Duration taken for the anal sphincter pressures to stabilize prior to anorectal manometry

Abstract

OBJECTIVES: Anorectal manometry (ARM) is an integral part of evaluating the anal sphincter function. The current recommendation of waiting for 5 min (lead-in-time) prior to beginning the recording has no evidence. A prolonged procedure may reduce patient compliance. RESULTS: We analyzed data from 100 consecutive patients who underwent 3-dimensional ARM at a single center. Their pressure studies were analyzed in consecutive 10-s segments, beginning from the time of insertion of the probe into the anal canal. We defined stabilization of the pressure as the absence of a pressure difference among two consecutive 10-s segments. The study population had 31 males. Their mean age was 33.0 years (SD-14.4). The mean time for the pressure to stabilize was 84.2 s (SD-29.5), range 17.2-203.7 s, 95th percentile 136.2 s. Eleven and one participant(s) took longer than 120 and 150 s for the pressure to stabilize, respectively. There was no correlation of sex (Mann-Whitney U test, p = 0.89) and the time to pressure stabilization. Age and the time to stabilize (Spearman rho - 0.246, p = 0.017) showed a weak negative correlation. A lead-in-time of 5 min, as recommended by present guidelines may be unnecessary. Waiting for 150 s/2½ min may be sufficient and will minimize the procedure duration.