bowel malabsorption

43. 12. Clinical significance of bowel sounds
LIMITATIONS
• Conflicting information in the literature about auscultation technique
and how to interpret normal and abnormal findings.
• Practitioners undertake abdominal auscultation in different ways
without a standardized, evidence-based approach.
• Normal findings can be found in the abnormal bowel, and abnormal
findings in a normal bowel.

44. 12. Clinical significance of bowel sounds
QUERIES
• Does the findings of either normal or abnormal bowel sounds hold
any clinical significance?
• Should bowel sound auscultation still be included within a physical
assessment?

45. 12. Clinical significance of bowel sounds
Does the findings of either normal or abnormal bowel sounds hold
any clinical significance?
Studies Interpretation
Fairclough and Silk (2009) auscultation does not contribute much to the assessment of abdominal disease
unless there are signs of an acute abdomen (e.g. severe pain with onset of <24
hours, pain before vomiting, fever, tachycardia, increased white blood cells,
guarding, rebound tenderness, abdominal distension and hypoactive bowel
sounds).
Bursey et al (2000) bowel sounds as not particularly diagnostic.
The finding of high-pitched sounds with acute small bowel obstruction was
considered clinically useful.
Although the trend of changes in abnormal bowel sound over time was thought
to be of greater value than a one-off assessment finding.

46. 12. Clinical significance of bowel sounds
Does the findings of either normal or abnormal bowel sounds hold
any clinical significance?
Studies Interpretation
Kahan et al (2009) abdominal auscultation was not necessary, claiming in support of this statement
that bowel sounds have poor specificity and sensitivity.
Smith (2007) provided more details of the diagnostic significance of hyperactive bowel sounds
with a small bowel obstruction: specificity 89–94%, sensitivity 40–42% and
likelihood ratio 5.0.
However, there was no clinical research to support these statistics, the specificity
and sensitivity of hypoactive/absent sounds were not covered, and other literature
with similar information could not be found for comparison.

47. 12. Clinical significance of bowel sounds
Does the findings of either normal or abnormal bowel sounds hold
any clinical significance?
• Absent/hypoactive bowel sounds are only one piece of the puzzle
when assessing a patient.
• Bowel sounds on their own have not contributed significantly to
helping the practitioners identify a clinical problem,

48. 12. Clinical significance of bowel sounds
Does the findings of either normal or abnormal bowel sounds hold
any clinical significance?
• Although they could have increased confidence in the differential diagnosis
derived from a variety of abdominal abnormalities.
• However, it could be argued that practitioners, continue to auscultate for
bowel sounds out of habit and tradition, without truly needing the
auscultation findings to make a diagnosis and plan suitable interventions.

49. 12. Clinical significance of bowel sounds
Should bowel sound auscultation still be included within a physical
assessment?
• Like many other aspects of clinical practice, there is no true evidence
base to either support or refute the inclusion of abdominal
auscultation within a physical assessment.

50. 12. Clinical significance of bowel sounds
Should bowel sound auscultation still be included within a physical
assessment?
• Until further research with more definitive advice becomes available,
practitioners must continue to use clinical judgment, intuition, past
experience and personal interpretation of the available literature to
make their own individual decision on how best to perform
auscultation and the value of listening for bowel sounds when
undertaking an abdominal physical assessment.

52. REFERENCES
• Baid H (2006) The process of conducting a physical assessment: a nursing perspective. Br J Nurs
15(13): 710–14
• Bickley LS, Szilagyi PG (2009) Bates’ Guide to Physical Examination and History Taking. 10th edn.
Lippincott Williams & Wilkins, Philadelphia
• Bursey RF, Fardy JM, MacIntosh DG (2000) Examination of the abdomen. In: Thomson ABR,
Shaffer EA (eds). First Principles of Gastroenterology: The Basis of Disease and an Approach to
Management. 4th edn. AstraZeneca, Mississauga, Ontario
• Chew R (2008) Crash Course: Gastrointestinal System. 3rd edn. Mosby Elsevier, Edinburgh
• Cox C, Steggall M (2009) A step-by-step guide to performing a complete abdominal examination.
Gastrointestinal Nursing 7(1): 19–17

