The A-a Gradient (ABG Interpretation - Lesson 16)

A lecture on the ways in which the ABG can be used to assess oxygenation, focusing on the alveolar gas equation and the A-a gradient. Several examples of ABG interpretation are included.

[StrongMed]

prince blaker, I'm glad you enjoyed the video. The A-a gradient is solely a function of the efficiency of the alveolar capillary membrane. It is impacted by decreased total surface area, increased membrane thickness, or maldistribution of blood and/or ventilation. In hypoventilation, ventilation isn't maldistributed, but rather is decreased equally everywhere. Therefore, A-a gradient is normal.

[nomad]

I have an exam coming up tomorrow, and going through your videos these last hours has been more helpful than 3 weeks of our pulmonary block. I don't know how to thank you! The clear diagrams, and effort put into the presentation, the logical progression. Everything about this is great.

[jonemorice]

Thank you .i work in PICU and i have never ever understand ABG like the way you give and now i am an ABG boss interpreter.thank u alot

[sinclair]

Your logistics are on point. Thank you very much. Every department needs logic that makes a difference between proper diagnosis and proper treatment.

[ImpulseFortune]

Just to note a potential update (and as a side note, a thousand thanks for this fantastic lecture series): according to the new definition, PaO2/FiO2 ratios of 200-300 may now be considered "mild ARDS"; "acute lung injury" no longer exists.

[alihami]

In comparison with the latest guidelines ur presentation is still valuable and comprehensive
Thanks a lot

[umbukole]

Amazing, really very good simple approach, I found this video while randomly youtube-ing. I am definitely going to see the rest of your lectures now. Well done for making A-a Gradient seems that easy.

[StrongMed]

Another way to look at it is in hypoventilation, the hypoxemia isn't due to a pathophysiologic problem with the alveolar-capillary membrane, but rather due to derangement in the partial pressures of the gases in the alveoli.

[sunving]

Thank you Dr Strong, I seem to pick up more from listen to this lecture once more. How wonderful is the Internet! I got the PaO2/FiO2 which I just read somewhere regard to Covid-19

[paulhep]

fantastic lecture. studying for emergency medicine exams and that was very clarifying.

[StrongMed]

MrBhotu, thanks for your enthusiasm. I'm trying to get these up as fast as possible, but I've exhausted the lectures that I already had written and which just needed narration recorded and transfer into video format. Creating de novo lectures is taking a little more time. Hope to have the next one up by tomorrow (affect of supplemental O2 on the ABG), and realistically to finish up the remainder of the ABG course by mid summer.

[LaitoChen]

Thanks. I was hoping for an explanation on why the A-a gradient remains the same in hypoventilation, but the rest of the lecture was on point GJ

[vishveshbhatt]

I love your lectures and how do you come up with such beautiful music everytime? Simply love both

[TheRawPhoenix]

Just a miracle! Thank you so much! I wish you could teach at my school sir! You're an absolute delight to learn from -- so easy to understand and concise! I really enjoy your lectures!!

[scarecrowzero]

great explanation for A-a grad. Thank you very much.

[subiOm]

Thank you so much for this video Dr. Strong. Very helpful.

[Aleen]

amazing explain especially the phtots are very simole and useful, ,, thank you very much

[nittijain]

sir desperately waiting for ur remaining lectures on abg videos ...excellent material slides ...very quick even for revisions without missing any points

[MikeBirkhead]

One additional cause of normal A-a gradient (besides hypo ventilation and high altitude) would be any cause of increased CO2 production (sometimes sepsis)
- this is according to a lecture by a pulmonology fellow.
- this can be deduced from the alveolar equation-- where PAO2 is determined by PaCO2

[haneen]

Finally i learned this equation. Thank you sooo much