What is the most common method used to monitor blood oxygen saturation during polysomnography?

Pulse oximetry is a non-invasive method widely used to monitor blood oxygen saturation during polysomnography. This technique employs a small device, often clipped to a fingertip or earlobe, which uses light sensors to measure the amount of oxygen in the blood. The reason for its prevalence in sleep studies is due to its ability to provide real-time data on oxygen saturation levels without needing to perform more invasive procedures. This is particularly beneficial in a sleep setting, where patient comfort and minimal disturbance are crucial.

In contrast, capnography focuses on measuring carbon dioxide levels rather than oxygen saturation, which does not directly assess the oxygenation status of the blood. Invasive blood sampling is not practical or efficient for continuous monitoring during sleep studies, as it would require frequent blood draws, leading to discomfort and potential complications for the patient. Transcutaneous monitoring measures oxygen and carbon dioxide through the skin, but it is less commonly used than pulse oximetry due to factors such as accuracy, cost, and ease of use. Therefore, pulse oximetry remains the most common and effective method for monitoring blood oxygen saturation in the context of polysomnography.