Objective To evaluate the safety and efficacy of optimal lung volume strategy in electively high-frequency oscillatory ventilation (HFOV)-treated extremely low birth weight infants (ELBW) with acute respiratory distress syndrome (RDS) requiring mechanical ventilation.

Methods Newborns with gestational age ⩽27 weeks and/or birth weight ⩽1000 g, are electively treated with HFOV (Draeger Babylog 8000 plus). An “optimum volume strategy” was adopted with step-by step continuous distending pressure (CDP) increases with a target FiO₂ ⩽0.25, as a marker of optimal alveolar recruitment. Surfactant was given after recruitment phase if CDP was >10 cm H₂O. Extubation was attempted with CDP ⩽6 cm H₂O, FiO2 ⩽0.25 and amplitude ⩽30%.

Results 73 newborns (mean gestational age 26.2 ± 1.2 weeks, birth weight 760 ± 198 g) were studied: 57 (78%) required surfactant, 63 (87%) survived, 18 (28%) developed bronchopulmonary dysplasia, 10 (14%) had intraventricular haemorrhages >2°. Significant correlations were found between CDP and tidal volume at 24 h of life: a positive correlation in surfactant-treated patients (r²  =  0.20, p<0.01), suggesting that higher tidal volume may be needed when higher CDP is used to recruit and maintain optimal inflation of a less compliant respiratory system; a negative correlation (r²  =  0.50, p<0.05) in not-surfactant treated babies, suggesting a possible over-inflation in more compliant respiratory systems. 58 patients (79.5%) were directly extubated from HFOV, 53 (91%) successfully (not requiring re-intubation for 72 h). The only different parameter before extubation between successfully and not successfully extubated infants was DCO₂, significantly higher in the first group: 30 ± 10 versus 18 ± 12 (p<0.05).

Conclusions Our protocol of elective HFOV in ELBW infants has proved to be safe and effective in the management of acute RDS. Weaning the CDP ⩽6 cm H₂O with FiO₂ ⩽0.25 is feasible during HFOV and extubation at these settings is successful in 91% of cases.