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? Anaesthesia-Critical Care.

1. ©2015 MFMER | slide-1
Inferior Vena Cava Guided Fluid
Resuscitation
Pro – Con Debate
William ‘Brian’ Beam – Hon Liang Tan
Critical Care Grand Round
26 Feb 2015

2. ©2015 MFMER | slide-2
 Have responded with nothing to disclose.
William (Brian) Beam, MD
Hon Liang Tan, MBBS
Critical Care Grand Rounds
Disclosure Summary

3. ©2015 MFMER | slide-3
 Planning committee members who have nothing to disclose:
Richard A. Oeckler, MD, PhD, Co-Director
Juan N. Pulido, MD, Co-Director
Kim Jones, Program Coordinator
Disclosure Summary
As a provider accredited by ACCME, Mayo Clinic College of Medicine (Mayo School of CPD) must ensure balance, independence,
objectivity and scientific rigor in its educational activities. Course Director(s), Planning Committee Members, Faculty, and all others
who are in a position to control the content of this educational activity are required to disclose all relevant financial relationships with
any commercial interest related to the subject matter of the educational activity. Safeguards against commercial bias have been put in
place. Faculty also will disclose any off label and/or investigational use of pharmaceuticals or instruments discussed in their
presentation. Disclosure of this information will be published in course materials so those participants in the activity may formulate
their own judgments regarding the presentation.
Critical Care Grand Rounds
Disclosure Summary Continued

4. ©2015 MFMER | slide-4
Learning Objectives
• Interpret ultrasound findings of the inferior vena
cava in critically ill patients.
• Translate ultrasound findings of the inferior vena
cava to clinical management of critically ill
patients.
• Identify the limitations of using ultrasound
guided fluid resuscitation.

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Introduction
• Care of the critically ill patient involves:
• Rapid diagnosis
• Targeted treatment of underlying pathology
while
• Supporting organ function and
• Avoiding iatrogenic harm

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Introduction
• A Major Tenet of Critical Care:
• Optimization of cardiovascular function:
• Vasopressive/inotropic medication
• Mechanical ventilation
• Hemoglobin/oxygen carrying capacity of
blood
• Fluid intervention/resuscitation

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Introduction
• Increased use of ultrasound in the Intensive
Care Unit (ICU)
• Technological advances
• Greater affordability
• Safe
• Rapid
• Non-invasive
• Repeatable

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Introduction
• Inferior Vena Cava Guided Fluid Resuscitation
• Many investigators/publications
• Various IVC US parameters demonstrated
• But conclusions are conflicting and medical
opinions are not unanimous.

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Introduction
• In this Pro – Con Debate, we aim to
• Enhance your understanding of the US
derived IVC parameters
• Explore the controversies of this modality in
the care of the critically ill
• Enable you to arrive at YOUR conclusions
for YOUR practice.

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Assessment of the Inferior Vena Cava
using ultrasound is useful in guiding
fluid resuscitation.
A. Yes
B. No
A. B.
0%0%

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Intensivists should routinely use
ultrasound assessment of the IVC to
guide fluid resuscitation in critically ill
patients.
A. Yes
B. No
A. B.
0%0%

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Inferior Vena Cava Guided Fluid Resuscitation
PRO
Brian Beam

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Premise #1
• Determining the intravascular volume status of
critically ill patients is DIFFICULT
• And not something we always do well

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Dry, Wet or Just Right
Hypovolemia
Hypervolemia
Optimal Tissue Perfusion
Chinn (Producer) & Marsh (Director). (2008). Man on
Wire [Motion Picture]. USA: Magnolia.

15. ©2015 MFMER | slide-15
http://www.express.co.uk/news/weird/164768/Tightrope-walker-trips-1-600ft-in-the-air
Mohsenin. J of Critical Care (2015) Epub ahead of Print.

