Bowel sounds

Bowel SoundsJibran Mohsin

Resident, Surgical Unit ISIMS/Services Hospital, Lahore

QUERIES1. Source of bowel sounds2. Position of patient3. Part of stethoscope to be used?4. Site of auscultation5. Minimum amount of time to auscultate before concluding that no bowel sounds are present?6. Normal frequency7. Sequence8. How to hold stethoscope?9. Features of normal bowel sounds10. Hypoactive bowel sounds 11. Hyperactive bowel sounds12. Clinical significance of bowel sounds

1. Source of bowel sounds

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Pendular movements

Mixing contractions (segmentation contractions)

Tonic contractions

Propulsive movements

Anti-peristaltic movements

1. Source of bowel soundsM

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Pendular movements


Tonic contractions



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)


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Pendular movements


Tonic contractions



• 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


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Pendular movements


Tonic contractions



• 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

1. Source of bowel sounds

Mov

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smal

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Pendular movements


Tonic contractions



• 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


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Pendular movements


Tonic contractions



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).


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Pendular movements


Tonic contractions



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.


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Pendular movements


Tonic contractions



• 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.

2. Position of Patient

• Lying on back/Supine

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

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, 2009Kahan et al, 2009Macleod’s Clinical examination,12th edition, pg. 204SRB’s clinical methods in surgery, 1st edition, pg. 469-470Bedside techniques: Methods of clinical examination,3rd edition, pg. 164Hutchisons clinical methods, 22nd edition, pg. 132

Rushforth 2009Seidel et al 2006

4. Site of auscultation?



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


Interpretation ReferencesSeveral 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




6. Normal frequencyInterpretation 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

6. Normal frequency

6. Normal frequency

6. Normal frequency

7. Sequence1st 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)

7. Sequence

7. Sequence

7. Sequence

8. How to hold the stethoscope?

• not putting pressure on the diaphragm otherwise peristalsis could be stimulated and thereby mask the true auscultation findings.

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.

9. Features of normal bowel sounds

(Volume/ intensity)

Pitch depends on

1. Distension of bowel2. Proportion of gas &

fluid


• Intermittent• Frequency: already discussed

• Quality: Gurgling/Clicking/Rumbling• Pitch: Low (or moderate)

• Irregular pattern

(interspersed with an occasional high-pitches noise/tinkle)


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.

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.


• Document abdominal auscultation findings a simply

‘ bowel sounds present’

with the assumption that they are normal sounds.

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

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

11. Hyperactive bowel soundsNormal 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

11. Hyperactive bowel sounds

• Acute (small gut) mechanical intestinal obstruction

Normal bowel sounds

Hyperactive Bowel sounds

Hypoactive bowel sounds

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

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.


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?


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.



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.



• 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,



• 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.


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.


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.

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

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

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

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

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

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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

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• 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

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Bowel sounds

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