Reliability of colonic manometry

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As noted in a previous blog entry (Gastroesophageal Reflux: I know it when I see it | gutsandgrowth), it is often surprising how variable test result interpretation can be in the hands of experts.  The most recent example of this is with colonic manometry (JPGN 2012; 55: 548-51).

In the current study, 57 colonic motility studies were independently reviewed by 5 experts. The youngest and least experienced was 45 years old with 8 years of experience.  The oldest and most experienced was 63 years old with 28 years of experience.

Unanimous differentiation of normal and abnormal motility studies was present in 69%.  In 81% of the studies, 4 of 5 were in agreement about whether the study was normal.

Specific measurements noted the following:

  • Fairly high degree of agreement with fasting high-amplitude propagating contractions (HAPC): 66% with unanimous agreement,  and 82% with at least 4 of 5 observers in agreement.
  • The gastrocolonic response had the most inconsistency with only 19% in unanimous agreement and 45% with at least 4 of 5 in agreement.
  • The postprandial measurements were reported to be useful in only 3-24% of the studies.

Colonic manometry studies “require interpretation of a complex visual bowel motility pattern and are subject to interpretation bias.” One proposal by the authors of the study would be to limit colon motility studies to 60 minutes followed by bisacodyl stimulation.  Further studies will be necessary to determine whether this will improve the reliability of colonic manometry interpretation.

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