337 - Bubble Continuous Positive Airway Pressure with Occlusive Mask for Superior Functional Residual Capacity Support in Respiratory Distress Syndrome

Publication Number: 337.4154

Jessica E. Shui, Harvard Medical School, Lynnfield, MA, United States; Glasiele Alcala, Harvard Medical School, Boston, MA, United States; Carolyn J,. La Vita, Massachusetts General Hospital, Boston, MA, United States; Romal K. Jassar, MassGeneral Hospital for Children, Boston, MA, United States; Rodica Turcu, Harvard Medical School, Boston, MA, United States; Julia O. Davis, MassGeneral Hospital for Children, Newton, MA, United States; Paul H. Lerou, MassGeneral Hospital for Children, Boston, MA, United States; Lorenzo Berra, Massachusetts General Hospital, Boston, MA, United States

Background: Across centers, there is a variation in practice for the preferred device and interface to deliver continuous positive airway pressure (CPAP) to support neonatal functional residual capacity (FRC). CPAP, a type of noninvasive respiratory support, is commonly delivered to neonates by mechanical ventilators or underwater bubble devices. Effective CPAP is determined by a consistent delivery of a prescribed positive end expiratory pressure (PEEP) to allow optimal alveolar recruitment, consistent FRC, and in turn optimal gas exchange. Reliable PEEP delivery may be CPAP device dependent but could also be due to other factors, such as nasal interface. Common interfaces include RAM Cannula and occlusive designs. Real-time, functional lung imaging is feasible with electrical impedance tomography (EIT).

Objective: We investigated whether late preterm neonates with respiratory distress syndrome (RDS) have higher FRC when supported with bubble CPAP via an occlusive mask interface compared to ventilator CPAP via RAM Cannula.

Design/Methods: This crossover study compared EIT acquired lung physiology measurements while supported on ventilator CPAP via RAM Cannula versus ventilator CPAP via occlusive mask versus bubble CPAP via occlusive mask, in preterm neonates >32 weeks gestation and less than 72 hours old, receiving CPAP for RDS. Prescribed PEEP level was not changed with different CPAP modalities. An Enlight 2100 (Timpel, Sao Paulo, Brazil) EIT belt was wrapped around the chest at T4 and changes in electrical impedance was measured in the thorax (Figure 1). Change in end expiratory lung impedance (surrogate of FRC) was acquired. After a washout period, a t-test of electrical impedance measurements averaged over two minutes was performed between CPAP modalities.

Results: Mean end expiratory lung impedance (FRC surrogate) in five neonates when supported with ventilator CPAP via RAM Cannula was -6.71, SD 13.47 vs mean end expiratory lung impedance (FRC surrogate) when supported with bubble CPAP via occlusive mask was 71.30, SD 55.61; p=0.05 (Figure 2).

Conclusion(s): Late preterm neonates with active RDS have higher FRC when supported with bubble CPAP via occlusive mask interface compared to ventilator CPAP with RAM interface. Analysis of EIT measured tidal volume differences between all three trialed CPAP modalities is underway.

Figure 1
PAS 2025 Fig 1.pdfOrientation of typical impedance measurements in the thorax using electrical impedance tomography (EIT), and graphic of an infant wearing an EIT belt.

Figure 2
PAS 2025 Fig 2 CPAP.pdfAverage end expiratory lung impedance (surrogate of functional residual capacity) while supported on baseline ventilator continuous positive airway pressure (CPAP) via RAM cannula compared to bubble CPAP via occlusive mask interface at the same prescribed level of positive end expiratory pressure.