HEMODYNAMICS MONITORING IN CRITICALLY ILL
PATIENTS: ASSESSMENT OF FLUID STATUS AND
MEASURES OF VOLUME RESPONSIVENESS

Bass...
Measuring Cardiac Output
• The function of the heart is to transport blood
to deliver oxygen to the cells of the body to
e...
Measuring Cardiac Output
Invasive methods are well accepted, but there is
increasing evidence that these methods are
neith...
Measuring Cardiac Output
The Fick Principle
• First described by Adolf Fick in 1870
• The rate at which oxygen is consumed...
Measuring Cardiac Output
The Fick Principle
• VO2 = CO x (CA – CV)
• CO = VO2 / (CA – CV)
– (CA – CV) Arteriovenous oxygen...
Measuring Cardiac Output
The Fick Principle
• Invasive
• Requires time for the sample analysis
• Accurate oxygen consumpti...
Measuring Cardiac Output
Pulmonary Artery Thermodilution
• Injection of 10 ml of cold glucose into the pulmonary
artery an...
Measuring Cardiac Output
Pulmonary Artery Thermodilution
• The Swan - Ganz catheter or PAC, was
introduced to clinical pra...
Measuring Cardiac Output
Pulmonary Artery Thermodilution
• PAC use is complicated by
– arrhythmias
– infection
– pulmonary...
CVP AS A MARKER OF INTRAVASCULAR
VOLUME STATUS AND RESPONSE TO FLUIDS
• CVP is NOT RELIABLE for judging intravascular volu...
Assessment of Fluid Status and Measures of
Volume Responsiveness
Passive Leg Raising and Artery Peak Velocity

• Doppler e...
Assessment of Fluid Status and
Measures of Volume Responsiveness
IVC Diameter Variation
• Measure proximal IVC AP diameter...
IVC Evaluation

Bassel Ericsoussi, MD

16
Normal: IVC diameter 1-3 cm

• Subcostal view of the IVC passing through the liver and
17
draining into the rightBassel Er...
Volume Responsive: IVC diameter <1 cm

Bassel Ericsoussi, MD

18
Not Responsive: IVC diameter >3 cm

Bassel Ericsoussi, MD

19
Assessment of Fluid Status and
Measures of Volume Responsiveness
Pulse pressure variation
LIMITATIONS OF IVC AND PULSE
PRESSURE VARIATIONS
• All patients must be:
– Passively ventilated – heavily sedated
– Large ...
Assessment of Fluid Status and
Measures of Volume Responsiveness
Passive Leg Raising and Stroke
Volume Variation
• Straigh...
Statistical Analysis Of Arterial Pressure
Flotrac/Vigileo
• By analyzing the shape of the arterial pressure
waveform, the ...
Statistical Analysis Of Arterial Pressure
Flotrac/Vigileo
• Disadvantages
– Inability to provide data regarding right-side...
HEMODYNAMICS MONITORING IN CRITICALLY ILL PATIENTS: ASSESSMENT OF FLUID STATUS AND MEASURES OF VOLUME RESPONSIVENESS
HEMODYNAMICS MONITORING IN CRITICALLY ILL PATIENTS: ASSESSMENT OF FLUID STATUS AND MEASURES OF VOLUME RESPONSIVENESS
HEMODYNAMICS MONITORING IN CRITICALLY ILL PATIENTS: ASSESSMENT OF FLUID STATUS AND MEASURES OF VOLUME RESPONSIVENESS
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HEMODYNAMICS MONITORING IN CRITICALLY ILL PATIENTS: ASSESSMENT OF FLUID STATUS AND MEASURES OF VOLUME RESPONSIVENESS

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Invasive methods are well accepted, but there is increasing evidence that these methods are neither accurate nor effective in guiding therapy

An accurate and non-invasive measurement of CO is the best method of cardiovascular assessment

