Impact of oximetry resolution on detection of oxyhemoglobin desaturation events and hypoxic burden in patients with obstructive sleep apnea.

BACKGROUND

Oxyhemoglobin desaturation events (ODE) are major contributors to the detection and classification of obstructive sleep apnea (OSA). However, variations in pulse oximetry resolution may affect ODE detection and, consequently, the oxyhemoglobin desaturation index (ODI) and the hypoxic burden (HB). We hypothesized that traditional low-resolution pulse oximetry (TRPO, 1 %), which is designed to round up decimal points in the readout, compared to high-resolution pulse oximetry (HRPO, 0.1 %), impacts on ODI and HB.

METHODS

Consecutive deidentified diagnostic sleep studies of patients with suspected OSA, recorded between February and June 2023, were extracted from the Biologix database and analysed. HRPO data from the Biologix oximeter was compared with mathematically generated TRPO data. ODI and HB differences between HRPO and TRPO were compared using oxyhemoglobin desaturation criteria of 3 % and 4 %. Effect sizes were assessed using Cohen's d. Confusion matrices, Bland-Altman plots and Cohen's Kappa were used to assess the agreement on ODI measurements between HRPO and TRPO.

RESULTS

A total of 9551 diagnostic sleep studies were analysed. Compared to the HRPO, the TRPO significantly overestimated ODI and HB for the 3 % desaturation criterion: ODI3 %: 14.3 [6.9-25.3] vs. 21.1 [12.0-34.0] events/h; HB3 %: 23.5 [10.2-46.1] vs. 33.2 [17.8-57.1] % min/h; as well as the 4 % desaturation criterion (p < 0.0001 for all comparisons). Overestimation of ODI and HB was amplified among patients with no or mild forms of OSA.

CONCLUSION

TRPO overestimates the ODI due to the rounding effect, leading to overestimation of OSA diagnosis, OSA severity and HB determination.