fluid optimization concept based on dynamic parameters of hemodynamic monitoring
TRANSCRIPT
![Page 1: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/1.jpg)
Fluid Optimization Concept Based On Dynamic Parameters
Of HDM
DR. SURENDRA KUMAR
FNB-CCM
RTIICS KOLKATA
![Page 2: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/2.jpg)
Hemodynamic Truths
• Tachycardia is never a good thing
• Hypotension is always pathological
• There is no normal cardiac output
• CVP is only elevated in disease• Peripheral edema is of cosmetic
concern
CONSIDER OF A CASE OF SEPSIS
![Page 3: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/3.jpg)
Routine Haemodynamic Monitoring
Mandatory
Clinical Examination
ECG
Pulse Oxymetry
End Tidal CO2 Monitoring
Blood Pressure Monitoring
Non-invasive
Invasive
Urine output
ABG
Non-mandatory
Central Venous Pressure
Pulmonary Artery pressure
Cardiac Output
Ultrasound
Novel Technologies
Functional HD Monitoring
![Page 4: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/4.jpg)
Protocol for Early Goal-directed Therapy
• Rivers protocol for hemodynamic management in severe sepsis or septic shock.
![Page 5: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/5.jpg)
![Page 6: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/6.jpg)
![Page 7: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/7.jpg)
![Page 8: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/8.jpg)
![Page 9: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/9.jpg)
What do we expect from a hemodynamic monitoringsystem?
•This question depends on the monitor. •At least, we expect a monitor to accurately measure
•CO •fluid responsiveness
![Page 10: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/10.jpg)
Integrative hemodynamic monitoring approach
Ramsingh et al. Critical Care 2013, 17:208
• The goal of most functional HDM parameters is to
predict fluid responsiveness in critically ill pts
![Page 11: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/11.jpg)
Is cardiac output responsive to intravascular fluid loading?
• Assumes that venous return and LV preload are the primary determinants of cardiac output (Starling’s Law of the Heart)
• Assumes low LV end-diastolic volume (EDV) equals preload-responsiveness
• Attempts to assess EDV through surrogate measures• CVP, PAOP, LV end-diastolic area, RV EDV, intrathoracic blood volume
![Page 12: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/12.jpg)
Determinants of Cardiac Output
• CO = HR x SV
• Stroke Volume is determined by:• Preload
• Afterload
• Contractility
![Page 13: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/13.jpg)
What is Preload?
• Preload is the force or “load” which stretches the ventricle of the heart, that determines the force-length relationship
• Preload can be measured only in lab
• We measure surrogates for preload
• Pressure vs Volume
![Page 14: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/14.jpg)
Frank Starling Curves
Factors Affecting Preload
![Page 15: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/15.jpg)
Fluid optimization concept based on stroke volume monitoring.
The concept of cardiac output maximization based on fluid administration and stroke volume monitoring. Small boluses of fluid are administered intravenously (200 to 250 ml at a time) until the stroke volume increases by <10%.
![Page 16: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/16.jpg)
Assessment of volume responsiveness Fluid responsiveness should be detected before deciding to administer volume expansion, especially in patients in whom fluid overload should be particularly avoided, i. e., patients with septic shock and/or ARDS.
For this purpose, ‘static markers ’ of cardiac preload have been used for many years.
Nevertheless, a very large number of studies clearly demonstrate that neither pressure nor volume markers of preload can predict fluid responsiveness
• -CVP and PAOP poor predictors of fluid status
• Cardiac filling pressures did not predict fluid responders from non-responders. [Osman, et al. CCM 2007 ]
![Page 17: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/17.jpg)
Preload ( Filling Pressures) Assessment
CVP
RAP
RVEDP
PCWP
LVEDP
LVEDV
LVEDV determines LVEF
![Page 18: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/18.jpg)
dynamic approach
a ‘dynamic approach’ has been developed for assessing volume responsiveness.
The concept is to assess preload dependency by observing the effects on cardiac output of changes in cardiac preload induced by various tests.
