Download - Right Heart Catheterization
Copyright © 2011 American Heart Association.
Right Heart CatheterizationRight Heart Catheterization
Sripal Bangalore, M.D., M.H.A.and
Deepak L. Bhatt, M.D., M.P.H., F.A.H.A
Copyright © 2011 American Heart Association.
OverviewOverviewRight Heart Catheterization (RHC)
Indications Contraindications / Caution Equipment Technique Precautions Cardiac Cycle Pressure monitoring
Zeroing and Referencing Fast flush test/ Square wave test
Pressure wave interpretation Cardiac output Derived measurements
No universally accepted indication as right heart (pulmonary artery, PA) catheterization has not been shown to improve outcomes1
However it is useful in the following diagnostic and therapeutic applications
Diagnostic
Differentiation of various etiologies of shock and pulmonary edema
Evaluation of pulmonary hypertension
Differentiation of pericardial tamponade from constrictive pericarditis and restrictive cardiomyopathy
Diagnosis of left to right intracardiac shunts
Therapeutic
Guide to fluid management and hemodynamic monitoring of patients after surgery, complicated myocardial infarction, patients in shock, heart failure, etc.
IndicationsIndications
1Sandham JD et al. A randomized, controlled trial of the use of pulmonary-artery catheters in high-risk surgical patients. N Engl J Med 2003;348(1):5-14
Copyright © 2011 American Heart Association.
No absolute contraindications for use of PA catheter. Extreme care needed particularly in patients with severe pulmonary hypertension and in the elderly
Fluoroscopic guidance recommended in patients with pre-existing left bundle branch block (risk of complete heart block if right bundle damaged during catheter insertion)
Contraindications / CautionContraindications / Caution
Copyright © 2011 American Heart Association.
EquipmentEquipment
2% chlorhexidine skin prep Sterile gown, gloves, hat and mask Sterile drape 2% lidocaine solution for local anesthesia Micropuncture needle and sheath (optional) Sterile ultrasound probe cover and gel Introducer sheath and needle Pulmonary artery (Swan-Ganz) catheter Sterile flush Pressure tubing, transducer and monitor
Copyright © 2011 American Heart Association.
EquipmentEquipmentPulmonary Artery (Swan-Ganz) CatheterThese are 7F to 7.5F system catheters and are available as femoral vein
insertion to continuous cardiac output cathetersBalloon inflation valve
Proximal injectate lumen hub
VIP lumen hub
Distal PA lumen hubBalloon inflation syringe
Thermistor connector
Reproduced with permission from Edward Lifesciences, Irvine, California
Copyright © 2011 American Heart Association.
Technique- MicropunctureTechnique- Micropuncture Insertion site: Internal jugular vein, subclavian vein, antecubital vein, or
femoral vein
After the site is prepped and draped, local anesthesia is administered at the site by giving 5 to 10 cc (depending on the site) of 2% lidocaine using a 25G needle
Vein entered using a needle (preferably micropuncture) and preferably under ultrasound guidance (especially for internal jugular vein)
After ensuring that the needle is indeed in a vein (dark, non-pulsatile flow or checking pressure or oxygen saturation), the guidewire is introduced into the micropuncture needle and the needle exchanged for a micropuncture sheath
If there is difficulty in wiring and the micropuncture wire needs to be removed, remove both the needle and the wire as a unit
Attempting to remove just the guidewire can result in the guidewire tip shearing off the needle tip with subsequent guidewire embolization
Exchange the micropuncture catheter for the introducer sheath
Copyright © 2011 American Heart Association.
TechniqueTechnique
Preparing the catheter Under sterile conditions, remove the pulmonary artery catheter from
the packaging Flush the proximal and distal ports with saline to ensure an air free
system and place stopcocks on the ends Fill the balloon inflation syringe with 1.5 cc of air and inflate the
balloon under saline to ensure no air leaks in the balloon Prepare the pressure monitoring system for use according to
institutional practice, ensuring an air free system
Copyright © 2011 American Heart Association.
