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 1-9 - 3 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
- JVD flat in supine position
- persistent leg edema
- 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
- leg edema the same
- 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
UNa UOsm > SOsm UNa
UNa > 40
< 10 > 20 YES NO < 10 > 20
Volume Mineralcorticoid SIADH OTHER Cirrhosis CKD
Depletion Deficiency Nephrosis
CHF
7. QUESTION
What type of hyponatremia does this patient have and how should it
be managed?
A. 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
A. 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.
A. Not sure
consult nephrology for an opinion about the hyponatremia
9. 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. 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
27. PROCEDURE
Landmarks
Aproach #1 – Xiphoid View
1 Most common approach
2 Place probe longitudinally just below the
xiphoid process with the probe marker to the
patient’s head
3 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
30. PROCEDURE
Landmarks
Aproach #2 – Anterior Mid-Axillary View
1 Place probe longitudinally in right anterior
mid-axillary line with marker towards the
head
2 Look for IVC running longitudinally adjacent
to liver crossing the diaphragm.
3 Track superiorly until it enters right atrium
confirming that it is the IVC and not the
aorta.
32. PEARLS
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
34. PEARLS
Mechanical Ventilation
1 Causes reversal of IVC changes with
respiration
2 Maximum diameter with inspiration,
minimum diameter with expiration
35. PEARLS
IVC v Aorta
Aorta IVC
Thick, echogenic walls Thin walls
Pulsatile Usually not pulsatile
High flow velocity Low flow velocity
Not compressable Compressable
No respiratory variation Respiratory variation
Above vertebral bodies Right of vertebral bodies
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. CASE
Correlation Between IVC Diameter Plus CI and CVP
IVC Max Diameter CI CVP
(cm) (mmHg)
100%
< 1.5 0-5
(total collapse)
1.5-2.5 > 50% 6-10
1.5-2.5 < 50% 11-15
> 2.5 < 50% 16-20
0%
> 2.5 >20
(no collapse)
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
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