1. ULTRASOUND OF INFERIOR VENA CAVA

2. OBJECTIVES
Describe indications for using ultrasound at the bedside to image the inferior vena cava.
Describe how to performing bedside ultrasound of the inferior vena cava.
Use the findings on ultrasound to guide assessment of intravascular volume status.
Generate group discussion regarding the potential value of learning this procedure for patient management

3. CASE
46 M was admitted with alcoholic hepatitis and newly diagnosed cirrhosis with ascites. On exam he had flat JVD in supine position, tense abdominal distension, and moderate leg edema to the knees. He was started on a 28 day Trental protocol
Hospital Course
Day paracenteses;
- removal of 11 liters of ascitic fluid.
Day 10
- JVD flat in supine position
- Abdomen still distended but not tense
- moderate leg edema
- Na = 136, Cr = 1.0, BUN = 11
- furosemide started at 20 mg QD
- spironolactone started at 50mg QD.

4. CASE Day 12 - JVD flat in supine position - persistent leg edema
- apparent increase in abdominal girth on exam
- Na = 134, Cr = 0.7, BUN = 12
- furosemide increased to 40mg QD
Day 19
- abdominal girth same to slightly decreased
- Na = 136, Cr = 0.8, BUN = 12
- furosemide increased to 80mg QD
- spironolactone increased to 200mg QD

5. CASE Day 21 - JVD flat in supine position - leg edema the same
- Abdominal girth the same
- Na = 130, Cr = 0.9, BUN = 10
Day 24
- JVD flat in the supine position
- Abdominal girth the same to slightly increased
- Na = 127, Cr = 0.7, BUN = 13, Urine Na < 10
Daily weights and Input/Output measures were collected sporadically and could not be assessed for any trends.

6. CLASSIC HYPONATREMIA Hypovolemic Euvolemic Hypervolemic
UNa
UOsm > SOsm
UNa > 40
UNa
< 10
> 20
YES NO
< 10
> 20
Volume Depletion
Mineralcorticoid Deficiency
SIADH
OTHER
Cirrhosis
Nephrosis
CHF
CKD
Fluid Restriction plus
Diuretics
Volume Replacement
Fluid Restriction

7. QUESTION
What type of hyponatremia does this patient have and how should it be managed?
Hypovolemic hyponatremia
stop diuretics; begin normal saline infusion; liberalize po fluid intake; monitor Na over the course of the next several days; if Na does not improve or worsens, entertain hypervolemic hyponatremia as the cause
Hypervolemic hyponatremia
increase the diuretics and tighten the fluid restriction; monitor Na over the course of the next several days; if Na does not improve or worsens, entertain hypovolemic hyponatremia as the cause.
Not sure
consult nephrology for an opinion about the hyponatremia

8. INDICATIONS IVC Ultrasound Spontaneously Breathing
Mechanical Ventilation
Volume Status / CVP
Fluid Responsiveness

9. Intravascular Volume Status / CVP
INDICATIONS
Assessing
Intravascular Volume Status / CVP
VOLUME DEPLETED STATES
- Hyponatremia
Acute Kidney Injury (? Prerenal)
Diuretic therapy
Sepsis
VOLUME OVERLOAD STATES
Hyponatremia
Heart Failure
Cirrhosis with ascites
Anasarca

10. Fluid Responsiveness in Shock
INDICATIONS
Assessing
Fluid Responsiveness in Shock
- IVC diameter does not correlate with right atrial pressure in patients who are intubated with shock
- Measuring the variation in IVC diameter in these situations can help determine whether the patient’s blood pressure will respond to fluids or whether inotropic support (i.e. dobutamine) will be needed

11. Anatomy
The inferior vena cava returns blood from the body to the right atrium
Formed by the convergence of the illiac veins
Retroperitoneal
Right of the aorta
Normal size <2.5 cm
Varies w respiration

12. Respiratory variation
Expands w/ expiration
Contracts w/ inspiration
Due to changing intrathoracic pressures.

13. Respiratory Variation
Figure 2: Physiological respiratory variations in IVC diameter in a healthy volunteer breathing quietly.: From:
IVC diameter decreases on each inspiration.

14. Measuring the IVC Diameter
Measure IVC 2cm distal to right atrium

15. Inspiratory (Minimal) IVC Diameter

16. Maximum (Expiratory) IVC Diameter

17. M-Mode IVC Diameters

18. CAVAL INDEX (CI) CI = maximum (expiratory) diameter
minimal (inspiratory) diameter
CI =
maximum (expiratory) diameter

19. CAVAL INDEX (CI) 0%
100%
Volume
Overload
Volume
Depletion

20. Correlation Between IVC Diameter Plus CI and CVP
IVC v CVP
Correlation Between IVC Diameter Plus CI and CVP
IVC Max Diameter
(cm) CI
CVP
(mmHg)
< 1.5
100%
(total collapse)
0-5
> 50%
6-10
< 50%
11-15
> 2.5
16-20 0%
(no collapse)
>20

21. M-Mode Volume Depletion

22. M-Mode Volume Overload

23. Correlation Between IVC Diameter Plus CI and CVP
IVC v CVP
Correlation Between IVC Diameter Plus CI and CVP
IVC Max Diameter
(cm) CI
CVP
(mmHg)
< 1.5
100%
(total collapse)
0-5
> 50%
6-10
< 50%
11-15
> 2.5
16-20 0%
(no collapse)
>20

