LAUSR

Background The pattern of oxygen saturation (SaO2) measured by pulse oximetry at the finger after apnea-induced hypoxemia has been shown to be a delayed and distorted version of the same measurement at the ear (i.e. in close proximity to carotid chemoreceptors). The impact of these different sites of recording on measures of hypoxemia during Cheyne-Stokes respiration (CSR) in heart failure (HF) patients is not known. Aims and objectives The aim of this study was to investigate the difference in SaO2 measured at the ear and at the finger during CSR in HF patients. Methods We studied 8 HF patients who developed CSR during a 40min laboratory recording of SaO2 by two identical pulse oximeters with finger and ear probe. The average SaO2, the mean value of oxygen desaturations and of minima and maxima and the delay between ear and finger signals were computed and compared by bias and 95% limits of agreement (LoA). Results Data are reported in Table as mean±SD. The delay between finger and ear signals was 20.6±7.2s. Conclusions This pilot study shows that, despite little, non-significant bias, the LoA were rather wide, indicating poor agreement between SaO2 measurements at the ear and finger, with clinically relevant differences in some patients. This may potentially lead to wrong assessment of the hypoxemic burden in some HF patients during CSR.