Validity Of Heart Rate Obtained Via Pulse Oximetry

Abstract

In addition to monitoring oxygen saturation in those with chronic obstructive pulmonary disease (COPD), pulse oximetry is used to monitor heart rate (HR) during exercise testing and training. However, evidence validating the use of pulse oximeters for HR monitoring is lacking. PURPOSE The purpose of this study was to evaluate the validity of two commercially available pulse oximeters for the measurement of HR as compared to heart rates determined from an electrocardiogram (ECG). METHODS HR was measured in 33 COPD patients (age=68.7±10.7 yrs) at rest, during a graded exercise test, and during recovery. The Ohmeda pulse oximeter (Biox 3740; Louisville, CO) was placed on the right hand throughout the test, and the Respironics pulse oximeter (Model 950; Kennesaw, GA) was placed on the left hand. HR was also determined from a 12-lead ECG. RESULTS HR values from oximetry were significantly correlated to the ECG HR, Ohmeda (r=0.892, p < 0.001) and Respironics (r=0.722, p < 0.001). The ECG HR (102.3±24.3) was not significantly different from Ohmeda HR (98.1±24.2), nor was the ECG HR (102.3±24.4) significantly different from the Respironics HR (96.4±21.9). Inspection of Bland-Altman plots revealed a mean difference between the ECG and Ohmeda of 4.2 (95% CI: −18.0 to 26.2), and a mean difference between the ECG and Respironics of 5.9 (95% CI: −28.3 to 40.0). CONCLUSIONS Despite significant correlations and no significant mean differences between HR measures obtained from the pulse oximeters and those from the ECG, the Bland-Altman analysis suggests a large level of disagreement between the HR from the two pulse oximeters and the ECG HR. Therefore, use of these pulse oximeters for monitoring HR should be limited. Supported by NIH grants HL53755 and AG10484.