IVC ultrasound

Revision as of 17:53, 7 March 2015 by Rossdonaldson1 (talk | contribs) (References)

Background

  • Though contriversal, IVC measurement by ultrasound can estimate volume status and fluid responsiveness
    • There is moderate evidence to support that IVC diameter is consistently low in hypovolemia vs euvolemia[1]
    • It is suggested that IVC change can estimate fluid responsiveness with a Sn 0.78 and Sp 0.86[2]
  • Measure both absolute diameter of IVC and percent collapse during inspiration of spontaneously breathing patients
  • Can use as a dynamic assessment after intervention (giving fluids)
  • Unclear if applicable to intubated patients

Technique

  • Use curvilinear (abdominal) probe or phased array (cardiac) probe
  • In subxyphoid cardiac view (epigastric), fan probe laterally to view the IVC draining into the right atrium
    • may start with subxyphoid view, place right atrium in center of screen and rotate probe 90 degrees clockwise to find IVC
    • Use M-mode to measure IVC collapse during inspiration or estimation can be made in 2D with IVC in longitudinal axis

Measurements

Correlations Between IVC Size and CVP[3]

IVC (cm) Respiratory Change CVP (cm H2O)
<1.5 Total collapse 0-5
1.5-2.5 >50% collapse 6-10
1.5-2.5 <50% collapse 11-15
>2.5 <50% collapse 16-20
>2.5 No change >20

Measure 2cm from IVC/RA junction or 1cm from IVC/hepatic vein junction

Classic Ultrasound Findings For Critically Ill Patients

Disease IVC Cardiac Lung (Phased Array) Lung (Linear)
MI Focal WMA
Mod/Poor squeeze
NL or B-lines Sliding
Tamponade RA collapse with filling
RV collapse with filling
NL Sliding
PTX NL or Hyperdynamic Lung point
Consolidated lung
Absent lung sliding
Sepsis Hyperdynamic squeeze NL (see pneumonia) Sliding
Pneumonia NL or ↓ Hyperdynamic squeeze Unilateral B-lines Sliding
Decompensated HF Mod/Poor squeeze Bilateral B-lines Sliding
PE RV > LV
McConnell's sign
NL or Unilateral B-lines Sliding

See Also

References

  1. Dipti A, et al. Role of inferior vena cava diameter in assessment of volume status: a meta-analysis. AJEM. 2012; 30:1414-1419.
  2. Zhang Z, et al. Ultrasonographic measurement of the respiratory variation in the inferior vena cava diameter is predictive of fluid responsiveness in critically ill patients: systematic review and meta-analysis. Ultrasound Med Biol. 2014. May; 40(5):845-53.
  3. Goldflam K, et al. Focus on: Inferior vena cava ultrasound. ACEP News. June 2011.