TechniqueTechniqueInserting the catheter The pulmonary artery (PA) catheter can be inserted either under
fluoroscopic guidance (preferred) or under the guidance of the pressure wave forms
Fluoroscopic guidance is recommended in patients with markedly enlarged RA or RV, severe tricuspid regurgitation, or in those with left bundle branch block
A PA catheter with the balloon inflated is designed to be flow-directed and will follow the direction of blood flow (right atrium to pulmonary arteries)
The catheter should be advanced to the vena cava/RA junction, the approximate distance (as measured on the PA catheter) from the site insertion is below
Site of Insertion Distal to the Vena Cava/RA junction (cm)
Internal jugular vein 15 to 20
Subclavian vein 10 to 15
Antecubital vein (Right) 35 to 40
Antecubital vein (Left) 45 to 50
Femoral vein 25 to 30RA = right atrium
Copyright © 2011 American Heart Association.
TechniqueTechniqueInserting the catheter Once the catheter tip reaches the junction of the vena cava and right atrium,
the balloon is inflated with 1.5 cc of air and the pressure waveforms noted The following sequential waveforms will be noted as the catheter passes
through the cardiac chambers Right atrial (RA) waveform
Right ventricular (RV) waveform
a c v
xy
a c v
xy
a c v
xy
Copyright © 2011 American Heart Association.
TechniqueTechniqueInserting the catheter
Pulmonary artery (PA) pressure waveform
Pulmonary capillary wedge pressure (PCWP) waveform Similar to RA pressure waveform except slightly higher
Normal insertion tracing will therefore appear as below For RV to PA - observe changes in diastolic pressure (increase) as
the systolic pressure stays the same
a c v
xy
a c v
xy
a c v
xy
a c v
x y
Copyright © 2011 American Heart Association.
TechniqueTechniqueInserting the catheter Once a PCWP tracing is seen, deflate the balloon The catheter should be withdrawn 1-2 cm to remove any redundant length or
loop in the RA or RV. Keep the tip in a position where full or near full inflation volume is necessary to produce a wedge tracing
The balloon should be deflated and the pressure wave form seen should now be that of the PA. If still the PCWP, it is likely that the catheter is distal and should be retracted until a PA pressure tracing is seen
The ideal position of the catheter is the zone 3 region of the lung (lower zone) For subsequent wedge tracings, the balloon should be inflated with the
minimum amount of air to produce a wedge tracing. Excess can cause “overwedging” where the PCWP will be higher due to transmittal of pressure from the balloon and with loss of characteristic waveforms
Removing the catheter The catheter should always be removed with the balloon deflated to avoid
damaging the valves
Copyright © 2011 American Heart Association.
TechniqueTechniquePrecaution Always advance the catheter with the balloon inflated (catheter is flow-directed, also
reduces ventricular irritability and ectopy) Never leave the catheter wedged in the PA for longer than necessary, to avoid the risk
of pulmonary artery rupture/pulmonary infarction Do not overinflate the balloon If wedge is obtained at volumes <1.0cc, pull the catheter back to a position where full
or near-full inflation volume (1.0 to 1.5cc) produces a wedge tracing Before balloon reinflation, always check the waveform to ensure no distal migration Never withdraw the catheter with the balloon inflated to avoid valvular damage Never use fluids (saline) to inflate the balloon In situations where multiple attempts at advancing the catheter to the PA fail, a
0.025” guidewire can be used under fluoroscopic guidance to help advance the catheter to the PA
Always maintain catheter tip in a main branch of the PA If performed via the internal jugular or the subclavian vein route and without
fluoroscopic guidance, chest x-ray should be obtained post procedure to rule out pneumothorax and to verify catheter position
Never flush catheter with balloon wedged in the PA
0 100 200 300 400 500 600 700 800
0
30
60
90
120
Atrial Systole
Ventricular Systole Ventricular Diastole
EKG
Time (msec)
Pressure (mm Hg)
P
QRS Complex
TP
Aorta
Dicrotic Notch
Left Ventricular Pressure
ac
v
x
yLeft Atrial Pressure
Cardiac Cycle
Cardiac Cycle
Left Sided Pressures
0 100 200 300 400 500 600 700 800
0
15
30
Atrial Systole
Ventricular Systole Ventricular Diastole
EKG
Time (msec)
Pressure (mm Hg)
P
QRS Complex
TP
PA Pressure
Dicrotic Notch
Right Ventricular Pressure
ac
v
x
yRight Atrial Pressure
Cardiac Cycle
Cardiac Cycle
Right Sided Pressures
Copyright © 2011 American Heart Association.
