Influence of the examination position and distension medium on the rectal sensory test in patients with functional constipation

Purpose: To evaluate the impact of two different parameters (body position and distension medium) on the rectal sensory test in patients with functional constipation and provide data support for the development of standardized operating procedures in clinical practice. Methods: Based on a single-center process of the rectal sensory test, 39 patients with functional constipation were recruited for rectal sensory test under different body positions and distension mediums. Results: Among the items of the Constipation Scoring System, the score of frequency of bowel movements showed a negative correlation with the first constant sensation volume (r = -0.323, P = 0.045). Conversely, the score of painful evacuation effort showed a positive correlation with the desire to defecate volume (r = 0.343, P = 0.033). There was a statistically significant difference in the first constant sensation volume (when the distension medium was gas) measured in different body positions (left lateral position, sitting position, squatting position), and the data measured in the squatting position were significantly higher than those in left lateral position (P < 0.05). In terms of research on distension medium, it was found that the first constant sensation volume measured in the squatting position (when the distension medium was water) was significantly lower than that of gas (P < 0.05). Conclusion: For patients with functional constipation, there are differences in the results of rectal sensory tests between body positions and distension mediums. When conducting multicenter studies, it is necessary to unify the standard operating procedure (SOP) for operational details to ensure consistency and reliability of the test results.