Question

1. Explain the factors that interfere with oxygenation of the blood in patients with emphysema. 2. Explain why expiratory is significantly impaired in patients with emphysema. 3. Explain why heart failure may develop in patients with emphysema. 4. Explain three possible causes of pulmonary edema. 5. Explain which is more likely to ovcur with acute pulmonary edema-- hypoxemia, hypercapnia, or both equally.

Answer 1

1) In emphysema, oxygenation of blood cant happens properly. Now the question is why oxygenation is interrupted in emphysema? To know the answer first we need to know the alveoli structure because the gas exchange is occurred by the alveoli and oxygen is loaded in the blood through alveoli. Alveoli are air sac and inside it is divided into many small compartments by inner walls. In normal alveoli, inhaled air spread between the small compartments. For this, each compartment gets less air so the air gets large surface area and large surface area means more diffusion and more diffusion means oxygen will easily get into the blood. But in emphysema, inner walls of alveoli are damaged and ruptured. For this, the small compartments fuse together and make the only one compartment. Now when inhaled air comes, it is not spreading and all air is stuffing in one compartment so the surface area becomes less for the gas. This makes less amount of oxygen loading in the blood.

2) While exhaling the gas, alveoli shrink and force the carbon dioxide to get out of the body. As already mentioned that in emphysema, inner walls of alveoli are ruptured. Because of this alveoli can't shrink properly. For this, it can't give force properly on carbon dioxide. That is why expiratory is significantly impaired in patients with emphysema.

3) Remembering the first question's answer I told that in emphysema oxygen can't come into the blood properly. So due to this lack of oxygen, the heart's cells will not get the proper oxygen. There will be hypoxia in the heart and that can lead to cell damage so the heart will not work properly. And due to less oxygen of blood, blood pressure will also increase. Due to high BP, heart rate will also increase. So a heart with damage cell and high heart rate can lead to heart failure.

4) Three possible causes:-

a) congestive heart failure:- In congestive heart failure heart cant able to pump proper amount of blood throughout the body. So when oxygenated blood comes from the lungs, the heart is not able to circulate that blood from the lungs throughout the body. For this blood pressure increase in the small vessels of the lungs that leads to the leakage of fluid from the small vessels. And this leakage of fluid causes pulmonary edema.

b) Any kind of infection can cause pulmonary edema. Inflammation will be there in the case of infection and edema is one of the signs of inflammation.

c) In kidney failure, pulmonary edema can occur. Due to kidney failure, body fluid start accumulating in different organs. So in kidney failure fluid can accumulate in the lungs also.

5) In the acute pulmonary edema, fluids start accumulation in the air sacs. This gas exchange cant happens properly. Oxygen can't get into the blood means hypoxemia and similarly carbon dioxide cant gets out from the body means hypercapnia. So in the case of acute pulmonary edema hypoxemia and hapercapnia both can occur.