A REVIEW OF THE PRINCIPLES OF PULSE OXIMETRY AND ACCURACY OF PULSE OXIMETER ESTIMATES DURING EXERCISE

This article reviews the principles of pulse oximetry and assesses the accuracy of pulse oximeter measurements obtained during exercise, bas ed on reports of 10 studies that evaluated 24 pulse oximeters. Nine of the studies used cycle exercise, and 1 study utilized treadmill runni ng for mode of activity. Subject populations included patients with ca rdiovascular or pulmonary disorders, nondisabled individuals, and athl etes. Studies were performed under normoxic and hypoxic conditions, an d 5 of the 10 studies validated 18 pulse oximeters at arterial oxyhemo globin saturation (%HbO2) levels of less-than-or-equal-to 78%. Sixteen of the 24 pulse oximeters (67%), from 7 of the 10 studies, observed p ulse oximeter estimates (%SpO2) during exercise to be accurate, at lea st when %HbO2 was greater-than-or-equal-to 85% in nonsmokers. However, the degree of accuracy of the pulse oximeters was variable, even amon g the same models Recent studies suggest the current generation of fin ger-probe-equipped pulse oximeters may be more accurate than ear-probe -equipped models. We recommend that clinicians carefully secure the pr obe, monitor signal strength, be wary of %SpO2 values of less-than-or- equal-to 68% to 78% to avoid undetected severe hypoxemia, and be alert to whether a patient is a smoker, in which case %SpO2 will likely be overestimated. Researchers interested in using pulse oximeter estimate s should validate their particular pulse oximeter(s) via arterial bloo d sampling.