Cerebral Oxygenation Patterns during Electroclinical Neonatal Seizures

A 2,950-g-weighted infant was born at 35 weeks' gestation by emergency C-section due to abnormal cardiotocography. Full neonatal resuscitation was required; Apgar's scores were 1–4–4, cord gas pH 6.87, base deficit 18.4 mmol/L. The infant was admitted to the neonatal intensive care unit immediately after birth and started on therapeutic hypothermia due to clinical signs of hypoxic-ischemic encephalopathy (HIE) and suppressed activity of the amplitude-integrated EEG (aEEG). A continuous monitoring of cerebral oxygen saturation (cSO₂) by near-infrared spectroscopy (NIRS), which used to provide useful information on brain oxygenation and, indirectly, the underlying haemodynamics fluctuations, was associated for the whole cooling period. At 45 hours of life, the infant developed serial clinical seizures (prolonged hypertonic spasms of upper and lower limbs) with electrographic correlate, requiring treatment with midazolam, phenobarbital, and phenytoin. During this period, rhythmic cSO₂ fluctuations (range: 62–94%) were seen at NIRS monitoring ([Fig. 1]). These cSO₂ patterns showed an evident temporal relationship with ictal aEEG activity and were no longer evident after seizures ceased. This finding suggests the occurrence of possible neurovascular coupling mechanisms during neonatal seizures; in this context, NIRS might play role as a complementary monitoring tool in infants at high ictal risk.

Fig. 1 Cerebral oxygenation (cSO₂) patterns and cerebral function monitoring (CFM) trace during seizures (highlighted by blue bars). Drops in peripheral oxygen saturation < 80% are marked as desat. Ongoing medications are shown as blue triangles (boluses) and blue lines (continuous infusions). Ventilation modality and changes in inspired oxygen fraction (FiO₂) are also provided. SIPPV+VG, synchronized intermittent positive pressure ventilation + volume guarantee.

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