Table 1.

Area based oxygen desaturation metrics that can be candidates for “hypoxic burden” in OSA

Authors	Metric name	Definition	Automated?	Outcomes
Azarbarzin et al.[26,56▪]	Hypoxic burden [HB]	Sum of areas bounded below by SpO2 Nadir and above by a predefined baseline for each event based on search of candidate desaturations	Yes; however requires search window parameters	• CV risk • CPAP treatment to reduce CV events
de Chazal et al.[52]	Respiratory event desaturation transient area [REDTA]	Sum of the area between the SpO2 trace and the 100% baseline for all manually scored respiratory events	Yes; however requires manually scored respiratory events and search window parameters	• CV risk
Karhu et al.[53▪▪]	Desaturation severity [DesSev]	Sum of desaturation areas bounded below by the SpO2 Nadir and above by a “desaturation baseline” that is based on the starting point of the desaturation	Yes; however requires manually scored respiratory events	• CV risk • Daytime Sleepiness
Linz et al.[55]	Hypoxia load [HL]	Total area bounded below by the raw SpO2 curve and above by the 100% value	Yes; no parameters required	• CV risk • CPAP treatment to reduce CV events
Parekh et al.[4▪▪,57]	Hypoxic burden [HB]	Sum of areas bounded below by SpO2 Nadir and above by the left- and right-peak of the desaturation event	Yes; no parameters required	• CV risk • Daytime sleepiness • Hypertension • CPAP treatment success for vigilance

CPAP, continuous positive airway pressure; CV, cardiovascular.