Background: Aerosolized medications that have been used in infants receiving ventilatory support have not been shown to be effective clinically among the smallest patients. The aim of this study was to characterize the delivery of aerosolized albuterol sulfate in vitro under simulated neonatal ventilatory conditions using a novel ventilator circuit/patient interface connector.
Methods: A Babylog(®) ventilator (VN500(®); Draeger), a novel ventilator circuit/patient interface (VC) connector (Afectair(®); Discovery Laboratories, Inc.), a TwinStar(®) HME (Draeger) low-volume filter, and either a test lung (Draeger) or lung simulator ASL 5000(®) (IngmarMed) were used. Intermittent mandatory ventilation conditions were set to replicate the most typical ventilation conditions for premature infants. Continuous positive airway pressure was also used to measure aerosol delivery with active respiratory drive from the patient. Albuterol sulfate (0.5 mg/mL) was loaded into the drug reservoir of a Misty Finity(®) nebulizer (Airlife(®); Cardinal Health) and connected to the ventilator circuit either via a "T" connector as described by the manufacturer [standard of care (SoC)] or via the VC connector. Albuterol extracted from the filters was analyzed using qualified high-performance liquid chromatography. In addition, a laser diffraction spectrometry (Spraytec(®); Malvern) and white-light spectrometry (Welas model 2100; Palas GmbH) were used to determine particle size distribution (PSD).
Results: Compared with SoC, the amount of albuterol delivered using the VC connector was significantly greater (p<0.001) under simulated neonatal ventilatory conditions. Additionally, the PSD profile of albuterol sulfate delivered using the VC connector was more representative of the PSD profile directly from the nebulizer.
Conclusions: The use of the VC connector increased the delivery of albuterol sulfate and resulted in a PSD profile at the patient interface that is more consistent with the PSD profile of the selected nebulizer when compared with SoC. This VC connector may be a useful, new approach for the delivery of aerosolized medications to neonates requiring positive pressure ventilatory support.