1999 OPEN FORUM Abstracts

FIRING A METERED-DOSE INHALER AWAY FROM THE PATIENT REDUCES AEROSOL DELIVERY DURING MECHANICAL VENTILATION

J B Fink, MS, RRT, M. Goode, MD, R. Dhand, MD. Div of Pulm and Crit Care Med, Hines VA Hospital, Loyola Stritch School of Med, Hines, IL.

Background: Several actuator devices for delivering aerosol from metered-dose inhalers (MDI) during mechanical ventilation are designed to direct the ?plume? of aerosol away from the patient, into the oncoming inspiratory gas flow.

Methods: To determine whether directing the plume from the MDI away from the patient improves aerosol delivery, four puffs of albuterol (360mg) were administered from a MDI containing albuterol (Ventolin, Glaxo) into 6 brands of spacer/actuator (Allegiance Unidirectional, Hudson inline, ACE, OptiVent, MediSpacer, AeroChamber MV) during mechanical ventilation (VT 800 ml, peak flow 40 L/min, rate 12/min), under dry conditions. Each device was placed in the inspiratory limb of the ventilation circuit, with the plume directed toward or away from the patient airway. Delivery of albuterol (% of nominal dose (SE) to the bronchi of an intubated (8.0 mm ETT) tracheo-bronchi model was determined.

Results: Firing the MDI towards the patient improved aerosol delivery to the bronchi with each device tested. Conclusion: During mechanical ventilation, all devices tested delivered more albuterol to the bronchi when the output of the MDI was directed towards the patient. Devices designed to fire the plume away from the patient (ACE, Optivent, Medispacer) were more efficient when directing the MDI output towards the patient.

OF-99-177