PA Catheter Placement and Values (Nursing)

00:01 Next, let's discuss the PA catheter placement in relationship to the heart.

00:06 The PA catheter travels down the superior vena cava into the right atrium, and then crosses the tricuspid valve and goes into the right ventricle.

00:14 It takes a bend upwards and crosses the pulmonic valve and then terminates in the pulmonary artery.

00:20 It's important to take note of where the ports are in relationship to the heart.

00:24 The infusion port sits in the superior vena cava, the CVP port sits in the right atrium and gives us our central venous pressure.

00:33 And the PA port sits in a branch of the pulmonary artery and given us our pulmonary artery pressures.

00:41 We've discussed our arterial line monitoring, our central venous monitoring, and we've talked about the pulmonary artery catheter.

00:47 Let's talk about the pulmonary artery catheter values that we get from it.

00:51 The first one is our central venous pressure monitoring, our normal value is 2-8 mmHg.

00:57 This is normal and normal people with normal size hearts and normal vasculature.

01:02 A lot of times we like our patients to have a CVP more to 10-12, depending on what's going on with the patient.

01:09 Years ago, we used to think that this was an absolute value, meaning if the CVP is at 8 or if the CVP is at 10, then our patient is normal bulimic and they do not need any more fluid resuscitation.

01:21 We're now finding that this should be treated as a relative value, and that we should trend it with the patient, meaning every patient, their heart needs maybe a different number of millimeters of mercury with our central venous pressure.

01:34 Maybe some do well with an 8, maybe some need a pressure of 10 or 12, depending on if there RV is a little bit more dilated.

01:43 So your central venous pressure can also be called your right atrial pressure or your preload.

01:49 It's your preload because it's the pressure going into the right side of the heart.

01:54 This can be an indication of your fluid volume status, and your right ventricular function.

02:00 So wait, we think this could be also RV function or fluid volume status.

02:04 How do I know the difference? Well, it can be difficult.

02:07 That's why we don't use it as an absolute value anymore, but rather a trending value when it comes to fluid volume status.

02:13 If you look up and your patient has a fluid volume status of a CVP of 10, 15 or even 20 mmHg that doesn't automatically mean they're hypervolemic.

02:24 It could mean that the RV (right ventricle) is starting to fail, and that blood is backing up into the right atrium.

02:32 If this is the case, we should probably talk to the provider, maybe get an echocardiogram to see how that right ventricle is doing.

02:40 Now central venous pressure can be elevated in conditions of hypervolemia, right ventricular failure, tricuspid stenosis, cardiac tamponade, chronic LV failure and pulmonary hypertension.

02:52 Basically, anything that prevents blood flow from traveling through the right ventricle through the lungs and to the left ventricle is going to backup and elevate our central venous pressure.

03:02 Central venous pressure is decreased in conditions of hypovolemia, vasodilation and tachycardia.

03:07 Now, in hypovolemia, and vasodilation, both of those are reducing the pressure going back into the right side or reducing that preload.

03:14 Hypovolemia by not having enough fluid volume in the vasculature and vasodilation by dilating the vasculature too much for it to be able to create the pressure.

03:26 CVP is decreasing tachycardia, because the right atrium does not have enough time for it to fill creating that pressure.

03:34 Moving on to pulmonary artery pressures.

03:37 Our normal pulmonary artery pressures is about 20/8-30/15 mmHg.

03:43 When you think of pulmonary artery pressure, I want you to think about the pressure that's inside the pulmonary artery being the blood pressure, right.

03:51 So on our left side of our heart, the blood pressure is 120s/60s, 120s/80s.

03:59 Well, that's the pressure that's inside the aorta.

04:02 But in our pulmonary artery pressure 20/8-30/15 mmHg, that's the blood pressure that's inside the pulmonary artery.

04:11 Our first number is our pulmonary artery systolic number that's created when the RV contracts.

04:17 So with this number, I want you to think of lungs.

