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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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.


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.

right heart catheterization

Documents

right heart pulmonary

needle tip

use of pulmonary

micropuncture catheter

micropuncture wire

antecubital vein

subclavian vein

right bundle