BACKGROUND: Opportunities for adjunct therapies with cooling in neonatal encephalopathy are imminent; however, robust
biomarkers of early assessment are lacking. Using an optical platform of broadband near-infrared spectroscopy and diffuse
correlation spectroscopy to directly measure mitochondrial metabolism (oxCCO), oxygenation (HbD), cerebral blood flow (CBF), we
hypothesised optical indices early (1-h post insult) after hypoxia-ischaemia (HI) predicts insult severity and outcome.
METHODS: Nineteen newborn large white piglets underwent continuous neuromonitoring as controls or following moderate or
severe HI. Optical indices were expressed as mean semblance (phase difference) and coherence (spectral similarity) between signals
using wavelet analysis. Outcome markers included the lactate/N-acetyl aspartate (Lac/NAA) ratio at 6 h on proton MRS and TUNEL
cell count.
RESULTS: CBF-HbD semblance (cerebrovascular dysfunction) correlated with BGT and white matter (WM) Lac/NAA (r
2 = 0.46,
p = 0.004, r
2 = 0.45, p = 0.004, respectively), TUNEL cell count (r
2 = 0.34, p = 0.02) and predicted both initial insult (r
2 = 0.62,
p = 0.002) and outcome group (r
2 = 0.65 p = 0.003). oxCCO-HbD semblance (cerebral metabolic dysfunction) correlated with BGT
and WM Lac/NAA (r
2 = 0.34, p = 0.01 and r
2 = 0.46, p = 0.002, respectively) and differentiated between outcome groups (r
2 = 0.43,
p = 0.01).
CONCLUSION: Optical markers of both cerebral metabolic and vascular dysfunction 1 h after HI predicted injury severity and
subsequent outcome in a pre-clinical model
