What’s The Difference Between Oxygen Saturation And PaO2?

I often teach classes for RNs who are orienting to our preoperative and recovery areas. Hypoxemia and hypoxia occur commonly among our perioperative patients so I spend a lot of time on recognizing early signs of respiratory distress such as tachycardia, tachypnea, cyanosis, agitation, and changes in mental status.

Pulse oximetry is one obvious monitoring tool to identify hypoxemia and hypoxia. I find that one frequent area of confusion relates to understanding the important distinction between arterial partial pressure of oxygen (PaO2) and oxygen saturation (O2 sat). I am not alone. Multiple studies have identified this as a knowledge gap. One study of pediatric nurses showed that while 84% of the clinicians felt they had received adequate training, only 40% correctly identified how a pulse oximeter worked, and only 15% had a correct understanding of the oxyhemoglobin dissociation curve. This is such a key concept that we all must take pains to ensure our staff understands how to use this valuable monitoring tool. Some of the material below is from my book Anyone Can Intubate. Continue reading