Oxygen saturation measurement method, there are two main: 1, arterial blood gas analysis, the most commonly used arterial blood gas analysis in hospitals to measure oxygen saturation, because this measurement method is more accurate, but belongs to the invasive examination. Measurement of arterial blood gas oxygen saturation should be collected arterial blood, in the radial artery or femoral artery collection, and then use the blood gas analyzer to analyze and determine. 2, percutaneous oximetry monitoring, you can use the monitor above the percutaneous oximetry, but also with a separate percutaneous oximetry measurement, clamping the end of the finger measurement. This kind of transcutaneous oximetry monitoring is less accurate and will have some error.