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

Area of Science:

• Neonatal Physiology
• Cardiovascular Research
• Respiratory Support

Background:

• Current use of continuous positive airway pressure (CPAP) in preterm infants is limited to 4-8 cmH2O.
• Concerns exist regarding potential adverse effects of high-CPAP on pulmonary overexpansion and the cardiovascular system.

Purpose of the Study:

• To investigate the effects of high-CPAP on pulmonary blood flow (PBF), cerebral blood flow (CBF), and jugular vein pressure (JVP) in preterm lambs post-birth.
• To compare the outcomes of low-CPAP, high-CPAP, and dynamic high-CPAP.

Main Methods:

• Preterm lambs were delivered at 133/146 days gestation and instrumented with flow probes and catheters.
• Lambs received either low-CPAP (5 cmH2O), high-CPAP (15 cmH2O), or dynamic high-CPAP (15 decreasing to 8 cmH2O).
• Measurements of PBF, CBF, and JVP were taken for up to 30 minutes post-birth.

Main Results:

• Mean PBF was significantly higher in high-CPAP and dynamic high-CPAP groups compared to the low-CPAP group.
• Cerebral blood flow (CBF) and jugular vein pressure (JVP) remained similar across all CPAP groups.
• High-CPAP groups required less ventilation support and intubation, with no increased incidence of pneumothorax compared to low-CPAP.

Conclusions:

• High-CPAP (15 cmH2O) did not impede the necessary increase in pulmonary blood flow at birth in preterm lambs.
• High-CPAP effectively supported preterm lambs without adverse effects on cerebral blood flow or jugular vein pressure.
• These findings suggest that higher CPAP levels may be safely utilized in neonatal respiratory support.