Weekly Versus Daily Changes of In-Line Suction Catheters: Impact on Rates of Ventilator-Associated Pneumonia and Associated Costs

BACKGROUND: An earlier randomized, controlled trial showed that weekly or as-needed (as opposed to daily) changes of in-line suction catheters were associated with substantial cost savings, without a higher rate of ventilator-associated pneumonia (VAP). To examine the impact of decreasing the frequency of in-line suction catheter changes in our medical intensive care unit, we conducted an observational study, comparing the catheter costs and frequency of VAP during (1) a control period, during which in-line suction catheters were changed daily, and (2) a treatment period, during which the catheters were changed every 7 days or sooner if needed, for mechanical failure or soilage.

METHODS: All adult patients admitted to our 18-bed medical intensive care unit were evaluated for the 3-month interval 1 year prior to the practice change (May through July 1998) and for the 3 months after implementing the new policy (May through July 1999). To avoid bias related to usual seasonal variation in VAP frequency, we also determined (via medical records) the VAP rate during May through July 1997. The occurrence of VAP was ascertained by an infection control practitioner, using criteria established by the Centers for Disease Control and applied in a standard fashion. The VAP rate was calculated as the mean number of VAPs per 100 ventilator-days for each 3-month interval. Use of ventilators, humidifiers, and non-heated-wire, disposable circuits was uniform during the study, as were policies regarding humidity, temperature settings, and frequency of routine ventilator circuit changes.

RESULTS: During the control period 146 patients accounted for 1,075 ventilator-days and there were 2 VAPs (0.19 VAPs per 100 ventilator-days). During the treatment period 143 patients accounted for 1,167 ventilator-days and there were no VAPs. The mean ± SD duration of in-line suction catheter use during the treatment period was 3.8 ± 0.8 days, and 51% of the patients had the same catheter in place for > 3 days (range 4-9 days). The actual cost of catheters used during the treatment period was lower than during the control period ($1,330 vs $6,026), predicting annual catheter cost savings of $18,782.

CONCLUSIONS: We conclude that (1) a policy of weekly (vs daily) change of in-line suction catheter is associated with substantial cost savings, with no significant increase in the frequency of VAP, and (2) to the extent that these findings confirm the results of prior studies they support a policy of changing in-line suction catheters weekly rather than daily.