IVC ultrasound

Background

• Inferior vena cava measurement by ultrasound to estimate volume status
• 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

Measurements

IVC	% Collapse during inspiration^	CVP
<1.5cm	>50%	0-5
1.5-2.5cm	>50%	5-10
1.5-2.5cm	<50%	10-15
>2.5cm	Little phasicity	15-20

^Measure ~2cm from IVC/RA junction

• Can ask patient to sniff or valsalva to evaluate collapse

References

Dawson, M. Mallin, M. Introduction To Bedside Ultrasound: Volumes 1 and 2.Emergency Ultrasound Solutions. 2012 Inkling File

See Also

• Ultrasound (Main)