Cerebral fuels within the first week of life in very preterm infants: a cohort study.

Abstract

Background: Ketones and lactate may contribute towards overall cerebral fuel availability in term infants, yet the availability of such cerebral fuels in very preterm infants is unclear. We undertook a prespecified substudy to explore ketone and lactate concentrations in the first week of life in infants recruited to the REACT trial (real-time continuous glucose monitoring in the newborn): an international multicentre randomised controlled trial of 182 very low birth weight infants investigating the use of continuous glucose monitoring in glycaemic care.

Methods: Ketone and lactate measurements were prospectively collected over the first week of life using the Nova Biomedical point-of-care meter. A longitudinal analysis was undertaken to explore lactate and ketone concentration trends across time and their relationships with blood glucose, baseline demographics, nutritional support and insulin treatment.

Results: Data were available for 168 infants (85 females) including 2902 blood glucose, 2084 ketone and 2017 lactate samples. The mean (SD) gestational age was 27.4 (2.0) weeks. Lactate concentrations were higher initially, with mean (SD) 1.72 (1.26) mmol/L on day 2 and lowered to 1.19 (1.1) mmol/L on day 7. Ketone concentrations remained consistently low at 0.1 mmol/L. Neither simultaneous blood glucose concentrations, macronutrient intake nor receipt of insulin was consistently related to ketone or lactate concentrations.

Conclusion: In this cohort of very preterm infants, there were persistently low concentrations of ketones and relatively higher concentrations of lactate throughout the first week of life. Future research should evaluate changes in these metabolites during episodes of acute hypoglycaemia or hyperglycaemia over more prolonged periods of neonatal intensive care.