16. ©2015 MFMER | slide-16
Dry, Wet or Just Right
Chinn (Producer) & Marsh (Director). (2008). Man on Wire
[Motion Picture]. USA: Magnolia
http://www.express.co.uk/news/weird/164768/Tightrope-walker-
trips-1-600ft-in-the-air

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Determining Volume Status:
Tools of the Trade
Risk
-Potential for
Harm
Benefit
-Diagnostic Yield
• History
• Exam
• Non-Invasive
monitors
• Labs
• Ultrasound
• Invasive monitors

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Premise #2
• We must thoroughly understand the diagnostic
tools we plan to utilize.
• If we don’t then we as providers WILL make
errors in therapeutic decision making
JAMA 1990; 264:2928-32.

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Premise #3
• The best clinicians make decisions after
synthesizing the entire clinical picture!

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Premise #4
• Ultrasound is a tool that holds tremendous
potential to assist in clinical decision making in
critically ill patients.
http://www.intropsych.com/ch07_cognition/learning_curve.html

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Focused Transthoracic Ultrasound
European Journal of Anaesthesiology 2004; 21: 700-707)

22. ©2015 MFMER | slide-22European Journal of Anaesthesiology 2004; 21: 700-707)

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Premise #5
• “Static” measurements which attempt to infer
intravascular volume status are generally poor
predictors of intravascular volume
Shippey. Critical Care Med. 1984. Vol 12. No 2.

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Premise #5
• “Static” measurements which attempt to infer
intravascular volume status are generally poor
predictors of intravascular volume
• *Except maybe at the extremes*
Shippey. Critical Care Med.
1984. Vol 12. No 2.

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Static Measurement of IVC
• Cadaveric Study of 69 Livers
• Examined retrohepatic segment of IVC
• Median Diameter of IVC was 2.3 cm (range
1.5 to 8.2 cm)
Indian J Gastroenterol 2009(November–December):28(6):216–220
Image from: http://thesocietypages.org/socimages/2014/07/page/3/

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Premise #6
• Dynamic indices of intravascular volume are
more helpful in guiding fluid administration
Pulse Pressure
Variation
Dynamic Changes
of IVC diameter
Dynamic changes in aortic
flow velocity/stroke volume
assessed by Doppler methods End-expiratory
occlusion test
Dynamic changes of
the plethysmographic
waveform
Passive leg
raising

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Ultrasound of the IVC
Images from:
https://web.stanford.edu/group/ccm_echocardio/cgi-bin/mediawiki/index.php/IVC
http://echocardiographer.org/TTE.html

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Dynamic Changes in IVC Diameter:
The Physiology
Utilizes the interplay between the
compliance of the IVC and cyclical
changes in intra-thoracic pressure during
the respiratory cycle

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Dynamic Changes in IVC Diameter:
The Physiology
Images from: https://web.stanford.edu/group/ccm_echocardio/cgi-
bin/mediawiki/index.php/IVC

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Dynamic Changes in IVC Diameter:
The Physiology
Image from: https://web.stanford.edu/group/ccm_echocardio/cgi-
bin/mediawiki/index.php/IVC

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Dynamic Changes in IVC Diameter:
The Physiology
Abdomen Thorax

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Dynamic Changes in IVC Diameter:
The Physiology
Bodson and Vieillard-Baron Critical Care 2012, 16:181
Unfortunately,
the Devil is in the Details
Spontaneous Mechanical Ventilation
• Normal
• Increased Intra-Ab
Pressure

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Dynamic Changes in IVC Diameter
• The IDEAL STUDY
• Enrolls critically ill patients with
hemodynamic instability and uncertainty
regarding intravascular volume status
• Accurately performs measurement of
dynamic change in IVC diameter
• Accurately measures change in stroke
volume after fluid challenge

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Spontaneously Breathing Patients- Corl
• 30 spontaneously breathing ED patients
suspected to be hypovolemic
• No correlation between fluid
responsiveness and IVC Index
Emergency Medicine Australasia (2012) 24, 534–539

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Spontaneously Breathing Patients- Muller
• 40 spontaneously breathing ICU pts with
circulatory failure
• Measured IVC 2-3 cm from the right atrium
• Responsiveness: 15% increase in subaortic
velocity time index (VTI) after 500 mL
Hetastarch bolus
• cIVC = (Dmax-Dmin)/Dmax x 100
• Cutoff: cIVC 40%
• PPV 72%
• NPV 83%
Critical Care 2012, 16:R188

