Objective: To compare the effectiveness and safety of very early high-frequency oscillatory ventilation (HFOV) with conventional mechanical ventilation (CMV) in treatment of the respiratory distress syndrome (RDS) and to evaluate their impact on the incidence of chronic pulmonary disease and early and late morbidity of very low-birthweight neonates.
Design: A prospective randomized clinical trial.
Setting: Tertiary neonatal intensive care unit in the Perinatology Center in Prague.
Patients: 43 premature newborns, delivered in the Department of Obstetrics in the Perinatology Center, were randomly divided into two groups (HFOV and CMV) immediately after delivery; 2 patients in each group died, 2 fulfilled crossover criteria from CMV to HFOV, and 2 were excluded because of congenital malformations. Nineteen patients treated with HFOV were therefore compared with 18 infants in the CMV group.
Methods: The two contrasting modes of ventilation were introduced immediately after intubation. Maintenance of optimal lung volume in HFOV to optimize oxygenation and the therapeutic administration of surfactant after fulfilling defined criteria are important points of the strategy and design of the study.
Measurements and main results: Except for a higher proportion of males in the HFOV group (p<0.02), the basic clinical characteristics (gestational age, birthweight, Apgar score at 5 min, umbilical arterial pH), the two groups were similar. In the acute stage of RDS, infants treated with HFOV had higher proximal airway distending pressure with HFOV for 6 h after delivery (p<0.05). For a period of 12 h after delivery lower values for the alveolar-arterial oxygen difference (p<0.03) were noted. The number of patients who did not require surfactant treatment was higher in the HFOV group (11 vs. 1, p<0.001). In the HFOV group the authors found a lower roentgenographic score at 30 days of age (p<0.03) and a lower clinical score in the 36th postconceptional week (p<0.05), using these two scoring systems for assessing chronic lung disease according to Toce scale. The incidence of pneumothorax, pulmonary interstitial emphysema, intraventricular hemorrhage and retinopathy of prematurity in both groups was the same.
Conclusions: HFOV, when applied early and when the clinical strategy of maintenance of optimal lung volume is used, improves oxygenation in the acute stage of RDS, reduces the need of surfactant administration, and can decrease the injury to lung tissue even in extremely immature newborns to whom surfactant is administered therapeutically.