HIGH-FREQUENCY OSCILLATORY VENTILATION VE RSUS CONVENTIONAL POSITIVE-PRESSURE VENTILATION IN NEONATES

High-frequency oscillatory ventilation (HFOV) ensures gas exchange wit h tidal volumes that are smaller than the anatomic dead space. This ca n be expected to reduce the risk of barotrauma and volotrauma. However , proof that HFOV decreases neonatal mortality and morbidity has not b een obtained. This study is a retrospective evaluation of the first ye ar of use of HFOV in a neonatal intensive care unit. Infants treated w ith HFOV were compared with those who received conventional positive-p ressure ventilation (PPV) during the same period. HFOV was used with h igh pressures (mean pressure 2-5 cm H2O above those used for PPV) to m aintain alveolar recruitment. All neonates who were ventilated within 24 hours of birth were included (n = 92, including 38% treated by HFOV ) except those who were ventilated after a surgical procedure. Patient s were assigned to the HFOV group based on availability of the oscilla tor (OHFI(R), Dufour). Outcomes in the subgroup of premature babies bo rn before 32 weeks of gestational age were studied separately. Evaluat ion criteria were mortality, ventilation-indued complications (pneumot horax, bronchopulmonary dysplasia, and intracerebral hemorrhage), and ventilation parameters during the first 48 hours. Severity at baseline was comparable in the two groups. There was no difference in mortalit y (22%). HFOV was associated with nonsignificant improvements in time under ventilation (66 vs 96 hours) and in rates of occurrence of intra cerebral hemorrhage (7% vs 15%) and bronchopulmonary dysplasia (4% vs 11%). Fractional concentration of inspired oxygen (FiO(2)) decreased f aster in the HFOV group (p < 0.001). Results were comparable in the pr emature babies born before 32 weeks and in the overall study populatio n. The findings from this study are in keeping with the recent literat ure. They should be interpreted with caution given the small sample si ze and absence of randomization. Because the mechanisms involved in HF OV have not yet been fully elucidated, uncertainties remain as to opti mal use of this technique. A large body of experimental mental and cli nical data suggest that HFOV should be used with large pulmonary volum es. Early use of HFOV may be warranted since lesions due to barotrauma can develop very rapidly under PPV.