Bowel sounds are produced by movement in the small intestine. The diaphragm of the stethoscope should be used to listen in the right upper quadrant or all four quadrants for at least 5 minutes. Normal bowel sounds occur every 5-10 seconds and have a low to moderate pitch and intermittent quality. Hypoactive sounds are absent or diminished while hyperactive sounds are excessive or high pitched. Interpretation of bowel sounds can be difficult due to variation.

1. Bowel Sounds
AAMIR HELA
PG 3rd year
GMC Jammu

2. QUERIES
1. Sourceof bowelsounds
2. Position of patient
3. Part of stethoscope to beused?
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 holdstethoscope?
9. Features of normal bowelsounds
10. Hypoactive bowel sounds
11. Hyperactive bowel sounds
12. Clinical significance of bowelsounds

3. 1. Source of bowelsounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Toniccontractions
Propulsive movements
Anti-peristaltic movements

4. 1. Source of bowelsounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Toniccontractions
Propulsive movements
Anti-peristaltic movements
• Wavesof contraction moving in downwarddirection
along gut;
• Seenasside to side movement during surgery
• Rhythmic lengthening and shortening of gutloops;
• myogenic origin;
• serve to reassume gut loops within limited spaceof
abdominal cavity

5. 1. Source of bowelsoundsMovementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Toniccontractions
Propulsive movements
Anti-peristaltic movements
• 12 per minute (duodenumand proximal jejunum) and 8-9 per minute (terminal ileum)
• Help in mixing intestinalcontents with digestive juices
• Also increasevascularand lymphatic flow, aids inabsorption
• Decreasethe transit time, further favors digestion and absorption

6. 1. Source of bowelsounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Toniccontractions
Propulsive movements
Anti-peristaltic movements
• Involves relatively larger segments of
intestine with intermediate zonesof
relaxation (large segments of intestine are
isolated from eachother)
• Serveto increase transit time toallow
digestion and absorption

7. 1. Source of bowelsoundsMovementsofthesmall
intestine
Mixing contractions
(segmentation contractions)
Toniccontractions
Propulsive movements
Anti-peristaltic movements
1. Peristalsis in the smallintestine
Pendular movements
• Occur irregularly and don’t travel along whole of intestine (unlike
esophageal and gastric peristalsis); i.e. canoccur in any part of small
intestine
• Produced in response to stretch (myentericreflex)
• 1st moves in both directions but immediately its travel upwardsis
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 terminalintestine)
• Very weak and usually die out after travelling only3-5cm, very rarely >
10 cm. (net movement along small gut normally averageonly 1
cm/min; i.e. 3-5 hours needed for passageof chyme from pylorus to
ileocecal valve).

8. 1. Source of bowelsounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Toniccontractions
Propulsive movements
Anti-peristaltic movements
2. Propulsive effect of segmentationmovements:
• Also travel 1 cm or soin anal direction and duringthat
time help propel the food down theintestine.
3. Peristaltic Rush(Rush Peristalsis):
• Contrary to normally weak small bowel peristalsis,
intense irritation of intestinal mucosa, asoccurs in some
severe casesof infectious diarrhea (intestinal obstruction
proximal to lesion), cancauseboth powerful and rapid
peristalsis
• 2-25 cm/min (average 10cm/min)
• Travellong distances in small gut within minutes,
sweeping the contents of intestine into the colon and
thereby relieving the small intestine of irritativechyme
and excessive distension.

9. 1. Source of bowelsounds
Movementsofthesmall
intestine
Pendular movements
Mixing contractions
(segmentation contractions)
Toniccontractions
Propulsive movements
Anti-peristaltic movements
• Resembles peristalsis in every aspectbut
moves in opposite direction ie.Orally
• Normally occur in 2nd and 3rd parts of
duodenum; causing regurgitation of its
contents into stomach lowering of acidityof
gastric contents
• Also occur in terminal ileum: preventsrapid
entry of ileal contents into cecum, thus
favoring intestinal absorption.

10. 2. Position ofPatient
• Lyingon back/Supine

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

12. 4. Site of auscultation?
1st school ofthought 2nd school ofthought
listening in one site on the abdomen until bowelsounds are
heard, don’t move it from site to site,
right to umbilicus(umbilicalregion)
Closeto ileocecal junction
in all 4quadrants
Rationale Becausesounds are easily transmitted throughout the
abdomen, auscultating in one place issufficient
if an abnormality is fond in thefirst
area
References Bickley and Szilagyi, 2009
Kahanet al, 2009
Macleod’s Clinical examination,12th edition, pg. 204
SRB’sclinical 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 al2006

13. 4. Site of auscultation?

14. 4. Site of auscultation?

15. 4. Site of auscultation?

16. 5. Minimum amount of time toauscultate before
concluding that no bowel soundsare present?
Interpretation Studies
Varied from 30 secondsto Epstein, 2008
7 minutes Coxand Steggall,2009
Many authors advised to auscultate forat Smith, 1987;
least 5 minutes if no soundsheard McConnell, 1994;
initially Kirton, 1997;
Mehta, 2003;
Estes, 2006;
Seidel et al, 2006;
Jarvis, 2008

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

18. 5. Minimum amount of time toauscultate before
concluding that no bowel soundsare present?

19. 5. Minimum amount of time toauscultate before
concluding that no bowel soundsare present?

20. 5. Minimum amount of time toauscultate before
concluding that no bowel soundsare present?

