Feasibility of airway pressure release ventilation in infants with near end stage- neonatal bronchopulmonary dysplasia

Abstract

Background: Ventilated premature infants with severe, advanced bronchopulmonary dysplasia (BPD) often require high mean airway pressure (MAP) and FiO2 to maintain acceptable gas exchange using conventional mechanical ventilation techniques such as synchronized intermittent mandatory ventilation (SIMV). In addition, they are at risk to develop ep isodes of severe respiratory failure (BPD spells). We report our experience with airway pressure release ventilation (APRV), a ventilation modality which allows spontaneous respiration during a relatively long high pressure phase followed by a shorter release period allowing for CO2 removal from the conducting airways. Despite the higher MAP, the unique APRV flow pattern is thought to decrease volutrauma. Objective: To determine the feasibility and safety of APRV in neonates with severe BPD. Design/methods: Approval for this retrospective review was obtained from Childrens Hospital Los Angeles (CHLA) Institutional Review Board. Patients with advanced BPD treated in the Newborn and Infant Critical Care Unit at CHLA that received APRV at the discretion of the attending neonatologist for develo ping severe respiratory failure between May 2004 and June 2005 were identified and their medical records reviewed. Results: Nine patients were placed on APRV using the AVEA ventilator (CareFusion, San Diego, CA). Eight infants were former extremely premature infants with severe BPD and 1 infant was born at term infant with suspected surfactant protein-B defi ciency. Mean gestational and postmenstrual age was 26.7± 4.9 and 50.5± 9.8 weeks, respectively at the time of initiation of APRV. The duration of APRV was 17.5± 11.9 days. On APRV, patients received higher MAP (29 vs. 15 cm H2O; p < 0.001) and lower FiO2 (0.5 vs. 0.3; p = 0.38) compared to SIMV with pressure support, high-frequency oscillatory ventilation or high-frequency jet ventilation. Seven of the 9 patients had clinical improv ement on APRV within 3 days defined by fewer episodes of severe desaturation, variability in FiO2, and vasopressor/inotrope support. In addition, none of th e infants received pharmacological neuromuscular blockade after the initiation of APRV. Despite the higher MAP, patients did not develop air-leaks and remained hemodynamically stable with normal blood pressure and urine output. Conclusions: These preliminary data indicate that infants with severe BPD tolerate the use of APRV without apparent adverse effects. However, it remains unclear whether APRV is indeed safe and beneficial in former very preterm neonates with seve re BDP and episodes of respiratory failure. Randomized controlled studies are required to determine the safety, efficacy and l ong-term morbidities of this mode of ventilation in neonates.