[Reproducibility of pulse oximetry in the fingers of the hands]

Partial oxygen saturation from pulse oximetry is most often obtained from the fingers of the hands; however, it is not known whether any of the fingers are ideal for estimating partial oxygen saturation.

To describe the partial oxygen saturation behaviour obtained from the fingers of both hands.

Using a cross-sectional analytical design, the partial oxygen saturation was consecutively estimated in the fingers of both hands. Demographic data were obtained from healthy subjects, and they were analyzed using repeated-measures analysis of variance; reproducibility was calculated using the mean difference (limits of agreement) and its magnitude using the intraclass correlation coefficient or ICC (95% confidence interval [95% CI]); a p value < 0.05 was considered significant.

1000 determinations of partial oxygen saturation were studied from the fingers of both hands of 100 subjects (64% women) whose average age was 34 ± 10 years old and whose body mass index (BMI) was of 23.5 ± 5 kg/m2. Partial oxygen saturation was 90.3 ± 4% and reproducibility was almost perfect in all combinations; however, the right index finger versus right ring finger combination was the best: 90.3 ± 4.1% versus 90.5 ± 4% mean difference (limits of agreement) -0.2 (2.5, -2.8) between both and the ICC (95% CI) 0.942 (0.916, 0.961).

Partial oxygen saturation is reproducible in all fingers, with no clinically relevant differences.