Hemodynamic Monitoring and Volume Management€¦ · Hemodynamic Monitoring and Volume Management...
Transcript of Hemodynamic Monitoring and Volume Management€¦ · Hemodynamic Monitoring and Volume Management...
Hemodynamic Monitoring and
Volume Management
Lakhmir S. Chawla, MD
Division of Renal Diseases and Hypertension
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Overview
• Blood Pressure Monitoring
• Assessment of Intravascular Volume
• Volume Responsiveness
– Where are you on the Starling Curve?
• Cardiac Output Monitoring
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Measurement of Blood Pressure
• Stethescope plus BP Cuff
• Dinamap
• Arterial line
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Old School
•Advantages
– Accurate systolic and
diastolic measurement
– Individual validation not
needed
•Disadvantages
– Cumbersome
– Operator variability
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Oscillometric Blood
Pressure Measurement
•Advantages
– Easy to use
– Faster than manual
– Measures MAP, not SBP or DBP
•Disadvantages
– Does not measure systolic or
diastolic directly; uses ratio
formula to estimate SBP and
DBP
– Assumes NSR
– Motion Artifact
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Overestimate Underestimate
(Too much pressure to occlude) (Too little pressure to occlude)
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Skipped Values in the
DINAMAP algorithm
• Skipped SBP
– 89, 119, 120, 124, 125, 130, 140, 141, 150,
160, 170, 180, 190, and 200 mm Hg
• Skipped HR
– 95, 99, 103, 106, and 109 bpm.
Skip Patterns in DINAMAP-Measured Blood Pressure in 3 Epidemiological Studies
Kathryn M. Rose. (Hypertension. 2000;35:1032.)
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Invasive Arterial BP Monitoring
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Central Peripheral
Effects of Systolic and Diastolic
BP
• SBP rises (approx 20-30 mm Hg)
• DBP falls
• Pulse Pressure Widens
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Quality Assurance with Arterial
Lines
• Square Root Test
• Waveform assessment
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Overdamped
decreased SPB, increased DPB
Check for clot, large air bubbles, soft tubing
Underdamped
Increased SPB, ringing artifacts in waveform
Remove bubbles, often small, replace tubing with larger bore,
add damping device
Hemodynamic monitoring : invasive and noninvasive clinical application 3rd ed.
Gloria Oblouk Darovic. Philadelphia : W.B. Saunders Co., 2002.
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Summary of Arterial Pressure
Assessment
• If you are not measuring the BP yourself, think prescribe in MAP terms, not SBP or DBP
• When using an arterial line, know its location, evaluate its wave form
• As we become more and more technology dependent
Trust, BUT Verify
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Assessment of Intravascular
Volume
• Bedside- Physical Exam
– JVP
– Orthostatics
• Central Venous Pressure
• Pulmonary Artery Wedge Pressure
• Stroke Volume
• Stroke Volume Variation
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Physical Exam
• Jugular Venous Pressure
– Observer Variability
– Difficult in obese and edematous patients
– Trending problematic
• Orthostatics
– Can be helpful
– Difficult to do in critically ill patients
– Specific but not sensitive
– Result Binary; Following trend difficult
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Physical Exam
• Does not reliably predict intravascular
volume status
• Classic Triad - Jugular venous
distension, crackles on auscultation,
and peripheral edema
•Crit Care Med 2001; 29: 1502-1512
•N Engl J Med 1983; 308:263–267
•Crit Care Med 1984; 12:107–112
•Crit Care Med 2001; 29:1635–1636
•Intensive Care Med 2001; 27:1238
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Portable CXR
• The classic radiographic signs of volume overload (pleural effusions, septal lines, peribronchial cuffing, or distribution of lung densities) are poor predictors of LVEDP
•Crit Care Med 2001; 29: 1502-1512
•Crit Care Med 2001; 29:1635–1636
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Central Venous Pressure (CVP)
• Advantages
– Can be trended
– Objective Measure
• Disadvantages
– Not helpful in the absence of cardiac output measure
– Significantly affected by respiration and PEEP
Michard F et al Chest 2002; 121:2000–2008
Kumar A et al Crit Care Med 2004; 32:691–699
Shippy CR et al Crit Care Med 1984; 12:107–112
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Central Venous Pressure
• Does NOT predict cardiac
preload or volume status
•Michard F et al Chest 2002; 121:2000–2008
•Kumar A et al Crit Care Med 2004; 32:691–699
•Shippy CR et al Crit Care Med 1984; 12:107–112
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Pulmonary Capillary Wedge
(Occlusion ) Pressure
• Value generated by right sided heart catheterization (typically balloon guided)
• Under idealized conditions, PCWP (PAOP) represents left ventricular end diastolic pressure (LVEDP)
• LVEDP is a surrogate for LV end diastolic volume which should represent pre-load
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Pulmonary Capillary Wedge Pressure
• Advantages
– Measures left sided pressures as
compared CVP
• Disadvantages
– Somewhat invasive & more side effect than
CVP
– Accuracy dependent on optimal placement
– Wedge pressure must be read by
experienced operator
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Pulmonary Capillary Wedge Pressure
Contrary to expectations
• PCWP fails to correlate with LVEDV or
stroke volume
• The wedge is NOT a good measure of intravascular volume status.
