The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

SECONDHAND AEROSOL EXPOSURE DURING MECHANICAL VENTILATION WITH AND WITHOUT EXPIRATORY FILTERS: AN IN-VITRO STUDY.

Arzu Ari1, James B. Fink1, Robert Harwood1, Beverly Williams1, Sue Pilbeam2; 1Georgia State University, Atlanta, GA; 2Maquet Inc, Wayne, NJ

Abstract body: Background: Concerns have been expressed about the risk of exposure to exhaled aerosols to clinicians and patients in the ICU. However research is limited. The purpose of this study was to quantify the amount of aerosol collected at the exhaust outlet of mechanical ventilators operated with and without filters in the expiratory limb. Methods: Ventilators tested in this study were divided into two categories: (1) Ventilators without Proprietary Filters: The Servo-i (Maquet) and Galileo (Hamilton) and (2) Ventilator with proprietary filters: PB 840 (Covidien). Each ventilator was attached to a simple test lung and operated at adult parameters (Vt 500 ml, RR 20 bpm, PIF 50 L/min, PEEP 5 cmH2O). Four separate doses of albuterol (2.5 mg/3mL) were administered via jet nebulizer (eValueMed, Tri-anim) placed at the “Y”. In Experiment A, a filter (Respirgard 303) was placed at the exhaust port. In Experiment B, two filters were attached to the ventilators without proprietary filters: (1) at the end of the expiratory limb and (2) at the exhaust outlet. Drug was eluted from filters and measured using spectrophotometry (276 nm). Descriptive statistics, independent samples t test and one way analysis of variance (ANOVA) were conducted to compare the amount of aerosol exiting from the exhaust filter of each ventilator. p<0.05 was considered statistically significant. Results: Table below shows % of total drug (mean ± SD) deposited. Drug deposited at the exhaust port without expiratory filter was >160 fold higher than with ventilator with the proprietary filter. Although the Respirgard filter was less efficient than the proprietary filter designed for use with the ventilator, placement in the expiratory limb reduced secondhand aerosol exposure significantly (p<0.05). Conclusion: Risk of exposure to secondhand or exhaled aerosol can account for > 45% of nominal dose as well as droplet nuclei produced by patients. Use of ventilators without expiratory filters increases the risk of exposure to aerosol released to atmosphere from the ventilator. Sponsored Research - None