I am trying desperately to figure out how PCWP measure Left Ventricular EDV, and I just can't wrap my brain around what I know must be a very obvious explanation.
I'm clear on the normal values and all that business, but I'm not getting the anatomy of the set-up. If the PA catheter is inserted through the RA, RV and then carried into the pulmonary artery and wedged, how is that reflecting what's going on next door?
I hope my question makes sense - I've dug out old AP books, everything and I'm stumped.
Thanks in advance.
ok , i hope i make this more simple and not more diffiuclt. The tip of the catheter sits in the pulmonary artery, and therefore picks up the pressures in the pulmonary artery, and those pressures behind the pulmonary artery (right ventricle), and in front of the pulmonary artery (left atrium). When the catheter is wedged, the balloon is up, and all the pressures behind the balloon(R ventricle) are occluded from the transducer, so we are only picking up pressures from the L side of the heart. Now during diastole, the mitral valve is open, so if we pick up pressure of the L atrium and the mitral valve is open we are also seeing pressures of the L ventricle. So, LVEDP (L ventricle end diastolic pressure) equals your PCWP (Pulmonarycapillary wedge pressure).
Last edit by dorimar on May 20, '06