Advanced Critical Care Ultrasound Quantitative Assessment Resource
Disclaimer
Quantitative measurements are generally de-emphasized for POCUS applications. When quantitative measures are used, we are more closely approximating diagnostic level echocardiographic standards and thorough training is generally required. This resource is meant to assist the advanced critical care ultrasound clinician by providing a summary of some core normal/abnormal values, equations and review basic techniques relevant to advanced critical care ultrasonography. It can also be used as a study resource for those preparing for the National Board of Echocardiography Special Competence in Critical Care Echocardiography exam. This resource is intended as an efficient reference and those seeking more in depth review are urged to use the references provided
Authors: Marko Balan, Derek Wu, Robert Arntfield
*Last updated: February 11, 2020
Anatomic Assessments
Quantitative assessments of chamber size are rarely necessary in POCUS applications. However, chamber size assessment may be helpful in determining the chronicity of disease (typically dilation takes time to develop), which may be relevant at the point-of-care when assessing LV and LA dilation. Furthermore, because RV size is often assessed in comparison to the LV, it can be difficult to accurately assess in patients with LV dilation. Current guidelines recommend volumetric assessment using biplane disc summation method but this is cumbersome and necessary views are not always possible in critically ill patients. Measuring the LA antero-posterior dimension remains widely used and may be useful when trying to determine the chronicity of a disease process (e.g. MR, diastolic dysfunction). Measuring LV and LA dimensions can be done with M-mode or 2D, the latter being preferred to ensure on axis measurements.
How To Obtain / Measurement | Normal Range (mm) | Caveats | |
---|---|---|---|
LV Chamber Diameter | PLAX, perpendicular to LV long axis, diameter at end-diastole at level of mitral leaflet tips | 38-58* | Single dimension may not represent entire LV (dilation can occur in other planes) |
RV Basal Diameter | RV-focused view, maximal transverse diameter in basal 1/3rd of the RV at end-diastole | 25-41* | • Single dimension may not represent entire RV (dilation can occur in other planes) • Highly dependent on probe position/angle due to RV’s crescent shape |
RV Mid Diameter | RV-focused view, transverse diameter at the level of papillary muscles (middle 1/3rd of the RV) at end-diastole | 19-35* | |
LA AP Dimension | PLAX measure antero-posterior distance perpendicular to the aortic root long axis (leading edge to leading edge) | 2.7-4.0 | Single dimension may not represent entire LA (dilation can occur in other planes) |
*approximations, actual normal measures differ by sex
J Am Soc Echocardiogr. 2015;28:1-39
Quantitative RV wall thickness measurement can help in determining the chronicity of pulmonary hypertension for example in assessment of possible acute pulmonary embolism or RV failure.
How To Obtain | Measurement | Normal Range (mm) | Caveats | |
---|---|---|---|---|
RV Wall Thickness | Subcostal or PLAX, minimize depth and adjust focus | At end-diastole at the level of the tip of the anterior TV leaflet | 1-5 | • Single measure may not represent entire ventricle • Borders may be difficult in cases of thickened pericardium |
J Am Soc Echocardiogr. 2015;28:1-39
Hemodynamic Assessment
Experienced clinicians can accurately assess LV ejection fraction with qualitative assessment. In critically ill patients however, cardiac output may be a more useful clinical end point in guiding resuscitation and hemodynamic support. For children and patients at extremes of size, cardiac index should be used instead of cardiac output. EPSS is a variable traditionally used with M-mode imaging where higher values have been associated with decreased LV EF; EPSS should not be used in isolation when assessing LV systolic function.
