PA Catheters Flashcards
CVP measured and reflects
Measured in the RA or SVC, measure of RV filling or diastolic pressure
What are the 4 ports of the thermodilution catheter?
1) Distal –> PAP, PCWP, SVO2
2) Inflation –> Balloon 1.5cc air inflatable
3) Thermistor –> Measures core temp, CO
4) Proximal –> RAP/CVP, can infuse solutions, prn meds
Where can we infuse meds in PA catheter?
Proximal, but not continuous meds. Only PRN push meds and fluids only
Can we infuse blood through PA catheter?
No, small diameter risk of occlusion and damage to RBCs
Right atrium normal pressure
3-8
Right ventricle normal pressure
15-25 (Systolic)
0-8 (End diastolic)
Pulmonary Artery normal pressure
15-25 (Systolic)
8-15 (Diastolic)
10-20 (Mean)
PCWP normal pressure
6-12 (non vented pt)
What causes the diacrotic notch on the PA waveform?
Closure of the pulmonic valves
Where is the phlebostatic axis?
4th ICS mid clavicular line
What does CVP/ RAP reflect?
Preload of the RA, indicator of RV function
What can elevate CVP/RAP?
Hypervolemia, tricuspid valve stenosis/regurg, RV failure, RV MI, constrictive pericarditis, pulmonary HTN, LV failure, intrathoracic pressures
What does PASP reflect?
Pressure in PA when RV ejecting blood into it. Reflects RV function and indirectly left heart (via pressure changes in pulmonary circulation)
What can elevate PASP?
Constrictive pericarditis, hypoxemia (pulmonary arterioles constrict), LV dysfunction, mitral valve stenosis/regurg, increased pulmonary blood flow due to shunting
What does PADP reflect?
In absence of pulm HTN, reflects left heart pressures (pressure in left ventricle at end of diastole). Affected by changes in pulmonary circulation and left heart
What can elevate PADP?
Volume overload, LV failure, mitral valve issues, intrathoracic pressures, pulm HTN
What does PCWP reflect?
Left atrial filling pressures (in systole the wedge reflect LAFP, in diastole LVEDP). Is recorded as a mean reflecting left heart function.
How does the PADP relate to PCWP?
When pulm vascular resistance is normal, PADP correlates to PCWP (PADP is 1-4 above PCWP), so PADP can be used to monitor left heart pressures ONLY if the pt has no significant pulmonary disease that raises PA pressures
Why is PADP and PCWP useful in fluid management
Changes show up 24-48 hrs before changes reflect in CVP in response to left ventricular failure
How is PCWP affected by breathing
Decreases during inspiration, increases during expiration (spontaneous breathing)
When ventilated, PCWP increases during positive pressure inspiration and decreases during expiration
When should PCWP reading be taken
At end of expiration where there is no gas going in or out of lungs
What are complications of wedging?
1) Over wedging (Tracing climbs up in straight line)
2) Spontaneous wedge
3) Rupture of PA balloon
4) PA hemorrhage, rupture
5) Clot in lumen, air bubbles, kink in lumen causes dampened pressure tracing
How is cardiac output correlated to surface area under the time-temperature curve?
Normal cardiac output –> Smooth upstroke to peak, then gradual downslope to baseline. Smooth curve
High cardiac output –> Fast upstroke to peak, quick downstroke. Small area under curve
Low cardiac output –> Slow upstroke to peak. slow recovery to baseline (large area under curve)
What is the selection criteria for cardiac output curve?
1) Minimum of 3 cardiac outputs taken
2) Curves as “normal” as possible
3) +- 10% variability around median value
What is cardiac index?
Calculated using pt body surface area obtained from Dubois chart (dry weight used)
What is normal CO and CI?
CO: 4-8 L/min
CI: 2.5-4.5 L/min
What is PVR?
Pulmonary Vascular Resistance –> Measures afterload of right ventricle
Normal PVR = 155-255 dynes/sec/cm-5
What is SVR?
Systemic vascular resistance –> Measures afterload of left ventricle
Normal SVR = 800 - 1200 dynes/sec/cm-5
What can increase PVR?
Lung problems causing pulmonary HTN, hypoxemia causing arteriole constriction, pulmonic valve stenosis,
What can increase SVR?
Hypothermia, shock, catecholamines, drugs, hypovolemia
What can decrease PVR and SVR?
Vasodilation, sepsis, hyperthermia, endotoxins
What measurements monitor preload?
RAP (R heart)
PCWP (L heart)
PADP
What measurements monitor afterload?
PVR (R heart)
SVR (L heart)
What measurements monitor contractility?
CO
CI
What treatments can decrease preload?
Diuretics, morphine, vasodilators (NTG, nipride)
What treatments can increase preload?
Fluids, vasopressors (decrease venous pooling)
What treatments can decrease afterload?
Vasodilators (NTG, nipride), ACE inhibitors, milrinone, antihypertensives, nitric oxide, flolan, IABP
What treatments can increase afterload?
Vasopressors
Inotropes
Treat cause
What treatments can improve contractility?
Inotropes (dobutamine, dopamine, milrinone, epi, dig)
Calcium (not given unless deficiency)
Correct cause
