A comparison of two pulse oximeters. Assessment of accuracy at low arterial saturation in paediatric surgical patients.

The accuracy of the Ohmeda Biox 3700 and the Nellcor N100E was assessed in 25 cyanosed children. The readings obtained from the two pulse oximeters were compared with arterial blood measurements using a Radiometer OSM-2 co-oximeter. Both pulse oximeters differed significantly from the co-oximeter measurements and in these patients the error of both machines exceeded the manufacturers' claims. However, the machines appeared to reflect changes in saturation accurately in the same patient.