Pulmonary Circulation Flashcards
How does compliance of pulmonary vasculature compare to systemic vasculature?
Pulmonary vascular is way more (7x) compliant.
Normal mean arterial pressure (MAP) of the pulmonary circulation?
9-15 mmHg.
(vs. 85-100 mmHg in the systemic)
The resistance is also much lower
How does blood flow vary in bases of lungs vs. apices?
More blood flow in bases, due to gravity.
Cardio review: formula for pulmonary vascular resistance (PVR)?
(Mean PA pressure - Mean LA pressure) / Pulmonary Blood Flow
What effects do increases pulmonary arterial and/or venous pressure have on PVR?
Increased pressures -> decreased resistance.
not sure how this fits in with the stated formula, though
What effects do the extremes of changes in lung volume have on PVR?
Lungs to small or lungs too big both increase PVR.
3 chemical stimuli that can increase PVR?
Acidemia.
Alveolar hypoxia. (hypoxic vasoconstriction to mitigate V/Q mismatch)
Hypercarbia.
3 hormones that increase PVR?
Catecholamines, angiotensin, endothelins
3 “hormones” that decrease PVR?
Acetylcholine, prostacyclin, NO.
Defintion of pulmonary HTN?
Increased PA pressure, usually due to increased PVR.
How can acute pulmonary embolism cause shunting?
Increased RA pressure can cause a patent foramen ovale (PFO) to open.
Additionally, shunt-like effects can be caused by blood flow being redirected to areas of low ventilation.
What’s cor pulmonale?
Right heart failure..
What was the point about sometimes the patient with the higher PA pressure is healthier?
The PA pressure can only be high if your heart is working. PA pressures will often decline with heart failure.
Endothelial thickening, intimal proliferation, smooth muscle hypertrophy etc. etc. can contribute to pulmonary HTN.
Okay. We’re not really what the main driver of this process is.
What’s a really good therapy for pulmonary arterial hypertension (PAH)… if you can be on a continuous drip?
Epoprostenol (Flolan) - a prostainoid.
There are other versions that can be given subcutaneously, or inhaled.
