Optimal Therapeutic Hypothermia Temperature Following Perinatal Asphyxia: A Magnetic Resonance Spectroscopy Biomarker & Immunohistochemistry Study in the Newborn Piglet.

Nicola Jayne Robertson¹, Stuart Faulkner¹, Manigandan Chandrasekaran¹, Alan Bainbridge², David Price², Dorottya Kelen¹, Aron Kerenyi¹, Sudhin Thayyil¹, Elizabeth Powell¹, Ernest Cady², Gennadij Raivich¹, Xavier Golay³

Although therapeutic hypothermia is safe and effective for neonatal encephalopathy, 50% infants have adverse outcomes; clinical trials are exploring cooling to deeper temperatures for longer periods. We used our validated piglet model of perinatal asphyxia to assess the effect of cooling to 35oC, 33.5oC, and 30oC on 1H MRS-based biomarkers and immunohistochemical markers of cell death. Mild cooling (33.5oC and 35oC) was neuroprotective, but moderate cooling (30oC) led to increased cell death and raised Lac/Cr in the deep grey matter but not white matter / cortex. This confirms regional differences in optimal cooling temperatures and has importance for clinical protocols.