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Spontaneously Breathing Patients- Lanspa
• 14 spontaneously breathing ICU patients with
early sepsis
• Measured IVC prox to hepatic veins (0.5-3 cm
from RA junction)
• Volume Responsiveness: >15% increase CI
after 10 ml/kg bolus
• cIVC= (Dmax-Dmin)/Dmax x 100
• Cutoff: cIVC 15%
• PPV 62%
• NPV 100%
Shock. 2013 Feb;39(2):155-60

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Spontaneously Breathing Patients-
Conclusion
• cIVC >40% - Fluid responsive- maybe
• cIVC <15% - NOT fluid responsive
cIVC= (Dmax-Dmin)/Dmax x 100

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Mechanically Ventilated Patients- Moretti
• 29 patients with SAH. Intubated, sedated,
paralyzed. MV, TV= 8 mL/kg
• IVC measured 2 cm caudal from suprahepatic
vein
• Responsiveness: 15% increase in CI after 7
ml/kg Hetastarch bolus
• dIVC= (Dmax-Dmin)/Dmin x 100
• Cutoff: dIVC 16%
• PPV 70.5%
• NPV 100%
Neurocrit Care (2010) 13:3-9

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Mechanically Ventilated Patients- Barbier
• 20 patients with severe sepsis. MV, TV 8.5
ml/kg, PEEP 4
• IVC measured upstream from suprahepatic vein
• Volume Responsiveness: 15% increase in CO
after 7 ml/kg plasma expander
• dIVC= (Dmax-Dmin)/Dmin x 100
• Cutoff: dIVC 18%
• PPV 90%
• NPV 90%
Intensive Care Med (2004) 30:1740–1746

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Mechanically Ventilated Patients- Feissel
• 39 patients in septic shock. MV, TV 8-10 mL/kg
• IVC measured 3 cm from RA
• Volume Responsiveness: 15% increase in CO
after 8 ml/kg Hetastarch bolus
• ∆IVC= (Dmax-Dmin)/[(Dmax + Dmin)/2] x 100
• Cutoff: ∆IVC 12%
• PPV 93%
• NPV 92%
Intensive Care Med (2004) 30:1834–1837

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Mechanically Ventilated Patients:
Conclusion
• In hemodynamically unstable patients who are
mechanically ventilated without spontaneous
respiratory effort and TV ≥8 ml/kg
• dIVC >18% - fluid responsive
• dIVC <16% - NOT fluid responsive
• What about ∆IVC cutoff of 12%?
dIVC= (Dmax-Dmin)/Dmin x 100
∆IVC= (Dmax-Dmin)/[(Dmax + Dmin)/2] x 100

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Mechanically Ventilated Patients:
Simplified Conclusion
• In hemodynamically unstable patients who are
mechanically ventilated without spontaneous
respiratory effort and TV ≥8 ml/kg
• dIVC >20% - likely fluid responsive
• dIVC <10% - likely NOT fluid responsive
dIVC= (Dmax-Dmin)/Dmin x 100

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Conclusion
• Determining optimal intravascular volume status
of ICU patients is difficult
• Evaluation of the dynamic changes of the
IVC with respiration is a low risk and readily
available tool that can provide useful
information in the appropriate clinical
settings

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Image from: http://jeffreyhill.typepad.com/english/2010/10/cartoon-throwing-the-baby-out-with-the-
bathwater.html
Limitations
IVC
US

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Inferior Vena Cava Guided Fluid Resuscitation
CON
Hon Liang Tan

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Setting boundaries
• I submit:
• An extremely small/flat IVC or high IVC-CI
likely indicates hypovolemia in the correct
clinical context.
• An extremely large IVC or low IVC-CI is likely
to indicate hypervolemia in the correct
clinical context.

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Setting boundaries
• But:
• "Correct clinical context" may be obvious to
the experienced clinician

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Defining the Case
• Thus,
• What we want to know is if it is useful in grey
zones / difficult cases.
• Limited/no value for difficult cases.
• In the hands of an inexperienced, it might
even be dangerous weapon.

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Inferior Vena Cava Guided Fluid
Resuscitation - Con
• What is the logic?
• What’s wrong with the logic?
• Why is the evidence contradictory?
• So why bother?

