SALBUTAMOL DELIVERY FROM A HYDROFLUOROALKANE PRESSURIZED METERED-DOSEINHALER IN PEDIATRIC VENTILATOR CIRCUITS - AN IN-VITRO STUDY

Study objectives: The aim of our study was to determine the in vitro d elivery of salbutamol from a pressurized metered-dose inhaler (pMDI) c ontaining hydrofluoroalkane (HFA) propellant through various delivery devices to four models of a pediatric lung, Design: To determine the e ffect of electrostatic charge, delivery of salbutamol was initially as sessed with a multistage liquid impinger (MSLI) through an inline nonc hamber device (Baxter MDI Adapter) and a small (Aerochamber MV) and a large (Nebuhaler) inline chamber device, Following this, the delivery was assessed to four lung models appropriate for a child of 70 kg, 50 kg, 15 kg, and 4 kg, with the same three reduced static devices insert ed directly into a pediatric ventilator circuit, Measurements and resu lts: Reduction of electrostatic charge improved small particle deliver y through holding chambers to the MSLI by 12 to 14%. In the ventilator model, the mean delivery was between 1.9% and 5.4% for the nonchamber device, between 14.3% and 27.2% for the small holding chamber, and be tween 7.2% and 25.7% for the large holding chamber. Delivery was the l east efficient in the 4-kg model compared to the 70-kg, 50-kg, and 15- kg models, Conclusions: Salbutamol from an HFA pMDI is delivered effic iently through inline holding chambers with reduced static in pediatri c ventilator settings, A large holding chamber has no advantage over a small holding chamber, In addition, salbutamol delivery is more effic ient through a holding chamber than through a nonchamber device.