5. Anatomy
• The IVC returns blood from the
body to the right atrium
• Formed by the convergence
of the illiac
veins
• Retroperitoneal
• Right of the aorta
• Normal size 1.5-2.5 cm
• During expiration,
• In a spontaneously breathing
patient,
• Just distal the hepatic vein
• Varies with respiration
13. Main Idea
• Change of IVC diameter > 50% = possible hypovolemia.
• Change of < 20% indicates = will probably not respond
to fluid challenge.
• IVCD < 0.9 cm (spont. breathing), < 1.2 (ventilated) =
Hypovolemia (COP likely to increase after Fluid Challenge).
• IVCD > 2 cm = Euvol./Hypervolemia
(No response to Fluid Challenge).
22. • Most common approach
• Place probe longitudinally just below the xiphoid
process with the probe marker to the patient’s
head (Curvi-linear Probe)
• 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
Xiphoid View
29. 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.
• Similar to Morrison’s pouch view in FAST exam?!
42. Pearls & Pitfalls
Bowel Gas
1 May impede visualization in the
xiphoid view
2 Gentle graded pressure may help
move bowel out of way
3 Don’t press too hard or will collapse
IVC causing false measurements
4 Consider anterior mid-axillary view
44. Plethoric (dilated) IVC
• Mitral regurgitation
• Aortic stenosis
• Status Asthmaticus
• Right Heart Failure.
Pearls & Pitfalls
45. Mechanical Ventilation
Causes reversal of IVC changes with
respiration
“Maximum diameter with inspiration, minimum
diameter with expiration”
Pearls & Pitfalls
46. (False) Collapse of IVC
• Diaphragmatic breathing (Kimura 2011)
“Important in the ICU”
• Raised intra-abdominal pressure
(in animal studies: Takata 1990)
• Even pressure from the probe! (anecdotally)
Pearls & Pitfalls
47. Aorta
Thick, echogenic walls
Pulsatile
High flow velocity
Non-compressible
No respiratory variation
Above vertebral bodies
IVC
Thin walled
Usually not pulsatile
Low flow velocity
Compressible
Respiratory variation
To the right of vertebral
bodies
IVC vs. Aorta
Pearls & Pitfalls
66. “The value of experience is not in
seeing much, but in seeing wisely”
William Osler
67. References
• ACEP Policy Statement on Emergency Ultrasound Guidelines. Ann. Emerg. Med. 2009;53:550-70
• De Lorenzo RA, Morris MJ, William JB, et al. Does a simple bedside sonographic measurement
of the inferior vena cava correlate to central venous pressure? J. Emer. Med. 2011; 42(4);
429-436.
• Kosiak W, Swieton D, Piskunowicz M. Sonographic inferior vena cava/aorta diameter index, a new
approach to the body fluid status assessment in children and young adults in emergency
ultrasound preliminary study. Acad. J. Emerg. Med. 2008;26:320-5
• Nagdev AD, Merchant RC, Tirado-Gonzalez A, et al. Emergency department bedside
ultrasonographic measurement of the caval index for noninvasive determination of low central
venouspressure. Ann.Emerg.Med. 2010;55:290-5.
• 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;30:1834-7.
• 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;18:98-
101.
• 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.
• Emcrit.org.