The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

ILOPROST DRUG DELIVERY DURING INFANT MECHANICAL VENTILATION: INFLUENCE OF NEBULIZER POSITION DURING CONVENTIONAL AND HIGH FREQUENCY VENTILATION.

Rob DiBlasi1,2, Shuijie Shen1, Dave Crotwell2, John Salyer2, Tara Mahaffey3, Delphine Yung4; 1Center for Developmental Therapeutics, Seattle Children’s Research Institute, Seattle, WA; 2Respiratory Care Department, Seattle Children’s Hospital, Seattle, WA; 3Respiratory Care Department, Harborview Medical Center, Seattle, WA; 4Department of Pediatrics, University of Washington, Seattle, WA

INTRODUCTION: Iloprost Inhalation Solution is a selective pulmonary vasodilator that has been used in critically ill neonates with hypoxic lung disease and pulmonary hypertension. There are currently no recommendations for selecting aerosol delivery devices or how those devices should be configured to efficiently deliver Iloprost during mechanical ventilation. Moreover, many clinicians are hesitant to deliver aerosolized drugs during high frequency oscillatory ventilation (HFOV) because it is believed that medication delivery is negligible due to the small volumes, short inspiratory times and high gas flows used with this form of ventilation. We designed studies in vitro to test the hypothesis that there were no differences in drug delivery between conventional and HFOV, testing two different nebulizer locations with each ventilator. METHODS: A neonatal test lung model (ASL 5000, Ingmar Medical) was configured with compliance 1.0 mL/cmH2O and resistance: 50 cmH2O/L/s. The lung model was ventilated with a conventional ventilator and HFOV with standard settings and heated-humidification (39°C) connected to a 3.5 Fr ET- tube. The Aeroneb Pro® (Aerogen, Galeway, Ireland) was tested in two different locations: 1) between the patient wye and the ET-tube (Proximal) and 2) between the ventilator and humidifier (Distal). Iloprost (30 mcg) was nebulized in three trials with three new nebulizers in each of the circuit locations. A filter was placed at the distal end of the ET- tube for each trial. Iloprost was recovered by eluting the filter with ethanol and quantified using high pressure liquid chromatography. Differences between mean drug mass were compared at each condition using ANOVA with Tukey post-hoc tests. Significance was determined as p < 0.05. RESULTS: During conventional and HFOV, drug delivery was greater with the nebulizer placed in the proximal position compared to the distal position (p < 0.05). There was nearly a 3-fold greater increase in drug delivery during HFOV than conventional ventilation (Figure). DISCUSSION/CONCLUSIONS: Iloprost drug delivery is best achieved when the nebulizer is placed between the ET tube and patient-wye during neonatal mechanical ventilation. Future investigations will be needed to better understand why drug delivery appears to be more efficient during HFOV than conventional ventilation. Sponsored Research - Actelion provide Iloprost drug for this study.