The Science Journal of the American Association for Respiratory Care

2004 OPEN FORUM Abstracts

Rationale for and Cost Implications of Changing Bubble Humidifier from Standard Use to PRN in Low-Flow Pediatric Applications.

Khris E. O’Brien, RRT. Children’s Hospital of Wisconsin, Milwaukee, WI

: Our pediatric institution has historically used bubble humidifiers for all low-flow oxygen systems. This is not standard practice in adult institutions. Patient incidents related to leakage in the disposable humidifier prompted us to question the practice in the pediatric patient population as small leaks may go undetected when used at low flows.

Method: Evidence-based literature searches were conducted. Causal factors related to patient incidents were reviewed. Two brands of bubble humidifiers were evaluated. Cost saving analysis was performed.

Results: Our evidence based literature search revealed no data that proved the necessity of a bubble humidifier with low-flows. The incidents which caused us to evaluate our practice involved patients that were receiving oxygen via nasal cannula at less than 3 LPM. While no harm came to the patients, oxygen flows were increased based on patient’s low pulse oximeter saturation readings. The patients were changed to low flow oxygen directly from a nipple adaptor, resulting in an immediate improvement in pulse oximeter saturation readings and the ability to decrease the oxygen flow. Evaluation of the patient’s humidifiers revealed that the pop-off would often not sound at the prescribed liter-flow. Allegiance Humidification Kit #2D0803 is manufactured to pop off at 2 psi; Allegiance Humidifier Kit #002620 is manufactured to pop off at 4 psi. The manufacturer recommends testing the pop off at 4 LPM. Both humidifiers revealed similar failures due to small leakage at low flows, although Kit #002620 had fewer failure occurrences. The pop-off often sounded at higher flows >4 LPM, but would not sound when at a lower prescribed liter flow. Some did not sound even at the higher flows. Failure was often not evident upon set-up, but was generally noted within several shifts. While not every humidifier failed, failure was unpredictable. Beginning January 2003, the hospital instituted procedure changes which allowed for optional use of a bubble humidifier for flows less than 4 LPM. Whenever the bubble humidifier is used, the pop-off function is assessed upon set-up and every shift. Cost savings analysis comparing 18 months prior to and 18 months post the procedure change has revealed a cost savings of $7,651.00. Total usage decreased from 8,073 to 2247 during the 18 month period. This analysis does not include time savings related to counting, stocking or storage space savings.

Conclusions: Low-flow bubble humidifiers are only used upon parent/patient request or nasal irritation at Children’s Hospital of Wisconsin. Bubble humidifiers continue to be used for all higher-flow applications (greater than 4 LPM). Since instituting the procedure changes, complications related to humidifier malfunction have been rare and cost savings continue to increase. Further evaluation may be warranted regarding patient comfort, additional brands of bubble humidifiers and the necessity for bubble humidifiers at low-flows in the pediatric population.