In vitro evaluation of aerosol delivery by different nebulization modes in pediatric and adult mechanical ventilators

Abstract

BACKGROUND: Aerosol delivery through mechanical ventilation is influenced by the type of aerosol generator, pattern of nebulization, and a patient’s breathing pattern. This study compares the efficiency of pneumatic nebulization modes provided by a ventilator with adult and pediatric in vitro lung models. METHODS: Three pneumatic nebulization modes (inspiratory intermittent [IIM], continuous [CM], and expiratory intermittent [EIM]) provided by the Galileo Gold ventilator delivered medical aerosol to collection filters distal to an endotracheal tube with adult and pediatric test lungs. A unit dose of 5 mg/2.5 mL albuterol was diluted into 4 mL with distilled water and added to a jet nebulizer. The nebulizer was placed proximal to the ventilator, 15 cm from the inlet of the heated humidifier chamber with a T-piece and corrugated aerosol tubing and powered by gas from the ventilator in each of the 3 modes. Time for nebulization was recorded in minutes. Albuterol samples collected in the inhalation filter, nebulizer, T-piece, and corrugated tubing were eluted with distilled water and analyzed with a spectrophotometer. RESULTS: The inhaled drug, as a percentage of total dose in both lung models, was 5.1–7.5%, without statistical significance among the 3 modes. Median nebulization times for IIM, CM, and EIM were 38.9, 14.3, and 17.7 min, respectively, and nebulization time for the 3 modes significantly differed (P