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) cmH(2)O 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.