Published in: Health & Medicine

HEMODYNAMICS MONITORING IN CRITICALLY ILL PATIENTS: ASSESSMENT OF FLUID STATUS AND MEASURES OF VOLUME RESPONSIVENESS

  1. 1. HEMODYNAMICS MONITORING IN CRITICALLY ILL PATIENTS: ASSESSMENT OF FLUID STATUS AND MEASURES OF VOLUME RESPONSIVENESS Bassel Ericsoussi, MD Pulmonary & Critical Care Specialist
  2. 2. Measuring Cardiac Output • The function of the heart is to transport blood to deliver oxygen to the cells of the body to ensure their survival and proper function and to remove the cellular wastes – Cardiac Output (CO) = SV × HR – Ejection Fraction (EF) = (SV / EDV) × 100% – Stroke Volume (SV) = EDV – ESV – Cardiac Index (CI) = CO / Body Surface Area (BSA)
  3. 3. Measuring Cardiac Output Invasive methods are well accepted, but there is increasing evidence that these methods are neither accurate nor effective in guiding therapy An accurate and non-invasive measurement of CO is the best method of cardiovascular assessment
  4. 4. Measuring Cardiac Output The Fick Principle • First described by Adolf Fick in 1870 • The rate at which oxygen is consumed is a function of the rate of blood flows and the rate of oxygen picked up by the red blood cells • VO2 = CO x (CA – CV) • CO = VO2 / (CA – CV) – (CA – CV) Arteriovenous oxygen difference
  5. 5. Measuring Cardiac Output The Fick Principle • VO2 = CO x (CA – CV) • CO = VO2 / (CA – CV) – (CA – CV) Arteriovenous oxygen difference • VO2 calculated using an assumed oxygen consumption • CaO2 = Hb x 1.34 x SaO2 + 0.003 PaO2 • CvO2 = Hb x 1.34 x SvO2 + 0.003 PvO2
  6. 6. Measuring Cardiac Output The Fick Principle • Invasive • Requires time for the sample analysis • Accurate oxygen consumption samples are difficult to acquire
  7. 7. Measuring Cardiac Output Pulmonary Artery Thermodilution • Injection of 10 ml of cold glucose into the pulmonary artery and measuring the temperature distally using the same catheter with temperature sensors set apart at a known distance 6–10 cm • Calculate the Cardiac Output from a measured time/temperature curve (The "thermodilution curve") – low CO registers temperature change slowly – high CO registers temperature change rapidly – The degree of change in temperature is directly proportional to the CO • 3-4 passes are usually averaged to improve accuracy
  8. 8. Measuring Cardiac Output Pulmonary Artery Thermodilution • The Swan - Ganz catheter or PAC, was introduced to clinical practice in 1970 • Due to hospital acquired infection, we don’t use continuous invasive cardiac monitoring in the Intensive Care Unit. • Use of the PAC is still useful in right heart study in the cardiac catheterization laboratory today.
  9. 9. Measuring Cardiac Output Pulmonary Artery Thermodilution • PAC use is complicated by – arrhythmias – infection – pulmonary artery rupture – right heart valve damage • Recent studies in patients with critical illness, sepsis, acute respiratory failure and heart failure suggest use of the PAC does not improve patient outcomes
  10. 10. CVP AS A MARKER OF INTRAVASCULAR VOLUME STATUS AND RESPONSE TO FLUIDS • CVP is NOT RELIABLE for judging intravascular volume status • A low CVP generally can be relied upon as supporting positive response to fluid loading • Target CVP 8–12 mmHg • Higher target CVP of 12-15 mmHg should be achieved – – – – Mechanically ventilated patients Decreased ventricular compliance Pulmonary artery hypertension Increased abdominal pressure
  11. 11. Assessment of Fluid Status and Measures of Volume Responsiveness Passive Leg Raising and Artery Peak Velocity • Doppler evaluation of arterial peak velocity variation In the responder patient, passive leg raising induced an increase of arterial peak velocity by 15%
  12. 12. Assessment of Fluid Status and Measures of Volume Responsiveness IVC Diameter Variation • Measure proximal IVC AP diameter 3 cm from the RA • Spontaneous breathing  > 50% decrease in the IVC diameter with inspiration predicts responsiveness to volume expansion • Positive pressure ventilation  > 12% increase in the IVC diameter with inspiration predicts responsiveness to volume expansion Max D – min D / average D > 12% Max D - min D / min D > 18%
  13. 13. IVC Evaluation Bassel Ericsoussi, MD 16
  14. 14. Normal: IVC diameter 1-3 cm • Subcostal view of the IVC passing through the liver and 17 draining into the rightBassel Ericsoussi, MD atrium.
  15. 15. Volume Responsive: IVC diameter <1 cm Bassel Ericsoussi, MD 18
  16. 16. Not Responsive: IVC diameter >3 cm Bassel Ericsoussi, MD 19
  17. 17. Assessment of Fluid Status and Measures of Volume Responsiveness Pulse pressure variation
  18. 18. LIMITATIONS OF IVC AND PULSE PRESSURE VARIATIONS • All patients must be: – Passively ventilated – heavily sedated – Large tidal volume 10-12 ml/kg – Off vasopressors – Sinus rhythm – Absence of increased abdominal pressure • Good luck finding these patient Bassel Ericsoussi, MD 21
  19. 19. Assessment of Fluid Status and Measures of Volume Responsiveness Passive Leg Raising and Stroke Volume Variation • Straight leg raising test: Can be done on any patient – Sinus or irregular rhythm – Spontaneous breathing or on ventilator – On pressors or off pressors • Use apical 5 chamber view and measure the aortic blood flow (stroke volume) • Raise legs to 45 degree (you have just given a “blood bolus” 500 ml blood in legs returned to the heart) • Wait 30-60-90 sec (highest values within 90 sec) • Recheck the stroke volume – SVV > 12% Bassel Ericsoussi, MD 22
  20. 20. Statistical Analysis Of Arterial Pressure Flotrac/Vigileo • By analyzing the shape of the arterial pressure waveform, the effect of vascular tone is assessed allowing calculation of SV. • Cardiac Output (Q) is then derived utilizing the equation Q=HR*SV. • While these invasive arterial monitors do not require intracardiac catheterisation from a pulmonary artery catheter, they do require an arterial line and are invasive.
  21. 21. Statistical Analysis Of Arterial Pressure Flotrac/Vigileo • Disadvantages – Inability to provide data regarding right-sided heart pressures, or mixed venous oxygen saturation – The measurement of pressure in the artery to calculate the flow in the heart is irrational and of questionable accuracy – Arterial pressure monitoring is limited in patients off ventilation, in atrial fibrillation, in patients on vasopressors and in patients with a dynamic autonomic system such as in sepsis

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