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The Evidence
•Kumar A et al Crit Care Med 2004 Vol. 32, No. 3
• Sakka SG, Intensive Care Med 1999; 25:
•843–846
• Jardin F, Intensive Care Med 1994; 20:550–554
•Calvin JE, Crit Care Med 1981; 9:437–443
•Calvin JE,. Surgery 1981; 90:61–76
•Diebel L, J Trauma 1994; 37:
•950–955
•Martyn JA,. J Trauma 1981; 21:
•619–626
• Lichtwarck-Aschoff M,. Intensive
•Care Med 1992; 18:142–147
•Tousignant CP, Anesth Analg 2000; 90:351–355
•Thys DM,. Anesthesiology 1987; 67:630–634
•Ellis RJ, J Thorac Cardiovasc Surg 1979; 78:605–613
• Hoeft A, Anesthesiology 1994; 81:76–86
•Douglas PS, Ann Thorac Surg 1987; 44:31–34
•Hansen RM, Anesthesiology 1986; 64:764–770
•Tuman KJ, J Cardiothorac Vasc Anesth 1995; 9:2–8
•Buhre W, Eur J Anaesthesiol 1999; 16:11–17
•Dennis JW, J Vasc Surg 1992; 16:372–377
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A, Initial CVP
and SVI
B, Δ in CVP and
SVI in response to
saline
C, Initial PWP and SVI
D, Δ in PWP and SVI
in response to saline.
Pulmonary artery occlusion
pressure and central venous
pressure fail to predict ventricular
filling volume, cardiac
performance, or the response to
volume infusion in normal
subjects
Kumar, Anand MD; Critical Care
Medicine: Volume 32(3) March
2004 pp 691-699
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•2-D echo LVEDVI compared to SVI
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Volume Responsiveness
Increase in cardiac output with
volume bolus
CO = HR x SV
•Stroke Volume corrected for BSA = SVI
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Renal Considerations
• Pre-renal (low FeNa)
– Not necessarily volume depleted
– Decreased Renal Perfusion Pressure
RPP = CO x RVR
CO = cardiac output
RVR = Renal Vascular Resistance
Optimize RPP
Flow is preferable to resistance
Dobutamine versus phenylephrine
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If Physical Exam, CVP, and
PCWP do not determine volume
status, how do we optimize our
patients?
Build a Starling curve one patient at a time
Assess the effect of volume infusion on stroke volume
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Volume seeking versus room for diuresis
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Stroke Volume Variation
• Based on clinical observation that respi-
phasic variation of arterial pressure in
intra-vascular volume depletion
• Quantitative Measure
• Available on Pulse Contour Systems
•Anesth Analg. 2003 May;96(5):1254-7.
•Eur J Anaesthesiol. 2004 Feb;21(2):132-8.
