Aerosol Delivery During Mechanical Ventilation: A Predictive In-Vitro Lung Model

Publisher Website
Google Scholar
Abstract
Objective: to compare aerosol delivery from a standard (Bennett) nebulizer, a submicronic (Ultravent) nebulizer, a metered dose inhaler (MDI) plus small holding chamber, and an MDI plus large holding chamber, using a laboratory model simulating a mechanically ventilated patient. Method: saline solution (for the nebulizers) and fenoterol MDI's were radiolabelled and the model set up. After 15 minutes nebulization, or after single puffs from MDI, 1 minute static images were taken of the filter (representing the 'lungs'). Radioactivity in the filter was then counted and expressed as a percentage of the initial radioactivity in the nebulizer, or per puff from MDI. Counts were also made of the endotracheal tube (ETT) and chamber in a subgroup of studies. Results: radioactivity delivered to the filter from MDI plus large chamber (30.3 ± 7.4%) (mean ± 1SD) and MDI plus small chamber (27.7 ± 5.1%) was significantly greater than from Bennett (4.6 ± 2.1%) and Ultravent (1.3 ± 0.4%) nebulizers. In experimen...