Intra- and inter-raters reliability and concordance in the evaluation of perineal pressure in nulliparous

Abstract

AIMS: To verify intra and inter-rater reliability and concordance in the assessment of perineal pressure in nulliparous women. METHODS: Young, healthy, nulliparous, non-pregnant women who had had sexual intercourse and had a correct contraction of the perineal musculature on physical examination were included. Women were excluded if they used other muscles in a visually perceptible way during the perineal contraction; with changes in the pelvic muscles tone; with urinary incontinence; with cognitive alterations; with disease that could affect the muscular and nervous tissues; or practitioners of high-impact physical activity. The participants were submitted to two assessments of perineal pressure on the same day, with different evaluators. After one week the protocol was repeated. Perineal pressure was determined by means of a perineometer and obtained by the difference between the maximum pressure (Pmax) and the minimum pressure (Pmin) recorded by the device, in millimeters of mercury. Sustained contraction (SC) was evaluated by the time in seconds. In order to determine reliability, the intraclass correlation coefficient (ICC) was used. Bland-Altman test was used for the concordance analysis. Comparison of means was performed by the Wilcoxon test. A value of p≤0.05 was considered significant. RESULTS: Ten participants were included, with a mean age of 23.8±2.9 years and a body mass index of 22.2±1.8 kg/m2. The evaluator A obtained excellent intra-rater reliability for Pmin (ICC=0.86, p<0.01) and Pmax (ICC=0.92, p<0.01); very good reliability for perineal pressure (ICC=0.65, p=0.01); and no statistical significance for SC. For evaluator B, there was no statistical significance for Pmin and Pmax, but there was very good reliability for perineal pressure (ICC=0.78, p<0.01) and SC (ICC=0.70, p<0.01). In the inter-rater analysis (A vs B), on day 1 there was no statistical significance for Pmin, Pmax and perineal pressure; but there was very good reliability for SC (ICC=0.71, p<0.01). On day 2, there was no statistical significance for Pmin and Pmax, but there was very good reliability for perineal pressure (ICC=0.62, p=0.02) and good for SC (ICC=0.56, p=0.03). There was agreement between intra and inter-rater measurements. CONCLUSIONS: Perineal pressure measurements showed very good intra-rater reliability and good to very good inter-rater reliability, with intra and inter-rater concordance.