What is O2 desaturation?
This stands for oxygen desaturation. During the sleep study, your pulse oximeter measures the blood oxygen levels. The normal blood oxygen saturation is 98%-100%. When the blood oxygen saturation falls below 90% during sleep, it is considered abnormal and qualifies for a diagnosis of sleep apnea. In patients with severe sleep apnea, the oxygen saturation may fall below 60% during apneic episodes.