Comparison of manual and ultrasonographic evaluation of bladder size in patients prior to laparoscopy

Catheterization of the bladder may reduce laparoscopic complications although an enlarged bladder may be impalpable in overweight patients or following previous lower abdominal surgery. This study assessed bladder size by manual examination and transcutaneous ultrasound (US). Consecutive patients (n = 90; median age 55 years [20-85]; 61 females) undergoing laparoscopy were studied prospectively. All patients voided preoperatively and catheterization was performed if estimated US bladder volumes exceeded 300 ml. Manual assessment failed to detect bladder enlargement in any patients (sensitivity: 0%; specificity: 4.4%), whereas ultrasound identified four patients at risk of bladder injury due to unsuspected enlargement (4.4%). Three of these patients were either overweight or obese and one patient had previous lower abdominal surgery. Of 12 patients (13%) catheterized, three had or developed urinary tract infections. Preoperative voiding does not guarantee bladder emptying. Manual examination does not detect bladder enlargement reliably in the obese patient. Ultrasonography may improve patient selection for catheterization.