High- Resolution Colonic Manometry (HRCM)
High-resolution colonic manometry was performed on a custom-made platform (Medical Measurement Systems (MMS); Laborie, Toronto, ON, Canada). An 84-sensor water-perfused 105 cm long catheter was designed (Mui Scientific, Mississauga, ON, Canada). The spacing between sensor 1-48 was 1.5 cm while the spacing between the rest of the sensors was 1 cm. The catheter included one 10-cm long balloon between sensors 7 and 8. Sensor 1 was placed in the ascending colon. The catheter was inserted with minimal sedation (fentanyl i.v. 50 mcg and midazolam i.v. 2 mg) with the assistance of a colonoscope after a bowel cleaning procedure using an inert osmotic laxative (PEG-Lyte, Pendopharm, Montreal, QC, Canada), but no use of stimulant laxatives such as bisacodyl. For the bowel cleaning procedure, 3L of PEG (70 g/L) was taken between 4 and 6 pm the day before the procedure, with more water consumed as needed to have all solids removed. The next morning, 1L was taken at 4 am. The tip of the catheter was clipped to the mucosa via a fish line, a few centimeters distal to the cecum. The catheter was made of 100% silicon. After use, an extensive approved cleaning procedure was executed followed by sterilization. The subject was in the supine position during the entire recording, except during meal intake. Subject was instructed to report all events such as gas or liquid expulsion, bowel movements, pain, and discomfort. Subject was asked not to promote or prevent gas or liquid expulsion by increasing abdominal pressure or contracting the external anal sphincter if an urge arose. Artifacts caused by body movements such as changing body position, talking, coughing, laughing, and urination were noted immediately into the data acquisition files and excluded from the analysis.