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Pulmonary Function Tests (PFTs)

Duration: 29:55

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Feb 23 2019, 7:43 pm

Excuse me, can I add one more question? 
In a patient with obstructive disease, let's say asthmatic patient, the airway diameter is smaller, so how is he going to breath in the same amout of air. Is it a matter of time? 
I mean, he would breath the same amount of air as a normal person, but in more time? (with decreased slope factore  in a volume-time diagram for instance ? )



Feb 15 2020, 9:19 pm

In o structure lung disease inspiration is not issue as you create intrathoraccic negative pressure that pull your airway open and you breath In however expiration is issue as you r causing positive pressure compressing the airway + spasmatic smooth muscles around the airways due to asthma causing expiration issue hence low peak flow hence low FEV 1 and FVC and low ratio however usually in asthma FEV1 improves by 12% and FVC by 200 . 



Feb 23 2019, 7:16 pm

Dear Dr. Mobeen,
I would like to ask 2 questions. 

1) In a patient with emphysema, there  are dilated alvioli and "trapped air". So there is increased residual volume. So far so good, BUT, since the alvioli membranes are destroyed and on top of that there is trapped air, shouldn't that mean that the alvioli of the damadged area are less compliant and thus they can take in less air. ? So why is there a normal inspiration volume? I understand the normal FVC only because of an increased RV. But is the IV normal? Can the patient with emphysema inspire the same amount of air as with a normal person? 

2)  In the restrictive diseases, you mentioned that the scar is pulling airways open, (I understand it as pulling the airways out and they open ). Compliance is less. So IV is less.  But since the scar is pulling outwards, why do they tend to collapse?, why is the recoil force intact ? (since there is a force pulling in the opposite direction of that of collapsing ) and by extention why is the expiration process normal?

Thank you very much doctor. You are really making us better professionals. Can't thank you enough for all of your lectures (And this is a genuine expression of appreciation)

This video presents the lung function tests.

In this video we will learn about :

1. Normal lung volume capacities. 

2. Lung flow volume graph. 

3. Time volume graph. 

3. Changes in restrictive and obstructive lung diseases.

4. Extra pulmonary air way compression.

5. Blunting of the graph. 

Following answers are created by ChatGPT. Occasionally the answer may be harmful, incorrect, false, misleading, incomplete, or limited in knowledge of world. Please contact your doctor for all healthcare decisions. Also, double check the answer provided by the AI below.

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Dr. Mobeen Syed

Dr. Mobeen Syed

MD., MSc., MSc., BSc

Mobeen Syed is the CEO of DrBeen Corp, a modern online medical education marketplace. Mobeen is a medical doctor and a software engineer. He graduated from the prestigious King Edward Medical University Lahore. He has been teaching medicine since 1994. Mobeen is also a software engineer and engineering leader. In this role, Mobeen has run teams consisting of hundreds of engineers and millions of dollars of budgets. Mobeen loves music, teaching, and doing business. He lives in Cupertino CA.

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