Optimizing techniques for measuring anal resting and squeeze pressures with high-resolution manometry.

Abstract

The optimal methods for measuring and analyzing anal resting and squeeze pressure with high-resolution manometry (HRM) are unclear. Anal resting and squeeze pressures were measured with HRM in 90healthy women, 35 women with defecatory disorders (DD), and 85 with fecal incontinence (FI). Pressures were analyzed with Manoview™ software and a customized approach. Resting pressures measured for 20, 60, and 300s were compared. During the squeeze period, (3 maneuvers, 20s each), the squeeze increment, which was averaged over 5, 10, 15, and 20s, and squeeze duration were evaluated. Compared to healthy women, the anal resting pressure, squeeze pressure increment, and squeeze duration were lower in FI (p≤0.04) but not in DD. The 20, 60, and 300s resting pressures were strongly correlated (concordance correlation coefficients=0.96-0.99) in healthy and DD women. The 5s squeeze increment was the greatest; 10, 15, and 20s values were progressively lower (p<0.001). The squeeze pressure increment and duration differed (p<0.01) among the three maneuvers in healthy and DD women but not in FI women. The upper 95th percentile limit for squeeze duration was 19.5s in controls, 19.9s in DD, and 19.3s in FI. Adjusted for age, resting pressure, and squeeze duration, a greater squeeze increment was associated with a lower risk of FI versus health (OR, 0.96; 95% CI, 0.94-0.97). These findings suggest that anal resting and squeeze pressures can be accurately measured over 20s. In most patients, one squeeze maneuver is probably sufficient.