Im just sitting here having a ball with ABG case studies and Im wondering about the PPo2 measurements. Now Ive always been taught in scuba that our PPo2 is the Fo2 of our mix multiplied by ATA. So, is this just the partial pressure of the gas in our lungs? I ask because doing ABG's the normal range for PPo2 mmhg is 70-100. So, I goes Im just wondering what is the difference between these two calculations? or how are they related?
PPo2 vs arterial PPo2
- Thread starter Young33
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
Arterial pO2 is measured in mmHg so you have to compare apples to apples, i.e. measure atmospheric pressure using the same unit. Standard atmospheric pressure is 760 mmHg. Partial pressure of O2 in the atmosphere is 20.9% of that, or 158.8 mmHg. The pO2 in the atmosphere is not the same as that in the alveoli, though, because the air in the alveoli is 100% humidified, which equates to about 47 mmHg pH2O. The alveoli also contain CO2, at a partial pressure of roughly 40 mmHg. You can employ the alveolar gas equation to calculate the partial pressure of O2 in the alveoli. The arterial pO2 will be somewhat less in a normal adult. The interactive alveolar gas equation is a great learning tool. Here is a calculator to help estimate A-a gradient. Have fun!
Best regards,
DDM
Best regards,
DDM
Similar threads
