Our study 20 years on: UK collaborative randomised trial of neonatal extracorporeal membrane oxygenation
The successful use of extracorporeal membrane oxygenation (ECMO) had first been reported by Hill in adults in 1972 [1], and Bartlett [2] in neonates in 1975. In 1979, a negative adult trial [2, 3] contrasted to consistently favourable results in neonates leading to the rapid adoption of neonatal ECMO in the USA. However the poor quality of the two early US trials of neonatal ECMO [4, 5] inhibited its wider diffusion with particular concerns about lack of evidence on cost-effectiveness and longterm outcomes [6]. Our trial [7] was a large randomised controlled trial (RCT) recruiting 185 neonates with severe respiratory failure. At 1 year of age 60 % survivors in the ECMO group were alive without severe disability, compared to 40 % in the conventional treatment group. These positive results spurred on the development of neonatal ECMO services internationally although some trialists criticised our pragmatic design based in a live health system, citing our failure to move conventionally treated babies to ‘expert’ centres [8]. Evidence supporting neonatal ECMO was presented in a meta-analysis rigorously which concluded that “A policy of ECMO in mature infants with severe but potentially reversible respiratory failure would result in significantly improved survival without increased risk of severe disability amongst survivors” [9]. One further RCT, only ever published in abstract form, was included in this meta-analysis. Of the 95 babies with persistent pulmonary hypertension (PPHN) enrolled, 93 % survived to hospital discharge compared to 54 % of those treated conventionally with no neurodevelopmental difference at 2-year follow-up [10], similar findings to our own study. Follow‐up studies Neurodevelopmental Follow-up of our trial cohorts at 4 years showed that the range of morbidity had widened since the 1-year assessments. Two-thirds of children recorded cognitive levels within the normal range. Sixty per cent of survivors had abnormal neuromotor function, but there were no differences between the two trial groups and no evidence of right-hemisphere deficits in veno-arterial ECMO survivors. Fifty per cent of known ECMO survivors had no disability compared 37 % of ‘conventional’ survivors. Behavioural difficulties were more commonly reported in the ‘conventional’ survivors than the ECMO survivors. At 7 years, a psychologist assessed 90 of the 100 children available for follow-up without prior knowledge of treatment allocation. Seventy-six per cent of children recorded a cognitive level within the normal range. The distribution of learning problems was similar in the two groups. A higher incidence of behavioural problems was noted among children treated conventionally. Importantly the beneficial influence of a policy of ECMO rather than conventional support was still present after 7 years, with some evidence of reduced morbidity in the ECMO group.