Late permissive hypercapnia and respiratory stability among very preterm infants: a pilot randomised trial

Abstract

ObjectiveDetermine if targeting higher transcutaneous carbon dioxide improves respiratory stability among very preterm infants on ventilatory support.DesignSingle-centre pilot randomised clinical trial.SettingThe University of Alabama at Birmingham.PatientsVery preterm infants on ventilatory support after postnatal day 7.InterventionsInfants were randomised to two different transcutaneous carbon dioxide levels targeting 5 mm Hg (0.67 kPa) changes with four sessions each lasting 24 hours for 96 hours: baseline-increase-baseline-increase or baseline-decrease-baseline-decrease.Main outcome measuresWe collected cardiorespiratory data evaluating episodes of intermittent hypoxaemia (oxygen saturations (SpO2)<85% for ≥10 s), bradycardia (<100 bpm for ≥10 s), and cerebral and abdominal hypoxaemia on near-infrared spectroscopy.ResultsWe enrolled 25 infants with a gestational age of 24 w 6 d±11 d (mean±SD) and birth weight 645±142 g on postnatal day 14±3. Continuous transcutaneous carbon dioxide values (56.8±6.9 in the higher group vs 54.5±7.8 in the lower group; p=0.36) did not differ significantly between groups during the intervention days. There were no differences in intermittent hypoxaemia (126±64 vs 105±61 per 24 hours; p=0.30) or bradycardia (11±16 vs 15±23 per hour; p=0.89) episodes between groups. The proportion of time with SpO2<85%, SpO2<80%, cerebral hypoxaemia or abdominal hypoxaemia did not differ (all p>0.05). There was moderate negative correlation between mean transcutaneous carbon dioxide and bradycardia episodes (r=−0.56; p<0.001).ConclusionTargeting 5 mm Hg (0.67 kPa) changes in transcutaneous carbon dioxide did not improve respiratory stability among very preterm infants on ventilatory support but the intended carbon dioxide separation was difficult to achieve and maintain.Trial registration numberNCT03333161.