Therefore, your PR interval may or may not be short and I wouldn't worry until you receive a full report. The PR interval is short in children and lengthens as we get older. A normal value in adults is 120 to 200 milliseconds. It is however shorter than 120ms in approximately 2 to 4% of the adult population.
It is SaO2 that measures oxygen saturation of hemoglobin, and it should be clear that it depends on the partial pressure of arterial oxygen. If PaO2 drops, there's less dissolved oxygen, and therefore less saturation of hemoglobin with oxygen.
RE: What is the difference between SpO2 and SaO2 in pulse oximetry? I know pulse oximetry measures hemoglobin saturation to oxygen but what is the difference b/w SaO2 and SpO2?est Answer: The difference is how the measurement is taken SpO2 is an indirect measurement using a finger probe, ear sensor or similar device. SaO2 is a direct measurement using a blood sample such as an arterial blood gas analysis. Source(s): Grogling Â· 5 years ago.