McKinney TB, et al. - Experts sought to compare the air-charged (AC) and water-perfused (WP) catheters for differences in measuring pressures for voiding dysfunction. They assessed the patients with empty bladders and at volumes of 50-100 mL, 200 mL, and maximum capacity with cough and Valsalva maneuvers. Findings suggested that similarly accurate results were yielded by cystometrogram and maximum voiding pressure measurements done with either water or air charged catheters and were seen to be comparable. More variability was noted at low bladder volumes <50 mL.