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High-frequency oscillatory ventilation comparable to conventional ventilation
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High-frequency oscillatory ventilation was equivalent in efficacy to conventional ventilation in preterm infants but did not appear more beneficial for any particular subset in this population, according to recent study data.
Researchers from various sites in the United States, Europe and Australia conducted a systematic review and meta-analysis of trials on the use of high-frequency oscillatory ventilation (HFOV) use in comparison with conventional ventilation use in preterm infants. Primary outcomes were death; death or bronchopulmonary dysplasia at 36 weeks’ postmenstrual age; or severe neurological events.
Individual patient data from 10 randomized studies involving 3,229 preterm infants were included in the analysis. Mean gestational age was 27.3 weeks and mean birth weight was 989 g.
Results indicated that the HFOV use was not related to a significant difference in risk when compared with conventional ventilation. The RR of death or bronchopulmonary dysplasia at 36 weeks’ postmenstrual age was 0.95 (95% CI, 0.88-1.03), according to the researchers, and the RR of death or severe neurological events was 1.00 (95% CI, 0.88-1.13).
The researchers also noted that use of HFOV led to a slight reduction in need for surgical closure of patent ductus arteriosus when compared with conventional ventilation. There was some indication that HFOV was associated with decreased risk of retinopathy of prematurity stage II or more.
Data showed that these results did not differ significantly for sex of the infant; gestational age at birth; birth weight less than the 10th percentile; presence of chorioamnionitis; oxygenation index at trial entry; antenatal treatment with corticosteroids; and whether or not the antenatal corticosteroid therapy was complete. – by Melissa Foster
Cools F. Lancet. 2010; doi:10.1016/S0140-6736(10)60278-4.
Studies of preterm animals with respiratory distress syndrome treated with HFOV using an optimal lung recruitment strategy have demonstrated less lung injury compared with conventional mechanical ventilation. However, clinical trials in preterm infants have often provided conflicting results due to small numbers of infants, various HFOV devices and therapeutic approaches, and different outcome measures. This meta-analysis of 10 different randomized, multicenter controlled trials involved 3,229 preterm infants and failed to demonstrate any significant benefits of early HFOV when death, bronchopulmonary dysplasia, or neurodevelopmental impairment were analyzed as primary outcome variables. Although the meta-analysis is a powerful statistical technique, it also has significant limitations that the authors readily acknowledge.
Several important findings were identified in this analysis. First, HFOV was associated with increased pulmonary air leak, presumably due to the use of higher mean airway pressures used to promote lung recruitment. It may be advisable to avoid HFOV in infants with significant air leak and use alternative treatment strategies employing lower mean airway pressures (eg, high frequency jet ventilation). Next, initiation of HFOV within 1 to 4 hours of birth was associated with improved outcome, suggesting that earlier (but not immediate) initiation of this treatment strategy was potentially beneficial in infants with progressive respiratory difficulties. Finally, treatment with HFOV was associated with a reduced incidence of surgical intervention for a hemodynamically significant patent ductus arteriosus as well as retinopathy of prematurity. Again, these findings may be due to the use of higher mean airways pressures, which can reduce pulmonary blood flow, as well as inspired oxygen concentrations. The most significant limitation of this study involves the analysis of short-term outcome measures (bronchopulmonary dysplasia, neurodevelopmental impairment), which may not necessarily correlate with longer-term clinical status. Many studies of preterm infants are now examining both pulmonary and neurodevelopmental outcome at 1 to 2 years corrected gestational age using respiratory diaries, pulmonary questionnaires, pulmonary function testing and formal neurodevelopmental testing. This is being done to improve the accuracy of predicting longer-term outcome, which should provide more information that should contribute to more powerful meta-analyses in the future.
– Jonathan M. Davis, MD
Chief of Newborn
Medicine, The Floating Hospital for Children at Tufts Medical Center; Professor
of Pediatrics,
Tufts University School of Medicine