Dropped abdominal pressure at void in women

Abstract

Introduction and hypothesis: "Dropped p_abd at void" occurs when p_abd decreases below the previous resting pressure during voiding time. We sought clinical factors associated with this phenomenon and evaluated whether its correction modifies the urodynamic diagnosis.

Methods: Retrospective cross-sectional study of non-neurological consecutive symptomatic women. The following definitions were used: "dropped p_abd at void": decrease in p_abd at Q_max ≥ 5 cmH₂O; bladder outflow obstruction (BOO) (p_detQmax ≥ 25 cmH₂O + Q_max ≤ 12 ml/s and female BOO index (p_detQmax - 2.2*Q_max) > 18; "low detrusor contraction strength": PIP1 (p_detQmax + Q_max) < 30. In patients with "dropped p_abd at void", p_detQmax was corrected.

Results: A total of 360 women were analyzed. Ninety-five percent of the women had a variation in p_abd at Q_max between -13 and 53 cmH₂O. "Dropped p_abd at void" was found in 100 women (27.8%). History of stress urinary incontinence (SUI) surgery was significantly higher (p = 0.016) and symptoms of mixed urinary incontinence were significantly lower (p = 0.030) in patients with "dropped p_abd at void". On multivariate analysis only the history of SUI surgery maintained its significance (OR = 1.787 [95% CI: 1.058, 3.017], p = 0.030). When correcting p_detQmax in women with "dropped p_abd at void", 2 or 5 patients lost BOO diagnosis (depending on how it was diagnosed) and 7 patients gained a "low detrusor contraction strength" diagnosis.

Conclusions: Approximately one-quarter of women had "dropped p_abd at void", which was associated with a history of SUI surgery. Correction of p_detQmax would lead to a 2.5% to 3.33% diagnostic modification.

Keywords: Abdominal pressure; Micturition; Urodynamics; Women.