![Page 19: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/19.jpg)
![Page 20: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/20.jpg)
Dynamic parameters
• Systolic pressure variation
• Pulse pressure variation
• Stroke volume variation
• Passive leg raising
• Pleth variability index
![Page 21: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/21.jpg)
Normal Spontaneous Breathing
Variation of peak systolic pressure by < 5 mm Hg
Pulsus Paradoxus : Adolf Kussmual
‘Disappearing pulse during inspiration and return in expiration’
Exaggeration of this response - constrictive pericarditis
- Cardiac Tamponade
- Severe lung disease
Arterial Pressures and Respiration
Swing!
![Page 22: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/22.jpg)
Morgan et al: Anesthesiology: 1966
Effect of Positive Pressure on Blood flows
Aortic Blood Flow
Pulmonary Artery Flow
Vena Cava Flow
![Page 23: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/23.jpg)
Arterial Pressures and IPPV
Inspiratory increase in SBP
followed by
a decrease on expiration
Also known as
Systolic Pressure Variation
Pulse Pressure Variation
Reverse Pulsus Paradoxus Reverse swing!
![Page 24: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/24.jpg)
Systolic pressure variation
![Page 25: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/25.jpg)
• The SPV consists of an upward swing ( up) as well as a fall ( down)
• This phenomenon is an extension of the ‘pulsusparadoxux’
• Can be used only during IPPV
• If the sum of up + down > 15 mmHg, then that patient will respond to fluids (preload)
![Page 26: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/26.jpg)
if ∆PP is low (<13%), then a beneficial haemodynamic effect of volume expansion is veryunlikely, and inotropes or vasoactives drugs should be proposed in order to improve haemodynamics. In contrast, if ∆PP is high (>13%), then a significant increase in cardiac index in response to fluid infusion is very likely.
![Page 27: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/27.jpg)
![Page 28: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/28.jpg)
Pulse pressure variation
The first application of this ‘dynamic’ concept consisted of quantifying the variations in stroke volume induced by positive-pressure ventilation
The arterial pulse pressure (systolic minus diastolic arterial pressure) as a surrogate of stroke volume has been proposed to predict fluid responsiveness through its respiratory variation .
![Page 29: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/29.jpg)
SVV to determine Preload Responsiveness
International Panel Point of View Article; 2009
![Page 30: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/30.jpg)
SPV /SVV AlgorithmF. Michard 2009
![Page 31: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/31.jpg)
Other surrogates of stroke volume• Aortic blood flow measured by esophageal Doppler
• Subaortic peak velocity measured by echocardiography
• Stroke volume estimated from pulse contour analysis
Finally,
• analysis of respiratory variations of the diameter of the IVC using TTE or of the SVC using TEE can also be used to assess fluid responsiveness in mechanicall y ventilated pts
• the non-invasive arterial pulse pressure estimated by the volume-clamp method or the amplitude of the plethysmographic waveform. All the se non-invasive methods still require confirmatory studies.
![Page 32: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/32.jpg)
PVI >17 %
Relation between respiratory variations in pulse oximetry plethysmographic waveform amplitude and arterial pulse pressure in ventilated patients.
Adapted from Cannesson et al., 2005
![Page 33: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/33.jpg)
Limitations of the respiratory variation in stroke volume for predicting fluid responsiveness
1. Spontaneous Breathing Activity
2. Cardiac Arrhythmias
3. High Frequency Ventilation
4. Presence Of Increased Abdominal Pressure
5. Open-chest Surgery
6. Low Tidal Volume
7. Low Compliance Of The Respiratory System[ < 30 ml/cm H2O] ...........recent clinical study
![Page 34: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/34.jpg)
Practical Limitations of PPV
• Requires fixed HR• Atrial fibrillation, frequent PVCs
• Requires no spontaneous ventilatory efforts• Can not use during CPAP, PSV
• Magnitude of PPV or SVV will change with changing tidal volume
• Heart failure may give false positive response!