24. PROCEDURE Positioning Supine
Degree of head elevation has not been shown to make a significant difference in measurements

25. PROCEDURE
Probe Selection
Low frequency 2-5 MHz
Curvalinear probe

26. PROCEDURE
Approach #1 – Xiphoid View

27. PROCEDURE Landmarks Aproach #1 – Xiphoid View Most common approach
Place probe longitudinally just below the xiphoid process with the probe marker to the patient’s head
Look for IVC going into right atrium – may need to move probe 1-2cm to patient’s right and then tilt it slightly towards the heart

28. IVC Longitudinal

29. Approach #2 – Anterior Mid-Axillary View
PROCEDURE
Approach #2 – Anterior Mid-Axillary View

30. PROCEDURE Landmarks Aproach #2 – Anterior Mid-Axillary View
Place probe longitudinally in right anterior mid-axillary line with marker towards the head
Look for IVC running longitudinally adjacent to liver crossing the diaphragm.
Track superiorly until it enters right atrium confirming that it is the IVC and not the aorta.

31. IVC Anterior Mid-Axillary View

32. PEARLS Bowel Gas May impede visualization in the xiphoid view
Gentle graded pressure may help move bowel out of way
Don’t press too hard or will collapse IVC causing false measurements
Consider anterior mid-axillary view

33. Plethoric (dilated/sluggish) IVC
PEARLS
Plethoric (dilated/sluggish) IVC
Volume overload
Cardiac tamponade
Mitral regurgitation
Aortic stenosis

34. Mechanical Ventilation
PEARLS
Mechanical Ventilation
Causes reversal of IVC changes with respiration
Maximum diameter with inspiration, minimum diameter with expiration

35. PEARLS IVC v Aorta Aorta IVC Thick, echogenic walls Pulsatile
High flow velocity
Not compressable
No respiratory variation
Above vertebral bodies
IVC
Thin walls
Usually not pulsatile
Low flow velocity
Compressable
Respiratory variation
Right of vertebral bodies

36. Aorta – Longitudinal View

37. SonoSite 180 Plus

38. SonoSite 180 Plus

39. SonoSite 180 Plus
Changing and Inserting the Transducer

40. SonoSite 180 Plus
Insert the transducer
Twist lock counterclockwise

41. SonoSite 180 Plus
Fold lock down

42. SonoSite 180 Plus
Ready to power-up machine

43. SonoSite 180 Plus
Power Button

44. SonoSite 180 Plus

45. SonoSite 180 Plus

46. SonoSite 180 Plus

47. SonoSite 180 Plus Wrong Transducer is Connected
Correct Transducer Menu
GYN OB
Abdominal

48. SonoSite 180 Plus
2D View (default)
M-Mode

49. SonoSite 180 Plus
GAIN
Changes the contrast on the screen

50. SonoSite 180 Plus

51. SonoSite 180 Plus

52. CASE An IVC Ultrasound was performed at the bedside.
Maximum IVC diameter during expiration = 1.10 cm. The
Minimum IVC diameter during inspiration = 0 cm.
Caval Index = 100% (total collapse)

53. Correlation Between IVC Diameter Plus CI and CVP
CASE
Correlation Between IVC Diameter Plus CI and CVP
IVC Max Diameter
(cm) CI
CVP
(mmHg)
< 1.5
100%
(total collapse)
0-5
> 50%
6-10
< 50%
11-15
> 2.5
16-20 0%
(no collapse)
>20
Interpretation:
Mixed hyponatremia
(intravascular volume depletion plus free water excess from cirrhosis)

54. CASE Treatment: one liter of normal saline IV to expand
intravascular volume
- reduced free water oral intake from
1500cc to 1000cc/d
- Continued current diuretic dosing to
remove free water
Result:
In 3 days, the patient’s Na progressively increased to 136

55. REFERENCES
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Blehar DJ, Dickman E, Gaspari R. Identification of congestive heart failure via respiratory variation of inferior vena cava
diameter. Am. J. Emerg. Med. 2009;27:71-5.
Chen L, Santucci KA, Kim Y. Use of ultrasound measurement of the inferior vena cava diameter as an objective tool in the
assessment of children with clinical dehydration. Acad. Emerg. Med. 2007:14:841-5.
Feissel M, Michard F, Faller JP, et al. The respiratory variation in inferior vena cava diameter as a guide to fluid therapy. Intensive
Care Med. 2004;30:
Fields JM, Lee PA, Jenq KY, et al. The interrater reliability of inferior vena cava ultrasound by bedside clinician sonographers in
emergency department patients. Acad. Emerg. Med. 2011;18:
Kircher BJ, Himelman RB, Schiller NB. Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior
vena cava. Am J. Cardiol. 1990;66:493-6.
Randazzo MR, Snoey ER, Levitt MA, et al. Accuracy of emergency physician assessment of left ventricular ejection fraction and
central venous pressure using echocardiography. Acad. Emerg. Med.2003;10:973-7.
-ACEP Policy Statement on Emergency Ultrasound Guidelines. Ann. Emerg. Med. 2009;53:550-70
Nagdev AD, Merchant RC, Tirado-Gonzalez A, et al. Emergency department bedside ultrasonographic measurement of the caval
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56. DISCUSSION