Functional Comparison of Two Large Volume Nebulizers

Abstract

Background:

Bland aerosol therapy via large volume nebulizer remains a standard of care in tracheostomy patients (1). Our facility routinely provides care for > 20 tracheostomy patients on a daily basis, and respiratory care is solely responsible for all aspects of their tracheostomy care needs. After a recent product substitution, staff began to anecdotally report a negative quantitative and qualitative change in the sputum characteristics of their tracheostomy patients. Given the timing of these reports, the new product became immediately suspect. It was felt that the new large volume nebulizer was inferior to the old one, with reduced aerosol output being the cause of thicker and more tenacious secretions. Aerosol characteristics of both the old and new large volume nebulizer were not readily available. Our study set out to objectively evaluate both products.

Methods:

A bench study utilizing a hygrometer placed in line at the distal end of an aerosol circuit via a tee piece. This placement would evaluate function as aerosol was delivered. Standard large bore aerosol tubing was utilized. Outputs from the two nebulizers (Teleflex, Temecula, CA; AirLife, San Diego, CA) were sampled at varying flows and FIO₂ illustrated in Table 1. The minimal FIO₂ (0.28) was sampled, as was a 1:1 entrainment ratio at a FIO₂ of .60 and a maximal FIO₂ (no entrainment) for each device.

Results:

There was no statistically significant difference noted in the humidity level provided by either device again as noted in Table 1. Readily visible mist output was noted on all but one FIO₂/flow combination on one device. Ambient temperature (22.8 C) and RH (59%) were constant throughout the study.

Conclusions:

The product change occurred during the winter season, and ambient conditions from that time are not known and are thus unable to be duplicated. It is possible that the ambient conditions were the cause of the clinical concern and that the product substitution had no effect. It should be noted that the finer mist from the low flow/low FIO₂ combination more than likely contributed to the cause of the complaint(s). Reference: Egan’s Fundamentals of Respiratory Care, 9th Edition Disclosures: The authors claim no conflicts of interest in this research.