Background: Blockage of indwelling catheters in situ longer than 30 days is an ongoing management issue but evidence on amelioration is lacking.  In Canada, one strategy used by homecare nurses is saline catheter washouts; in the UK, another strategy is flushing with a commercially available catheter washout product consisting of citric acid 3.23%, light magnesium oxide 0.38%, sodium bicarbonate 0.7%, and disodium editate 0.01%.  Based on laboratory studies, it is believed that routine flushing with the sterile commercial solution prevents or reduces blockage events.  No randomized trials have been conducted to assess the product in the clinical care setting.  In this study, we  examined whether catheter washouts prevent catheter blockage.

Method: Multisite randomized controlled 3 group trial: control (usual care, no washout), saline washout, or commercial washout solution.  Adults with long term indwelling catheters with MMSE > 23 living in community, supportive, or continuing care were recruited.  At baseline visit, the catheter was changed followed by weekly home visits for 8 weeks, with checks for catheter patency, urine pH and catheter flush (depending on group assignment).  Endpoints were 8 weeks (completion date), three or more catheter changes in the 8 week period, or symptomatic urinary tract infection requiring antibiotics.

Results:  110 potential participants were screened; 74 were enrolled and randomized; 53 completed 8 weeks of data collection. Dropouts included 3 catheter changes or UTI (16), haematuria, latex sensitivity, deceased/severe illness, or personal choice. Using Kaplan-Meier survival curve analysis no statistical difference between the groups was found in time to first catheter change.

Conclusion/Implications: High attrition in the study means that current evidence remains insufficient to state whether catheter washout with saline or a commercially prepared product is more effective than usual care in preventing blocking.