The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

AIRWAY PRESSURE RELEASE VENTILATION IMPROVES VENTILATION/OXYGENATION USING LOWER PEAK INSPIRATORY PRESSURES IN PREMATURE NEONATES WITH RESPIRATORY FAILURE

Alan M. Fujii1, Kunal Sampat1,Daniel Gavin1



Background: Premature Neonates with respiratory distress syndrome requiring conventional mechanical ventilation may require high airway pressure and FiO2. We describe our experience with airway pressure release ventilation (APRV on an Evita XL, Drager®, Lubeck, Germany), used as a rescue ventilation mode in premature newborns with respiratory failure. APRV applies a prolonged elevated airway pressure (Phi) for a time interval (Thi) to maintain adequate lung volumes and promote alveolar recruitment, analogous to continuous positive airway pressure or high frequency oscillatory ventilation. APRV adds a time-cycled "pressure release" phase (Plo), commonly to 0 cm H20, for a brief time interval (Tlo), usually 0.2 seconds, to facilitate CO2 removal. The neonate's spontaneous respirations are utilized at an optimized lung volume, while pressure release provides a second mechanism for CO2 removal. We report our experience with APRV rescue in 7 premature infants with severe pulmonary disease.

Results:
We utilized APRV ventilation in 7 patients with a birth weight 788 ± 73 grams (mean ± SEM), and gestational age 25.2 ± 0.4 weeks. The patients were supported with SIMV or high frequency ventilation with peak inspiratory pressure 22.6 ± 1.5 cm H20 at a post-natal age 21.0 ± 4.2 days when APRV was started. Baseline pCO2 was 62.9 ± 2.6 mmHg and FiO2 68.3 ± 8.8 %. After institution of APRV, the pCO2 declined by 11.8 ± 3.0 mmHg (P = 0.01) and FiO2 declined by 29.9 ± 9.6 % (P = 0.03), while Phi was decreased by 9.6 ± 1.1 cm H20 (P< 0.01), over the course of 9.7 ± 3.2 hours. Anecdotally, one patient who was deemed clinically unstable on high frequency JET ventilation stabilized on APRV.

Discussion:
We report a small case series of extremely premature infants with respiratory failure who were successfully managed using APRV. APRV achieved adequate mechanical ventilation in these infants, lowering pCO2,and FiO2, at a lower peak inspiratory (Phi) pressure. No adverse events occurred on this ventilator setting.