ABSTRACT
OBJECTIVES: To determine the feasibility of delivering inhaled treprostinil during mechanical ventilation and spontaneous unassisted ventilation using the Tyvaso Inhalation System and the vibrating mesh nebulizer. We sought to compare differences in fine particle fraction, and absolute inhaled treprostinil mass delivered to neonatal, pediatric, and adult models affixed with a face mask, conventional, and high-frequency ventilation between Tyvaso Inhalation System and with different nebulizer locations between Tyvaso Inhalation System and vibrating mesh nebulizer. DESIGN: Fine particle fraction was first determined via impaction with both the Tyvaso Inhalation System and vibrating mesh nebulizer. Next, a test lung configured with neonatal, pediatric, and adult mechanics and a filter to capture medication was attached to a realistic face model during spontaneous breathing or an endotracheal tube during conventional ventilation and high-frequency oscillator ventilator. Inhaled treprostinil was then nebulized with both the Tyvaso Inhalation System and vibrating mesh nebulizer, and the filter was analyzed via high-performance liquid chromatography. Testing was done in triplicate. Independent two-sample t tests were used to compare mean fine particle fraction and inhaled mass between devices. Analysis of variance with Tukey post hoc tests were used to compare within device differences. SETTING: Academic children's hospital aerosol research laboratory. MEASUREMENTS AND MAIN RESULTS: Fine particle fraction was not different between the Tyvaso Inhalation System and vibrating mesh nebulizer (0.78 ± 0.04 vs 0.77 ± 0.08, respectively; p = 0.79). The vibrating mesh nebulizer delivered the same or greater inhaled treprostinil than the Tyvaso Inhalation System in every simulated model and condition. When using the vibrating mesh nebulizer, delivery was highest when using high-frequency oscillator ventilator in the neonatal and pediatric models, and with the nebulizer in the distal position in the adult model. CONCLUSIONS: The vibrating mesh nebulizer is a suitable alternative to the Tyvaso Inhalation System for inhaled treprostinil delivery. Fine particle fraction is similar between devices, and vibrating mesh nebulizer delivery meets or exceeds delivery of the Tyvaso Inhalation System. Delivery for infants and children during high-frequency oscillator ventilator with the vibrating mesh nebulizer may result in higher than expected dosages.
Subject(s)
Antihypertensive Agents/administration & dosage , Drug Delivery Systems/instrumentation , Epoprostenol/analogs & derivatives , Hypertension, Pulmonary/therapy , Nebulizers and Vaporizers , Respiration, Artificial , Administration, Inhalation , Adult , Aerosols , Antihypertensive Agents/therapeutic use , Child , Child, Preschool , Combined Modality Therapy , Epoprostenol/administration & dosage , Epoprostenol/therapeutic use , Feasibility Studies , Humans , Infant, Newborn , Models, Anatomic , Particle Size , VibrationABSTRACT
Acute pulmonary vasodilator testing (AVT) is essential to determining the initial therapy for children with pulmonary arterial hypertension (PAH). This study aimed to report the initial experience with inhaled treprostinil used for AVT in children with PAH and to evaluate the hemodynamic change after inhaled treprostinil compared with inhaled nitric oxide. This prospective cohort study was designed for 13 children who underwent AVT with inhaled treprostinil or oxygen plus inhaled nitric oxide (iNO) during catheterization. Inhaled treprostinil was delivered during cardiac catheterization by adapting the Optineb ultrasonic nebulizer via either a flow-inflating bag or the manual mode of the anesthesia system. The median age of the patients was 10 years (range 4-17 years). The etiologies of PAH included idiopathic PAH and associated PAH. All the patients tolerated inhaled treprostinil without marked clinical worsening and received six or nine breaths (36 or 54 µg) of treprostinil. The median of the total treprostinil doses was 1.53 µg/kg (range 0.71-2.89 µg/kg). Inhaled treprostinil was administrated via an endotracheal tube (n = 8), anesthesia mask (n = 3), or laryngeal mask airway (n = 2). Inhaled nitric oxide (iNO) and inhaled treprostinil significantly decreased the mean pulmonary artery pressure and the pulmonary vascular resistance index compared with baseline. Three adverse events were reported after inhaled treprostinil, including cough and mild to moderate hypotension with higher doses. All adverse events resolved without any intervention. This study report is the first to describe the use of inhaled treprostinil for AVT in children with PAH. In this small pediatric cohort, inhaled treprostinil was effectively delivered and well tolerated and may be useful for AVT.
