Preterm infants are exposed to frequent painful procedures and agitating stimuli over the many weeks of their hospitalization in the neonatal intensive care unit (NICU). The adverse neurobiological impact of pain and stress in the preterm infant has been well documented, including neuroimaging and neurobehavioral outcomes. Although many tools have been validated to assess acute pain, few methods are available to assess chronic pain or agitation (a clinical manifestation of neonatal stress). Both nonpharmacologic and pharmacologic approaches are used to reduce the negative impact of pain and agitation in the preterm infant, with concerns emerging over the adverse effects of analgesia and sedatives. Considering benefits and risks of available treatments, units must develop a stepwise algorithm to prevent, assess, and treat pain. Nonpharmacologic interventions should be consistently utilized prior to mild to moderately painful procedures. Sucrose may be utilized judiciously as an adjunctive therapy for minor painful procedures. Rapidly acting opioids (fentanyl or remifentanil) form the backbone of analgesia for moderately painful procedures. Chronic sedation during invasive mechanical ventilation represents an ongoing challenge; appropriate containment and an optimal environment should be standard; when indicated, low-dose morphine infusion may be utilized cautiously and dexmedetomidine infusion may be considered as an emerging adjunct.

Background Standard-dose caffeine improves white matter microstructural development assessed by diffusion MRI. We hypothesized that early high-dose caffeine would result in further improvement in white matter microstructural development. Methods Seventy-four preterm infants (≤30 weeks gestational age) were randomly assigned to either a high (80 mg/kg IV) or standard (20 mg/kg IV) loading dose of caffeine citrate in the first 24 hours of life. MRI and neurobehavioral testing were undertaken at term equivalent age. Infants returned at 2 years of age for developmental testing. Results Clinical characteristics were similar between groups, with the exception of higher maternal age in the high-dose caffeine group. There was an increased incidence of cerebellar hemorrhage in infants randomized to high-dose caffeine (36% vs. 10%, p=0.03). Infants in the high-dose caffeine group also demonstrated more hypertonicity (p=0.02) and more deviant neurologic signs (p=0.04) at term equivalent age. Diffusion measures at term equivalent age and developmental outcomes at two years of age did not differ between groups. Conclusions Preterm infants randomized to early high-dose caffeine had a higher incidence of cerebellar injury with subsequent alterations in early motor performance. The results of this pilot trial discourage a larger randomized controlled trial.

Objective To investigate the association of morphine exposure in very preterm infants with cerebral volumes and neurodevelopmental outcome from birth through middle childhood. Study design Observational study of very preterm infants in the Victorian Infant Brain Study cohort. 230 infants born <30 weeks’ gestational age or <1,250 g were recruited from all admissions to the neonatal intensive care unit (NICU) of the Royal Women’s Hospital. 57 (25%) infants received morphine analgesia during their NICU stay at the attending physician’s discretion. Primary outcomes were regional brain volumes at term and 7 years; neurobehavioral performance at term; and cognitive, motor, emotional, behavioral, communication, and executive function scores at age 2 and 7 years. Linear regressions were used to compare outcomes between participants who did and did not receive morphine. Results At term, preterm infants who received morphine had similar rates of grey matter injury to no-morphine infants, but a trend towards smaller cortical volumes in the orbitofrontal (pleft=0.002, pright=0.01) and subgenual (pleft=0.01) regions. At seven years, cortical volumes did not differ between groups. At 2 years, morphine-exposed children were more likely to show behavioral dysregulation (p=0.007) than no-morphine children, but at seven years no detrimental impacts of morphine on neurobehavioral outcome were observed. Conclusions Low-dose morphine analgesia received during neonatal intensive care was associated with early alterations in cerebral structure and short-term neurobehavioral problems that did not persist into childhood.

Background Fentanyl is commonly utilized in preterm infants. Relatively little is known regarding the neurodevelopmental outcomes of preterm infants exposed to fentanyl. Objective To investigate the association between cumulative fentanyl dose and brain injury and diameters in a cohort of preterm infants Methods Data on demographics, perinatal course, and neonatal course, including total fentanyl exposure prior to term equivalent age, were retrospectively evaluated for 103 infants born at ≤ 30 weeks gestational age who underwent magnetic resonance imaging at term equivalent age (mean gestational age 26.9 ± 1.8 weeks). Magnetic resonance images were evaluated for brain injury and regional brain diameters. Developmental testing was conducted at term equivalent and 2 years of age. Results Seventy-eight infants (76%) received fentanyl (median cumulative dose 3 μg/kg, interquartile range 1 – 441 μg/kg). Cumulative fentanyl dose in the first week of life correlated with the incidence of cerebellar hemorrhage after correction for covariates (OR 2.1, 95% confidence interval 1.1 – 4.1). Cumulative fentanyl dose before term equivalent age correlated with reductions in transverse cerebellar diameter after correction for covariates including the presence of cerebellar hemorrhage (r = 0.461, p = 0.002). No correlation was detected between cumulative fentanyl dose and development at 2 years of age. Conclusions Higher cumulative fentanyl dose in preterm infants correlated with a higher incidence of cerebellar injury and lower cerebellar diameter at term equivalent age. Our findings must be taken with caution, but emphasize the need for future prospective trials examining the risks and benefits of commonly utilized analgesic agents in preterm infants.