AUTHOR=Martherus Tessa , Crossley Kelly J. , Rodgers Karyn A. , Dekker Janneke , Demel Anja , Moxham Alison M. , Zahra Valerie A. , Polglase Graeme R. , Roberts Calum T. , te Pas Arjan B. , Hooper Stuart B. 

TITLE=High-CPAP Does Not Impede Cardiovascular Changes at Birth in Preterm Sheep

JOURNAL=Frontiers in Pediatrics

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2020.584138

DOI=10.3389/fped.2020.584138

ISSN=2296-2360

ABSTRACT=<p><bold>Objective:</bold> Continuous positive airway pressures (CPAP) used to assist preterm infants at birth are limited to 4–8 cmH<sub>2</sub>O due to concerns that high-CPAP may cause pulmonary overexpansion and adversely affect the cardiovascular system. We investigated the effects of high-CPAP on pulmonary (PBF) and cerebral (CBF) blood flows and jugular vein pressure (JVP) after birth in preterm lambs.</p><p><bold>Methods:</bold> Preterm lambs instrumented with flow probes and catheters were delivered at 133/146 days gestation. Lambs received low-CPAP (LCPAP: 5 cmH<sub>2</sub>O), high-CPAP (HCPAP: 15 cmH<sub>2</sub>O) or dynamic HCPAP (15 decreasing to 8 cmH<sub>2</sub>O at ~2 cmH<sub>2</sub>O/min) for up to 30 min after birth.</p><p><bold>Results:</bold> Mean PBF was lower in the LCPAP [median (Q1–Q3); 202 (48–277) mL/min, <italic>p</italic> = 0.002] compared to HCPAP [315 (221–365) mL/min] and dynamic HCPAP [327 (269–376) mL/min] lambs. CBF was similar in LCPAP [65 (37–78) mL/min], HCPAP [73 (41–106) mL/min], and dynamic HCPAP [66 (52–81) mL/min, <italic>p</italic> = 0.174] lambs. JVP was similar at CPAPs of 5 [8.0 (5.1–12.4) mmHg], 8 [9.4 (5.3–13.4) mmHg], and 15 cmH<sub>2</sub>O [8.6 (6.9–10.5) mmHg, <italic>p</italic> = 0.909]. Heart rate was lower in the LCPAP [134 (101–174) bpm; <italic>p</italic> = 0.028] compared to the HCPAP [173 (139–205)] and dynamic HCPAP [188 (161–207) bpm] groups. Ventilation or additional caffeine was required in 5/6 LCPAP, 1/6 HCPAP, and 5/7 dynamic HCPAP lambs (<italic>p</italic> = 0.082), whereas 3/6 LCPAP, but no HCPAP lambs required intubation (<italic>p</italic> = 0.041), and 1/6 LCPAP, but no HCPAP lambs developed a pneumothorax (<italic>p</italic> = 0.632).</p><p><bold>Conclusion:</bold> High-CPAP did not impede the increase in PBF at birth and supported preterm lambs without affecting CBF and JVP.</p>