Effect of tidal volume and nebulizer type and position on Albuterol delivery in a pediatric model of mechanical ventilation

Abstract

BACKGROUND: Optimization of factors affecting aerosol delivery during mechanical ventilation in the pediatric population is important. We hypothesized that increasing the tidal volume (VT), using a vibrating mesh nebulizer, and placing the nebulizer at the ventilator would increase lung dose/delivery efficiency. METHODS: Continuous-output jet and vibrating mesh nebulizers loaded with albuterol (2.5 mg/3 mL) were compared when placed before the Y-piece and at the ventilator. The model consisted of a ventilator operated in pressure-regulated volume control ventilation mode at a breathing frequency of 20 breaths/min, PEEP of 5 cm H2O, FIO2 of 0.4, inspiratory time of 0.75 s, and bias flow of 0.5 L/min with a humidifier (37 ± 1.5°C) and an adult heated-wired circuit. VT values of 100, 150, 200, and 300 mL were studied. The circuit was connected in series to a 5.5-mm inner diameter endotracheal tube with a filter (lung dose) interposed between them. Delivery efficiency was calculated as a percentage of the nominal dose captured on the filter. Albuterol content was analyzed by spectrophotometry (276 nm). RESULTS: No differences in lung dose/delivery efficiency were found at different VT values for the jet nebulizer (both positions) and the vibrating mesh nebulizer (ventilator). Lung dose/delivery efficiency was higher (P