Defining the Reliability of Bladder Scan in Obese Patients with Postoperative Urinary Retention

Abstract

Introduction: Postoperative urinary retention (POUR) is a common problem. Patients are prophylactically catheterized to prevent detrusor damage and pain from bladder distention. This may result in unnecessary catheterization. Bladder scans are used to check for POUR before a patient is catheterized. There is a paucity of data pertaining to its reliability in postoperative obese patients. Methods: We prospectively collected data in postoperative patients in the surgical ward. Only postoperative patients were included. Patients were catheterized based on the clinical judgement of the treating physician. The nurses collected 5 bladder scan readings using a portable bladder scanner before catheterizing a patient and recording the volumes collected. The mean of bladder scan readings was compared with the volume collected during catheterization. Intraclass correlation coefficient (ICC) was used to judge reliability. Results: We collected data in 95 patients, and 62 (27 women, 35 men) were included in the final analysis. ICC in all subjects was 0.76 (95% CI, 0.63-0.85), indicating good reliability. ICC for 17 (27.9%) patients with a BMI >30 kg/m2 (Class I obesity), and 9 (14.8%) patients with a BMI >35 kg/m2 (Class II obesity) was 0.75 (95% CI, 0.61-0.84) in both the groups, suggesting good reliability with respect to correlation between the average of bladder scan measurements and volume collected during catheterization. Conclusion: The bladder scan is a reliable measure of urine volume and correlates well with catheterization volume. This holds true even in patients with obesity, both class I and II. This study emphasizes the reliability of bladder scan use before catheterization in postoperative patients irrespective of the BMI.