Effect of ventilator circuit changes on ventilator-associated pneumonia: a systematic review and meta-analysis.

BACKGROUND Recent guidelines concerning prevention of ventilator-associated pneumonia recommend that ventilator circuits should not be changed routinely, but in practice circuit changes at regular intervals persist. METHODS We searched the MEDLINE, EMBASE, and SCOPUS databases and reviewed citations to identify articles that reported the results of randomized controlled trials and sequential comparison studies that provided a clearly defined intervention of circuit changes (interval > or = 2 d) and the outcome measure of the development of ventilator-associated pneumonia in mechanically ventilated adult patients. Both authors independently assessed the validity of the included studies, and extracted data using a pre-designed data-collection form. We used a random-effect model to combine data from studies that compared circuit changes every 2 days versus every 7 days, and circuit changes at regular intervals versus no routine circuit change. RESULTS The search yielded 10 reports, which included 19,169 patients. Compared to patients exposed to circuit changes every 7 days, patients who received circuit changes every 2 days had a higher risk of ventilator-associated pneumonia (odds ratio 1.928, 95% confidence interval 1.080-3.443). Compared to no routine circuit change, changing the ventilator circuit at a 2-day or 7-day interval was associated with an odds ratio of 1.126 (95% confidence interval 0.793-1.599). There was a trend of reduced risk of pneumonia as circuit-change intervals were extended. CONCLUSIONS Frequent ventilator circuit changes are associated with a high risk of ventilator-associated pneumonia. No routine circuit change is safe and justified. Hospital infection-control policies and bedside practitioners should translate the evidence into clinical practice, if they haven't done so already.