Normal | Mildly Abnormal | Moderately Abnormal | Severely Abnormal | |
---|---|---|---|---|
LV EF (%) | 52-74* | 41-51* | 30-40 | <30 |
LV SV | 60-120 mL* | |||
Cardiac Output | 4-8 L/min | |||
Cardiac Index | 2.5-4 L/min/m^2 |
*approximations, actual values differ by sex and age
J Am Soc Echocardiogr. 2015;28:1-39
How To Obtain | Measurement | Typical Values | Caveats | |
---|---|---|---|---|
LVOT Diameter | PLAX view zoom-in on LVOT | Inner edge to inner edge diameter perpendicular to LVOT long axis at AV annulus (location of attachment of cusps to LVOT) at mid systole | ~2cm | • Lack of consensus regarding measurement technique • Small error in LVOT diameter can cause large effect on CO due to squaring of the radius • Assumes LVOT to be circular whereas it is oval |
LVOT VTI | A5C view with PWD at LVOT or just apical to AV annulus | Measure VTI (negative direction) of systolic period | ~19cm | • PWD gate must be located where LVOT diameter measured • Assumes laminar flow through LVOT |
EPSS* | PLAX | Measure distance from tip of anterior mitral leaflet to interventricular septal wall at maximal opening during early systole | <0.7-1cm | • Single isolated surrogate measure, rather than a true measure of LV function • Should not be used in isolation • Confounded by LV dilation and left-sided valvular disease |
* EPSS >7mm associated with LVEF≤30% in ED population ordered an echo with sensitivity 100% and specificity 52% (Am J Emerg Med. 2014 Jun;32(6):493-7)
LV Systolic Function Calculators
SV = π (LVOT radius)2 * LVOT VTI
CO=HR * SV
CI=CO/BSA
BSA (Mosteller formula) =√[wt (kg) X ht (cm)/3600]
How To Obtain | Measurement | Abnormal Values | Caveats | |
---|---|---|---|---|
TAPSE | Apical view with proper alignment of M-mode through longitudinal axis of TV annular excursion | Apical displacement of TV annulus during systole | <1.7cm | • Angle dependent • Should not be used in isolation |
RV S' | A4C with TDI gate on the TV annulus or the middle of the basal segment of the RV free wall | Peak velocity of during systole | <9.5cm/s |
J Am Soc Echocardiogr. 2015;28:1-39
IVC/RAP
Although commonly used for assessment of fluid responsiveness the IVC has very limited utility for this indication except in extreme cases and is regarded as generally useless as a marker of fluid responsiveness by most. It can however be used to estimate RA pressures in spontaneously breathing non-mechanically ventilated patients, if a CVC is not available to get the true value.
IVC How to Obtain | Caveats | IVC Size | IVC Collapsibility with sniff | RAP (mmHg)* |
---|---|---|---|---|
Subcostal long-axis view with patient supine, measure 1-2cm from IVC-RA junction (or at level of hepatic vein), at end-expiration | • Movement of IVC during inspiration can cause off-axis imaging • Lack of consensus on measurement technique • Can be confused with aorta | <2.1cm | >50% | 3 |
<2.1cm | <50% | 8 | ||
>2.1cm | >50% | 8 | ||
>2.1cm | <50% | 15 |
*has not been validated in mechanically ventilated patients
J Am Soc Echocardiogr. 2015;28:1-39
Assessment of RVSP can be useful in patients with acute right heart failure, pulmonary hypertension and to monitor potentially harmful effects of mechanical ventilation (particularly in patients with severe lung injury). The simplified Bernoulli equation makes several assumptions including ignoring the blood’s viscous friction, flow acceleration and the initial blood velocity. RVSP is equal to PASP in the absence of obstruction or pressure gradient in the RVOT or PV.
How to obtain | Measurement | Normal values | Caveats | ||
---|---|---|---|---|---|
TR peak velocity | Assess in all views where TR jet is visualized with CWD | Peak velocity of TR jet from CWD envelope | <35-40mm Hg | •Not available in all patients |
J Am Soc Echocardiogr. 2010;23:685-713
RVSP Calculator
RVSP = 4V2 + RAP
Diastology
Assessment of diastolic dysfunction has limited applications at the point-of-care however there are associations with clinically relevant outcomes in critically ill patients. Diastolic dysfunction in conjunction with elevated LA pressures are important variables in patients with respiratory failure/pulmonary edema/ARDS, and those who fail to wean from mechanical ventilation. The 2016 guidelines simplified previous ones but unfortunately are cumbersome and frequently not possible to apply in critically ill patients. Greenstein and Mayo (2018) proposed a simplified approach to the assessment of diastolic dysfunction in critically ill patients using two variables listed below.
