I am having a difficult time understanding what these mean:
I am studying oximetry in school, and I can't find a clear definition in my books or medical encyclopedia.
Feb 15, '04
SpO2: what you read off the pulse oximetry machine (pulse oximetry oxygen saturation). Normal is 95-100%.
SvO2: oxygen saturation in central venous blood (it's like the SaO2 of venous blood). Normal is 75%. If you subtract the SvO2 from the SaO2, you can identify how much oxygen is being used by the patient. For example: SaO2 = 100%, and SvO2 = 75%, oxygen consumption is 25%.
PaO2: amount of oxygen dissolved in the blood, measured as a partial-pressure of oxygen. This oxygen is not attached to hemoglobin, rather it is free and floating around in the blood. Tissues cannot use PaO2 effectively and only about 3% of tissue oxygenation comes from the PaO2. Normal is 80-100 torr.
SaO2: amount of hemoglobin that has oxygen bound to it. 100% means that all hemoglobin binding sites have oxygen bound to them. This is measured on a blood gas. 97% of tissue oxygenation comes from the SaO2. Normal is 95-100%.
I hope this helps,
David Woodruff. MSN, RN, CNS, CCRN
President, Ed4Nurses, Inc.
Last edit by dwoodruff on Feb 15, '04
Feb 15, '04
a lot! That helped!