Assessment of in-line filters to prolong the life of intravenous cannulae in cystic fibrosis patients.

Twelve patients with cystic fibrosis received 12 courses of intravenous antibiotics, each over 10-14 days, both with and without the use of an extended-life disposable filter. The design of the trial was to replace the Venflon cannulae as they became non-patent and inserting a filter on alternate occasions. Thus each patient acted as her/his own control. Comparison of times during which cannulae remained patent showed a 50% improvement with use of a filter for 4 patients and no change for 7 patients. There was no significant difference associated with the use of a filter for the group as a whole but our small sample size excludes modest improvements.