Even though PA measurements are not routinely utilized, it is a great concept to grasp and understand. Many symptoms from various disease conditions reflect what is happening to your patient and understanding the pathophysiology behind these conditions make for better nurse anticipation and better patient outcomes.
For example: patient with existing COPD, stable BP (101/62), placed on BiPAP, has a drop on blood pressure after 30 mins, 88/45. If you understand what the BiPAP does to the pulmonary vasculature, you can understand why there's a drop in BP.
Or, what sepsis does to your SVR with subsequent drop in BP and compensatory response of your HR.
Just think of the cardiovascular system as a system of pipes and valves, just like the plumbing system in your house. Key things you need to keep in mind:
1. Direction of flow (IVC/SVC --->RA--->TV--->RV--->PV... etc)
2. What systems and/or chamber lies before and after each valve
3. The normal pressure values before and after each valve. (before=closed, after=open)
I would put a lot of effort into understanding these normal values, what they mean, and the effect of disease processes have on these parameters. To me, this is a very exciting concept to grasp.
But it doesn't end there. Once you've collectively put together your understanding of the RAAS, sympathetic/parasympathetic response, catecholamines, as well as your understanding of mechanism of actions of antiarrythmics, pressors, vasodilators, ventilator management, etc, everything just falls into place.