Week 5 Flashcards
Ventilation - define
air coming in through the atmosphere going into the alveoli
Diffusion - define
Air going from alveoli into capillaries
Gas levels in alveoli -PaO2–effect? - PaCO2
-High because it’s coming in; makes it goes into capillary - 0; allows for CaO2 to diffuse in
Gas level in blood - PaO2; importance? - CO2; importance?
- when O2 first enters the blood it is at 100 but after it goes through the body and then makes it back to the lungs the pressure has dropped to 40; having low pressure allows for oxygen from lungs to diffuse in because it goes from high to low - allows for CO2 to diffuse from capillary into alveoli
Define exertional dyspnea
Difficulty breathing with exertion
Common lung infection in HIV patients?
Tuberculosis
mechanisms behind pulmonary HTN
it could be backup from Lt side of heart (she’s got an ejection murmur so there’s obviously some dysfunction there) increase in left ventricular pressure could backup and cause increased left atrial pressure which would cause increased pressure on the pulmonary veins.
What happens to the vessels when you have endothelial damage?
You lose compliance, fibrosis- intimal thickening, vascular tone increases so you don’t get dilation.
do opioids cause lung damage?
Flash pulmonary edema
what can HIV do to vasculature?
- HIV Is associated with valvular defects in the heart and it is also associated with vascular changes. - thickens up, radius of vessels decreases –> resistance increases
How to differentiate between heart failure and pulmonary edema (pulmonary htn) due to opioid use? - order; why?
- order Echocardiogram and BNP - if BNP is low then not coming from heart but if BNP is high there is higher chance it is heart failure
what could increases in pulmonary pressure do to the right side
right side of heart could be undergoing changes in pressure, changes in contractile function leading to failure which is why you see the pitting edema.
Differences of pulmonary vasculature vs systemic vasculature?
. Arterioles in systemic vascular really hold their shape, but here is pulmonary vasculature the arterioles are a lot more expandable and collapsible.
Types of vasculature in lungs
- alveolar: inside/in between the alveoli - extralveolar: outside the alveoli.
Alveolar vasculature changes during inspiration. why? what happens to resistance?
Vessels are gonna get compressed and elongated because alveolar volume increases - Resistance increases and therefore bloodflow decreases
Extra alevolar vasculature changes during inspiration. - why?
- Resistance decreases - Interpleural pressure become more negative. Because of that, transmural pressure across the extraalveolar vessels increases and pulls the vessels open decreasing the resistance and increasing blood flow
What happens to alveolar and extra-alveolar vasculature during expiration?
- alveolar vessels are going to shorten and increase their radius so resistance starts to decrease whereas in the extra alveolar vessels, resistance increases.
How does pumonary HTN alter pulmonary vasculature resistance - what happens to vascular reactivity?
- She has intimal thickening and narrowing of some of the vessels so her resistance is increased - decreased vascular reactivity
What happens to blood flow in lungs during exercise? - what happens to MPAP? - term for this? - what can help with this?
- You increase blood flow d/t increased production of metabolites. The whole point of the pulmonary/circulatory system is to get O2 in and CO2 out. - Your mean arterial pulmonary pressure (MPAP) decreases because as your blood flow/perfusion pressure starts to increase with exercise, you oppose hydrostatic pressure, and so it helps to open up new arteries (increased distension). And so you recruit more blood vessels. - Recruitment: recruiting more arterioles to have more blood flow - Distension: distending the arterioles to reduce the pressure. It allows for more blood flow so that you can pick up more O2 and meet the metabolic demand.
What happens when a patient with pulmonary htn tries to exercise? - what happens to MPAP
- She would not be able to meet metabolic demand because she can’t distend due to the vascular changes in her vessel - MPAP stays elevated because they don’t have recruitment and distension
Effect of gravity on pulmonary blood flow - standing up - laying down
- gravity pulls blood to the bottom of the lungs when standing up - gravity is more proportional, so your blood flow is more proportionate.
Zones of pulmonary blood flow and gravity - ventilation - resitance to blood flow - zone 1
- Ventilation becomes more proficient as you move down the zones. As you get further and further down the lung, the alveoli are more of their normal shape, so they can change their volume to allow for more efficient ventilation. - As you get further and further down the lungs, resistance to blood flow decreases, and so you get increased blood flow. □ Zone 2: ® Arterial pressure is higher than alveolar pressure ® You have matched ventilation and perfusion –> proper gas exchange ® Zone 2 is what happens during exercise. As you start to exercise, your zone 2 starts to expand. □ Zone 3 ® Arterial pressure is the highest and venous pressure is higher than alveolar pressure ® Greatest amount of blood flow in this zone ® Perfusion>ventilation so no proper V/Q matching, so gas exchange not that efficient ® Too much perfusion and little ventilation, and nothing gets in ® There’s so much blood flow in this zone, but the alveoli are smaller and although there is some ventilation, the blood just goes right through
Zone 1 - where is it? - alveolar pressure - Perfusion - Factors increasing size of alveoli - young vs old - terminology for this zone - things that can increase in zone 1
- At the top of the lung -Alveolar pressure is the highest - There is ventilation here, but no perfusion -> there is so much ventilation that the alveoli get really big and there is no perfusion. - Alveoli are also getting big/expanding because gravity is just pulling them down - So even though your alveoli here are bigger because of gravity pulling them down, your efficiency to move air in and out isn’t that great. - Zone 1 usually doesn’t happen in a healthy young person during exercise, but as you age, you might start to get some increases in zone 1. - This is called dead space. - PEEP (positive end-expiratory pressure), Hemorrhage, General anesthesia
Zone 2 - arterial vs alveolar pressure - perfusion; effect? - what happens during exercise
- Arterial pressure is higher than alveolar pressure - You have matched ventilation and perfusion –> proper gas exchange - Zone 2 is what happens during exercise. As you start to exercise, your zone 2 starts to expand.









