A comparison of fifteen pulse oximeters. Part I: A clinical comparison; Part II: A test of performance under conditions of poor perfusion.

Fifteen pulse oximeters were compared. Their physical characteristics, price, warranty, information handling and displays were catalogued. Times for changes in data display and susceptibility to interference were assessed. A model for comparison of oximeters under conditions of poor perfusion was developed using a tourniquet to progressively diminish limb perfusion pressure (systolic minus tourniquet pressure). The oximeters evidenced a wide variety of features and performance in poor perfusion states. Instruments lacking a beep varying in pitch with saturation or a waveform/pulse bar display of plethysmograph signal were considered less satisfactory. The majority of instruments, with some notable exceptions, performed remarkably well in a state of diminished perfusion. The study demonstrates that purchasers of pulse oximeters need to exercise care in assessing the suitability of particular instruments to their specific requirements.