> For the complete documentation index, see [llms.txt](https://thisispiggy.gitbook.io/my-wiki/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://thisispiggy.gitbook.io/my-wiki/01-step-1/pulmonary/04-pulmonary-circulation.md).

# 04 Pulmonary Circulation

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/normal%20pulmonary%20circulation,%20pressure,%20wall%20thickness/README.md)..

![](https://f001.backblazeb2.com/file/wikiFiles/V3LoAtI.jpg)

![](https://f001.backblazeb2.com/file/wikiFiles/AbRizZk.jpg)

* lower p: doesn't need to go as far

## Blood O2 Content

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/systemic%20vs%20pulmonary%20vs%20fetal%20circulation%20differences.%20What%20happens%20in%20low%20O2%20level%20in%20each)..

![](https://f001.backblazeb2.com/file/wikiFiles/1QmlQab.jpg)

* fetal: less blood to lungs, not important in womb

![](https://f001.backblazeb2.com/file/wikiFiles/8QdVJwe.jpg)

## Diffusion

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/Diffusion%20of%20gas%20exchange%20depends%20on%20what%203%20factors/README.md)..

![](https://f001.backblazeb2.com/file/wikiFiles/GzsYv4m.jpg)

* more pressure difference of O2 in air/blood: more diffusion
* more area: more diffusion
* thickness: less diffusion

![](https://f001.backblazeb2.com/file/wikiFiles/6WVYrTb.jpg)

![](https://f001.backblazeb2.com/file/wikiFiles/N8AXESb.jpg)

* emphysema: alveoli destroyed, low DLCO
* fibrosis: thicker, low DLCO
* diffusion of CO same as DLCO

## Diffusion-Perfusion

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/N2O,%20O2,%20CO%20diffusion-perfusion%20limitations/README.md)..

![](https://f001.backblazeb2.com/file/wikiFiles/u3cTwpT.jpg)

* infuse 3 gases into lungs at Pa concentration, ideally reach Pa concentration
* N2O: at length 0, no N2O diffuse into blood; diffusion rises very rapidly along capillary length to max value
* CO: rises slowly, never gets to maximum concentration
* O2: some O2 from veins at length 0, rise relatively rapidly until max value

![](https://f001.backblazeb2.com/file/wikiFiles/rcpUv61.jpg)

* gas must diffuse through and get carried away

![](https://f001.backblazeb2.com/file/wikiFiles/6hGMIGM.jpg)

* N2O: barrier not a factor
* N2O rapidly diffuse through 
* only determination for rate of rise of N2O is how fast blood flowing, carrying away molecules, rapid rise in partial pressure

![](https://f001.backblazeb2.com/file/wikiFiles/97Mo4zh.jpg)

* barrier is major factor for diffusion
* slow rise
* diffusion main factor. Perfusion not a factor

![](https://f001.backblazeb2.com/file/wikiFiles/JQh1wk1.jpg)

![](https://f001.backblazeb2.com/file/wikiFiles/DqpJqcr.jpg)

* N2O: only thing slow or speeds up concentration is blood flow rate
* O2: same
* CO: uptake limited by diffusion

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/O2%20diffusion,%20perfusion%20limitation,%20diseases%20and%20exercise/README.md)..

![](https://f001.backblazeb2.com/file/wikiFiles/JQh1wk1.jpg)

![](https://f001.backblazeb2.com/file/wikiFiles/bz0pP6D.jpg)

* diffusion limited
* concentration of O2 in blood falls = hypoxemic

![](https://f001.backblazeb2.com/file/wikiFiles/fjJD2RP.jpg)

* at rest: blood flows slowly, lots of time to pick up O2
* exercise: blood flow faster, gets further before reach maximum, but still does even in patients exercising
* exercise alone should not make someone hypoxemic

## Pulmonary Resistance

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/pulmonary%20vascular%20resistance%20causes/README.md)..

![](https://f001.backblazeb2.com/file/wikiFiles/HhFsMPH.jpg)

* alveolar: blood supplying alveolus
* arteriolar: blood supplying lung parts outside alveoli
* inhale: increase resistance from alveolar vessels
* exhale: increase resistance from arteriolar vessels
* FRC: lowest point of pulmonary vascular resistance

## Pulmonary Hypertension

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/pulmonary%20HTN%20pressure%20vs%20normal.%20Significant%20physical%20finding,%20symptoms,%20complication)..

![](https://f001.backblazeb2.com/file/wikiFiles/O98gMgJ.jpg)

![](https://f001.backblazeb2.com/file/wikiFiles/Fkmolqs.jpg)

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/pulmonary%20htn%20diagnosis/README.md)..

![](https://f001.backblazeb2.com/file/wikiFiles/AmwnbwP.jpg)

* right heart cath: cath into PA from heart

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/pulmonary%20HTN%20calculation,%20causes/README.md)..

![](https://f001.backblazeb2.com/file/wikiFiles/gd6yFeM.jpg)

* V: energy needed to drive flow
* I: how fast you want to go
* R: resistance to flow
* Ppa high in pulmonary hypertension, if any of the variables increased

![](https://f001.backblazeb2.com/file/wikiFiles/JUKpdtm.jpg)

* high CO: increase flow through lungs
* most common cause of PHTN nothing to do with lungs but with left heart

![](https://f001.backblazeb2.com/file/wikiFiles/ai4NGwH.jpg)

* chronic hypoxia vasoconstrict

![](https://f001.backblazeb2.com/file/wikiFiles/SkszuyY.jpg)

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Pulmonary/primary%20pulmonary%20HTN%20gene,%20symptoms,%20treatment/README.md)..

![](https://f001.backblazeb2.com/file/wikiFiles/NewTo6X.jpg)

![](https://f001.backblazeb2.com/file/wikiFiles/0ktxgCu.jpg)

* Epoprostenol: IV, must infuse constantly, cumbersome