Randomised trial of high frequency oscillatory ventilation or conventional ventilation in babies of gestational age 28 weeks or less: respiratory and neurological outcomes at 2 years

Abstract

Background:The long term outcome of children entered into neonatal trials of high frequency oscillatory ventilation (HFOV) or conventional ventilation (CV) has been rarely studied. Objective: To evaluate respiratory and neurodevelopmental outcomes for children entered into the United Kingdom Oscillation Study, which was designed to evaluate these outcomes. Methods: Surviving infants were followed until 2 years of age corrected for prematurity. Study forms were completed by local paediatricians at routine assessments, and parents were asked to complete a validated neurodevelopmental questionnaire. Results: Paediatricians' forms were returned for 73% of the 585 surviving infants. Respiratory symptoms were common in all infants, and 41% had received inhaled medication. Mode of ventilation had no effect on frequency of any symptoms. At 24 months of age, severe neurodevelopmental disability was present in 9% and other disabilities in 38% of children, but the prevalence of disability was similar in children who received HFOV or CV (relative risk 0.93; 95% confidence interval 0.74 to 1.16). The prevalence of disability did not vary by gestational age, but boys were more likely to have overall disability. Developmental scores were unaffected by mode of ventilation (relative risk 1.13; 95% confidence interval 0.78 to 1.63) and were lower in infants born before 26 weeks gestation compared with babies born at 26-28 weeks. Conclusions: Initial mode of ventilation in very preterm infants has no impact on respiratory or neurodevelopmental morbidity at 2 years. HFOV and CV appear equally effective for the early treatment of respiratory distress syndrome.

Neonatal and infant outcome in boys and girls born very prematurely

“…Table 4 shows that disability (either severe or otherwise and based on parental assessment (ref. 16)) was present at 24-mo follow-up in 53% of boys as compared with 39% of girls. This difference remained significant after adjustment for birth weight, gestational age, and oxygen dependence at 36 wk Maximum number of children with follow-up data = 70% of UK surviving children (366/521).…”

“…Some follow-up data have already been reported but sex differences were not the main focus of those analyses (16). In addition to exploring neonatal factors, we now present a sequential analysis to show how sex differences in infant outcomes change (or not) when adjustment is made for important neonatal factors.…”

“…Follow-up data analyzed included outcomes obtained at 24 mo using a parent-completed neurodevelopmental questionnaire which recorded information on health status and anthropometry (16). From these questions, the outcomes "severe disability, " "other disability, " or "no disability" were derived.…”

“…From these questions, the outcomes "severe disability, " "other disability, " or "no disability" were derived. "Severe disability" is at least one extreme response in one of the following clinical domains: neuromotor, vision, hearing, communication, or other physical disabilities; "no disability" is a normal or missing response to all clinical domains, as described in Marlow (2006) (16). A parental assessment of cognitive development (PARCA) was used that has been validated against Bayley Scales of Infant Development-II and comprises statements of development taken from the Bayley and the MacArthur language tests (18).…”

“…It may be therefore that there are less marked differences in outcome for boys and girls following the introduction of these treatments. When, however, we followed up a group of very prematurely born infants in whom corticosteroids and surfactant were almost universally used, we found that male sex was a risk factor for poorer lung function (14), increased respiratory morbidity (15), and poorer neurological function overall (16). In this article, we build on our previous analyses to try to understand causal pathways by first exploring sex differences in a range of neonatal outcomes and then using statistical models to sequentially adjust later outcomes for neonatal differences.…”