Fig. 2
Performance of the sleep apnea and SpO2 measures in predicting postoperative respiratory depression. AHI: apnea–hypopnea index, SpO2 STD: standard deviation of overnight SpO2 signal, SpO2 ENT: entropy of overnight SpO2 signal, BAB: below average burden, ODB AVG: average of normalized desaturation burdens of overnight desaturation episodes with ≥ 3% drops, ODB STD: standard deviation of normalized desaturation burdens of overnight desaturation episodes with ≥ 3% drops, ODB ENT: entropy of normalized desaturation burdens of overnight desaturation episodes with ≥ 3% drops, NDB: Overall nocturnal desaturation burden. All models included sex, BMI, and pre-existing cardiorespiratory disorders (arterial hypertension, coronary artery disease, stroke, angina, myocardial infarction, heart failure, coronary revascularization, asthma, chronic obstructive pulmonary disease) to adjust for patients’ demographics. The error bars show the 95% confidence interval