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What is the logic?
• The logic:
• IVC connected to right atrium
• Compliant IVC
• Distention = intra-luminal pressure = right
atrium pressure

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What is the logic?
• Correlation demonstrated. Or was it?
• 83 patients: US assessment followed by
“floatation catheter” within 24 hours.
• RA pressure (range 0 to 28 mm Hg)
IVC Characteristic Correlation Coefficient
Expiratory Diameter 0.48
Inspiratory Diameter 0.71
Percentage Collapse 0.75

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What is the logic?
• Percentage Collapse:
• Discrimination of RA pressure > 10 mm Hg
maximized at 50% level of collapse.
• Wonderful!
• Or it is?

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What’s wrong with the logic?
• It does not account for:
• Patient characteristics
• Intra-luminal factors
• Extra-luminal factors
• Operator/technical factors
• Problems with measurement

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What’s wrong with the logic?
• Patient characteristics
• Patient POSITION
• American Society of Echocardiography
(ASE)
• Left lateral decubitus

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What’s wrong with the logic?
• In ICU, what do we do?
• Supine, head up 30 degrees!
• IVC changes shape in different positions.
• IVC larger in supine than in left lateral.

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What’s wrong with the logic?
• Patient characteristics
• Changes of the IVC with AGE
• 200 patients : 17 to 94 years old.
• Age
• Inversely correlated with IVC diameter.
• Proportionally increases IVC-CI.

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What’s wrong with the logic?
• Patient characteristics
• ETHNICITY/PHYSIQUE of patients (Asian)
• IVC > 19mm = RAP >10mmHg
(sensitivity, 75%; specificity, 78%)
• IVC-CI > 30%
(sensitivity, 75%; specificity, 83%).

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What’s wrong with the logic?
• Patient characteristics
• LIVER DISEASE
Max IVC Diameter (cm) IVC Reduction (cm) Sniff
Normal 2.35 +/- 0.34 1.30 +/- 0.67
Cirrhotic 1.74 +/- 0.35 0.03 +/- 0.09

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What’s wrong with the logic?
• Intra-luminal factors
• Right ventricular compliance
• Tricuspid valve disease
• Obstruction distal to right atrium
• Blood flow diversion

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What’s wrong with the logic?
• Intra-luminal factors
• RV COMPLIANCE/DIASTOLIC FAILURE
• Close correlation between LV and RV
diastolic parameters.

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What’s wrong with the logic?
• Intra-luminal factors
• RV COMPLIANCE/DIASTOLIC FAILURE
• > 1/3 have LV diastolic dysfunction on
admission.
• >1/3 develop reversible diastolic
dysfunction at least once during
admission.

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What’s wrong with the logic?
• Intra-luminal factors
• TRICUSPID VALVE DISEASE
• Tricuspid Regurgitation/Stenosis
• OBSTRUCTION DISTAL TO RIGHT
ATRIUM
• Pulmonary valve disease
• Pulmonary Hypertension
• Numerous causes
• Tumor

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What’s wrong with the logic?
• Intra-luminal factors
• BLOOD FLOW DIVERSION
• Pathological states – portosystemic
shunts
• Relationship between IVC parameters
and volume status in such situations
has not been validated

64. ©2015 MFMER | slide-65
What’s wrong with the logic?
• Extra-luminal factors
• Intra-thoracic pressure
• Spontaneous vs mechanical ventilation
• Intra-pericardial pressure
• Intra-abdominal pressure

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What’s wrong with the logic?
• Extra-luminal factors
• INTRA-PERICARDIAL PRESSURE
• Cardiac tamponade
• INTRA-THORACIC PRESSURE
• Tension pneumothorax
• Spontaneous vs mechanical ventilation

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What’s wrong with the logic?
• Extra-luminal factors
• INTRA-THORACIC PRESSURE
• Spontaneous ventilation
• Respiratory pattern
• Abdominal/diaphragmatic breathing
resulted in greater IVC-CI compared to
thoracic breathing