![Page 35: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/35.jpg)
PPV and SVV during IPPV
• Reflect complex interactions between preload and afterload
• Potential false positive PPV with inspiration• Severe CHF-Reverse Bernheim Effect
• Cor pulmonale- Minimize ventricular interdependence
• Potential false positive SVP with inspiration• Stiff chest wall + large tidal volume: Valsalva Maneuver
• Whenever ITP increases rapidly
• These limitations dissolve with passive leg raising
![Page 36: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/36.jpg)
Limits of Preload-Responsiveness• Preload Preload-responsiveness
• Preload-responsiveness Need for fluids
• The means of altering preload matters• Size of Vt, passive leg raising, spontaneous breaths
• Different measures of pressure or flow variation will have different calibrations
• Pinsky Intensive Care Med 30: 1008-10, 2004
![Page 37: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/37.jpg)
Alternatives to the respiratory variation of hemodynamic signals: recent advances
Critical Care 2013, 17:217
![Page 38: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/38.jpg)
The end-expiratory occlusion test[EEO]
it was demonstrated that if a 15-sec EEO test increased the arterial pulse pressure or the pulse contour-derived cardiac output by more than 5 %, the response of cardiac output to a 500 ml saline infusion could be predicted with good sensitivity and specificity.
ADVANTAGE
is that it exerts its hemodynamic effects over several cardiac cycles and thus remains valuable in case of cardiac arrhythmias. [main]
can be used in pts with spontaneous breathing activity, unless marked triggering activity interrupts the test.
![Page 39: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/39.jpg)
Marik et al. Annals of Intensive Care 2011, 1:1
![Page 40: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/40.jpg)
The ‘mini’ fluid challenge
Obviously, the easiest way to test preload responsiveness is to administer fluid and to observe the resulting effect on cardiac output.
Nevertheless, the disadvantage of the ‘classical’ fluid challenge is that it consists of administration of 300–500 ml of fluid. Because it is not reversible, such a fluid challenge may contribute to fluid overload, especially when it is repeated several times a day
It consists of administering 100 ml of colloid over 1 min and observe the effects of this ‘mini’ fluid challenge on stroke volume, as measured by the sub aortic velocity time index using transthoracic echocardiography. In a clinical study, an increase in the velocity time index of more than 10 % predicted fluid responsiveness with a sensitivity of 95 % and a specificity of 78 %
![Page 41: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/41.jpg)
• Advantage
small volume of fluid is unlikely to induce fluid overload even if repeated several times a day
easy to perform and can be assessed in a non-invasive way
• Nevertheless, a strong limitation is that, even in cases of preload-dependency, such a small volume infusion will unavoidably induce only small changes in cardiac output. This test, therefore, requires a very precise technique for measuring cardiac output
Disadv.--------cannot be used in the presence of cardiac arrhythmias
![Page 42: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/42.jpg)
The passive leg-raising testpassively transfers a significant volume of blood from the lower part of the body toward the cardiac chambers: Passive leg-raising (PLR) partially empties the venous reservoir and converts a part of the unstressed blood volume to stressed volume. In this connection, PLR increases right and left cardiac preload. Eventually, the increase in left cardiac preload results in an increase in cardiac output depending upon the degree of preload reserve of the left ventricle. The increase in cardiac preload induced by PLR totally reverses once the legs are returned back to the supine position.
In summary, PLR acts like a reversible and short-lived ‘self ’ volume challenge
since the test exerts its effects over several cardiac and respiratory cycles, it remains a good predictor of fluid responsiveness in patients with spontaneous breathing activity (even non-intubated) or cardiac arrhythmias
![Page 43: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/43.jpg)
Passive leg raising: five rules, not a drop of fluid!
![Page 44: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/44.jpg)
Fluid challenges and PLR
45 degrees 45 degrees
Patients who are fluid responsive will show a 10% -15 % rise of SV in 30 to 90 seconds. SV % increase by 10-15% preload responsive.
![Page 45: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/45.jpg)
Benefits of Passive Leg Raising (PLR)In situations where it is not possible to use SVV, the effects of fluid loading can be replicated by using PLR.
PLR acts like a ‘self volume challenge’
Equivalent to 150 – 300 ml volume
if a patient is responsive to PLR, they will be responsive to fluid administration
The PLR test is reversible, and therefore useful in patients with fluid-loading related complications
If the increase in cardiac preload induced by PLR induces significant changes in SV (a to b), the patient will likely be fluid responsive
If the same changes in cardiac preload during PLR do not significantly change SV (a’ to b’), the heart is likely preload dependent and should not be administered
Examples
Sources:Michard, F. Touch Briefings 2007: 47-48
Monnet, X. Yearbook of Intensive Care & Emergency Medicine 2007: 542-548
![Page 46: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/46.jpg)
The postural change used for performing the PLR test is important
. If PLR is started from the 45° semirecumbent position, the induced increase in central venous pressure is larger than if started from the supine position Because mobilizes blood coming not only from the inferior limbs but also from the large splanchnic compartment.
