Intravenous in-line filters: filtering the evidence

The routine use of intravenous in-line filters on infusion lines has been controversial for many years, with strong advocates, detractors and many fence-sitting observers. The purpose of this review was to examine the literature for new developments and to cast the net a little wider than in previous reviews in an attempt to draw useful parallels.

There were recent major policy statements or recommendations from a working party of the British Pharmaceutical Nutrition Group and from the US Centres for Disease Control. The first was focussed on filters and was broadly in favour, the second was not focussed on the subject but made quite a strong statement against, on microbiological issues alone. The major purpose of filters, however, is particulate contamination, and whilst there was little in the literature directly on this subject, useful parallels could be drawn from papers describing the therapeutic use of particles and also from their effects in intravenous drug users.

When all the available information is considered, and the role of filters in particulate contamination, in-line chemical precipitates, identifying problems in parenteral therapy practice, microbial contamination and entrapped air is examined, the case for routine use appears strong.