Correspondence to: performance of the new SmartCardia wireless, wearable oximeter: a comparison with arterial SaO2 in healthy volunteers

In a recent publication in BMC Anesthesiology, Rincon, et al.present accuracy data for three pulse oximeters with sensors located at three different anatomic sites. Their results for the Masimo Radical with fingertip sensor are erroneous, and we present valid data here. Rincon, et al.show a Bias ± Precision of 2.02 ± 4.6, while the correct laboratory values are -0.01 ± 1.16. The most probable reason for these invalid data is that insufficient time was used at each saturation plateau to allow stabilization of SpO(2) readings on a fingertip sensor. It has been shown in the literature that fingertip sensors require at least a full minute of stable oxygenation conditions before their readings will be the same as earlobe sensors.