The Science Journal of the American Association for Respiratory Care

1995 OPEN FORUM Abstracts

AN EVALUATION OF O2 BLEED RATES WITH THREE DIFFERENT BRANDS OF BLENDERS

Julie Ballard BS, RRT and John Salyer BS, RRT. Primary Children's Medical Center, Salt Lake City, Utah.

Introduction: We sought to determine the amount of O2 that is wasted due to bleed by three brands of blenders.

Methods: We tested 10 Sechrist Air-Oxygen Mixers Model 3500 HL, 11 Bird Low Flow Microblenders Model 3920, and 3 Bio-Med Low Flow Air/Oxygen Blenders Model 2003. We attached the blenders to a piped in source of air, and an E-cylinder of O2 via the same preset two-stage regulator(Veriflow). Each run consisted of attaching the blender to the gas sources, leaving all flow meters turned off, checking all fittings for leaks using a sudsy solution, and recording the psi in the E-cylinder. The system was then left attached to the gas sources for [approx] 1 hour, at the end of which the psi and the time elapsed were recorded. Two of the blenders were equipped with detachable auxiliary flow meters for flow ratesɛ L/m. These were tested with and without the flow meters attached. We then computed flow per minute for each blender according to this formula: (psi x 0.28)/elapsed time in minutes = liters of O2 bleed per minute where psi was the pressure difference in the E-cylinder between the start and finish of each run. Results for each blender type were then averaged and tested for statistical significance using ANOVA factorial with significance set at P < 0.05.

Results: We found statistically significant and financially important differences between the amount of O2 wasted by the different blenders. Results are in the figure below.

SEE ORIGINAL GRAPH

Discussion: The table below lists the potential costs per blender per day assuming our cost of O2 at $.533/100 ft³ and 28.3 L/100 ft^3.

Daily Cost Yearly Cost

Sechrist $1.71 $624.15

Bird AF $.61$222.65

Bio-Med AF $0.43 $156.95

Clearly, leaving blenders plugged in continuously with auxiliary flow meters attached contributes significantly to costs. In our 35 bed NICU where Sechrist blenders are used. this amounts to [approx] $21,845 per year.

OF-95-138

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