Research Article: Early arterial blood gas parameters, clinical features, and neuroimaging findings in neonates undergoing therapeutic hypothermia for suspected hypoxic-ischemic encephalopathy: a retrospective single-center study
Abstract:
Hypoxic-ischemic encephalopathy (HIE) remains an important cause of neonatal mortality and long-term neurodevelopmental impairment. Although therapeutic hypothermia is the standard treatment for term and near-term infants with suspected moderate-to-severe HIE, the relationships among early blood gas parameters, clinical findings, and radiologic abnormalities in cooled neonates are not fully defined.
This retrospective observational study included neonates aged 0–28 days who underwent therapeutic hypothermia for suspected HIE at any neonatal intensive care unit and were subsequently evaluated by the Department of Pediatric Neurology at Biruni University Hospital. Demographic and perinatal characteristics, blood gas parameters, seizure status, electroencephalographic findings, antiepileptic treatment, cranial ultrasonography, and cranial MRI findings were obtained from medical records. Final HIE classification was assigned retrospectively after review of the clinical course, documented seizures, serial neurologic findings, electroencephalographic data, and neuroimaging findings.
A total of 22 neonates were included. Final HIE classification identified no final evidence of HIE in 16 patients (72.7%), stage 1 HIE in 1 (4.5%), stage 2 HIE in 3 (13.6%), and stage 3 HIE in 2 (9.1%). Compared with neonates without HIE, those with any HIE had significantly lower bicarbonate levels ( p =?0.010). Blood gas pH and 5?min Apgar scores also tended to be lower in the HIE group, although without statistical significance. Neonates with seizures had lower gestational age ( p =?0.002) and more negative base excess values ( p =?0.029). Concordance between cranial ultrasonography and MRI was low; many neonates with normal ultrasonography had abnormal MRI findings.
Lower bicarbonate levels were associated with the presence of any-stage HIE compared with no final evidence of HIE, while more severe metabolic acidosis was associated with seizure occurrence. The bicarbonate finding was consistent with previously established evidence and should be interpreted as supportive rather than novel. The discordance between cranial ultrasonography and MRI was consistent with the previously established greater sensitivity of MRI and was considered a supportive secondary finding.
Introduction:
Hypoxic-ischemic encephalopathy (HIE) remains an important cause of neonatal mortality and long-term neurodevelopmental impairment. Although therapeutic hypothermia is the standard treatment for term and near-term infants with suspected moderate-to-severe HIE, the relationships among early blood gas parameters, clinical findings, and radiologic abnormalities in cooled neonates are not fully defined.
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