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
Background:
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.