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What’s wrong with the logic?
• Extra-luminal factors
• INTRA-THORACIC PRESSURE
• Spontaneous ventilation
• "Sniff Test”
• Unable to standardize patient effort
• Respiratory distress
• Tidal volume
•

68. ©2015 MFMER | slide-69
What’s wrong with the logic?
• Extra-luminal factors
• INTRA-THORACIC PRESSURE
• Mechanical ventilation
• Paralysis? Mode?
• Chest wall / lung compliance?
• Tidal volume (8-10 ml/kg) / PEEP?
12%
18%

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What’s wrong with the logic?
• Extra-luminal factors
• INTRA-ABDOMINAL PRESSURE
• Intra-Abdominal Hypertension
• 32-56%
• Abdominal Compartment Syndrome
• 2-10%
• Conversely, open abdomen?

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What’s wrong with the logic?
• Operator/technical factors
• Technical difficulties in assessing the IVC
• Potential error in measurement
• Inter-operator variability
• Site of measurement

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What’s wrong with the logic?
• Operator/technical factors
• TECHNICAL DIFFICULTIES
• Impossible in up to 18% of patients

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What’s wrong with the logic?
• Operator/technical factors
• TECHNICAL DIFFICULTIES
• IVC moves
• Vertically by 21.9 mm
• Horizontally by 3.9 mm
• M mode not measuring same point.

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What’s wrong with the logic?
• Operator/technical factors
• ERRORS IN MEASUREMENT
• Foreshorten views

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What’s wrong with the logic?
• Operator/technical factors
• ERRORS IN MEASUREMENT
• IVC-CI = Max diameter – Min Diameter
Max Diameter
• Small error (in mm) results in large
changes

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Spontaneous Breathing Patient
cIVC= (Dmax-Dmin)/Dmax x 100
cIVC >40% - Fluid responsive
cIVC ≤15% - NOT fluid responsive
Mechanically Ventilated patient, no
respiratory effort, TV 8-10 mL/kg
dIVC= (Dmax-Dmin)/Dmin x 100
dIVC >18% - fluid responsive
dIVC <16% - NOT fluid responsive
∆IVC= (Dmax-Dmin)/[(Dmax + Dmin)/2] x 100
∆IVC >12% - fluid responsive
∆IVC <12%- NOT fluid responsive

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What’s wrong with the logic?
• Operator/technical factors
• SITE OF MEASUREMENT
• IVC collapses unequally

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What’s wrong with the logic?
• Operator/technical factors
• SITE OF MEASUREMENT
• IVC collapses unequally
• Different site of measurement =
different dimensions
• Long axis view from lateral trans-
hepatic window may make the IVC
appear to collapse less

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What’s wrong with the logic?
• Operator/technical factors
• SITE OF MEASUREMENT
• No consensus of where to measure.
• ASE: 0.5 – 3 cm from right atrium.

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What’s wrong with the logic?
• Operator/technical factors
• INTER-OPERATOR VARIBILITY
• Inter-operator agreement among trained
ED physicians is moderate.

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Why is the evidence contradictory?
• Studies do not uniformly account for:
• Patient characteristics
• Intra-luminal factors
• Extra-luminal factors
• Operator/technical factors

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So why bother?
• Multiple confounders/factors affect IVC
parameters
• Purported IVC parameters cut offs overlap
significantly
• Exact values cannot be established with
certainty
• Can lead to erroneous conclusions
• No evidence to show better outcomes

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So why bother?
• Even if RAP = CVP
• So what??

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Conclusion
• Ultrasound assessment of IVC is NOT useful in
guiding fluid resuscitation when it matters most.
• Routine assessment of IVC in the critically ill
patient is NOT necessarily diagnostic or
warranted.

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Post Debate Evaluation
*High stakes*

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Assessment of the Inferior Vena Cava
using ultrasound is useful in guiding
fluid resuscitation.
A. Yes
B. No
A. B.
0%0%

86. ©2015 MFMER | slide-87
Intensivists should routinely use
ultrasound assessment of the IVC to
guide fluid resuscitation in critically ill
patients.
A. Yes
B. No
A. B.
0%0%

87. ©2015 MFMER | slide-88
Questions & Discussion
Tan.Honliang@mayo.edu
Beam.William@mayo.edu