The infusion method trial of void vs standard catheter removal in the outpatient setting: a prospective randomized trial

Abstract

• To ascertain if filling the bladder with warm normal saline before trial of void (TOV) reduces time to decision of outcome of TOV and time to discharge compared with standard in-dwelling catheter (IDC) removal in the outpatient setting. • A prospective randomized controlled trial (not blinded) was carried out in the day procedure unit. Randomization was done using computer-generated random numbers. The sample size was calculated based on initial pilot data using α= 0.05 and β= 0.2 and a clinically important reduction of ≥60 min for time to decision of outcome of TOV (primary outcome measure). • In all, 60 consecutive patients were recruited from two referral sources: presentations of acute urinary retention to the emergency department and patients discharged home after failing TOV postoperatively. • The infusion method group (32 patients) had 300-500 mL warm normal saline infused into the bladder before removing their IDC and the control group (28) had standard IDC removal. • Data were collected and analysed using the two-tailed Mann-Whitney U-test. Statistical significance was set at P < 0.05. • The median time to decision was 135.0 (95% confidence interval CI 95.0-190.0) min in the infusion group and 247.5 (95% CI 189.6-294.1) min in the control group. • Patients undergoing a bladder infusion had a shorter discharge time [180.0 (95% CI 126.0-226.9) min] than patients in the standard-IDC-removal group [262.5 (95% CI 233.8-315.0) min]. • The infusion arm shortened time to decision by 112.5 min (P < 0.001) and time to discharge by 82.5 min (P < 0.001). • Furthermore, patients in the infusion group were 1.56 times more likely to achieve catheter-free state after TOV (risk ratio 1.56, 95% CI 1.03-2.36; P= 0.03). • The infusion method for TOV is safe and expeditious, making it ideal for the outpatient setting. This randomized study shows that the infusion method enables a rapid determination of outcome of TOV with a greater chance of success and shortened discharge times.