Current Controversies in Newer Therapies to Treat Birth Asphyxia

Despite major advances in monitoring technology and knowledge of fetal and neonatal pathophysiology, neonatal hypoxic-ischemic encephalopathy (HIE) remains one of the main causes of severe adverse neurological outcome in children. Until recently, there were no therapies other than supportive measures. Over the past several years, mild hypothermia has been proven to be safe to treat HIE. Unfortunately, this neuroprotective strategy seems efficient in preventing brain injury in some asphyxiated newborns, but not in all of them. Thus, there is increasing interest to rapidly understand how to refine hypothermia therapy and add neuroprotective or neurorestorative strategies. Several promising newer treatments to treat birth asphyxia and prevent its devastating neurological consequences are currently being tested. In this paper, the physiopathology behind HIE, the currently available treatment, the potential alternatives, and the next steps before implementation of these other treatments are reviewed

Extracorporeal Membrane Oxygenation Use in Asphyxiated Newborns Treated with Hypothermia: Review of the Current Evidence

Asphyxiated newborns may be hemodynamically unstable during their first days of life. They often present with severe persistent pulmonary hypertension and/or cardiac dysfunction, which may require aggressive supportive management to maintain homeostasis and prevent further brain injury. In the most severe cases, extracorporeal membrane oxygenation (ECMO) may be required to ensure adequate oxygenation, ventilation and cardiac output. However, due to the risk of irreversible brain injury, clinicians often are concerned about offering ECMO to these newborns. Therapeutic hypothermia during the first days of life has become the standard of care for these newborns to improve their prognosis; however, this treatment in itself has been associated with increased hemodynamic instability and coagulopathy. An additional concern with using ECMO in these newborns is the potential increased bleeding risk when continuing the hypothermia treatment during the ECMO course. This chapter reviews the reported feasibility of performing hypothermia during ECMO. We also review the reported outcomes of asphyxiated newborns treated with hypothermia and ECMO and highlight their potential survival without neurodevelopmental impairments. Thus, ECMO should be considered as a therapeutic option for asphyxiated newborns treated with hypothermia

The Impact of Ventilation on the Development of Brain Injury in Asphyxiated Newborns Treated with Hypothermia

Birth asphyxia and the resulting neonatal encephalopathy are a significant cause of mortality and long-term morbidity in children. Hypothermia is currently the only neuroprotective treatment to have been clinically tested in large trials to prevent the development of brain injury in some term asphyxiated newborns. Most of the asphyxiated newborns treated with hypothermia are intubated at birth as per resuscitation measures and remain on mechanical ventilation during some part of the hypothermia treatment or during the whole length of the treatment. They also may present with oxygenation problems. Very often, they present with hypocapnia that can be worsened with the use of mechanical ventilation during the first days of life. When taking care of these newborns, a few important points should be remembered about the impact of asphyxia and therapeutic hypothermia on oxygenation and ventilation. In this article, we review some of the physiopathology behind neonatal encephalopathy and the implications of brain cooling from a respiratory point of view. Strategies to optimize oxygenation and ventilation for these newborns, as well as to prevent further brain injury, are also discussed based on a current literature review

Method for performing cerebral perfusion-weighted MRI in neonates

Cerebral perfusion-weighted imaging (PWI) in neonates is known to be technically difficult and there are very few published studies on its use in preterm infants. In this paper, we describe one convenient method to perform PWI in neonates, a method only recently used in newborns. A device was used to manually inject gadolinium contrast material intravenously in an easy, quick and reproducible way. We studied 28 newborn infants, with various gestational ages and weights, including both normal infants and those suffering from different brain pathologies. A signal intensity-time curve was obtained for each infant, allowing us to build perfusion maps. This technique offered a fast and easy method to manually inject a bolus gadolinium contrast material, which is essential in performing PWI in neonates. Cerebral PWI is technically feasible and reproducible in neonates of various gestational age and with various pathologie

Long-term outcome of preterm infants treated with nasal continuous positive airway pressure

This study's aim was to assess neurodevelopmental and growth outcome until the age of 4 years of premature infants placed on early nCPAP, in the setting of the neonatal intensive care unit (NICU) and follow-up program of the Division of Neonatology of the Department of Pediatrics of the University Hospital, Lausanne, Switzerland. All consecutive inborn infants weighing <1500g or <32 weeks of gestational age admitted to the NICU during two periods of 12 months—7.1996-6.1997 and 7.1998-6.1999—were compared before and after the systematic application of early nCPAP. Of 172 infants admitted to the NICU, 150 (87%) survived. 126 (84%) were tested at 6 months' corrected age, 121 (81%) at 18 months' corrected age, and 117 (78%) at the age of 4 years. Detailed perinatal data were collected. Follow-up included neurological examination, developmental testing and measurement of growth parameters. Statistical analyses were performed. Early application of nCPAP and avoidance of mechanical ventilation showed no adverse effects on neurodevelopment and growth. A significantly higher developmental quotient was found in the nCPAP group at 18 months' corrected age. Several trends were also noted in the nCPAP group with a decrease of intraventricular hemorrhage and in "abnormal neurodevelopment” at 6 months corrected age, a bigger head circumference at all different tested ages and a greater height at 6 and 18 months corrected ages. In conclusion, our study of developmental outcome documents the absence of any harmful effect of early application of nCPAP to treat respiratory failure in very low birthweight infant

