Exam 7 - CVP / PAP Flashcards
1
Q
CVP
A
- very good estimation of RAP (pre-load of R heart)
- pressure of blood in vena cava as it is returned
- DIRECTLY assesses R heart function (RVEDP)
- INDIRECTLY reflects venous return (therefore CO)
- INDIRECTLY assesses L heart function
- 2 to 6 mmHg
- 65-80%
2
Q
End RV diastole
A
- RA and RV pressures are the same
3
Q
Why CVP is an indirect assessment of L heart function
A
- In healthy heart: LVEDP = (2 x RVEDP) + 2
- RVEDP = CVP
- Also good because it is in a circuit…just stuff in between
4
Q
LV failure
A
- RV can compensate temporarily until it gets burnt out
5
Q
Factors that increase CVP
A
- Hypervolemia (overfilling…we can do this!)
- Forced exhalation
- Tension pneumothorax
- Heart failure
- Pleural effusion
- Decreased CO
- Cardiac tamponade
- PEEP / mechanical ventilation
6
Q
Factors that decrease CVP
A
- Hypovolemia (perfusionist underfill or bleeding)
- Deep inhalation
- Shock / vasodilation
7
Q
Venous return and CO
A
- Equal over time
- Otherwise blood accumulates in pulmonary or systemic
- increase in venous pressure increases venous return
- blood flow through entire systemic circulation is both CO and venous return….they are equal
8
Q
Blood volume in Veins
A
- 64%
9
Q
6 factors affecting venous return
A
- Musculovenous pump (n/a on CPB)
- Decresed venous capacitance (symp. Tone increases CVP/VR)
- Respiratory pump (thoracic pressure negative when inhale)
- Vena Cava compression (compressed cava lowers VR)
- Gravity (standing decreases VR)
- Pumping heart (no valve between atria and veins)
10
Q
CVP insertion sites
A
- catheter toward RA
- 20cm: subclavian / internal-external jugular
- 60 cm: femoral
- also can do antecubital
11
Q
CVP kit
A
- Penetration syringe (can use big needle with this)
- Dilator
- Scalpel
- guide syringe/needle
- anesthesia syringe
- needle holding sponge
- big needle
12
Q
Seldinger technique
A
- Venous puncture w/ introducer needle
- guide wire through needle –> needle removed
- dilator passed over needle
- dilator removed and catheter placed over wire
- wire removed
13
Q
Level to monitor CVP
A
- Phlebostatic Axis = 4th intercostal space / mid-axillary
- level of atria
14
Q
Complications of CVP
A
- infection
- air (Bad if PFO)
- catheter shearing
- thrombophlebitis (clots at insertion site)
- Extravasation of fluid/drugs
- pneumothorax
- hemothorax
- pericardial tamponade
15
Q
CVP wave form
A
- A: End Diastole / Atrial contraction (RVEDP)
- C: Early systole / Tricuspid bulging
- X: Mid systole / Atrial relax
- V: Late systole / Systolic filling of atrium
- Y: Early diastole / Early ventricle filling
16
Q
CVP and CPB
A
- heart is empty
- CVP should be zero
- If not….get better VR!
- change height of Reservoir
- cannulation?
- reduce flow?
- AVD
- Kinetic assist venous drainage (KAVD)
- VAVD
17
Q
Restricting Venous return line
A
- Arterial flow > return
- fills heart / increase preload / increase atrial pressure
- total controls of pre-load
18
Q
Swan-Ganz catheter
A
- PA catheter
- original 2 lumens…now 6
- more than 1 million used annually in US
19
Q
PA catheterization
A
- through vein….through R side of heart…into PA
- measures R heart and pulmonary pressures
- Indirectly L heart pressures - invasive and can be risks
20
Q
PA cath indications
A
- management of cardiopulmonary pressure/flows
- cardiovascular function
- surgical patients w/ systemic dysfunction
- shock
- pulmonary status
- severe hypotension
21
Q
Contradictions for PA cath
A
- severe coag defects (can cause hemorrhaging)
- prosthetic right heart valve
- endocardium pacemaker (knot up with electrode)
- severe vascular disease
22
Q
Direct measurements from PA cath
A
- CVP / RV pressure
- PA pressures (PAWP)
- CO
- SvO2
23
Q
Indirect measurements from PA cath
A
- SVR (MAP-CVP / CO x80)
- PVR
- CI (CO/BSA)
24
Q
Cardiac Output (Thermodilution)
A
- 10cc cold saline (10C) injected into RA through proxml lumen
- solution mixes w/ blood as it moves through RV into PA
- thermistor registers change in blood temp
- computer plots change in temp over time
- calculates area under curve
- perform 3-4 times and take average
- Also have continuous CO catheters so you don’t have to inject fluid
- uses thermal coil to heat blood to 44
25
Q
Fiber optic PA cath
A
- measures SvO2
- Reflected red light off of oxy/deoxy hemoglobin
- computer gets % fraction
26
Q
PA pacing catheters
A
- 3 atrial / 2 ventricular electrodes
- temporary pacing
27
Q
PA cath insertion sites
A
- R internal jugular (preferred)
- L internal jugular
- subclavian
- External jugular
- femoral
- antecubital
28
Q
RA to RV waveform
A
- gets bigger
- RA pressure = RVEDP = RV filling = preload
29
Q
RV to PA waveform
A
- get dicrotic notch (Pulmonary valve closure)
30
Q
PA to PCWP
A
- balloon lodges into distal branch of PA
- PCWP = LAP
- Mean PCWP = LVEDP….filling pressure
- Flat line waveform again
31
Q
PAWP
A
- measures LV filling….LV preload
- Mean PAWP reflects LA pressure = LVEDP
- when balloon inflated….waveform flattens…deflate and it returns
32
Q
Over-wedging
A
- continuously rising buildup of pressure
33
Q
PAP Waveform
A
1- Systolic ejection into PA (first valley)
2- Closure of Pulmonic valve (dicrotic notch)
3- End diastole (second valley)
34
Q
PA systolic pressure
A
- shows RV function and pulmonary circ pressures
- increased by:
- L to R shunt (ASD/VSD)
- pulmonary hypertension
- COPD
35
Q
PA diastolic pressure
A
- shows LV pressures
- LVEDP
- 6 to 12
- increased by: Volume overload
L heart dysfunction (failure, MR, MS, AS, AI) - decreased by: hypovolemia or severe tricuspid stenosis
36
Q
Problems getting hemodynamic data
A
- body position to transducer
- connection of transducer to catheter port
- cardiac dysfunction
- MI - PCWP goes up
- LV dysfunction
- Tachycardia - catheter whip
- vent problems
37
Q
Complications of PA cath
A
- arrhythmia
- balloon rupture
- knotting
- infection
- thrombus
- pulmonary ischemia
- damage to PA
- cardiac perforation or tamponade