Diastolic Dysfunction: A Simplified Approach for Critically Ill Patients
E/e’ <14 and/or e’<8cm/s suggest diastolic dysfunction and correlate with clinical outcomes in critically ill patients
CHEST. 2018; 153(3):723-732 (Greenstein & Mayo, 20018)
How To Obtain | Measurement | Caveats | |
---|---|---|---|
Mitral E Wave | A4C view with PWD gate between open mitral leaflet tips during diastole | Peak velocity of early diastole wave (after T wave) | Arrhythmias Tachycardia Age-dependent |
Mitral A Wave | Peak velocity of late diastole wave (after P wave) | ||
Septal or Lateral E' | A4C view with TDI gate on septal or lateral side of mitral annulus | Peak velocity in early diastole (negative direction) | MV annular calcification RWMA affecting sampled segments |
TR Velocity | A4C or PSAX with CWD, whichever obtains highest velocity | Peak velocity during systole | • Dependent on accurate RA pressure estimation • TR jet may not be present in some patients |
LA Volume | A2C and A4C | Volume estimation by method of disks area length method, corrected for BSA | • Requires adequate LA wall resolution, limited utility in POCUS • Time-consuming |
J Am Soc Echocardiogr. 2016;29:277-314
For a complete determination of diastolic dysfunction as per the American Society of Echocardiography Guidelines:
Diastolic Dysfunction ToolIn patients with normal LV EF, select all below that applies: |
In patients without Normal LV EF or patients with normal EF but with myocardial disease:
J Am Soc Echocardiogr. 2016;29:277-314
Valvular Assessment
For many hemodynamically significant or catastrophic valvular lesions good quality 2D and colour doppler evaluation are often sufficient to make the diagnosis. Acute left-sided valvular disease (particularly acute AR and acute MR) can lead to hemodynamic collapse and further deterioration despite standard therapies for shock (i.e. vasopressors) and patients with such potential valvulopathy should be evaluated urgently. The mainstay of POCUS assessment of valvular disease is with 2D echocardiography and colour doppler. Two-dimensional echocardiography should assess for valvular prolapse, flail, perforations, restriction/stenosis/calcification and associated structural changes (chamber dilation). Colour doppler is used to evaluate valvular function as turbulent flow and regurgitation cannot be visualized without it. The following tables include some of the basic quantitative measures of valvular disease which may be used to add confidence for clinical presentations based on 2D and colour doppler. An important caution is that they are based on clinically stable patients with chronic valvular disease largely for surgical assessment and many variables may not be present or could be altered in critically ill patients with acute presentations. Expert consultation should be sought for comprehensive valvular evaluation and quantitative assessment.
Supportive 2D findings: calcifications, restricted valve movement, bicuspid valves
Supportive colour doppler findings: turbulent flow through AoV
How To Obtain | Measurement | Threshold for Severe Aortic Stenosis | Limitations/Caveats | |
---|---|---|---|---|
Peak Velocity | A5C with colour Doppler over LVOT/AoV and CWD through center of systolic jet | Max velocity of systolic ejection jet (negative direction) | ≥4m/s | • Requires adequate A5C view with parallel CWD alignment • Dependent on flow |
Mean Gradient | VTI of the systolic ejection jet (negative direction) | ≥40mm Hg | ||
Dimensionless Index | As described above -using CWD for aortic valve peak velocity or VTI -using PWD for LVOT peak velocity or VTI | DI =(LVOT VTI)/(Aortic Valve VTI) | <0.25 | |
Aortic Valve Area* | AVA=(LVOT Area X LVOT VTI)/(Aortic valve VTI) LVOT Area=πr^2 | <1cm2 | Errors in LVOT diameter result in large errors in AVA due to squaring when obtaining LVOT area |
