A Buccal Mucosal Oximeter Accurately Measures Arterial Oxyhemoglobin Saturation

While arterial oxyhemoglobin saturation (SaO₂) decreases during sleep in many patients with sleep apnea and pulmonary diseases, personalized oximeters suitable for multi-night monitoring of SpO₂ are not readily available. The present report describes a custom buccal mucosal intraoral oximeter that might provide the opportunity for such long-term monitoring given its strong accuracy in measuring SpO₂ over a range of clinically relevant hypoxemia.

The intraoral buccal mucosal oximeter was constructed by encapsulating a reflectance pulse oximeter in an overlay of the maxillary dentition. Accuracy was assessed during non-motion conditions in normal participants (n = 12) made progressively hypoxic by decreasing the partial pressure of end-tidal oxygen (PETO₂). CO-oximeter values of SaO₂ from arterial blood constituted the "gold standard" for comparison with the buccal mucosal oximeter's values. The oximeter's pulse rate and an electrocardiogram (ECG) determined heart rate were also compared.

Analysis of 325 paired SaO₂ values from the CO-oximeter and buccal mucosal oximeter yielded the following: r = 0.95; bias = 0.72; and accuracy root-mean-square (A_RMS) = 2.94%. Results from the pulse rate/ECG analysis were: r = 0.99; bias = 0.30; and A_RMS = 2.08 bpm.

These results reveal robust accuracy of the buccal mucosal oximeter measurement of SaO₂ and pulse rate, as shown by good agreement with a "gold standard" over a wide range of arterial hypoxemia. Such clinically acceptable accuracy indicates that this novel reflectance oximeter may prove useful in management of patients with sleep-induced hypoxemia by allowing for long-term monitoring of SaO₂.