Transitional Changes in Cerebral Blood Volume at Birth.

BACKGROUND

Near-infrared spectroscopy (NIRS) enables non-invasive measurements of changes in the concentration of oxygenated (x0394;HbO2) and reduced (x0394;HbR) haemoglobin. Changes in total haemoglobin (x0394;HbT = x0394;HbO2 + x0394;HbR) provide information on changes in cerebral blood volume (CBV).

OBJECTIVE

The aim was to evaluate the behaviour of CBV during immediate postnatal transition in term infants.

DESIGN

This observational study was conducted at the Medical University of Graz. NIRS measurements were carried out in term infants without need for respiratory support by using 'NIRO 200-NX' (Hamamatsu) over the first 15 min after birth.

RESULTS

109 infants with a mean gestational age of 38 + 6 weeks (±7 days) and birth weight of 3,242 g (±481) were included. Related to a reference value at minute 15, a significant decrease of HbT was observed for each minute within the study period. The mean (±SD) decrease of HbT of 17 (±40) µmol/l from minutes 2 to 15 represents a decrease of CBV of 1.0 ml/100 g brain (±2.2).

CONCLUSIONS

In healthy newborns, CBV decreased over the whole study period. This likely reflects a physiological process. The impact and clinical relevance of different CBV behaviour during immediate transition needs to be investigated in further studies.