*for atrial fibrillation or other arrhythmias average values for several measures (5-10) should be reported
J Am Soc Echocardiogr. 2009;22(1):1-23
J Am Soc Echocardiogr. 2017;30:372-92
DI Calculator
*can use either VTI or peak velocity to get the dimensionless index as long as you use the same one for LVOT and aortic valveAVA Calculator
LVOT Area Calculator
Supportive colour Doppler findings: large central jet, large flow convergence
How To Obtain | Measurement | Threshold for Severe AR | Limitations/Caveats | |
---|---|---|---|---|
Jet Width to LVOT Width | PLAX, zoomed view with color doppler | Width of regurgitant jet diameter as a ratio of LVOT diameter (regurgitant jet diameter)/(LVOT diameter) | 0.65 | May underestimate in eccentric jets |
VCW | PLAX | Measure narrowest width of jet at or just apical to the AoV | >0.6cm | • Cannot be used with multiple jets or bicuspid valves • Alignment of regurgitant jet and US beam may influence colour jet width |
Jet Deceleration, PHT | Best alignment of AR jet, typically A5C | Obtain A5C view and put colour Doppler box over LVOT and AoV, place CWD through regurgitant jet in parallel alignment, Trace angle of deceleration of AR jet | Steep, <200ms | Affected by LV filling pressures |
Diastolic Flow Reversal in Aorta | SC longitudinal view of abdominal aorta | PWD through proximal abdominal aorta | Prominent holodiastolic reversal | • Qualitative • Brief early diastolic reversal can be normal • False positives (AV fistulae in upper limb) • May not be holodiastolic in acute AR |
J Am Soc Echocardiogr. 2017;30(4):303-371
Jet Width to LVOT Width Calculator
Supportive colour doppler findings: colour jet occupies large area of LA or travels to back wall of LA, large width between MV leaflets during systole
Acute MR: 2D findings are crucial as acute MR leads to rapidly developing hypotension and increased LA pressure which can cause typical echo findings of chronic MR to be underestimated (regurgitation jet by colour doppler and ventricular dilation).
***HR, SBP should be recorded at time of assessment as loading conditions have significant effect on gradients
How To Obtain | Measurement | Threshold for Severe MR | Limitations/Caveats | |
---|---|---|---|---|
Colour Flow Jet Area : LA Area | A4C zoomed of LA with colour box over MV and LA | Trace both areas (regurgitant jet area)/(LA area) | >50% | • May underestimate eccentric jets • Affected by loading conditions (HR, SBP) |
CWD Jet | A4C with colour box over MV and LA and CWD through MR jet | Qualitative assessment of MR CWD shape | Triangular | • Qualitative • Affected by loading conditions (HR, SBP) • Lacks sensitivity |
VCW | PLAX zoomed with colour box over MV and LA | Measure narrowest width of jet at or just basal to MV | ≥0.7cm | • Independent of loading conditions (benefit) • Limited in presence of multiple jets and when MR is not holosystolic |
Mitral Inflow | A4C with PWD aligned with direction of blood from LA to LV and PW gate at leaflet tips | Peak velocity of E wave (first positive wave of diastole in TTE) | ≥1.2m/s *A wave dominant pattern excludes chronic severe MR | • Affected by diastolic function • Limited in atrial fibrillation, mitral valve stenosis • ECG strip may be needed |
Pulmonary Vein Flow Pattern | A4C with PWD placed 1cm into pulmonary veins | Qualitative assessment of negative Doppler flow in pulmonary veins during systole | Presence of systolic flow reversal in ≥2 pulmonary veins | • Requires high resolution at depth • May be affected by eccentric jet thus requires visualization of systolic reversal in 2 pulmonary veins • ECG tracing required |
J Am Soc Echocardiogr. 2017;30(4):303-371
Color Flow Jet Area: LA Area Calculator
Supportive colour doppler findings: large regurgitant jet, regurgitant flow may go all the way to hepatic vein.
