The Science Journal of the American Association for Respiratory Care

2004 OPEN FORUM Abstracts

A Comparison of Oxygen concentration delivery by small volume nebulizers

Donna D. Gardner, MSHP, RRT; Richard B. Wettstein, BS, RRT; Jana Wallace, BSRT, CRT; Anna Hernandez-Sanchez, BSRT, CRT; David C. Shelledy, PhD, RRT; Jay I. Peters, MD. The University of Texas Health Science Center at San Antonio, San Antonio, Texas.

INTRODUCTION: Small volume nebulizers (SVN) are commonly powered by oxygen or medical air. A review of the literature did not find any expected oxygen concentration (OC) associated with SVN's. We determined the oxygen concentrations (OC) delivered by three different small volume nebulizers (Salter Labs, Hudson and Airlife) by measuring pharyngeal OC in 10 normal subjects at flows of 6, 8, and 10 L/min.

METHOD:
A nasal catheter was positioned with the tip in the pharynx immediately behind the uvula. Oxygen flow of 6 L/min was administered via mouth piece on the Salter Labs SVN. Three samples were taken while the subject breathed at their resting level. The subject was then asked to double their respiratory rate for one minute at which time a fourth sample was taken. The procedure was then repeated with the subject breathing through an aerosol mask. This whole process was replicated at each L flow and on each device.

RESULTS:
The mean (SD) for OC on all brands using the mouthpiece and mask during normal and rapid breathing at prescribed flow rates were:

  All Nebulizers with mouthpiece All Nebulizers with a Mask
Normal breathing Rapid breathing Normal breathing Rapid breathing
Flow L/Min Mean (SD) Mean (SD) Mean (SD) Mean (SD)
6 42 (11) 40 (11) 44 (11) 41 (12)
8 49 (14) 47 (15) 51 ( 14) 48 (15)
10 55 (14) 51 (15) 57 (15) 54 (14)

The mean OC delivered increased with each increase in liter flow (6, 8 and 10 L/min) for all brands using mouthpiece or mask during normal and rapid breathing.

CONCLUSION:
Our data found a mean pharyngeal OC delivered via SVN was 40% or greater on flows of 6, 8, or 10 L/min. This has clinical implications when delivering medication via small volume nebulizer powered by oxygen.

Departmental Funding

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