The Science Journal of the American Association for Respiratory Care

2007 OPEN FORUM Abstracts

THE EFFECT OF USING A TIME LIMITED NEBULIZER DURING MECHANICAL VENTILATION ON THE AMOUNT OF MEDICATION DELIVERED FROM A SMALL VOLUME NEBULIZER IN A SIMULATED ADULT PATIENT

E. Italia1, A. Kurkowska1, T. Meade1, J. Iverson1, 2, J. Ciarlo1, 2, T. Blackson1, 2


Background: Numerous variables during aerosol medication delivery prevent the entire dose from reaching the lungs. A variable that has not been fully described in the literature is the effect that a timed nebulizer function has on dose delivery.
Purpose: To evaluate the amount of medication nebulized by the nebulizer function of (4) modern ventilators used to deliver a standard dose of Albuterol Sulfate (AS) and Ipratropium Bromide (IB).

Materials & Methods:
A Bear 1000 (B), Puritan Bennett 7200ae (PB), Drager E4 (D4), and Drager XL (DX) was used for testing. Prior to testing, each ventilator had its nebulizer function verified to insure that it met performance specifications. Four small volume nebulizers (SVN) were used and (3) tests were performed on each ventilator. Ventilators were set in the V-A/C mode (VT: 0.5L, RR: 12, PEEP: 5, PIFR: 70L/min, TI: 0.65sec, and FIO2: 0.21.). One circuit was used for all tests using humidified gas (37C). A unit dose of 0.5mg IB, diluted with NSS to a nominal volume of 2.5mL and 2.5mg of undiluted AS was used for each test. The volume and weight of medication and SVN were measured before and after each trial using a calibrated syringe and laboratory scale.

Results: No ventilator tested nebulized the entire dose in the time allotted. The D4, PB, DX, and B nebulized approximately 50% of the nebulizer fill volume, (47.6%, 51.1%, 49.7%, and 58.8% respectively). There was no significant difference in the amount of medication nebulized among ventilator brands tested, (p > 0.05).

Conclusions: The nebulizer function of the ventilators tested does not allow enough time for a standard dose of AS and IB to be delivered using one nebulizer activation. Approximately 50% of the nebulizer dose is not nebulized regardless of ventilator brand.
Clinical Implications: Reliance on a pre-timed ventilator nebulizer to insure full delivery of aerosolized medications may not be prudent. Legal documentation of medication dosage delivered via a mechanical ventilator’s timed nebulizer function is complicated by failure to nebulize the prescribed dose using any of the ventilators tested. Aerosol medication preparations designed for delivery during spontaneous breathing may not be the best choice for delivery via mechanical ventilation. Further study is warranted.


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