Morphine and fentanyl exposure during therapeutic hypothermia does not impair neurodevelopment

Julia K Gundersen; Ela Chakkarapani; Sally Jary; David A Menassa; Emma Scull-Brown; Adam Frymoyer; Lars Walløe; Marianne Thoresen

doi:10.1016/j.eclinm.2021.100892

Morphine and fentanyl exposure during therapeutic hypothermia does not impair neurodevelopment

EClinicalMedicine. 2021 Jun 5:36:100892. doi: 10.1016/j.eclinm.2021.100892. eCollection 2021 Jun.

Authors

Julia K Gundersen^{1

2}, Ela Chakkarapani², Sally Jary², David A Menassa^{1

3}, Emma Scull-Brown², Adam Frymoyer⁴, Lars Walløe¹, Marianne Thoresen^{1

2}

Affiliations

¹ Division of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
² Translational Health Sciences, St. Michael's Hospital, Bristol Medical School, University of Bristol, Bristol, United Kingdom.
³ The Queen's College, University of Oxford, Oxford, United Kingdom.
⁴ Department of Pediatrics, Stanford University, California, United States.

Abstract

Background: Hypothermia-treated and intubated infants with moderate or severe hypoxic-ischemic encephalopathy (HIE) usually receive morphine for sedation and analgesia (SA) during therapeutic hypothermia (TH) and endotracheal ventilation. Altered drug pharmacokinetics in this population increases the risk of drug accumulation. Opioids are neurotoxic in preterm infants. In term infants undergoing TH, the long-term effects of morphine exposure are unknown. We examined the effect of opioid administration during TH on neurodevelopmental outcome and time to extubation after sedation ended.

Methods: In this prospectively collected population-based cohort of 282 infants with HIE treated with TH (2007-2017), the cumulative opioid dose of morphine and equipotent fentanyl (10-60 µg/kg/h) administered during the first week of life was calculated. Clinical outcomes and concomitant medications were also collected. Of 258 survivors, 229 underwent Bayley-3 neurodevelopmental assessments of cognition, language and motor function at 18-24 months. Multivariate stepwise linear regression analysis was used to examine the relation between cumulative opioid dose and Bayley-3 scores. Three severity-groups (mild-moderate-severe) were stratified by early (<6 h) amplitude-integrated electroencephalography (aEEG) patterns.

Findings: The cumulative dose of opioid administered as SA during TH was median (IQR) 2121 µg/kg (1343, 2741). Time to extubation was independent of SA dose (p > 0.2). There was no significant association between cumulative SA dose and any of the Bayley-3 domains when analysing the entire cohort or any of the aEEG severity groups.

Interpretation: Higher cumulative opioid doses in TH-treated infants with HIE was not associated with worse Bayley-3 scores at 18-24 months of age.

Funding: The Bristol cooling program was funded by the Children's Medical Research Charity SPARKS managing donations for our research from the UK and US, the UK Moulton Foundation, the Lærdal Foundation for Acute Medicine in Norway and the Norwegian Research Council (JKG).