Background and Purpose Induced hypothermia is thought to work partly by mitigating reperfusion injury in asphyxiated term newborns. The purpose of this study is to assess brain perfusion in the first week of life in these newborns. Patients and Methods In this prospective cohort study, magnetic resonance imaging (MRI) and perfusion imaging by arterial spin labeling (ASL-PI) was used to assess brain perfusion in these newborns. We measured regional cerebral blood flow values on 1–2 MRIs obtained during the first week of life and compared them to values obtained in control term newborns. The same or later MRI scans were obtained to define the extent of brain injury. Results Eighteen asphyxiated and four control term newborns were enrolled; eleven asphyxiated newborns were treated with hypothermia. Those developing brain injury despite being treated with induced hypothermia usually displayed hypoperfusion on day of life (DOL) 1, and then hyperperfusion on DOL 2–3 in brain areas subsequently exhibiting injury. Asphyxiated newborns not treated with hypothermia who developed brain injury also displayed hyperperfusion on DOL 1–6 in brain areas displaying injury. Conclusions Our data show that ASL-PI may be useful for identifying asphyxiated newborns at risk of developing brain injury, whether or not hypothermia is administered. Since hypothermia for 72 hours may not prevent brain injury when hyperperfusion is found early in the course of neonatal hypoxic-ischemic encephalopathy, such newborns may be candidates for adjustments in their hypothermia therapy or for adjunctive neuroprotective therapies.

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Objective The purposes of this feasibility study are to assess: (1) the potential utility of early brain magnetic resonance imaging (MRI) in asphyxiated newborns treated with hypothermia; (2) whether early MRI predicts later brain injury observed in these newborns after hypothermia is completed; and (3) whether early MRI indicators of brain injury in these newborns represent reversible changes. Patients and Methods All consecutive asphyxiated term newborns meeting the criteria for therapeutic hypothermia were enrolled prospectively. Each of them underwent 1–2 “early” MRI scans while receiving hypothermia, on day of life (DOL) 1 and DOL 2–3, and also 1–2 “late” MRI scans on DOL 8–13 and at 1 month of age. Results Thirty-seven MRI scans were obtained in twelve asphyxiated neonates treated with induced hypothermia. Four newborns did develop MRI evidence of brain injury, already visible on early MRI scans. The remaining eight newborns did not develop significant MRI evidence of brain injury on any of the MRI scans. In addition, two patients displayed unexpected findings on early MRIs, leading to early termination of hypothermia treatment. Conclusions MRI scans obtained on DOL 2–3 during hypothermia seem to predict later brain injuries in asphyxiated newborns in this feasibility study. Brain injuries identified during this early time appear to represent irreversible changes. Early MRI scans might also be useful to demonstrate unexpected findings not related to hypoxic-ischemic encephalopathy, which could potentially be exacerbated by induced hypothermia. Additional studies with larger numbers of patients will be useful to more definitively confirm these results.

Objective To evaluate the efficacy and safety of passive cooling during transport of asphyxiated newborns. Study Design Retrospective medical record review of newborns with perinatal asphyxia transported for hypothermia between July 2007 and June 2010. Results Forty-three newborns were transported, 27 of whom were passively cooled. Twenty (74%) passively cooled newborns arrived with axillary temperature between 32.5 and 34.5 °C. One newborn (4%) arrived with a subtherapeutic temperature, and 6 (22%) had temperatures >34.5 °C. Time from birth to hypothermia was significantly shorter among passively cooled newborns compared with newborns not cooled (215 vs. 327 minutes, p<0.01), even though time from birth to arrival was similar (252 vs. 259 minutes, p=0.77). There were no significant adverse events related to passive cooling. Conclusions Exclusive passive cooling for hypoxic-ischemic encephalopathy results in significantly earlier achievement of effective therapeutic hypothermia without significant adverse events.