Accuracy and precision of pulse oximeter at different sensor locations in patients with heart failure.

Background: Despite its wide use in clinical practice, few studies have assessed the role of pulse oximetry in patients with heart failure. We aimed to evaluate the accuracy and precision of the pulse oximeter in patients with heart failure and to determine this accuracy at three different sensor locations.

Methods: Comparison of pulse oximetry reading (SpO₂) with arterial oxygen saturation (SaO₂) was reported in 3 groups of patients with heart failure (HF); those with ejection fraction (EF) >40%, those with EF <40%, and those with acute HF (AHF) with ST and non-ST segment elevation acute myocardial infarction (STEMI and non-STEMI).

Results: A total of 235 patients and 90 control subjects were enrolled. There were significant differences in O₂ saturation between control and patients' groups when O₂ saturation is measured at the finger and toe, but not the ear probes; p=0.029, p=0.049, and 0.051, respectively. In HF with EF>40% and AHF with O₂ saturations >90%, finger oximetry is the most accurate and reliable, while in HF with EF<40% and in patients with AHF with O₂ saturations <90%, ear oximetry is the most accurate.

Conclusion: Pulse oximetry is a reliable tool in assessing oxygen saturation in patients with heart failure of different severity. In HF with EF>40% and in AHF with O₂ saturations >90%, finger oximetry is the most accurate and reliable, while in HF with EF<40% and in patients with AHF with O₂ saturations <90%, ear oximetry is the most accurate. Further studies are warranted.