Water-Perfusion
The catheter delivered 0.1 ml/min sterile water via each sensor to a
total of 0.57 L per hour. A drainage tube (OD 3.3 mm) was placed in the
rectum to allow passive outflow of excess water. The remainder of the
water was expelled by colon motor activities or absorbed. Intraluminal
pressure in between motor patterns did not change during the recording
session (38), hence, the water inflow did not cause passive tonic
pressure changes.
Quantification and Statistical
analysis of HRCM
Data
All data were stored using the software developed by Medical Measurement
Systems (MMS; Laborie, Toronto, ON, Canada), and analyzed using programs
developed by Sean Parsons by Image J (National Institutes of Health,
Bethesda, MD, United States) and MATLAB (Mathworks, Natick, MA, United
States). After HAPWs were identified visually in Image J, they were
encircled free hand and a Contourer plug-in was used to set a 20 mmHg
isobar and accurately outline the HAPW to obtain its amplitude as an
average of all measured points within the contour. This method is
substantially different from measurements using low-resolution manometry
where only a few points along the motor pattern are considered. Other
motor patterns such as SPWs were measured through freehand outline using
a rectangular selection tool to obtain different characteristics such as
amplitude, duration, propagation length and velocity, if applicable.
Responses to stimuli were described and compared to baseline activity
and activity after meal. Data are given as mean ± SEM. Significance was
determined by ANOVA with multiple comparisons as mentioned in the table
footnotes using Prism 8 software (GraphPad, United States), P
< 0.05 was considered significant. Percentage of anal
sphincter relaxation was calculated by comparing the mean amplitude of
the anal sphincter in a 3-minute period before relaxation and the whole
period of relaxation. Due to the oscillatory nature of the anal
sphincter pressure, relaxation was quantified when it reached higher
than 25% of the average pressure value recorded in the 3-minute period
before the relaxation. The period of relaxation started with the first
sign of relaxation and ended with return to its baseline pressure. In
the middle of this period, complete anal sphincter relaxation could be
achieved. MATLAB was used to generate the 3D images.
Identified Motor Patterns by
HRCM
The focus of this case study was on propulsive motor patterns and their
coordination with anal sphincter relaxation. Therefore, the following
motor patterns were studied:
- Simultaneous pressure waves (SPWs) are pressure transients that occur
simultaneously at all sensors that record them, as identified by Rao
et al., (41) and De Schryver et al., (14), and further defined and
characterized by us (9, 10, 38). They have also been called
simultaneous contractions (40) or pan-colonic pressurizations (11).
- High- amplitude propagating pressure waves (HAPWs) are defined as
transient increases in pressure of more than 50 mmHg that propagate
almost always in anal direction (37). They are also called
high-amplitude propagating contractions or sequences (4).
- High- amplitude propagating pressure waves followed by simultaneous
pressure waves (HAPW-SPWs). A proximal HAPW can promptly switch to an
SPW at the transverse or descending colon (9) (37). The SPW within
this motor pattern is not pan-colonic.
- The colo-anal reflex: anal sphincter activity and its relaxation
associated with the motor patterns described above (37).