Pathophysiologic mechanisms involved in neonatal hypoxic ischemic encephalopathy (HIE) are associated with complex changes of blood flow and metabolism. Therapeutic hypothermia (TH) is effective in reducing the extent of brain injury, but it remains uncertain how TH affects cerebral blood flow (CBF) and metabolism. Ten neonates undergoing TH for HIE and seventeen healthy controls were recruited from the NICU and the well baby nursery, respectively. A combination of frequency domain near infrared spectroscopy (FDNIRS) and diffuse correlation spectroscopy (DCS) systems was used to non-invasively measure cerebral hemodynamic and metabolic variables at the bedside. Results showed that cerebral oxygen metabolism (CMRO 2i ) and CBF indices (CBF i ) in neonates with HIE during TH were significantly lower than post-TH and age-matched control values. Also, cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO 2 ) were significantly higher in neonates with HIE during TH compared with age-matched control neonates. Post-TH CBV was significantly decreased compared with values during TH whereas SO 2 remained unchanged after the therapy. Thus, FDNIRS-DCS can provide information complimentary to SO 2 and can assess individual cerebral metabolic responses to TH. Combined FDNIRS-DCS parameters improve the understanding of the underlying physiology and have the potential to serve as bedside biomarkers of treatment response and optimization. Keywords: cerebral blood circulation; cerebral hemoglobin oxygen saturation; cerebral metabolic rate of oxygen consumption; near infrared spectroscopy; neonatal hypoxic ischemic encephalopathy; therapeutic hypothermia INTRODUCTION Neonatal hypoxic ischemic encephalopathy (HIE) occurs in B2 to 3 per 1,000 live births in the USA, with devastating consequences including neurodevelopmental disabilities such as cerebral palsy, life-long cognitive impairment, and epilepsy.1 In HIE, there is a period of reduced blood flow (ischemia) and oxygen delivery (hypoxia) followed by reperfusion with transient energy recovery, and then a secondary energy failure.2 Treatment is aimed at preventing the cascade of events that begin with reperfusion and lead to secondary energy failure and inevitable cell death; this is the 'window of opportunity.' 3 Theories for injury mechanisms in this window suggest a central role for excitotoxicity and oxidative stress with the injury evolving over hours to weeks.2 Therapeutic hypothermia (TH) is the treatment of choice for HIE, as it is the only treatment with proven efficacy and acts through a variety of mechanisms, including those associated with decreased neuronal energy metabolism. 4 Although early studies showed that TH decreased rates of both mortality and disability, recently published long-term outcomes have demonstrated significance only for decreased mortality rates.5 In addition, a recent

Little is known about cerebral blood flow, cerebral blood volume (CBV), oxygenation, and oxygen consumption in the premature newborn brain. We combined quantitative frequency-domain near-infrared spectroscopy measures of cerebral hemoglobin oxygenation (SO2) and CBV with diffusion correlation spectroscopy measures of cerebral blood flow index (BFix) to determine the relationship between these measures, gestational age at birth (GA), and chronological age. We followed 56 neonates of various GA once a week during their hospital stay. We provide absolute values of SO2 and CBV, relative values of BFix, and relative cerebral metabolic rate of oxygen (rCMRO2) as a function of postmenstrual age (PMA) and chronological age for four GA groups. SO2 correlates with chronological age (r=−0.54, P value ⩽0.001) but not with PMA (r=−0.07), whereas BFix and rCMRO2 correlate better with PMA (r=0.37 and 0.43, respectively, P value ⩽0.001). Relative CMRO2 during the first month of life is lower when GA is lower. Blood flow index and rCMRO2 are more accurate biomarkers of the brain development than SO2 in the premature newborns.

Background To examine the use of abdominal ultrasound (AUS) as a diagnostic adjunct in the diagnosis of necrotizing enterocolitis (NEC) in cases where abdominal radiography (AXR) is equivocal in order to reduce unnecessary antibiotic use in neonates. Methods Retrospective study (2017–2019) of infants undergoing NEC evaluation with equivocal AXR findings (n = 54). Paired AXR and AUS were reviewed with respect to presence or absence of pneumatosis. Concordance of AUS findings with decision to treat for NEC was evaluated. Results Among 54 infants where AXR was equivocal, AUS demonstrated presence of pneumatosis in 22 patients (41%), absence of pneumatosis in 31 patients (57%), and was equivocal in 1 patient. All patients with pneumatosis on AUS were treated for NEC. Of 31 patients without pneumatosis on AUS, 25 patients (78%) were not treated for NEC. Patients without pneumatosis on AUS received a significantly shorter mean duration of antibiotics compared to those with pneumatosis (3.3 days (+/− 4.8 days) vs 12.4 days (+/− 4.7 days)); p < 0.001). Of those patients not treated, none required treatment within 1 week following negative AUS. Conclusion AUS is a valuable tool for evaluating the presence or absence of pneumatosis in the setting of equivocal AXR. Absence of pneumatosis on AUS informs clinical decision making and reduces unnecessary treatment and antibiotic usage.