Evaluation of a new pulse oximeter testing device

Abstract

Background: Valid routine testing of pulse oximeters and their sensors is problematic. A suitable testing device must not only generate the pulsatile signal the pulse oximeter requires for its operation, but must possess light absorption characteristics similar to those of living tissue. A new device called Pulse Oximeter Tester (POT) has recently become available which, it is claimed, addresses these problems. Purpose: To evaluate the POT as a suitable stimulus for pulse oximeters. Method: We tested all the pulse oximeters and their sensors with a set of POTs simulating blood oxygen saturation of 80%, 90% and 100%. The tests were performed at simulated heart rates of 30, 75 and 110 bpm. Results: The SpO2 readings (mean ± SD) obtained with the 80%, 90% and 100% POTs were 80.7 ± 1.3%, 90.3 ± 0.9% and 100 ± 0.0% respectively. There were no significant differences in readings obtained at the different simulated heart rates. Two pulse oximeters gave readings that deviated more than 2 SD from the mean. Their sensors were subsequently found to be defective. Conclusion: POTs provide suitable stimuli for testing pulse oximeters. In our study sample they were found to be highly specific, but of unknown sensitivity.