A-a gradient (Alveolar-arterial oxygen gradient)
This video is the 4th in a series of 4 videos on the alveolar air equation and its applications. The other 3 can be found on our page.
This introduces the concept of the A-a gradient and how it can be used clinically.
Ref:
1)John West Respiratory Physiology, The essentials
2)Egan's Fundamentals of Respiratory Care (9ed), Wilkins, Stoller and Kacmarek
3) Sibberson's Practical Math For Respiratory Care
Пікірлер: 10
you guys are really good at what you do ! I watch your videos all the time to complement my classes:)
Mate this is class. Well done great explanations.
another great one Ollie!
Great video! Could you please add one on spirometry in the diagnosis of obstructive and restrictive lung diseases? Thanks
loved it good work
Thank you so much
Causes of hypoxia : low inspired oxygen, hypoventilation, V/Q mismatch, diffusion block, shunt, and low Pmv02. Low mixed venous oxygen would not have an elevated A-a gradient, right?
In ur example, At sea level how do you knw the pco2 value of a fi02 50% supply? I suppose on a intubated ventilated pt, then remaining 50% of gas would be air for a FiO2 50 setting? Thx good explanation btw
@kentvun
5 жыл бұрын
How u knw is 50 50?
@RespiratoryReview
5 жыл бұрын
Yes, if you have the FiO2 set at 0.5 (or 50% O2), we know the gas mixture is by definition 50% oxygen. The ventilators are very accurate in their delivery of specific oxygen concentrations. The remaining 50% would be mostly nitrogen but also have some of the other gases found in air. As there is a neglible amount of CO2 in air the FiO2 doesn’t really impact the alveolar CO2 tension. The alveolar CO2 tension needed for the equation comes from the arterial CO2 and the RQ of 0.8.