Cardiac Ultrasound in Emergency Medicine: A Comprehensive Guide

1. Cardiac Ultrasound in Emergency Medicine Anthony J. Weekes MD, RDMS Sarah A. Stahmer MD For the SAEM US Interest Group

2. Primary Indications • Thoraco-abdominal trauma • Pulseless Electrical Activity • Unexplained hypotension • Suspicion of pericardial effusion/tamponade

3. Secondary Indications • Acute Cardiac Ischemia • Pericardiocentesis • External pacer capture • Transvenous pacer placement

4. Main Clinical Questions • What is the overall cardiac wall motion? • Is there a pericardial effusion?

5. Cardiac probe selection • Small round footprint for scan between ribs • 2.5 MHz: above average sized patient • 3.5 MHz: average sized patient • 5.0 MHz: below average sized patient or child

6. Main cardiac views • Parasternal • Subcostal • Apical

7. Wall Motion • Normal • Hyperkinetic • Akinetic • Dyskinetic: may fail to contract, bulges outward at systole • Hypokinetic

8. Orientation • Subcostal or subxiphoid view • Best all around imaging window • Good for identification of: • Circumferential pericardial effusion • Overall wall motion • Easy to obtain – liver is the acoustic window\

9. Subcostal View • Most practical in trauma setting • Away from airway and neck/chest procedures

10. Subcostal View • Liver as acoustic window • Alternative to apical 4 chamber view

11. Subcostal View

12. Subcostal View

13. Subcostal View • Angle probe right to see IVC • Response of IVC to sniff indicates central venous pressure • No collapse • Tamponade • CHF • PE • Pneumothorax

14. Parasternal Views • Next best imaging window • Good for imaging LV • Comparing chamber sizes • Localized effusions • Differentiating pericardial from pleural effusions

15. Parasternal Long Axis • Near sternum • 3rd or 4th left intercostal space • Marker pointed to patient’s right shoulder (or left hip if screen is not reversed for cardiac imaging) • Rotate enough to elongate cardiac chambers

16. Parasternal Long Axis

17. Parasternal Long Axis View

18. Parasternal Short Axis • Obtained by 90° clockwise rotation of the probe towards the left shoulder (or right hip) • Sweep the beam from the base of the heart to the apex for different cross sectional views

19. Parasternal Short Axis View

20. Parasternal Short Axis

21. Apical View • Difficult view to obtain • Allows comparison of ventricular chamber size • Good window to assess septal/wall motion abnormalities

22. Apical Views • Patient in left lateral decubitus position • Probe placed at PMI • Probe marker at 6 o’clock (or right shoulder) • 4 chamber view

23. Apical 4 chamber view • Marker pointed to the floor • Similar to parasternal view but apex well visualized • Angle beam superiorly for 5 chamber view

24. Apical 4 chamber view

25. Apical 2 chamber view • Patient in left lateral decubitus position • Probe placed at PMI • Probe marker at 3 o’clock • 2 chamber view

26. Apical 2 chamber view • Good look at inferior and anterior walls

27. Apical 2 chamber view • From apical 4, rotate probe 90° counterclockwise • Good view for long view of left sided chambers and mitral valve

28. Abnormal findings Pericardial Effusion

29. Case Presentation • 45 year old male presents with SOB and dizziness for 2 days. He has a long smoking history, and has complained of a non-productive cough for “weeks” • Initial VS are BP 88/palp, HR 140 • PE: Neck veins are distended • Chest: Clear, muffled heart sounds • Bedside sonography was performed

31. Echo free space around the heart • Pericardial effusion • Pleural effusion • Epicardial fat (posterior and/or anterior) • Less common causes: • Aortic aneurysm • Pericardial cyst • Dilated pulmonary artery

32. Size of the Pericardial Effusion • Not Precise • Small: confined to posterior space, < 0.5cm • Moderate: anterior and posterior, 0.5-2cm (diastole) • Large: > 2cm

33. Pericardial Fluid: Subcostal

34. Clinical features of Pericardial effusion • Pericardial fluid accumulation may be clinically silent • Symptoms are due to: • mechanical compression of adjacent structures • Increased intrapericardial pressure

35. Pericardial Effusion:Asymptomatic • Up to 40% of pregnant women • Chronic hemodialysis patients • one study showed 11% incidence of pericardial effusion • AIDS • CHF • Hypoproteinemic states

36. Symptoms of Pericardial Effusion • Chest discomfort (most common) • Large effusions: • Dyspnea • Cough • Fatigue • Hiccups • Hoarseness • Nausea and abdominal fullness

37. Cardiac Tamponade • Increased intracardiac pressures • Limitation of ventricular diastolic filling • Reduction of stroke volume and cardiac output

38. Ventricular collapse in diastole

39. Tamponade

40. Hypotension

41. Abnormal findings • Is the cause of hypotension cardiac in etiology? • Is it due to a pericardial effusion? • Is is due to pump failure?

42. Unexplained Hypotension • Cardiogenic shock • Poor LV contractility • Hypovolemia • Hyperdynamic ventricules • Right ventricular infarct/large pulmonary embolism • Marked RV dilitation/hypokinesis • Tamponade • RV diastolic collapse

43. Cardiogenic shock • Dilated left ventricle • Hypocontractile walls

44. Hypovolemia • Small chamber filling size • Aggressive wall motion • Flat IVC or exaggerated collapse with deep inspiration

45. Massive PE or RV infarct • Dilated Right ventricle • RV hypokinesis • Normal Left ventricle function • Stiff IVC

46. Case presentation ? overdose • 27 yo f brought in with “passing out” after night of heavy drinking. • Complaining of inability to breathe! • PE: Obese f BP 88/60 HR 123 Ox 78% • Chest: clear • Ext: No edema • Bedside sonography was performed

49. Chest pain then code • 55 yo male suffered witnessed Vfib arrest in the ED • ALS protocol - restoration of perfusing rhythm • Persistant hypotension • ED ECHO was performed