As a consequence, starting PLR from the semi-recumbent posture is more sensitive than starting from the horizontal posture to detect fluid responsiveness , so that this method should be considered as a standard.
![Page 47: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/47.jpg)
• A real-time measurement able to track hemodynamic changes in the time frame of PLR effects, i.e., 30–90 s, must be used. Indeed, the increase in cardiac output during PLR is not sustained when the leg elevation is prolonged.
• Effects < 30 sec.. Not more than 4 minutes
This aspect is particularly true in septic patients in whom capillary leak may account for an attenuation of the PLR effects after one minute
![Page 48: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/48.jpg)
This is why clinical studies that have tested the value of PLR to predict volume responsiveness used real-time hemodynamic measurements, such as
Aortic blood flow measured by esophageal doppler,
Pulse contour analysis-derived cardiac output,
Cardiac output measured by bio reactance or endotrachealbioimpedance cardiography ,
Subaortic blood velocity measured by echocardiography,
Ascending aortic velocity measured by suprasternal doppler
End-tidal carbon dioxide---more recently
![Page 49: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/49.jpg)
Limitations:
• Its effects cannot be assessed by observing the arterial pressure. Because arterial pulse pressure is only a rough surrogate of stroke volume.
• It needs more direct estimation of cardiac output.
• Not be used when mobilizing the patient is difficult e. G., In the operating room or in the case of head injury
![Page 50: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/50.jpg)
![Page 51: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/51.jpg)
How to assess the response to volume expansion?Effects of volume expansion on cardiac output
What is expected from fluid administration is a significant increase in cardiac output.
In this regard, it has been recently shown that changes in arterial pressure are relatively imprecise to estimate the effects of fluid infusion on cardiac output
In 228 patients who received a standardized saline infusion, fluid-induced changes in arterial pulse pressure were weakly correlated with the simultaneous changes in cardiac output (r = 0.56). Consequently, the changes in pulse pressure induced by volume expansion detected a positive response to fluid (i. e., an increase in cardiac output ≥ 15 %) with a specificity of 85 % but with a sensitivity of only 65 %; in other words, 20 % of cases were false negatives, meaning that in these patients, fluid administration significantly increased cardiac output whereas the arterial pulse pressure did not change to a large extent
![Page 52: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/52.jpg)
These results are explained by the fact that arterial pulse pressure is physiologically related to stroke volume but also inversely correlated with arterial compliance , which may differ among patients and may change over time in the same patient.
Moreover, the proportionality between pulse pressure and stroke volume is physiologically expected at the aortic level, but not at the peripheral arterial level because of the pulse wave amplification phenomenon.
![Page 53: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/53.jpg)
Another important point emphasized by the above cited studies, is that the fluid-induced changes in cardiac output are not reflected at all by the fluid-induced changes in mean arterial pressure (MAP).
Physiologically, the changes in MAP are dissociated from the changes in cardiac output because of the sympathetic modulation of the arterial tone, which tends to maintain MAP constant while cardiac output varies.
These results suggest that precise assessment of the effects of volume expansion should not rely on simple blood pressure measurements but should rather be based on direct measurements of cardiac output.
![Page 54: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/54.jpg)
The analysis of respiratory variation in stroke volume has received the largest level of evidence, but cannot be used in cases of
