A comparison of finger and forehead pulse oximeters in heart failure patients during maximal exercise

Background: Pulse oximeters, clinically used to measure oxygen saturation (SpO₂), rely on adequate perfusion of the tissues over which they are placed. Heart failure (HF) patients can have impaired peripheral perfusion which may compromise the accuracy of a peripherally placed pulse oximeter. This decrease in peripheral perfusion may be especially apparent during exercise. The objective of this study was to determine if pulse oximeter accuracy is dependent on location in heart failure patients during peak exercise. Methods: 20 participants with HF (7F, age 64.±11 yr) and 9 participants with coronary artery disease as controls (CAD: 3F, age 66±5 yr) performed a maximal exertion treadmill exercise stress test while wearing both finger and forehead pulse oximeters. Results: At peak exercise, the two pulse oximeters measurements of SpO₂ differed from each other by 3.8 ± 3.3% in the HF group (p<0.01) and 2.0 ± 1.4% in the CAD group (p = 0.065). The difference between the pulse rate from the pulse oximeters and the heart rate from the 12-lead ECG in the HF group was 12±20 BPM (p<0.01) for the finger pulse oximeter, and 2 ± 3 BPM (p = 0.162) for the forehead pulse oximeter. Conclusions: Forehead pulse oximeters may be more reliable compared to finger pulse oximeters in obtaining SpO₂ measurements in HF patients during a treadmill maximal exercise test.