Background CFOE represents the balance between cerebral oxygen delivery and consumption, and may be a useful method to assess oxygenation .Subjects Stable controls (n=41, median gestation 29 w); anaemic babies (n=36, median gestation 26.5w); hypotensive babies (n=22, median gestation 27w). Measurements During the neonatal period CFOE was calculated from the arterial saturation by pulse oximetry and cerebral venous saturation measured using near infrared spectroscopy on one occasion.

Results Mean CFOE (sd) in controls was 0.291(0.06), in anaemic babies was 0.310 (0.08) and hypotensive babies was 0.284 (0.06). There was no difference between CFOE in controls and anaemic babies (p=0.24) and hypotensive babies (p=0.71). When anaemic babies were transfused there was a decrease in CFOE to 0.276 (0.05) (p=0.02). There was no relationship between CFOE and blood pressure (n=22,r=0.26, p=0.24), a weak relationship with the haemoglobin concentration (n=91, r=-0.25,p=0.02) but not with the haemoglobin F fraction (n=55,r=0.23, p=0.09).

Conclusion CFOE is not significantly higher either in babies with anaemia or hypotension but decreased after blood transfusion. When oxygen delivery fell, oxygenation may have been maintained by cerebral blood flow autoregulation or decreases in oxygen consumption