21. 6. Normal frequency
Interpretation References
2-4 in number/minute SRB’sclinical methods in surgery, 1st edition, pg. 469-470
Every5-10 seconds, but frequencyvaries Macleod’s Clinical examination,12th edition, pg.204
Bedside techniques: Methods of clinical examination,3rd edition,
pg. 164;
Everyfew seconds Browse’s introduction to the symptoms and signsofsurgical
disease, 4th edition, pg. 390-391

22. 6. Normal frequency

23. 6. Normal frequency

24. 6. Normal frequency

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

26. 7.Sequence

27. 7.Sequence

28. 7.Sequence

29. 8. How to hold thestethoscope?
• not putting pressure on the diaphragm otherwise peristalsis couldbe
stimulated and thereby maskthe true auscultationfindings.

30. 8. How to holdstethoscope?
• BUT no research evidenceto support within the articlesand
textbooks reviewed.
• Technique appears to be based on tradition, personal preferenceand
anecdotal teaching, resulting in dissimilar advice being given in
literature.

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

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

33. 9. Features of normal bowelsounds

34. 9. Features of normal bowelsounds
• 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 forsamepatient.

35. 9. Features of normal bowelsounds
• Practical difficulties
• Failure to recognize very loud and long bowel sounds easily producedby
healthy bowel during an active stage of digestion asanormalsound.
• Borborygmus(P. borborygmi) =technical term for loud rumblingsounds
• Normal bowel sounds can be quite loud and often audible without a
stethoscope, which is not necessarily acasefor concern.

36. 9. Features of normal bowelsounds
• Document abdominal auscultation findings asimply
‘bowel sounds present’
with the assumption thatthey are normal sounds.

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

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

39. 11. Hyperactive bowelsounds
Normal bowelsounds Hyperactive bowel sounds (‘Noisyabdomen’)
Peristalsis normal Increased (Hyperperistaltic)
Frequency Low (5-35 mins) Increased (excessive bowel sounds)
(> 5/min ; SRBclinical methods)
Pitch Low to moderate Initially high frequency(frequent) loud lowpitched
gurgling/rumbling sounds (Borborygmi)
; often rising to acrescendo of high frequency highpitched
tinkling sounds
Quality Gurgling/Clicking/rumbling (Metallic) ‘Tinkling’
(Likeseawater entering alarge cavethrough anarrow entrance
or rain falling on atin roof)
(Amphoric in nature)
Volume/intensity/
loudness
low Increased (exaggerated bowel sounds)
Pattern Irregular Rhythmic pattern with peristaltic activity*
*Presenceof such soundswith patients experiences bouts of colicky abdominal pain  highlysuggestive of small bowel obstruction. In between bouts of peristaltic activity
and colicky pain, bowels is quiet and no sounds onauscultation

40. 11. Hyperactive bowelsounds
• Acute (small gut) mechanical intestinal obstruction
Normal
bowel sounds
Hyperactive
Bowelsounds
Hypoactive
bowel sounds

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

42. 12. Clinical significance of bowelsounds
LIMITATIONS
• Conflicting information in the literature aboutauscultation technique
and how to interpret normal and abnormalfindings.
• Practitioners undertake abdominal auscultation in different ways
without astandardized, evidence-based approach.
• Normal findings canbe found in the abnormal bowel, andabnormal
findings in anormal bowel.

43. 12. Clinical significance of bowelsounds
QUERIES
• Doesthe findings of either normal or abnormal bowelsounds hold
any clinical significance?
• Should bowel sound auscultation still be included within aphysical
assessment?

44. 12. Clinical significance of bowelsounds
Does the findings of either normal or abnormal bowel sounds hold
any clinicalsignificance?
Studies Interpretation
Fairclough and Silk (2009) auscultation does not contribute much to the assessmentof abdominal disease
unless there are signsof 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).
Burseyet al(2000) bowel sounds asnot particularly diagnostic.
Thefinding of high-pitched sounds with acute small bowel obstructionwas
considered clinically useful.
Although the trend ofchangesin abnormal bowel sound over time was thought
to be of greater value than aone-offassessmentfinding.

45. 12. Clinical significance of bowelsounds
Does the findings of either normal or abnormal bowel sounds hold
any clinicalsignificance?
Studies Interpretation
Kahanet al (2009) abdominal auscultation was not necessary, claiming in support of thisstatement
that bowel sounds have poor specificity andsensitivity.
Smith (2007) provided more details of the diagnostic significance of hyperactive bowelsounds
with asmall 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 otherliterature
with similar information could not be found for comparison.

46. 12. Clinical significance of bowelsounds
Does the findings of either normal or abnormal bowel sounds hold
any clinicalsignificance?
• Absent/hypoactive bowel sounds are only one piece of the puzzle
when assessinga patient.
• Bowel sounds on their own have not contributed significantlyto
helping the practitioners identify aclinicalproblem,

47. 12. Clinical significance of bowelsounds
Does the findings of either normal or abnormal bowel sounds hold
any clinicalsignificance?
• Although they could have increased confidence in the differential diagnosis
derived from avariety of abdominalabnormalities.
• 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 makeadiagnosis and plan suitableinterventions.

48. 12. Clinical significance of bowelsounds
Should bowel sound auscultation still be included within a physical
assessment?
• Likemany other aspects of clinical practice, there is no trueevidence
baseto either support or refute the inclusion of abdominal
auscultation within aphysical assessment.

49. 12. Clinical significance of bowelsounds
Should bowel sound auscultation still be included within a physical
assessment?
• Until further research with more definitive advice becomesavailable,
practitioners must continue to useclinical 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.

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57. Available at surgicalpresentations