Effect of Lung Recruitment on Pulmonary, Systemic, and Ductal Blood Flow in Preterm Infants

Objective

To determine the effect of lung recruitment on pulmonary, systemic, and ductal blood flow in preterm infants treated with primary high-frequency ventilation (HFV).

Study design

Thirty-four infants (median gestational age, 28 weeks) were included in this prospective cohort study. Changes in oxygenation in response to stepwise changes in the continuous distending pressure (CDP) were used to monitor lung recruitment during HFV. For each individual patient, the opening pressure (CDPo), closing pressure (CDPc), and optimal pressure (CDPopt) were determined. Ultrasound measurements of right ventricular output (RVO), superior vena cava (SVC), and ductus arteriosus (DA) flow were performed at the start of recruitment (CDPs), CDPo, and CDPopt.

Results

Increasing the CDP from 8 (CDPs) to 20 (CDPo) cmH₂O resulted in a decreased RVO (mean difference, −17%; 95% CI, −24, −10%) and unchanged SVC flow and ductal shunting. Transient low RVO and SVC flow values at CDPo were seen in 3 and 2 infants, respectively.

Conclusions

Lung recruitment during HFV in preterm infants does not appear to result in clinically relevant changes in pulmonary, systemic, and ductal blood flow.

Abbreviations: BPD, Bronchopulmonary dysplasia, CDP, Continuous distending pressure, CDPs, Continuous distending pressure at start of the recruitment procedure, CDPo, Opening continuous distending pressure, CDPopt, Optimal continuous distending pressure, CPAP, Continuous positive airway pressure, DA, Ductus arteriosus, HFV, High frequency ventilation, RDS, Respiratory distress syndrome, RVO, Right ventricular output, SVC flow, Superior vena cava flow, Spo₂, Transcutaneous oxygen saturation, VTI, Velocity time integral