How To Obtain | Measurement | Threshold for Severe TR | Limitations/Caveats | |
---|---|---|---|---|
Color Flow Jet Area | Best alignment of TR jet, often A4C, colour box over the TV and RA | Qualitative assessment of relative size of jet | Large central jet, may be eccentric | Qualitative, may be overestimated with central jets or underestimate with eccentric jets |
CWD Jet | Best alignment of TR jet, often A4C, colour box over TV and RA with CWD through center of TR jet | Qualitative assessment of density of CWD TR jet | Highly dense (i.e. white) TR jet | Qualitative |
VCV | RV inflow or A4C, zoomed with colour box over TV and RA | Measure narrowest width of jet at or just basal to TV | ≥0.7cm | • limited in cases of multiple jets • independent of loading conditions (benefit) |
Hepatic Vein Flow | Subcostal long axis of IVC and hepatic vein, PWD in lumen of hepatic vein | Semiquantitative assessment of flow reversal (positive deflection) during systole in hepatic vein | Systolic flow reversal | • limited in patients with Afib, AV dyssynchrony, paced rhythms • ECG strip required |
J Am Soc Echocardiogr. 2017;30(4):303-371
Pericardial Assessment
Remember false positives from epicardial fat which typically has some echogenicity/speckles, moves with the visceral pericardium and is classically located adjacent to the RV wall
Note: size of effusion does not necessarily correlate with tamponade physiology (chronicity plays a large role), loculated effusions may be difficult to visualize with TTE especially in post cardiac surgery patients (TEE may be indicated)
How To Obtain | Caveat | Qualitative Description | Pericardial Separation Distance |
---|---|---|---|
May be seen in multiple views, typically best in PLAX or S4C, Measured by distance of echo free space between parietal and visceral pericardium at end-diastole | Size of pericardial effusion does not necessarily correlate to presence of tamponade | Trivial | Seen only in systole |
Small | <10mm | ||
Moderate | 10-20mm | ||
Large | >20mm | ||
Very Large | >25mm |
J Am Soc Echocardiogr. 2013;26:965-1012
Always remember cardiac tamponade is a clinical diagnosis! Some findings may be attenuated, reversed or absent in patients on positive pressure ventilation. Typical signs of tamponade may not be present in patients with loculated/regional tamponade (most commonly post cardiac surgery patients). TEE may be necessary for accurate evaluation.
Supportive 2D findings: presence of pericardial effusion, dilated IVC, dilated hepatic veins, small LV cavity
Supportive doppler findings: reduced cardiac output along with the above 2D features
Feature Suggestive of Tamponade Physiology | How To Obtain | Measurement | Threshold Consistent with Tamponade Physiology | Caveats |
---|---|---|---|---|
IVC Dilation | SC long axis view of IVC +/- M mode | Measure diameter of IVC at end-inspiration and end-expiration | >2.1cm with <50% collapse (if spontaneously breathing) | Sensitive (seen in >90% of pts with tamponade) but not specific |
RA Chamber Collapse | A4C or S4C | Qualitatively or with M-mode, assess RA wall collapse during ventricular systole (start of R wave) | RA collapse >1/3 of systolic phase | Brief indentation of RA wall can occur in patients without tamponade |
RV Chamber Collapse | Assess in multiple views | Qualitatively or with M-mode, assess RV free wall collapse during diastole (start of T wave) | RV collapse >1/3 of diastolic phase | Difficult in tachycardic patients, may need to slow down speed or use M-mode |
Inspiratory Septal Bulge/Bounce/D-Shape | PSAX mid LV level Or PLAX | Qualitative assessment | Exaggerated septal bounce/bulge into LV especially during inspiration suggestive of ventricular interdependence | Multiple other causes: LBBB, RV paced rhythm, pulm HTN |
TV Inflow Respiratory Variability† | A4C with PWD at tip of TV leaflets | Measure the velocity of the TV first E wave after start of inspiration and expiration (TV-E-Vel peak exp - TV-E-Vel peak insp) / (TV-E-Vel peak exp) | >60% variability for peak tricuspid E inflow (calculated % will be a negative value)* | Can also be seen in obstructive lung disease, respiratory distress with excessive inspiratory negative pressure generation, constrictive pericarditis, acute pulmonary hypertension/pulmonary embolism |
MV Inflow Respiratory Variability† | A4C with PWD at tip of MV leaflets | Measure the velocity of the MV first E wave after start of inspiration and expiration (MV-E-Vel peak exp - MV-E-Vel peak insp) / (MV-E-Vel peak exp) | >30% variability for peak mitral E inflow** | |
Hepatic Vein Diastolic Flow | SC view of hepatic vein with PWD in hepatic vein lumen | Qualitative assessment of flow direction in hepatic vein during expiration | Hepatic vein flow blunting or reversal (away from the heart) during expiration | • Hepatic vein can be difficult to visualize • ECG tracing required |
*some suggest threshold of 40% variability for TV inflow variability
**some suggest threshold of 25% for MR inflow variability
†positive pressure ventilation can reverse, attenuate and even abolish the effect of respiratory variation in cardiac tamponade
J Am Soc Echocardiogr. 2013;26:965-1012
TV Inflow Respiratory Variability Calculator
MV Inflow Respiratory Variability
Pleural Assessment
Qualitative assessments of pleural effusion size are usually sufficient for most clinical decision making, however quantitative estimate of size may help in evaluation of evolution over time or in determining when the effusion has been completely drained. The following table does not apply to small or loculated pleural effusions.
