Interventions for the Management of Pain and Sedation in Newborns Undergoing Therapeutic Hypothermia for Hypoxic-Ischemic Encephalopathy: A Systematic Review.

Background: Newborn infants undergoing therapeutic hypothermia (TH) are exposed to multiple painful and stressful procedures. The aim of this systematic review was to assess benefits and harms of pharmacological and non-pharmacological interventions for the management of pain and sedation in newborn infants undergoing TH for hypoxic-ischemic encephalopathy.

Methods: We included randomized and observational studies reporting any intervention (either drugs or non-pharmacological interventions) to manage pain and sedation in newborn infants (> 33 weeks' gestational age) undergoing TH. We included any dose, duration and route of administration. We also included any type and duration of non-pharmacological interventions. Our prespecified primary outcomes were analgesia and sedation assessed using validated pain scales in the neonatal population; circulatory instability; mortality to discharge; and neurodevelopmental disability. A systematic literature search was conducted in the PubMed, Embase, CINAHL, Cochrane CENTRAL, Scopus, and Web of Science databases, with no language restrictions. Included studies underwent risk-of-bias assessment (Cochrane risk-of-bias tool and ROBINS-I) and data extraction performed by two authors independently. The plan had been to use effect measures such as mean difference for continuous outcomes and risk ratio for dichotomous outcomes, however the included studies are presented in a narrative synthesis due to their paucity and heterogeneity.

Results: Ten studies involving 3551 infants were included-one trial and nine observational studies. Most studies examined the use of phenobarbital or other antiepileptic drugs with primary outcomes related to seizure activity. The single trial that was included compared pentoxifylline with placebo. Among the primary outcomes, six studies reported circulatory instability and five reported mortality to discharge without relevant differences; two studies reported on neurodevelopmental disability and one study reported on pain scale. Three studies were ongoing.

Conclusions: We found limited evidence to establish the benefits and harms of the interventions for the management of pain and sedation in newborn infants undergoing TH. Long-term outcomes were not reported. Given the very low certainty of evidence-due to imprecision of the estimates, inconsistency and limitations in study design (all nine observational studies with overall serious risk of bias)-for all outcomes, clinical trials are required to determine the most effective interventions in this population.

Systematic review registration: PROSPERO registration number: CRD42020205755.