Mod1: Monitoring for Cardiac Surgery - CENTRAL VENOUS PRESSURE Flashcards
CENTRAL VENOUS PRESSURE - INDICATIONS
Secures vascular access for:
Evaluating cardiac function
CVP/RAP (preload)
To evaluate R atrial and ventricular function and tricuspid function
Administer fluids, vasoactive drug therapy, TPN fluid
Aspiration of air
Conduit for insertion pulmonary artery catheter or transcutaneous pacing leads
Difficult vascular access or repeated blood sampling required
CENTRAL VENOUS PRESSURE - INDICATIONS
T/F: CVP/RAP is a good indicator of left sided function
False
CVP/RAP is not a good indicator of left sided function
CENTRAL VENOUS PRESSURE - INDICATIONS
What are normal CVP/RAP values?
2-6 mmHg
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
What must be carefully considered when choosing a site for CVP cannulation?
Patient’s underlying medical condition
Clinical setting and skill level of anesthesia provider
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
What should be considered when selecting a site for CVP cannulation in a pt with underlying bleeding process
choose a site where bleeding from the vein or surrounding vessels can easily be detected and corrected
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
Between Internal jugular and subclavian approach which is preffered for CVP cannulation in a pt with Bleeding diatheses?
Internal jugular > subclavian approach
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
What is Bleeding diatheses?
an unusual susceptibility to bleed (hemorrhage) mostly due to hypocoagulability (a condition of irregular and slow blood clotting), in turn caused by a coagulopathy (a defect in the system of coagulation).
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
Between Internal jugular and subclavian approach which is preffered for CVP cannulation in a pt with Emphysema?
Internal jugular > subclavian approach
IJ is associated with a reduced chance of a pneumothorax
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
Why is the RIJ preferred for Transvenous pacing?
Direct route to right ventricle
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
Provider must be aware of the length of the catheter chosen in relation to the site of insertion. How many cm greater will proper positioning of the cather tip in th SVC be on the left vs the right?
3-5 cm greater on the left than right
This is why left sided catheter should be longer
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
What’s the most common site for CVP cannulation
Right internal jugular vein
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
What are advantages of the right IJ site for CVP cannulation?
Easily accessible (short/direct access to the RA)
Predictable anatomy
Good landmarks
High success rate (>90%)
Thrombus formation less likely (d/t high blood flow rate and pts can still move heads arround)
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
Which complications are associated with the right IJ when used as a CVP cannulation site?
Carotid artery puncture
Brachial plexus injury
Pneumothorax (esp. pts w/ short necks)
Hard to maintain sterility (esp. in pts w/ lots of oral seceretions)
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
Advantages of Left internal jugular vein site?
Same as right
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
What are “catheter length” considerations when the Left IJ is cannulated for CVP monitoring?
A longer catheter may be needed for the catheter to be seated in the right position
Remember that proper position of the catheter tip in the SVC will be 3-5cm greater on the left than on the right
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
Disadvantages of Left internal jugular vein site?
Thoracic duct damage
Cupola of the pleura higher on left side
(which potentially increase the risk for a pneumothorax)
Left IJ is smaller than the right IJ
Difficulty maneuvering catheter through jugular-SC junction
Carotid artery puncture
(LIJ seats more on top of the left carotid than the right IJ seats on top of the right carotid)
Embolization of dominant L cerebral hemisphere
Most providers have less experience with inserting lines on the left side
(Which creates and increased risk for adverse events)
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
Why is the risk of Thoracic duct damage greater with LIJ cannulation than with RIJ cannulation?
The Thoracic duct enters the venous system at the junction of the LIJ vein and the subclavian vein, so it can potentially be damaged
This is not the case on the right side because the thoracic duct typycally drains into the venous system at the level of the subclavian vein; so the risk of injury is lower
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
Where do thoracic ducts terminate? What’s the difference between Left vs right terminations?
On the left side, the Thoracic duct enters the venous system at the junction of the LIJ vein and the left subclavian vein, so it can potentially be damaged during cannulation
This is not the case on the right side because the thoracic duct typycally drains into the venous system at the level of the subclavian vein; so the risk of injury is lower
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
What are advantages of Subclavian Vein cannulation for CVP?
Easy accessibility
Good landmarks
Stability of catheter for long-term use
Easy to maintain sterility because it is farther away from pt’s nasal and oral secretions
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
What are disadvantages of Subclavian Vein cannulation for CVP?
High rate pneumothorax
Hemothorax
Pleural effusion
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
If attempt of cannulation of subclavian vein is unsuccessful on one side, attempt on contralateral side is contraindicated w/o first obtaining CXR. Why is that?
Because you do not want to cause bilateral pneumothorax
CENTRAL VENOUS PRESSURE - SITES OF CANNULATION
What should you be aware of regarding holding pressure if the cannula accidentaly enters the arterial circulation during subclavian vein cannulation?
Holding pressure will be more demanding
It’s much more difficult to hold pressure on the chest than it would be on the neck
CVP - SITES OF CANNULATION - External jugular vein
What are advantages of the EJ site for CVP cannulation?
Superficial and safe access (pt on heparin)
Both right and left are good options
CVP - SITES OF CANNULATION - External jugular vein
Why is the EJ vein not an ideal site for CVP cannulation?
Tortious nature
Lower success rate
Kinks at SC vein
Enters the SC vein at a steep angle
CVP - SITES OF CANNULATION - Antecubital vein
What are Advantages of the Antecubital vein when used as a CVP cannulation site?