Patient Position and Ventilation | Measurement | Pleural Effusion Size Estimation (mL) | Caveats | Reference |
---|---|---|---|---|
Sitting, spontaneously breathing | Maximal distance between diaphragm and visceral pleura at mid scapular line longitudinal axis at end-expiration | Distance (mm) X 16 | Patients with effusions ≤30mm not included | Interact Cardiovasc Thorac Surg. 2010;10(2):204-207. |
Supine, trunk elevated 15°, mechanically ventilated | Maximal distance between parietal and visceral pleura at end-expiration with transverse imaging plane at lung base | Distance (mm) X 20 | Patients with effusions <10mm not included Variations in ventilator settings may affect measurements | Intensive Care Med. 2006;32(2):318-321. |
Transcranial Doppler
A comprehensive transcranial doppler (TCD) assessment of multiple cerebral arteries can be technically challenging, time-consuming and outside the scope of even advanced POCUS practitioners. However isolated assessment of the middle cerebral artery through the transtemporal window is feasible, rapid and can provide valuable information at the point-of-care including midline shift, cerebral circulatory arrest, and vasospasm. It is imperative that the POCUS practitioner is aware of the applications and limitations of POCUS TCD.
Clinical Question | How To Obtain | Measurement | Threshold | Limitations/Caveats |
---|---|---|---|---|
Vasospasm in MCA | Place phased-array probe with marker pointing anteriorly at the transtemporal window (typically just anterior and superior to the patient’s ear. Identify the sella turcica/sphenoid bone and tilt/slide superiorly to identify the thalami and the third ventricle. Insert a large colour box to identify the Circle of Willis and then the ipsilateral MCA. Decrease depth and colour box to focus on the ipsilateral MCA. Insert a PWD gate in the MCA while ensuring optimal on-axis Doppler interrogation. | Trace the PWD envelope of one cardiac cycle; US machine will automatically calculate mean velocity | Mean Velocity Normal: <80cm/s Vasospasm: Mild: >120cm/s Moderate: >160cm/s Severe >200cm/s | • Operator dependent • Confounders include high/low hematocrit, hypotension/shock and other factors that may affect carotid artery flow (eg. stenosis) • Analysis of MCA flows alone does not rule out presence of vasospasm in other arteries |
ICP | Trace the PWD envelope of one cardiac cycle and the US machine will automatically calculate mean velocity, peak systolic velocity, and end diastolic velocity. The TCD preset will also calculate pulsatility index (PI). PI= (peak systolic velocity-end diastolic velocity)/(mean velocity) estimated ICP=(10.93XPI)-1.28 | Normal PI ~1.2 corresponding to ICP ~12mm Hg PI ~2 corresponds to ICP ~ 20mm Hg | • As above • PI correlates weakly with ICP but may be useful at extremes |
CHEST 2019; 157(1): 142-150.
Surg Neurol 2004; 62:45–51.
Neurocrit Care 2012; 17:58–66.
