The data from five trials comparing differing washout policies were sparse and trials were generally of poor quality or poorly reported. The evidence was too scanty to conclude whether or not washouts were beneficial. In the first instance we require further rigorous, high quality trials with adequate power to detect any benefit from washout being performed as opposed to none. Then trials comparing different washout solutions, washout volumes, frequencies/timings and routes of administration are needed.
Do catheter washouts extend patency time in long-term indwelling urethral catheters? A randomized controlled trial of acidic washout solution, normal saline washout, or standard care.
Blockage of long-term indwelling catheters with mineral deposit is an ongoing management issue, but evidence on optimal management is lacking. Our purpose was to examine whether catheter washouts prevent or reduce catheter blockage.
                A multisite randomized controlled trial.
                Adults with long-term indwelling catheters that required changing every 3 weeks or less, living in the community, and requiring supportive or continuing care were recruited. Participants were randomly assigned to 1 of 3 groups: control (usual care, no washout), saline washout, or commercially available acidic washout solution (Contisol Maelor Pharmaceuticals Ltd, Wrexham, UK).
                At baseline visit, the catheter was changed and participants were followed weekly for 8 weeks, with checks for catheter patency and urine pH. Participants randomized to saline or commercial solution had a weekly washout with the appropriate solution. Endpoints were 8 weeks (completion data), 3 or more catheter changes in the 8-week period, or symptomatic urinary tract infection (UTI) requiring antibiotics. The study hypothesis was that catheter life would be extended by 25% in the commercial solution group. It was not possible to blind participants or research nurses to washout versus no intervention, but participants in the saline and washout solution groups were blinded to solution type.
                One hundred twelve potential participants were screened; 73 were enrolled, randomized, and included in the final analysis. Of these, 53 completed the full 8 weeks of data collection; 16 terminated early because of 3 catheter changes or self-reported 'UTI'. Other reasons for termination were hematuria, latex sensitivity, deceased/severe illness, or personal choice. Analysis of variance was used to analyze mean differences on demographic variables and mean number of weeks in study. Kaplan-Meier survival curve analysis showed no statistical difference between the groups in time to first catheter change.
                At this time, the evidence is insufficient to state whether catheter washout with saline or Contisol is more effective than usual care with no washout in preventing blocking. No increased risk of UTI was associated with washout regimes.