Abstract
Summary: The accuracy of the Ohmeda Biox 3700 and the Nellcor N100E was assessed in 25 cyanosed children. The readings obtained front the two puise 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.