Intensive Care Med 2003; 29:1088–1094.
Estimated ICP Calculator
Other Lesions
Rarely acute presentation with hemodynamic significance, if acute suspected assess for obstructing MV vegetation
Supportive 2D findings: restricted opening, commissural calcification/fusion, LA enlargement, elevated RVSP
Supportive colour doppler findings: narrow diameter of turbulent flow at MV
***HR, SBP should be recorded at time of assessment as loading conditions have significant effect on gradients
How To Obtain | Measurement | Threshold for Severe MS | Caveats | |
---|---|---|---|---|
MV Area by Planimetry | PSAX at MV leaflet tips | Trace MV orifice in mid-diastole | <1cm^2 | Requires high resolution |
MV Area by PHT | A4C with colour box over MV and LA and CWD through jet | Measure slope of transmitral flow during diastasis (between E and A waves) 220/PHT | Affected by diastolic function and other factors | |
Mean Gradient | Trace contour of diastolic mitral flow, US machine will calculate mean velocity and mean gradient | >10mm Hg | Affected by loading conditions (HR, SBP) | |
RVSP | A4C or PS colour box over TV and RA with CWD through jet | Peak velocity during systole | >50mm Hg | Dependent on accurate RA pressure estimation |
J Am Soc Echocardiogr. 2009;22(1):1-23
MV Area by PHT Calculator
Supportive colour doppler findings: narrow diastolic inflow jet, turbulent flow during diastole
*all measures should be at end-inspiration, record HR during assessment
How To Obtain | Measurement | Threshold for Severe TS | Limitations/Caveats | |
---|---|---|---|---|
Mean Pressure Gradient | PS RV inflow or A4C with colour box over TV and RA and CWD through RV inflow | Trace VTI of RV inflow envelope and machine will calculate mean velocity and mean gradient | ≥5mm Hg | Affected by HR, ideal at 70-80bpm |
J Am Soc Echocardiogr. 2009;22(1):1-23
Pulmonic valve stenosis is usually congenital, and rare cause of acute illness.
How To Obtain | Measurement | Threshold for Severe PS | Limitations/Caveat | |
---|---|---|---|---|
Peak Velocity | PSAX or SC with colour box over PV and CWD aligned with blood flow through PV | Max velocity of systolic ejection jet (negative direction) | >4m/s | Visualization may be difficult Can be affected by RV systolic function |
J Am Soc Echocardiogr. 2009;22(1):1-23
Acute acquired pulmonic regurgitation with hemodynamic significance is rare yet mild PR is common in normal healthy subjects.
How To Obtain | Measurement | Threshold for Severe PR | Limitations/Caveats | |
---|---|---|---|---|
PR Jet Width : Pulmonary Annulus Ratio | PSAX, zoomed colour box over PV and RVOT | (regurgitation PR jet diameter) / (PV annulus diameter) | >0.7 cm | Can be misleading in eccentric jets or central jets with entrainment |
PR Jet Density and Contour | Best alignment of PR jet, typically PSAX or SC with colour box over PV and RVOT, CWD through PR jet | Qualitative assessment of CWD PR jet envelope density and slope | Dense jet with early termination of flow in diastole | Qualitative |
J Am Soc Echocardiogr. 2017;30(4):303-371
Pulmonary Annulus Ratio Calculator
Terminology
A2C- apical 2-chamber
A4C- apical 4-chamber
A5C- apical 5-chamber
AoV- aortic valve
BSA- body surface area
CWD- continuous wave doppler
EPSS- end-point septal separation
IVC- inferior vena cava
LV- left ventricle
LVOT- left ventricular outflow tract
MV- mitral valve
PLAX- parasternal long axis
POCUS- point of care ultrasound
PSAX- parasternal short axis
PWD- pulsed-wave doppler
RAP- right atrial pressure
RV- right ventricle
RVSP- right ventricular systolic pressure
S4C- subcostal 4-chamber
SC- subcostal
SVC- superior vena cava
TAPSE- tricuspid annular plane systolic excursion
TDI- tissue doppler imaging
VCW- vena contracta
VTI- velocity time integral