title: Accuracy sensitivity to carboxyhemoglobin, and speed of response of the Hewlett-Packard 47201A ear oximeter.
abstract: We have shown that the Hewlett-Packard 47201A ear oximeter measures arterial O2 saturation within 95 per cent confidence limits of +/- 4 per cent when arterial blood saturation is more than 65 per cent, but at lower saturations the oximeter consistently provides a reading that is too low. The oximeter is sensitive to carboxyhemoglobin, progressively overestimating arterial saturation as carboxyhemoglobin concentration increases from 0 to 18 per cent. The time response is exponential, with a normal time constant of 3 sec, but this is halved in the fast mode or operation.
mesh_terms: D002263:Carboxyhemoglobin / Q000032:analysis*; D004431:Ear, External / Q000098:blood supply; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D010092:Oximetry / Q000295:instrumentation* / Q000592:standards; D012044:Regression Analysis; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D002263:Carboxyhemoglobin