•Chest. 2005 Aug;128(2):848-54
•Anesth Analg. 2001 Apr;92(4):984-9
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ROC curve for CVP, PAOP, spontaneous venous pulse, and pulse pressure variation
Δ PP, change in pulse pressure; Δ SP, change is systolic pressure; PAOP, pulmonary artery
occlusion pressure; RAP, right arterial pressure. Michard F, Boussat S, Chemla D, et al.: Relation between respiratory changes in arterial pulse pressure and fluid
responsiveness in septic patients with acute circulatory failure.
Am J Respir Crit Care Med 2000, 162:134–138.
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ROC curves comparing the ability of the pulmonary artery occlusion pressure (PAOP), the left ventricular end-diastolic area index (EDAI), and the delta down component (dDown) of the positive pressure ventilation-induced arterial systolic pressure variation
Tavernier B et al. Anesthesiology. 1998 Dec;89(6):1313-21.
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Summary
Measures of Cardiac Output and Volume
Responsiveness
•Cardiac Output
– PAC thermodilution
– Pulse Contour
•Volume Responsiveness
– Transpulmonary
thermodilution (GEDVi)
– Stroke Volume Variation
•Pulse Contour – Offers CO and SVV monitoring
•PAC – CO monitoring, CVP, and PCWP
•GEDVi – Offers GEDVi, CO, and SVV
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Summary: How to monitor volume status
• Physical Exam
• Filling pressures
– CVP and PCWP
• Chest Radiograph
• Echocardiography
• Quantitative Measures of Cardiac Output
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In order to follow stroke volume,
an accurate measure of cardiac
output is required
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How to monitor cardiac output
• Thermodilution
– Pulmonary Artery Catheterization
– Transpulmonary – GEDV thermodilution
• Lithium Dilution
• Impedance Plethysmography
• Pulse Contour
• Esophageal Doppler
• TEE
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Impedance Cardiography (ICG)
• Alternating Current is Transmitted
Through the Chest
• Current Seeks Path of Least Resistance: The Blood Filled Aorta
• The ICG Measures the Baseline Impedance to this Current
• With Each Heartbeat, Blood Volume and Velocity in the Aorta Change
• ICG Measures the Corresponding Change in Impedance
• ICG Uses the Baseline and Changes in Impedance to Measure and Calculate Hemodynamic Parameters
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Aortic Blood Flow
Changes Impedance
Aorta ICG Waveform
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Global End Diastolic Volume
Index
• Requires CVP and thermodilution
arterial line
• Cold solution infused via CVP and
thermodilution curve generated
• This parameter is closely linked to intra-
thoracic blood volume
• Predicts volume responsiveness
Michard et al, CHEST 2003; 124:1900 –1908
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Li Dilution Cardiac Output • Technique
– Involves injecting small amount of Li into CVP and detecting dissappearance with special monitor on arterial line
• Reliabiltiy – As less invasive
– As good as PAC
• Drawbacks – Cumbersome
– Requires Li injectate
Crit Care Med 1997 25(11):1796-800
British Journal of Anaesthesia, 1993, Vol. 71, No. 2 262-266
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Pulse Contour Cardiac Output
• Utilizes Standard Arterial Line
• Calculates Stroke Volume
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Effect of vascular tone • The algorithm looks for characteristic
changes in the arterial pressure waveform that reflect changes in tone (i.e., MAP, Skewness, Kurtosis)
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Trending Stroke Volume
• Blood pressure is sampled at 100 Hz
• Changes in stroke volume will result in corresponding changes in the pulse pressure
• Whole waveform measure of the pulse pressure is achieved by taking the standard deviation of the sampled points of each beat
• Std(BP) Pulse Pressure Stroke Volume
• SV estimates are averaged over 20 seconds
PP SV
SBP
DBP
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Summary
• Most Reliable CO Monitor
– PA Catheter
– Pulse Contour
• Minimally Invasive
– LiCO
– Pulse Contour
• Non-Invasive
– Bioimpedance
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Conclusion
• Optimal assessment of intra-vascular volume status requires quantitative measures of cardiac output
• PA catheters reliably provide this function
• Echocardiography is also reliable
• Less invasive technologies are evolving and appear promising