A Population Model of Time-Dependent Changes in Serum Creatinine in (Near)term Neonates with Hypoxic-Ischemic Encephalopathy During and After Therapeutic Hypothermia

The objective was to apply a population model to describe the time course and variability of serum creatinine (sCr) in (near)term neonates with moderate to severe encephalopathy during and after therapeutic hypothermia (TH). The data consisted of sCr observations up to 10 days of postnatal age in neonates who underwent TH during the first 3 days after birth. Available covariates were birth weight (BWT), gestational age (GA), survival, and acute kidney injury (AKI). A previously published population model of sCr kinetics in neonates served as the base model. This model predicted not only sCr but also the glomerular filtration rate normalized by its value at birth (GFR/GFR0). The model was used to compare the TH neonates with a reference full term non-asphyxiated population of neonates. The estimates of the model parameters had good precision and showed high between subject variability. AKI influenced most of the estimated parameters denoting a strong impact on sCr kinetics and GFR. BWT and GA were not significant covariates. TH transiently increased sCr in TH neonates over the first days compared to the reference group. Asphyxia impacted not only GFR, but also the sCr synthesis rate. We also observed that AKI neonates exhibit a delayed onset of postnatal GFR increase and have a higher sCr synthesis rate compared to no-AKI patients. Our findings show that the use of sCr as marker of renal function in asphyxiated neonates treated with TH to guide dose selection for renally cleared drugs is challenging, while we captured the postnatal sCr patterns in this specific population. Graphical Abstract: [Figure not available: see fulltext.].</p

Neuroprotective therapies in the NICU in preterm infants:present and future (Neonatal Neurocritical Care Series)

The survival of preterm infants has steadily improved thanks to advances in perinatal and neonatal intensive clinical care. The focus is now on finding ways to improve morbidities, especially neurological outcomes. Although antenatal steroids and magnesium for preterm infants have become routine therapies, studies have mainly demonstrated short-term benefits for antenatal steroid therapy but limited evidence for impact on long-term neurodevelopmental outcomes. Further advances in neuroprotective and neurorestorative therapies, improved neuromonitoring modalities to optimize recruitment in trials, and improved biomarkers to assess the response to treatment are essential. Among the most promising agents, multipotential stem cells, immunomodulation, and anti-inflammatory therapies can improve neural outcomes in preclinical studies and are the subject of considerable ongoing research. In the meantime, bundles of care protecting and nurturing the brain in the neonatal intensive care unit and beyond should be widely implemented in an effort to limit injury and promote neuroplasticity. IMPACT: With improved survival of preterm infants due to improved antenatal and neonatal care, our focus must now be to improve long-term neurological and neurodevelopmental outcomes. This review details the multifactorial pathogenesis of preterm brain injury and neuroprotective strategies in use at present, including antenatal care, seizure management and non-pharmacological NICU care. We discuss treatment strategies that are being evaluated as potential interventions to improve the neurodevelopmental outcomes of infants born prematurely.</p

Long-term outcome of preterm infants treated with nasal continuous positive airway pressure

This study's aim was to assess neurodevelopmental and growth outcome until the age of 4 years of premature infants placed on early nCPAP, in the setting of the neonatal intensive care unit (NICU) and follow-up program of the Division of Neonatology of the Department of Pediatrics of the University Hospital, Lausanne, Switzerland. All consecutive inborn infants weighing &lt;1500 g or &lt;32 weeks of gestational age admitted to the NICU during two periods of 12 months-7.1996-6.1997 and 7.1998-6.1999-were compared before and after the systematic application of early nCPAP. Of 172 infants admitted to the NICU, 150 (87%) survived. 126 (84%) were tested at 6 months' corrected age, 121 (81%) at 18 months' corrected age, and 117 (78%) at the age of 4 years. Detailed perinatal data were collected. Follow-up included neurological examination, developmental testing and measurement of growth parameters. Statistical analyses were performed. Early application of nCPAP and avoidance of mechanical ventilation showed no adverse effects on neurodevelopment and growth. A significantly higher developmental quotient was found in the nCPAP group at 18 months' corrected age. Several trends were also noted in the nCPAP group with a decrease of intraventricular hemorrhage and in "abnormal neurodevelopment" at 6 months corrected age, a bigger head circumference at all different tested ages and a greater height at 6 and 18 months corrected ages. In conclusion, our study of developmental outcome documents the absence of any harmful effect of early application of nCPAP to treat respiratory failure in very low birthweight infants