Few complications
Typical location for PIC line placement
CVP - SITES OF CANNULATION - Antecubital vein
Which controversy surround CVP values when measured at the AC site?
Some studies suggest that CVP is higher when measured from an AC line, but this is not clinically significant
CVP - SITES OF CANNULATION - Antecubital vein
What are Disadvantages of the Antecubital vein when used as a CVP cannulation site?
Lowest success rate
Thrombosis
Thrombophlebitis
CVP - SITES OF CANNULATION - Femoral vein
What are Advantages of the Femoral vein when used as a CVP cannulation site?
High success rate
Easy landmarks
Large diameter
CVP - SITES OF CANNULATION - Femoral vein
What are disadvantages of the Femoral vein when used as a CVP cannulation site?
Catheter sepsis
Thrombophlebitis
Patients are unable to ambulate
CVP - SITES OF CANNULATION - Femoral vein
Why is the Femoral vein typically not an ideal site for more than 24 hrs?
Increased risk for infections
This also applies to the femoral areterial line
CVP - SITES OF CANNULATION - Femoral vein
Why should the Femoral line be inserted below the level of the inguinal line?
To decrease the risk of injury to the inguinal liguament
CVP - SITES OF CANNULATION - Femoral vein
What’s a difficulty with obtaining CVP measurements from a femoral line?
Will require a longer catheter line that resides in the IVC
CENTRAL VENOUS PRESSURE
WHERE SHOULD DISTAL ORIFICE OF any CVP CATHETER BE POSITIONED?
Insertion catheter (7.5 or 9 Fr.) into venous circulation and advancing until distal orifice positioned adjacent or within RA
CENTRAL VENOUS PRESSURE
WHERE SHOULD DISTAL ORIFICE OF CATHETER BE POSITIONED to Guide fluid management?
Tip positioned within either RA or vena cava near caval-atrial junction
CENTRAL VENOUS PRESSURE
For monitoring CVP waveform, why should the tip of the catheter BE POSITIONED within the atrium?
To accurately reflect pressure changes in RA
The waveform will not be dampened
CENTRAL VENOUS PRESSURE
WHERE SHOULD DISTAL ORIFICE OF CATHETER BE POSITIONED for Aspiration of air emboli?
Tip (prefer multiport) in RA near SVC-atrial junction
This is because air emboli will flow pass this point and accumulate in the superior aspect of the junction
And this will allow for optimal aspiration
INTERPRETING CVP WAVEFORM
CVP Waveform consists of five phasic events, which are?
Three ascents (a, c, v)
Two descents (x, y)
INTERPRETING CVP WAVEFORM - 3 Ascent Waves
What does the a wave represent?
Right atrial contraction
This is the highest pressure wave on the curve
Occurs at end-diatole
Follows P wave on EKG
INTERPRETING CVP WAVEFORM - 3 Ascent Waves
A large a wave could be indicative of which conditions?
Tricuspid stenosis
Pulmonary HTN
↓ RV compliance
INTERPRETING CVP WAVEFORM - 3 Ascent Waves
What does the c wave represent?
Isovolumetric ventricular contraction
This is the second ascent wave or the next highest wave on curve
Occurs as a result of the Bulging of closed tricuspid valve into RA during early phase of RV contraction as a consequence of Isovolumetric ventricular contraction
Occurs in conjunction with QRS wave
Always follows the EKG R-wave
INTERPRETING CVP WAVEFORM - 3 Ascent Waves
What does the v wave represent?
Right atrial filling
Occurs during late in ventricular systole while the Tricupsid valve is still closed and the atrium is filling
Occurs as a result of increase in RAP while atrium fills against a closed tricuspid valve
Peaks just after the EKG T-wave
INTERPRETING CVP WAVEFORM - 3 Ascent Waves
Large v waves could be indicative of which conditions?
Tricuspid regurgitation
RV papillary muscle ischemia
RV failure
Constrictive pericarditis
Cardiac tamponade
INTERPRETING CVP WAVEFORM - 2 Descent Waves
What does the x wave represent?
Systolic collapse of RA pressure
Occurs while the Tricupsid is pulling away in the RV during ventricular ejection
Tricuspid valve pulled downward at end of ventricular systole
INTERPRETING CVP WAVEFORM - 2 Descent Waves
What does the y wave represent?
Diastolic collapse of RA pressures
Occurs when Tricuspid valve opens & RA empties passively into ventricle
INTERPRETING CVP WAVEFORM
(Listen to slide 52)
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INTERPRETING CVP WAVEFORM
(listen to slide 52)
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INTERPRETING CVP WAVEFORM
In some pathologic conditions, the a, c & v waves can change dramatically. In A-fib and A-flutter there will be no a-waves any longer, why?
The RA is quivering and not contracting
INTERPRETING CVP WAVEFORM
Nodal rhythms, heart blocks and certain arrythmias will develop large a-waves or “canon-waves”, why?
The RA is contracting against a closed Tricupsid valve
INTERPRETING CVP WAVEFORM
Tricupsid stenosis or RV failure will also have the “canon-wave”, why?
The RA is contracting against a stenotic valve
INTERPRETING CVP WAVEFORM
In Tricupsid regurg, the c-wave and v-wave are fused, and the normal x-descent will disappear, why?
Effect of the regurgitant flow
