What physiological parameter correlates with oxygen levels in the blood during sleep?

Blood oxygen saturation directly measures the amount of oxygen carried in the blood and is a crucial parameter when assessing respiratory function and overall oxygenation during sleep. This measurement is often obtained through a pulse oximeter and is expressed as a percentage of oxygen-saturated hemoglobin relative to total hemoglobin in the blood.

Monitoring blood oxygen saturation is essential because low levels can indicate compromised respiratory function, which can lead to conditions such as sleep apnea. As a patient transitions through different sleep stages, varying metabolic demands may affect their oxygen levels; thus, tracking blood oxygen saturation helps clinicians evaluate the effectiveness of respiration and the body's ability to deliver oxygen to tissues.

Other physiological parameters listed, such as heart rate variability, carbon dioxide levels, and electroencephalography readings, do not specifically measure oxygen levels and are thus less directly correlated with the assessment of blood oxygenation. Heart rate variability can indicate autonomic nervous system function but does not provide direct information about oxygen saturation. Carbon dioxide levels can indicate respiratory function but are not a direct measure of oxygen levels. Electroencephalography is primarily used to assess brain activity and does not measure respiratory or circulatory parameters.