Pressure RecordingsPressure Recordings Always record pressure at end expiration (except in patients on PEEP) Under normal conditions, pressures will be lower in inspiration due to
decrease in intrathoracic pressure Before any pressure measurements are taken, it is imperative to perform
zeroing and referencing of the system Zeroing- accomplished by opening the system to air so as to equilibrate
with atmospheric pressure Referencing- accomplished by ensuring that the air-fluid interface of the
transducer is at the level of the patient heart (phlebostatic axis) (4th intercostal space midway between anterior and posterior chest wall) For every inch the heart is offset from the reference point of the
transducer, a 2mm Hg of error will be introduced. If the heart is lower than the transducer, the pressure will be erroneously low and if the heart is higher, the pressure will be erroneously high.
Fast flush test/ Square wave testing The dynamic response of the pressure monitoring system is determined
by measuring the resonant frequency and the damping coefficient of the system using the fast flush test
Copyright © 2011 American Heart Association.
Pressure RecordingsPressure Recordings
Performed by briefly opening and closing the valve in the continuous flush device
This produces a square ware pattern on the oscilloscope, an initial steep rise followed by a plateau, followed by steep fall below baseline which is then followed by oscillations. The pattern determines optimal versus suboptimal damping
Optimal damping- usually 1.5 to 2 oscillations before returning to baseline. This is ideal
Over damping- None to <1.5 oscillations before retuning to baseline. Common cause - air bubbles. Underestimation of systolic pressure. Diastolic pressure may not be affected
Under damping- >2 oscillations before returning to baseline. Common cause - excessive tube length, multiple stopcocks in the circuit, etc. Overestimated systolic pressure and underestimated diastolic pressure
Optimal Damping
Over Damping
Under Damping
Fast flush test / Square wave testing
Copyright © 2011 American Heart Association.
Pressure RecordingsPressure Recordings Always record pressure at end expiration (except in patients on PEEP) Under normal conditions, pressures will be lower in inspiration due to
decrease in intrathoracic pressure PCWP reflects left atrial pressure and hence the left ventricular end diastolic
pressure as long as ventricular compliance is normal or unchanging PCWP > LVEDP: Mitral valve stenosis or regurgitation, left atrial
myxoma, pulmonary vascular disease/embolism, increased pulmonary vascular resistance, cor pulmonale
PCWP < LVEDP: Early stages of diastolic dysfunction, aortic regurgitation, decreased ventricular compliance due to myocardial ischemia/infarction, positive pressure ventilation, etc.
Site Normal Values (mm Hg)
Mean Pressure (mm Hg)
Right Atrium 0-8 4
Right Ventricle 15-25/0-8 5-12
Pulmonary Artery 15-25/8-12 10-20
PCWP 9-23/1-12 6-12PCWP = Pulmonary Capillary Wedge Pressure
Copyright © 2011 American Heart Association.
Pressure Wave InterpretationsPressure Wave Interpretations
Wave pattern Mechanism Condition
Cannon ‘a’ wave AV dissociation Complete heart block, ventricular tachycardia, AVNRT
Tall ‘a’ wave Increased atrial pressure Mitral or tricuspid stenosis
No ‘a’ wave Loss of atrial kick Atrial fibrillation
Tall ‘v’ wave Increased volume during ventricular systole
Mitral or tricuspid insufficiency, VSD
Loss of ‘y’ descent Equalization of diastolic pressures
Cardiac tamponade
Exaggerated ‘y’ descent
Rapid diastolic filling Constrictive pericarditis
RA/ PCWP
AVNRT = Atrioventricular Nodal Reentry Tachycardia; VSD = Ventricular Septal Defect
Copyright © 2011 American Heart Association.
