Cerebral tissue oxygenation index in very premature infants

Aim: To describe normal values of the cerebral tissue oxygenation index (TOI) in premature infants. Methods: TOI was measured by spatially resolved spectroscopy in preterm infants on the first 3 days of life. Infants with an abnormal cranial ultrasound were excluded. Other simultaneously measured variables were Pao(2), Paco(2), pH, mean arterial blood pressure, heart rate, hoemoglobin, glycaemia, and peripheral oxygen saturation. Results: Fifteen patients with a median postmenstrual age of 28 weeks ere measured. There was a significant increase in median TOI over the first 3 days of life: 57% on day 1, 66.1 % on day 2, and 76.1 % on day 3. Multiple regression analysis showed no correlation between TOI and postmenstrual age, peripheral oxygen saturation, mean arterial blood pressure, Pao(2), Paco(2), and haemoglobin concentration. Conclusion: Cerebral TOI increases significantly in the first 3 days of life in premature babies. This increase probably reflects the increase in cerebral blood flow at this time.