The Echo Doesn't Lie by Murphy
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The document discusses the role of echocardiography (echo) in assessing hemodynamics and the complexities of using echocardiographic measurements in critically ill patients. It highlights the assumptions and limitations of different echocardiographic methods, emphasizing the importance of accurate measurement techniques to avoid errors in cardiac function assessments. Additionally, it covers various parameters used to evaluate fluid responsiveness and the impact of interventions in specific clinical scenarios.
The Echo Doesn't Lie by Murphy
- 1. DEIRDRE MURPHY ALFRED ICU THE ECHO DOESN’T LIE
- 2. ECHO DOESN’T LIE BUT IT CAN BEND THE TRUTH A LITTLE
- 3. ECHO IS BASED ON A NUMBER OF ASSUMPTIONS
- 4. ECHO IS BASED ON A NUMBER OF ASSUMPTIONS Sound travels at same speed though all tissues (It doesn’t) Echoes are generated from centre of the beam !
- 5. ZOETROPE TY THE TASMANIAN TIGER
- 6. Important in utilising the technology that we understand the limitations so that we can use it to its full potential
- 7. COMMON HAEMODYNAMIC INFORMATION and the pitfalls in their measurement..
- 8. CARDIAC OUTPUT fundamental measure in critically ill patient
- 9. LVOT method Assumes the LVOT is a cylinder We can measure the VTI of blood flow in the LVOT by placing a pulse wave doppler gate in LVOT This gives us the LVOT VTI
- 10. MATHS… Volume =CSA X height (distance) ! Stroke volume= π r2 X VTI ! Cardiac output= SV x heart rate
- 11. any measurement error will be squared ! CSA= π r2
- 12. Major pitfalls ! Flow acceleration at valve-measure 1 cm back Ensure line up with cursor-inaccurate if >10°
- 13. USE VIEW WITH THE BEST DOPPLER LINE UP- DIFFERENT FOR DIFFERENT PATIENTS 5 chamber view 3 chamber view
- 14. HOW DO YOU KNOW YOU’VE GOT A GOOD DOPPLER TRACE PW Doppler spectral outline Trace not “filled in”- in moving front of blood flow Not jagged feathery ends
- 15. Measurement of VTI or stroke distance Average 3 in sinus rhythm Average 5 if arrhythmia
- 17. THE LVOT IS ELLIPSOID ! ! ! !
- 18. AGREEMENT WITH THERMODILUTION Reasonable Operator needs to be aware of the sources of error !
- 19. Patient commenced on adrenaline after study LVOT measured at 1.0 cm, VTI N LVOT in adult 1.8-2.6
- 20. RVSP (PA PRESSURE ESTIMATION) Based on Bernoulli equation Pressure gradient =4V2 RVSP= PG + CVP PA pressure = RVSP
- 21. WHAT ARE THE REQUIREMENTS? Need to evaluate in a number of views to get the best line up with the colour jet
- 22. R SIDED CARDIAC OUTPUT Useful to quantify shunts, MCS RVOT inflow velocites lower and vary with respiration
- 23. PA Diastolic (PR jet) 8 mm (+ RAP) mmHg PA pressure estimation from Pulmonary Acceleration time
- 24. WHAT ABOUT VOLUME STATE AND ECHO?
- 25. EARLY STUDIES LOOKED AT LVEDA Problems as doesn’t take into account compliance afterload states
- 26. STATIC ESTIMATES OF R ATRIAL PRESSURE AND ECHO IVC dimension (spontaneous breathing) and collapsibility ! IVC = <2.1 and varies > 50% Estimated RAP =3 In between =8 IVC = > 2.1 and doesn’t vary Estimated RAP =15
- 27. L HEART PRESSURES Echo assessment of left atrial pressure ! Mitral valve E/e’ E/A > 2 PAOP >18 ! E/e’ > 15 PAOP > 18
- 28. SO MUCH FOR STATIC PARAMETERS..
- 29. FUNCTIONAL HAEMODYNAMICS Describing the effects of cardiorespiratory interactions in positive pressure ventilation
- 30. IVC distensibility index Change in IVC with positive pressure ! > 18% significant ! Sensitivity 90% Specificity 100% – Cut off of 18% –Max IVC D-min IVC D/ Mean IVC D Max IVC diameter-min IVC diameter/ mean IVC diameterFeissel et al ICM 2004
- 31. SVC collapsibility V useful as intrathoracic TOE >36% significant Max-Min/Max value Viellard-Baron et al ICM 2004
- 32. PULSE PRESSURE VARIABILITY/ STROKE VOLUME VARIABILITY Can assess with echo Need to be v entilated Sinus rhythm
- 34. Volume responsiveness and echo using passive leg raise VTI =19 VTI =27 45% Change in VTI (SV) of 12% predicts fluid responsiveness Lamia et al ICM 2007. Monnet at al CCM 2006
- 35. Mandeville. Can Transthoracic Echo be Used to Predict Fluid Responsiveness in Critically Ill? Crit Care Research and Practice 2012
- 36. 3 HEART BEATS INSPIRATION POST INSPIRATORY DROP IN LV OUTPUT ONLY IF VOLUME RESPONSIVE
- 37. BENEFIT OF USING ECHO assess for false positives
- 38. WOULD YOU GIVE FLUID TO EITHER OF THESE PATIENTS?
- 39. A VOLUME RESPONSIVENESS STUDY WILL TELL YOU BOTH
- 40. Increase intrathoracic pressure Increase RV after load Decreased RV stroke volume Decrease LV stroke volume
- 42. ECHO ASSESSMENT OF LV FUNCTION
- 43. FRACTIONAL SHORTENING ! many assumptions inaccurate if wall motion abnormality any errors in measurement will be cubed for EF measurement
- 44. BIPLANE SIMPSON’S 1. Trace ED area A4C 1. Trace ES area A4C
- 45. BIPLANE SIMPSON’S 3. Trace ED area A2C 4. Trace ES area A2C
- 46. EYEBALL METHOD
- 47. 3D ECHO Impressive pictures and more accurate quantification
- 48. RIGHT VENTRICLE
- 49. RV SYSTOLIC FUNCTION TAPSE >1.6cm (Tricuspid Annular Plane Systolic Excursion)
- 50. RV SYSTOLIC FUNCTION S’ > 10 cm/S N
- 51. SO WHY USE ECHO AS A HAEMODYNAMIC TOOL?? Tells you what the problem is currently (not just the haemodynamic effects of the problem) ! What’s causing it ! If what you are doing about it helps
- 52. CASE STUDY 72 yo man post CAGs X 2 and AVR “Good” LV intra-operative Hypotensive MAP 65 PAC: CO 3.6/ C.I 1.8 PA pressures 56/30 CVP 18 Management? Inotropes and vasopressor: Milrinone 10 mcg/min, adrenaline 7 mcg/min, Noradenaline 17 mcg/min
- 53. DIFFERENTIAL ? Tamponade ? Graft ischaemia
- 59. Dx LV outflow tract obstruction (with SAM) Rx: Avoid hypovolaemia Avoid inotropy Maintain afterload
- 62. DYNAMIC LVOTO Seen after cardiac surgery classically AVR Seen in non-cardiac surgery patients also esp elderly females with hx HTN and DM Haemodynamic situation worsened by inotropes and can contribute to downward spiral
- 63. SUMMARY Echo plays key role in assessment of haemodynamics Helps identify false positives in terms of volume responsiveness Adds a subtlety to the haemodynamic assessment Is user dependant and like any tool is more powerful when used optimally