Ventilation and Perfusion

Introduction to the concept of ventilation and perfusion, and discussion of the "3 zones" of ventilation / perfusion. Explained the key concept of hypoxic vasoconstriction in regulating ventilation and perfusion, and an example of pulmonary shunt.

[@rugzm]

You, sir, deserve a medal!

[@HealthEdSolutions]

Thank you!

[@amybell-young9496]

I am a final year masters physio student - we have loads of self directed learning so it is great to be taught key aspects of physiology by someone experienced who makes it so easy to understand and clinically relevant. Thanks so much!

[@HealthEdSolutions]

Thanks Amy!

[@kdpatel2]

you have made the lives of so many students easier. My patho group and I rely on your videos to teach us all of these concepts as we feel that we are not taught at all in our class! THANK YOU!!!

[@HealthEdSolutions]

Thanks so much for the kind words!

[@imogenewalters6163]

I appreciate the videos. They make these subjects in my pathophysiology course come alive and I understand the different systems much better with MedCram videos. Thanks so much to you and Dr. Sehult . The more ways I see something presented the more I understand the subject. I love the way you illustrate the subject and makes it interesting.

[@HealthEdSolutions]

Thank you Imogene for the kind words!

[@aliciabishop2592]

Thank you! I'm brand new to NP school and this gave me a much better understanding of ventilation and perfusion than I ever had in my undergraduate program.

[@HealthEdSolutions]

You’re welcome. Glad you found it helpful!

[@markgyger7068]

Really appreciate the video--it's really well done and easy to follow and understand. Nursing student at Scottsdale Community College in Arizona. Thank you!

[@HealthEdSolutions]

Thank you Mark:)

[@carriemann9426]

Great video. I can relate this to what I learned the other day, that calcium channel blockers can prevent hypoxic vasoconstriction. I saw a significant decline in O2 sat after starting a nicardipine drip and PO2 dropped to 47. Sat and PO2 improved as we titrated the drip off.

[@HealthEdSolutions]

Thank you Carrie and thanks for sharing!

[@lisab6952]

Thanks for this video, I am in a pathophysiology class at this time. I have an absolutely great instructor, so this will help me to understand this process before class.

[@HealthEdSolutions]

Thanks Lisa for watching!

[@abe8isback]

Outstanding, clear explanation. Thanks for making this available.

[@HealthEdSolutions]

Thank you Jim!

[@huongnvinh]

Great great great instruction. so helpful. thank you so much. and you have such a charming voice too.

[@HealthEdSolutions]

Glad it was helpful!

[@candyg3873]

Brilliant ! just understood concept of the shunt !

[@HealthEdSolutions]

Thanks so much, glad it was helpful!

[@samer692]

Your video is awesome. Thank you!

[@HealthEdSolutions]

Appreciate the kind words!

[@sztorm3390]

Great video! thank you!

[@HealthEdSolutions]

Thank you!

[@jaquelinemanuel5716]

you're a great professor. thanks!

[@HealthEdSolutions]

Thank you so much for the kind words.

[@kaelarichardson9604]

Very helpful video, thank you!

[@HealthEdSolutions]

Glad it was helpful!

[@bettinafratto1472]

Great video..

[@HealthEdSolutions]

Thank you Bettina for the kind words

[@amanyelsappan6891]

very helpful .thank you very much

[@HealthEdSolutions]

Thanks for watching! Glad it was helpful!

[@jbax8824]

Thanks! Very good explanation. I wish you would've included "physiologic dead space" in addition to shunts since they explain opposite effects of the V/Q spectrum.

[@HealthEdSolutions]

Thank you for the feedback!

[@nenahv3139]

I'm a bit confused about the three zones of the lung. Textbooks have led me to believe that both ventilation and perfusion are higher in the base of the lung rather than the apex. However, the gradient for perfusion at the base is steeper so the net affect is that V>Q at the apex, while V

[@HealthEdSolutions]

Thanks for the question. We've passed it along to the Health Ed Solutions medical review board.

[@valerieethos2650]

AMAZING!!!

[@HealthEdSolutions]

Thank you Esther!

[@bla69]

That was great, thank you!

[@HealthEdSolutions]

Thank you!

[@superbesli8016]

Thanks so much. I am at 42 and do not love read books. Yours videos are very helfull for remembering my loosing knowledge. Dear sir, can you discus more about pulmoner capacities e.g closing capasity and FRC and sepsis.

[@HealthEdSolutions]

Thank you for the feedback!

[@rdb5938]

Base of lung have more perfusion and ventilation then the apex of the lung
Perfusion in base is high - greater vascular pressure , more recruitment , distension, low resistant - great blood flow
Good. Ventilation- intrapleural pressure less negative , smaller transmural pressure gradiant
Smaller alveaoli more compliance
MORE Ventilation

[@HealthEdSolutions]

Thanks for the input and for watching the lesson!

[@dilshanpriyankara]

Dear Andrew. Nice explanation. I have a question. It s about your explanation near end of discussion. you described that if 25% of lung is not ventilated, the blood that pass through it would have saturation of zero , because its not ventilated. But that part of the lung will be perfused by pulmonary arteries which will have a venous saturation of 70%. So how its Zero????

[@HealthEdSolutions]

Thanks for the question. We've passed it along to the Health Ed Solutions medical review board.

[@medbites338]

Hi, great video! what app do you use to create videos like this one?

[@HealthEdSolutions]

Thanks for your inquiry. The whiteboard lessons are created using a Wacom Bamboo tablet. Thanks for watching!

[@charlesclintonmd]

Great!

[@HealthEdSolutions]

Thank you!