04:21 Any reason that it's high is typically because of lungs, or things that involve the lungs.

04:28 It's elevated in pulmonary hypertension, COPD, ARDS, which is acute respiratory distress syndrome, or pulmonary embolism.

04:36 All of those are preventing blood flow from going through the lungs when that RV contracts.

04:42 The bottom number is the pulmonary artery diastolic which is created when the right ventricle is at rest.

04:48 It is also called the left ventricular in diastolic pressure, which is kind of weird when you think about it.

04:54 When the RV is at rest the LV is at rest and you're in diastole, so why is it reading the left ventricle? Let me show you a diagram that can maybe clear it up just a little bit for you.

05:06 This picture here dissects the right side of the heart and the left side of the heart.

05:11 We have a Swan-Ganz that's sitting in the pulmonary artery, and it shows the heart in diastole.

05:16 So, in diastole, both pulmonic and/or aortic valves are closed in our tricuspid valve and a mitral valve is open.

05:24 So in diastole, that Swan-Ganz is read through the pulmonary artery, through the lungs, into the pulmonary vein, into the left atrium, and since that mitral valve is open, it's reading that pressure into the left ventricle.

05:38 So your pulmonary artery diastolic is also your left ventricular and diastolic pressure.

05:44 So it's reading that pressure going into the left ventricle.

05:48 Think about CVP.

05:49 Your CVP is the pressure going back into the right side.

05:53 Your PAD is a pressure going back into the left side.

05:59 Your pulmonary artery diastolic number is elevated in conditions of left ventricular failure, mitral valve disease, cardiac tamponade, pulmonary hypertension and pulmonary embolism.

06:10 So your CVP is elevated and right ventricular failure.

06:14 It's the same way with your PAD, it becomes elevated when the LV fails and pressure is backing up.

06:20 Also, mitral valve disease, mitral valve stenosis prevents blood flow from going through.

06:24 And cardiac tamponade, everything is increasing because there's pressure on everything from fluid outside of the heart.

06:31 And then with pulmonary hypertension and pulmonary embolism that's preventing blood flow from going through the lungs at a tremendous amount, which is elevating all of our numbers on the right side.

06:41 Our next value is our pulmonary artery wedge pressure.

06:44 This can also be called our pulmonary capillary wedge pressure, or left ventricular filling pressure or just our wedge pressure.

06:50 All of those terms mean the same thing.

06:53 When you inflate the balloon, what you're doing is effectively preventing blood flow in that branch of the lungs, in your reading the pressure after the lungs.

07:04 This is called your pulmonary artery wedge pressure because you're wedging the balloon against the vasculature preventing blood flow.

07:10 So really, you're you're creating that static column and you're seeing the pressure going into the left ventricle.

07:15 This is very common to your pulmonary artery diastolic pressure.

07:19 This indicates fluid status, the fluid going into the the left side of the heart and LV function.

07:26 So with CVP, it's your fluid status going into the right side of the heart and could be an indication of refunction.

07:33 Your wedge pressure is an indication of fluid status for your left side of the heart and LV function.

07:39 The wedge pressure can be elevated and mitral valve disease, left ventricular failure, cardiac tamponade, pericarditis, and fluid volume overload.

07:47 Everything that causes the PAD to increase would also cause your wedge pressure to increase.

07:54 So, why do we use wedge versus your pulmonary artery diastolic pressure? Well, technically your wedge will be about 3 mmHg less than your pulmonary artery diastolic number.

08:06 So a lot of times now, physicians don't even want us to wedge the balloon.

08:10 We'll just use the PAD number as our wedge pressure.

08:13 But there are some conditions where your wedge pressure will be different than your diastolic of your PA.

08:20 And those conditions if you have a right bundle branch block, severe mitral valve disease, pulmonary hypertension, left ventricular compliance issues and aortic or pulmonic valve insufficiencies.

08:31 Any of those, you'll need to wedge the balloon to get an accurate left ventricular end diastolic pressure.