Mayo Clinic Critical Care Grand Rounds (26 Feb 2015)
Pro-Con debate: The use of ultrasound assessment of the Inferior Vena Cava to guide fluid resuscitation: fact or fiction?
Hon LiangIntensivist, Anaesthetist, Home Care Advocate
Man on Wire– Phillippe Petit
1974 high-wire walk between the Twin Towers of New York's World Trade Center
Pole is used to increase rotational inertia and lower the center of gravity
Will carry metaphor further.
uncorrected hypovolemia leads to inappropriate vasopressor use, increased organ hypoperfusion/ischemia, increased mortality
Hypervolemia increased complications, ICU stay, and mortality
Uncorrected hypovolemia-> leading to inappropriate infusions of vasopressor agents->increase organ hypoperfusion and ischemia .
Overzealous fluid resuscitation has been associated with increased complications, increased length of intensive care unit (ICU) and hospital stay, and increased mortality. A review of the ARDSNet cohort demonstrated a clear positive association between the mean cumulative daily fluid balance and mortality .
Murphy and colleagues demonstrated a similar finding in patients with septic shock . Data from the “Vasopressin in Septic Shock Trial” demonstrated that the quartile of patients with the highest fluid balance at both 12 hours and 4 days had the highest adjusted mortality .
Assessment of preload and fluid responsiveness in intensive care unit.
How good are we? Mohsenin. J of Critical Care
Tools of the trade
- Cap refill
-Noninvasive– EKG, SpO2, NIBP, Urinary catheter, Skeletal muscle tissue oxygenation (StO2), tissue pCO2, Ultrasound
-Invasive– Art lines, CVP, FloTrac, TEE, TE Doppler, PA Catheters
Lactate, VBG, SVO2, ABG
Story of the Swan Ganz Catheter– Iberti et al– 1990– average score of 67%--- practicing physicians understanding of use and interpretation of SGC
No one test is perfect--- we need to use our heads
Is the left ventricular (LV) function normal?
Is the right ventricular (RV) function normal?
Is there a pericardial effusion?
What is the volume status of the patient?
Assessment for pericardial effusion
Evaluation of relative chamber size
Global cardiac function
Patient volume status- left ventricular (LV) size, ventricular function, and inferior vena cava (IVC) size
and respiratory change.
Shippey. Critical Care Med. 1984. Vol 12. No 2.
125I labeled albumin to measure total lung volume
Blood volume and hemodynamic variables measured after resuscitation during quiescent period
Mean +/- SE of values for the study
--- A great deal of effort has been invested into attempting to correlate CVP and IVC diameter
--- CVP isn’t really a reliable indicator thus any attempts to correlate with IVC diameter doesn’t really matter to me when making decisions regarding volume status in the ICU
CVP < 5 or >12 may be predictive of low or high blood volume
From subcostal 4 chamber view, translate the probe medially to visualize the right atrium on the right of the screen, and to see a large part of the liver: keep the same depth and direction, translate the tip of the probe toward the right shoulder.
Then rotate the probe counter-clockwise until you see the long axis of the IVC merging into the right atrium.
You will see the IVC passing through the liver and merging with the right atrium. Often, you can visualize the sub-hepatic veins merging in the IVC
Increased Intra-Ab or Intra-Thoracic P will lead to alterations in IVC diameter/distensibility
Changes in RA: RV dysfunction, TR, pericardial effusion, arrythmias….
ACF was defined as mean arterial pressure (MAP) < 65 mmHg, urine output < 0.5 mL/Kg/h, tachycardia, mottled skin and/or biological
signs of hypoperfusion (arterial blood lactate > 2 mmol/L).
cIVC– respiratory variation of IVC
ACF was defined as mean arterial pressure (MAP) < 65 mmHg, urine output
< 0.5 mL/Kg/h, tachycardia, mottled skin and/or biological
signs of hypoperfusion (arterial blood lactate > 2 mmol/L). The AUC of the ROC curve for cIVC was 0.77
(VCCI ≥ 15% had poor positive
predictive value (PPV, 62%), but excellent negative predictive value (NPV, 100%, p = 0.03,
Table 3). A threshold for VCCI ≥ 50% had fair positive (75%) and good negative (80%)
predictive value, although did not achieve statistical significance (p = 0.09).