[@gabmor7779]

wouldnt the O2 sats in the unventilated part of the lung be at about 75% since thats the venous saturation when it comes back to the heart? and the pO2 be also at what it usually is in the venous blood? i duno what that normaly is i guess at around 70% also

[@ronnynoneofyourbusinessgoo7892]

pO2 normally on returning is 40 mmHG, SaO2 70-75%, yes.

[@ronnynoneofyourbusinessgoo7892]

The idea generally is still correct. With your/ our values only..

[@HealthEdSolutions]

Thanks for the question Gab. We've passed it along to the Health Ed Solutions medical review board.

[@HealthEdSolutions]

Appreciate the input!

[@HealthEdSolutions]

Thanks for the input!

[@dr.abbasfadel1544]

its great

[@HealthEdSolutions]

Thank you!

[@OscarEggen]

Death space and shunting are extreme V/Q mismatch or pathological shunts?

[@HealthEdSolutions]

Thanks for the question. We will ask Dr. Wolf and see what he says!

[@lurkyism]

Thanx soo much sir..it's precious vedio...I hoppe you don't mind giving an explanation of in case of cpr it's possible that the heart work first and not the other way happened for the lung?

[@HealthEdSolutions]

Thanks for the feedback!

[@Bandy64]

A very “Goldilocks and the Three Bears” kinda story.

[@HealthEdSolutions]

Thanks for the comment Sandro :)

[@lurkyism]

sorry that my qs was not clear sir,..i searched alot to find what is the physiologic explanation that why the heart beat return first not the lungs? to clarify it more in cpr you can find pulse but not necessary with breathing BUT in other way around it's impossible to find breathing withou a pulse... is spite of the cardiad and respiratory centre both them in the same place which is brain stem!!!! i hope that i made my inquiry clear sir :)>>> thatn you so much in advance

[@HealthEdSolutions]

Thanks for the thoughts and input!

[@gabmor7779]

and would a peep help in such a scenario?
i would guess not because if the part of the lung that is inflammed and the alveoli of that part of the lung are filled with fluid, the peep wouldnt do anything , but in the other parts of the lungs it would inflate the alveoli leading to a narrowing of the vessels around and to diminished perfusion of the healthy lung areals, and therefor be counterproductive?

[@HealthEdSolutions]

Thanks for the question. We've passed it along to the Health Ed Solutions medical review board.

[@eliasjabbour31337]

excuse me, can you tell me the name of the program you are using to draw? and screen capture?

[@HealthEdSolutions]

Thanks for your inquiry. The whiteboard lessons are created using a Wacom Bamboo tablet. Thanks for watching!

[@TinkerBell052]

at 7:53, 2750ml what is 2750ml? vital capacity (IRV + TV+ ERV)?

[@HealthEdSolutions]

Thanks for the question. We've passed it along to the Health Ed Solutions medical review board.

[@remusomega]

Why would zone 2 increase if we vasconstrict zone 3? If pulmonary arteries are perfusing these regions in a parallel arrangement, then shoudlnt the pressure remain the same on either side of the alveoli on zone 1 & 2?

[@HealthEdSolutions]

Thanks for the question. We will ask Dr. Wolf and see what he says!

[@remusomega]

@@HealthEdSolutions I’ve been waiting at the edge of my seat for 4 years.

[@elenagouitel6041]

Would you be so kind to explain the Hypoxic vasoconstriction in a more easier way I don;t understand the connection to it with the 3 zones of the lung thanks

[@HealthEdSolutions]

Thanks Elena for the question. We've passed it along to the Health Ed Solutions medical review board.

[@AQGOAT24]

How do we know that Oxygen under resting conditions is perfusion limited?

[@HealthEdSolutions]

Thanks for the question. We've passed it along to the Health Ed Solutions medical review board!

[@karenmonaghan4338]

Although this seems correct in principal, the alveoli at the bottom of the lungs I understand to have better ventilation in a healthy lung because the alveoli are able to expand and fill with "fresh" air more efficiently because they are not already full. The alveoli at the top are already full of air so although they are larger and more open, ventilation is poor because the "balloon" is already full. So actual O2 exchange is poorer than one would expect.

[@HealthEdSolutions]

Thanks so much for the input here Karen!

[@ayaghurl]

I have read in "berne & levy" physiology book that ventilation and perfusion is lowest in the apex...and is highest in the base... why is it different from your video? i'm quite confused.. pls help.. thanks..

[@HealthEdSolutions]

Thanks for the question. We will ask Dr. Wolf and see what he says!

[@yinler92]

I have a question here, why the perfusion in zone 2 increase during systole and decrease during diastole?

[@HealthEdSolutions]

Thanks for the question. We will ask Dr. Wolf and see what he says!

[@daniels5347]

Is it really correct to assume that oxygen partial pressure in blood that perfuse unventilated alveoli is zero?

[@HealthEdSolutions]

Thanks for the question Daniel! We've passed it along to the Health Ed Solutions medical review board.

[@mone3ybagz]

***** you said in a previous video that the pulmonary arterioles dont have smooth muscle cell ...was that wrong ? :O

[@remusomega]

+mone3ybagz
All arterioles have smooth muscle.

[@HealthEdSolutions]

Thanks for the question. We've passed it along to the Health Ed Solutions medical review board.

[@HealthEdSolutions]

Thanks for the input!

[@laurenkokada]

Ventilation is highest at lung bases

[@HealthEdSolutions]

Thanks for the feedback!

[@majkelbenchecustodio5795]

zone 1 doesn't exist. it only happens during pathological conditions

[@HealthEdSolutions]

Thanks for the feedback and thoughts!