53. REFERENCES
• Epstein O [Q14: “Epstein et al” in text – which should it be?] (2008) The abdomen. In: Epstein O,
Perkin GD, Cookson J et al (eds). Clinical Examination. 4th edn. Mosby Elsevier, Edinburgh: 186–
225
• Estes MEZ (2006) Health Assessment and Physical Examination. 3rd edn. Thomson Delmar
Learning, Clifton Park, New York
• Fairclough PD, Silk DBA (2009) Gastrointestinal disease. In: Kumar P, Clark M (eds). Kumar and
Clark’s Clinical Medicine. 7th edn. Saunders Elsevier, Edinburgh: 241–318
• Ford MJ, MacGilchrist A, Parks RW (2009) The gastrointestinal system. In: Douglas G, Nicol F,
Robertson C (eds). Macleod’s Clinical Examination. 12th edn. Churchill Livingstone Elsevier,
Edinburgh: 184–215
• Harris S, Naina HV, Kuppachi S (2007) Look, feel, listen or look, listen, feel? Am J Med 120(2): e3

54. REFERENCES
• Hepburn MJ, Dooley DP, Fraser SL, Purcell BK, Ferguson TM, Horvath LL (2004) An examination of
the transmissibility and clinical utility of auscultation of bowel sounds in all four abdominal
quadrants. J Clin Gastroenterol 38(3): 298–9
• Jarvis C (2008) Physical Examination and Health Assessment. 5th edn. Saunders Elsevier, St Louis
• Kahan S, Miller R, Smith EG (2009) In a Page: Signs and Symptoms. 2nd edn. Lippincott Williams &
Wilkins, Philadelphia
• Kirton CA (1997) Assessing bowel sounds. Nursing 27(3): 64
• Madsen D, Sebolt T, Cullen L et al (2005) Listening to bowel sounds: an evidencebased practice
project: nurses find that a traditional practice isn’t the best indicator of returning gastrointestinal
motility in patients who've undergone abdominal surgery. Am J Nurs 105(12): 40–9

55. REFERENCES
• McChesney JA, McChesney JW (2001) Auscultation of the chest and abdomen by athletic
trainers. J Athl Train 36(2): 190–6
• McConnell EA (1994) Clinical do’s and don’ts: auscultating bowel sounds. Nursing 24(6):
20
• Mehta M (2003) Assessing the abdomen. Nursing 33(5): 54–5
• Ng Y (2009) Examination of the gastrointestinal and genitourinary systems. In: Jevon P
(ed). Clinical Examination Skills. Wiley-Blackwell, Oxford: 99–119
• Rhoads J (2006) Advanced Health Assessment and Diagnostic Reasoning. Lippincott
Williams & Wilkins, Philadelphia

56. REFERENCES
• Rushforth H (2009) Assessment Made Incredibly Easy! First UK edition. Lippincott
Williams & Wilkins, London
• Seidel Hm, Ball JW, Dains JE, Benedict GW (2006) Mosby’s Guide to Physical Examination.
6th edn. Mosby Elsevier, St Louis
• Smith CE (1987) Investigating absent bowel sounds. Nursing 17(11): 73–7
• Smith CE (1988) Assessing bowel sounds – more than just listening. Nursing 18(2): 42–3
• Smith DS (2007) Field Guide to Bedside Diagnosis. 2nd edn. Lippincott Williams & Wilkins,
Philadelphia, PA

57. REFERENCES
• Talley NJ, O’Connor S (2006) Clinical Examination: A Systematic Guide to Physical
Diagnosis. 5th edn. Churchill Livingstone Elsevier, Marrickville, NSW Australia
• Turner R, Angus BJ, Handa A, Hatton C (2009) Clinical Skills and Examination: The
Core Curriculum. Wiley-Blackwell, Oxford
• West M, Klein MD (1982) Is abdominal auscultation important? Lancet 320(8310):
1279
• Yen K, Karpas A, Pinkerton HJ, Gorelick MH (2005) Interexaminer reliability in
physical examination of pediatric patients with abdominal pain. Arch Pediatr
Adolesc Med 159(4): 373–6

58. Available at surgicalpresentations