W9 D2 - Hemodynamics

Question 1

What is a mixed venous blood gas?

Question 2

What are some indications for PA catheter?

Answer 2

Cardiogenic shock
Right & left sided heart failure
Severe chronic CHF
CV surgery
Pulmonary hypertension
Transplantation
Hypotension

Question 3

Why might PA catheter pressure increase when the volume remains the same?

Answer 3

Condition putting pressure on the heart:
cardiac tamponade, tension pneumothorax etc

Question 4

Where does the distal lumen sit and what does it do?

PA catheter

Answer 4

Sits in the PA to monitor
Measures:
* PAP
* Pulmonary capillary wedge pressure
* Obtains mixed venous to determine O2 consumption

Flush with NS
NEVER give meds through distal port, too far

Question 5

What is the inflating lumen for?

Answer 5

A balloon is present at the catheter tip, non occlusive
* 1.5 cc of air max, risk bursting artery or balloon
* special syringe

Inflated for insertion and measuring PCWP:
* catheter floats with the blood until wedged

always deflated otherwise

Question 6

What does the thermistor lumen do?

Answer 6

Measures patients core tempurature, required to measure CO

Question 7

What does the proximal lumen do?

Answer 7

In the right atrium
Used to
* monitor right sided heart function
* infuse intravenous boluses, IVP meds
* no continuous meds
* injection of solution for measure CO
* no packed RBCs

Question 8

How is a PA catheter inserted?

Answer 8

The balloon tip creates a flow directed catheter and follows the venous blood flow
* via a cordis (large bore central line), remove or keep after
* IJ and subclavian veins

Monitoring and confirmation
* each chamber has different waveforms to see during insertion
* confirm with CXR
* strict sterile technique

Question 9

Which lumens are transduced in a PA catheter?

Answer 9

Proximal and distal lumens
* shortest and deepest lumens

Question 10

Be able to draw normal waveforms and list the normal values

Answer 10

RAP 3-8 mmHg
RVP Systolic 15-25, diastolic 0-8
PAP Systolic 15-25, diastolic 8-15, mean 10-20
PCWP 6-12

Question 11

Why do we monitor PAP?

Answer 11

To monitor left ventricular functioning by measuring left ventricular end diastolic pressure

Question 12

What do we need to monitor/do for patients with a PAC as nurses?

Answer 12

• waveforms & pressures
• zeroing transducer, flushing
• maintaining transducer at 4th ICS
• check locking device and syringe
• document level of insertion
• dressing changes

Question 13

What does the diacrotic notch represent? PA vs ART?

Answer 13

ART: Start of diastole; closing of aortic valve
PA: start of diastole; pulmonic valve closing

Question 14

What would you be concerned about if the PAC is in the right ventricle?

Answer 14

Causing PVCs, V-tach, V-fib

Question 15

What does RAP measure and how?

Answer 15

Measures right ventricular function & preload:
* at the end of diastole the tricuspid valve opens and the pulmonic valve closes stopping blood flow briefly = pressure on RA is same as RV

Question 16

What might cause increased RAP / preload? How?

Answer 16

Hypervolemia = increased circulating volume
RV failure = decreased compliance & RV CO
TV stenosis = valve is narrow, increases resistance
TV regurgitation = valve doesn’t fully close, blood flows back into RA
Pulmonary embolus, edema, HTN, & ARDS = increased pressure in pulmonary vasculature increases afterload in RV decreasing RV CO
LVF = blood backs up into pulmonary veins, capillaries, arteries eventually to right side of heart

Tension pneumo, cardiac tamponade = pressure on the heart gives false volume change
Intraabdominal HTN, PEEP = increases intrathoracic pressure, not volume related

Question 17

What could cause a decrease in RAP (preload)?

Answer 17

Hypovolemia - decreases in circulating volume
Disruptive shock - massive vasodilation
Venous pooling - vasodilation decreases preload returning to heart

Question 18

What does pulmonary artery systolic pressure measure?

Answer 18

RV function
* when the pulmonic valve is open during systole, RV and PA pressure is equal
* indirectly reflects changes in lungs and left heart

Elevated PASP
* hypoxemia - pulmonary vasoconstriction = resistance
* LVF - back up of blood
* mitral stenosis / regurgitation - back up of blood
* pulmonary issues - increased pressure in pulmonary vasculature = ^ resistance

Decreased PASP
* hypovolemia
* vasodilation

Question 19

What does pulmonary artery diastolic pressure PADP measure? How?

Answer 19

Measures left heart pressures and preload
* affected by pulmonary circulation because the mitral valve is open & pulmonic is closed

Increases PADP
* hypervolemia
* LVF - blood backs up
* Mitral valve disease
* cardiac tamponade, tension pneumo, pulmonary pressure issues

Decrease PADP
* hypovolemia
* vasodilation

Question 20

What is the order of blood flow through the heart valves/chambers?

Answer 20

From Vena Cava
enters RA
Tricuspid valve
RV
Pulmonic valve to artery
Lungs
Pulmonic vein
LA
Mitral valve
LV
Aortic valve to aorta
BODY

Question 21

What does PCWP measure? How?

Answer 21

Left ventricular end diastolic pressure
* Blow up the balloon for 2 respiratory seconds, 10-15 seconds to occlude the PA
* Diastole: measure LVEDP pressure through LA to LV because mitral valve open
* Systole: measures left atrium filling pressure because mitral valve closed

normal 6-12 mmHg (non-vented)

Question 22

What is the relationship between PADP & PCWP?

Answer 22

If the patient has normal pulmonary function and vascular resistance is low then PADP and PCWP correlates
* able to monitor left heart pressures / preload with just PADP

Question 23

What does the RAP, PASP, PADP, PCWP measure?

Answer 23

RAP - preload, right side
PASP - RVF, pulmonary bed, left side indirectly
PADP - preload, left side, pulmonary bed
PCWP - preload , left side