W9 D2 - Hemodynamics Flashcards
What is a mixed venous blood gas?
What are some indications for PA catheter?
Cardiogenic shock
Right & left sided heart failure
Severe chronic CHF
CV surgery
Pulmonary hypertension
Transplantation
Hypotension
Why might PA catheter pressure increase when the volume remains the same?
Condition putting pressure on the heart:
cardiac tamponade, tension pneumothorax etc
Where does the distal lumen sit and what does it do?
PA catheter
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
What is the inflating lumen for?
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
What does the thermistor lumen do?
Measures patients core tempurature, required to measure CO
What does the proximal lumen do?
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
How is a PA catheter inserted?
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
Which lumens are transduced in a PA catheter?
Proximal and distal lumens
* shortest and deepest lumens
Be able to draw normal waveforms and list the normal values
RAP 3-8 mmHg
RVP Systolic 15-25, diastolic 0-8
PAP Systolic 15-25, diastolic 8-15, mean 10-20
PCWP 6-12
Why do we monitor PAP?
To monitor left ventricular functioning by measuring left ventricular end diastolic pressure
What do we need to monitor/do for patients with a PAC as nurses?
- waveforms & pressures
- zeroing transducer, flushing
- maintaining transducer at 4th ICS
- check locking device and syringe
- document level of insertion
- dressing changes
What does the diacrotic notch represent? PA vs ART?
ART: Start of diastole; closing of aortic valve
PA: start of diastole; pulmonic valve closing
What would you be concerned about if the PAC is in the right ventricle?
Causing PVCs, V-tach, V-fib
What does RAP measure and how?
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
What might cause increased RAP / preload? How?
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
What could cause a decrease in RAP (preload)?
Hypovolemia - decreases in circulating volume
Disruptive shock - massive vasodilation
Venous pooling - vasodilation decreases preload returning to heart
What does pulmonary artery systolic pressure measure?
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
What does pulmonary artery diastolic pressure PADP measure? How?
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
What is the order of blood flow through the heart valves/chambers?
From Vena Cava
enters RA
Tricuspid valve
RV
Pulmonic valve to artery
Lungs
Pulmonic vein
LA
Mitral valve
LV
Aortic valve to aorta
BODY
What does PCWP measure? How?
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)
What is the relationship between PADP & PCWP?
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
What does the RAP, PASP, PADP, PCWP measure?
RAP - preload, right side
PASP - RVF, pulmonary bed, left side indirectly
PADP - preload, left side, pulmonary bed
PCWP - preload , left side
