What physiological state is best assessed using overnight oximetry?

Overnight oximetry is a valuable tool for assessing nocturnal oxygen saturation levels, which is particularly relevant in diagnosing sleep apnea. During sleep, individuals with sleep apnea experience intermittent episodes of airway obstruction, leading to reductions in oxygen levels. Overnight oximetry can track SpO2 (peripheral capillary oxygen saturation) during sleep, identifying periods of hypoxemia associated with these apnea events.

Monitoring oxygen saturation trends while the patient is asleep helps distinguish sleep apnea from other conditions that may cause abnormal breathing patterns, making it a primary diagnostic method for this physiological state. The objective findings from overnight oximetry can provide insights into the severity and frequency of desaturation episodes, guiding further evaluation or treatment for sleep apnea.

Other conditions listed, such as acute asthma attacks, exacerbations of chronic obstructive pulmonary disease, and heart failure, may also impact oxygen levels, but they are typically assessed through different means and settings rather than through the specific context of overnight breathing patterns and oxygen saturation during sleep.