Background: FOE, the ratio of oxygen delivery (DO2) to consumption, may predict when DO2 is inadequate for metabolic demands, indicating a need for transfusion. Aim: To examine the relationship between FOE and haemoglobin concentration (Hb) and haemoglobin F fraction(HbF).

Subjects: 28 preterm neonates without clinical symptoms of anaemia.

Measurements: Arterial saturation by pulse oximetry, venous saturation and blood flow in the lower forearm by NIRS with venous occlusion.

Results: The mean (SD) FOE was 0.28 (0.05). FOE correlated negatively with Hb (r=-0.56, p=0.003) but there was no relationship with HbF(r=-0.1, p=0.68).

Conclusion: These findings contrasted with measurements over the upper forearm which had shown a higher mean FOE and a positive correlation with HbF. Values of forearm FOE vary according to the position of measurement. This may be due to the relative amount of muscle from which the measurements are made.