School-aged children who had received high-frequency oscillatory ventilation when they were born extremely prematurely showed modestly better lung function compared with those who had received conventional ventilation at birth, according to researchers.
Neurodevelopmental outcomes were comparable between the two groups.
The report was published online March 19 in the New England Journal of Medicine.
Dr. Sanja Zivanovic
In high-frequency oscillatory ventilation (HFOV), "a constant pressure is applied to improve lung volume and oxygenation, while ventilation is achieved with the use of very low tidal volumes." This strategy was compared against conventional ventilation in a randomized trial of 1-year outcomes at 25 medical centers in the United Kingdom, Singapore, and Australia in the early 2000s; the authors now report long-term outcomes in 319 of the participants who are now 11-14 years of age.
The primary long-term outcome – small-airway function as assessed by forced expiratory flow at 75% of the expired vital capacity (FEF-75) – was "significantly, albeit modestly" better after HFOV than after conventional ventilation. Results also were slightly better for other FEF measures, forced expiratory volume in 1 second, forced vital capacity, peak expiratory flow, and diffusing capacity, said Dr. Sanja Zivanovic of the Medical Research Council Centre for Allergic Mechanisms in Asthma at King’s College, London, and her associates.
The differences in lung-function measures were small, with an average of approximately 0.3 standard deviations. However, in a further analysis, 47% of the conventional-ventilation group fell below the 10th percentile for FEF-75, compared with only 37% of the HFOV group. This represents "a difference that is likely, in our opinion, to be of clinical importance," the investigators said (N. Engl. J. Med. 2014;370:1121-30 [doi:10.1056/NEJMoa1309220]).
"The poorer lung function in the conventional-ventilation group than in the HFOV group may have consequences over time – for example, by causing greater vulnerability to lung-function insults such a smoking," they noted.
"We were concerned that any respiratory benefit associated with the use of HFOV might have been associated with adverse neurodevelopmental outcomes, because in some trials HFOV has been associated with an increased risk of neonatal brain injury." However, no differences were found between the two study groups in health-related quality of life or behavior, and teachers rated the HFOV group as significantly better at art and design, information technology, and design and technology, "suggesting the possibility that visuospatial skills were better in that group than in the conventional-ventilation group," Dr. Zivanovic and her associates said.
This study was supported by the National Institute for Health Research Health Technology Assessment Programme, the South London Comprehensive Local Research Network, the Department of Health NIHR Biomedical Research Centre, and NIHR Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London. Dr. Zivanovic reported no financial conflicts of interest; some of her associates reported ties to Abbott Laboratories, Bear Medical Systems, SLE Ltd., and Novartis.