Abstract
Background: Drug delivery on ventilator circuits is difficult to control. In recent studies, our group has compared modern commercial nebulizers to breath enhanced technology (BET) with the goal of controlled drug delivery at all ventilator settings with and without humidification. Published studies revealed that BET successfully delivered controlled doses of drug with and without humidification. However, previous humidified experiments were performed with the nebulizer located on the “wet” side of the humidifier. A recent report found that this location is not tenable for any nebulizer because of excess condensation. The present study tested BET with the device located on the “dry” side of the humidifier.
Methods: Using radiolabeled saline, in vitro inhaled mass (IM) and mass balance were measured in a conventional ventilator circuit (Vyaire Avea connected to 2 1-L test lungs) and humidified with an F&P MR-850 humidifier. An InspiRx i-AIRE prototype nebulizer was connected to the inspiratory port of the ventilator. This nebulizer is designed to remain in place between treatments with drug added via a capped side port. All ventilator gas passed through the nebulizer (breath-enhancement) and the nebulizer was powered by medical air at 3.5 and 5 L/min. Low (0.13) and high (0.34) duty cycles were tested at fill volumes of 3 and 6 mL.
Results: IM ranged from 12-26% of nebulizer charge. Humidifier losses were negligible (3-5%). Circuit and ET tube losses totaled 15%. The major factor affecting delivery was nebulizer residual (30-50%) which was reduced to 30% with 5 L/min flow and 6 mL fill volume. Delivery data were similar to previously reported non-humidified BET nebulization.
Conclusions: For breath-enhanced nebulization, the dry side location allows controlled drug delivery defined by nebulizer flow and fill volume during humidification with heated wire circuits. Condensation and humidifier losses were not observed.
Footnotes
Commercial Relationships: Mr. McPeck no disclosures. Cuccia serves as a consultant to InspiRx, Inc. Dr. Smaldone serves as a consultant and member of the advisory board of InspiRx, Inc.
Support: This study was sponsored in part by InspiRx, Inc. Stony Brook University holds patents licensed to InspiRx.
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