1. Spontaneous breathing activity, 2. Cardiac arrhythmias, 3. Low tidal volume or 4. Low lung compliance.
Some more recently developed tests, such as the end-expiratory occlusion test, the ‘mini’ fluid challenge and the PLR test can be used as alternative methods, solving the problem of prediction of volume responsiveness in cases of spontaneous breathing activity and/or cardiac arrhythmias
![Page 55: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/55.jpg)
Marik et al. Annals of Intensive Care 2011, 1:1
![Page 56: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/56.jpg)
![Page 57: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/57.jpg)
![Page 58: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/58.jpg)
Key principles of hemodynamic monitoring
• Principle 1: no hemodynamic monitoring technique can improve outcome by itself
• Principle 2: monitoring requirements may vary over time and can depend on local equipment availability and training
• Principle 3: there are no optimal hemodynamic values that are applicable to all patients
![Page 59: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/59.jpg)
• Principle 4: we need to combine and integrate variables
![Page 60: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/60.jpg)
Relationship between CO, SvO2 & O2delivery
• O2 delivery CO
• Since O2 extraction by peripheral tissues is independent of
O2 delivery,
CO SvO2
Cardiac Output SvO2
25% extraction in peripheral tissues
100% saturatedArterial blood
75% saturation of venous blood
SvO2 - global index of tissue oxygenation
Principle 5: measurements of SvO2 can be helpful
![Page 61: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/61.jpg)
Limitations of SvO2
• SvO2 may be normal in presence of tissue hypoxia & anaerobic metabolism Sr. lactate
• SvO2 may be normal in presence of requirement of O2
in tissues if there is maldistribution of blood flow shunts in ESLD
• SvO2 may be normal OR high if tissues are not able to extract O2 from arterial blood ( severe sepsis)
![Page 62: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/62.jpg)
SvO2 Vs ScvO2
• Though SvO2 is more appropriate guide to early resuscitation of critically ill pts, it is practically not justifiable to place a PAC in all pts for obtaining a blood sample to measure SvO2
• More convenient to measure ScvO2 from central venous blood
• Studies have shown that ScvO2 > SvO2 & hence not a true representative of global tissue oxygenation
• ScvO2 is 5 – 7% > SvO2
![Page 63: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/63.jpg)
![Page 64: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/64.jpg)
• Principle 6: a high cardiac output and a high SvO2 are not always best
• Principle 7: cardiac output is estimated, not measured
• Principle 8: monitoring hemodynamic changes over short periods of time is important
This assessment of hemodynamic variations observed during the challenge of the cardiovascular system has been termed ‘functional hemodynamic monitoring’. Combining measures of multiple variables and their dynamic interactions in response to time and specific treatments often increases the sensitivity and specificity of these monitoring modalities to identify specific disease processes and quantify whether therapy is effective or not.
![Page 65: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/65.jpg)
• Principle 9: continuous measurement of all hemodynamic variables is preferable
• Principle 10: non-invasiveness is not the only issue
![Page 66: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/66.jpg)
MEASURING CARDIAC OUTPUT
The Fick Principle
Invasive methods• Pulmonary artery thermodilution (trans-right-heart thermodilution)• Pulse Pressure (PP) methods
• Calibrated PP – PiCCO, LiDCO• Non-calibrated PP - Statistical analysis of Arterial Pressure — FloTrac / Vigileo• Uncalibrated, pre-estimated demographic data-free — PRAM
Minimally invasive methods• Doppler ultrasound method• Echocardiography• Transcutaneous Doppler: USCOM• Transoesophageal Doppler: TOD
![Page 67: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/67.jpg)
Non-invasive methods• Pulse Pressure methods
• Non-invasive PP – Sphygmomanometry and Tonometry• Finapres methodology
• Impedance cardiography• Ultrasound dilution method• Electrical Cardiometry• Magnetic Resonance Imaging
MEASURING CARDIAC OUTPUT
![Page 68: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/68.jpg)
![Page 69: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/69.jpg)
ACCURACY AND PRECISION OF CARDIAC OUTPUT MEASUREMENTS
![Page 70: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/70.jpg)
Critical Care 2013, 17:208
![Page 71: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/71.jpg)
Ramsingh et al. Critical Care 2013, 17:208
![Page 72: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/72.jpg)
Finally……………………..
‘Finally, no monitoring tool, no matter how accurate, by itself
has improved patient outcome’ Michael Pinsky and Didier Payen
![Page 73: fluid optimization concept based on dynamic parameters of hemodynamic monitoring](https://reader030.vdocuments.site/reader030/viewer/2022032421/55a73f5c1a28ab0d748b460c/html5/thumbnails/73.jpg)
Thank you