A Study To Evaluate The Maximal Dose Administration At Two Different Locations In Two Different VDR4 High Frequency Percussive Ventilator (HPFV) Circuits

Portland State University

The purpose of this study was to determine if the positioning of a nebulizer at two different locations in the VDR4, a specialty ventilator, would result in differing dose administrations of a bronchodilator, Albuterol Sulfate. We hypothesized that placement near the endotracheal tube will provide greater dose deposition. The ventilator was set up to mimic the normal adult patient. Administration was done through the nebulizer placed in the ventilator circuit either before the humidifier or between the endotracheal tube and the VDR 4’s Phasitron. Three trials were performed using a standard dose of Albuterol for each trial. The mass of the delivered dose was measured via UV spectrophotometry and the percent dose delivered was calculated. With the double limb circuit, the deposition to the end of the endotracheal tube was greater when the nebulizer was placed before the humidifier (8.6%), rather than near the endotracheal tube (5.2%). The single limb circuit showed contrasting results, with greater deposition when the nebulizer was placed near the endotracheal tube (3.65%), as compared to the placement pre-humidifier (2.62%). Particle size was shown to be at 4.6-4.9 VMD. Maximal dose was achieved between the two circuits when the Aerogen was placed before the humidifier using the double limb circuit. In contrary to our expectations, data showed medication delivery was greater when the nebulizer was placed before the humidifier in the double limb circuit. We hypothesize now that releasing the medication into the circuit where the air is already saturated with water may possibly decrease the uptake of medication.