Three indirect methods for cardiac output determinations
Dye indicator dilution technique
Fick’s technique
Cardiac Output = Oxygen consumption in ml/min A-V Oxygen difference
Oxygen consumption measured using an oxygen hood
Normal oxygen consumption is 250 ml/min
A-V Oxygen difference = 13.4 x Hgb concentration x (SaO2-SvO2)
Most accurate in low output states and is considered the gold standard
Thermodilution technique
Known amount of solution (usually saline) is injected into the proximal port (right atrium) and mixes and cools the blood which is recorded by a thermistor located at the distal end of the catheter
Cardiac OutputCardiac Output
Copyright © 2011 American Heart Association.
Thermodilution technique
CO is inversely proportional to the area under the curve
Not reliable in patients with severe tricuspid or pulmonic valve regurgitation. Results in lower peak and a prolonged washout phase due to re-circulation resulting in underestimation of CO
Not reliable in patients with intra-cardiac shunts. Overestimates CO
Normal CO = 4 - 8L/min
Normal cardiac index (cardiac output indexed to body surface area) = 2.5 - 4.0 L/min/m2
Oxygen saturation (SO2) obtained from the PA is a rough measure of CO
PA SO2 >80 High CO (shunt, sepsis, etc.)
PA SO2 65-80 Normal CO
PA SO2 <65 Low CO
Cardiac OutputCardiac Output
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Derived ParametersDerived Parameters
Parameter Formula Normal Values
Systemic Vascular Resistance (MAP-RAP) x 80CO
700 to 1600 dynes/sec/cm2
(9-20 Wood Units)
Pulmonary Vascular Resistance
(MPAP-PCWP) x 80 CO
20 to 120 dynes/sec/cm2
(0.25-1.5 Wood Units)
Stroke Work Index (MAP-LVEDP) x SVI x 0.0136 45 to 75 gm-m/m2/Beat (LV)5 to 10 gm-m/m2/Beat (RV)
Shunt Fraction (SaO2- MvO2)(PvO2-PaO2)
1
Mitral Valve Area(Gorlin’s Equation)
CO (ml/min) 37.7 x DFP x HR x √ΔP
4 to 6 cm2
Aortic Valve Area(Gorlin’s Equation)
CO (ml/min)44.3 x SEP x HR x √ΔP
3 to 4 cm2
Aortic Valve Area(Modified Hakki Equation)
CO (l/min)√ΔP
3 to 4 cm2
Vascular resistance obtained is least accurate and most sensitive to minor inaccuracies in data acquisition
CO = Cardiac Output; DFP = Diastolic Filling Period; HR = Heart Rate; LVEDP = Left Ventricular End Diastolic Pressure; MAP = Mean Arterial Pressure; MPAP = Mean Pulmonary Artery Pressure; MvO2 = Oxygen saturation mixed venous; PaO2 = Oxygen saturation pulmonary artery; PCWP = Pulmonary Capillary Wedge Pressure; PvO2 = Oxygen saturation pulmonary veins; RAP = Right Atrial Pressure; SaO2 = Oxygen saturation arterial; SEP = Systolic Ejection Period; SVI = Stroke Volume Index.
Copyright © 2011 American Heart Association.
Constriction vs. RestrictionConstriction vs. Restriction
Parameter Constrictive Pericarditis Restrictive Cardiomyopathy
LVEDP-RVEDP, mm HG ≤ 5 > 5
RV Systolic, mm Hg ≤ 50 > 50
RVEDP/RVSP, mm Hg ≥ 0.33 < 0.3
RV/LV interdependence Discordance Concordance
Pressures Elevated with equalization of diastolic pressures
Elevated with equalization of diastolic pressures
RV/LV pressure waveform Dip and plateau (Square root sign) Dip and plateau (Square root sign)
RA pressure waveform Prominent y descent Prominent y descent
PCWP/LV respiratory gradient
≥ 5 <5
Hemodynamic parameters that help differentiate constrictive pericarditis versus restrictive cardiomyopathy
LVEDP = Left Ventricular End Diastolic Pressure; PCWP = Pulmonary Capillary Wedge Pressure; RA = Right Atrial; RVEDP = Right Ventricular End Diastolic Pressure; RVSP = Right Ventricular Systolic Pressure.