Sedation management during therapeutic hypothermia for neonatal encephalopathy: atropine premedication for endotracheal intubation causes a prolonged increase in heart rate

Abstract

Aim: Heart rate (HR) plays an important role in the assessment of stress during therapeutic hypothermia (TH) for neonatal encephalopathy; we aimed to quantify the effect on HR of endotracheal (ET) intubation and drugs given to facilitate it. If atropine premedication independently increased HR, the main indicator of effective sedation, we hypothesised that increased sedation would have been given.

Methods: Thirty-two, term, neonates recruited into a randomised pilot study comparing TH and TH combined with 50% Xenon inhalation were studied. Indications for ET intubation included: resuscitation at delivery, clinical need and elective re-intubation with a cuffed ET tube if randomised to Xenon. Standard intubation drugs comprised one or more of intravenous morphine, atropine, and suxamethonium. Local cooling guidelines were followed including morphine infusion for sedation.

Results: At postnatal hours five to eight atropine increased HR in a linear regression model (p<0.01). All other independent variables were excluded. Where more than one dose of atropine was given total morphine sedation given up to 8h into the treatment period was significantly higher (p<0.01).

Conclusion: We have shown that atropine premedication for ET intubation significantly increased HR, the main indicator of effective sedation and total morphine dose for sedation during early TH was increased where more than one dose of atropine was given. Bradycardia was not reported in any neonate, even without atropine premedication. We suggest that the use of atropine as part of standard premedication for ET intubation of term neonates undergoing TH should be reconsidered.

Keywords: Birth asphyxia; Induced hypothermia; Neonatal airway management; Neonatal resuscitation; Newborn.