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Inotropy Index accurately predictsInotropy Index accurately predictsfluid responsiveness in volumefluid responsiveness in ...
Introduction.Introduction.Inotropy (myocardial contractility) as aInotropy (myocardial contractility) as a conceptconcept ...
Volume ResuscitationVolume ResuscitationIs practiced every day in every ED in the worldIs practiced every day in every ED ...
Preload Inotropy AfterloadPreload Inotropy AfterloadWhy is inotropy so important?Why is inotropy so important?BP = SVR x H...
Initially, a fall in SVR or in CO can be compensated by anInitially, a fall in SVR or in CO can be compensated by anincrea...
Total Inotropy = PE + KE( = blood pressure + blood flow)Inotropy = BPm x SV x 10Inotropy = BPm x SV x 10-3-3++ 1 x SV x 10...
Inotropy IndexInotropy IndexBut how do we judge inotropy in patients of varying size,But how do we judge inotropy in patie...
Clinical ObservationClinical ObservationThe response of patients to volume loading isThe response of patients to volume lo...
Starling Curves and Inotropy IndexStarling Curves and Inotropy IndexLeft ventricular end diastolic volumeLeft ventricular ...
Patient Selection.Patient Selection.Convenience sample of 41 adult patientsConvenience sample of 41 adult patientsadmitted...
Shock Criteria – any 3 ofShock Criteria – any 3 ofHypotensionHypotensionTachycardiaTachycardiaImpaired Cerebral FunctionIm...
ObserverObserverObserver was not involved in clinicalObserver was not involved in clinicaldecision making – collected data...
Data collectedData collected1) Blood pressure1) Blood pressure- prior to any iv fluid then at 15 minute intervals using- p...
3) Cardiac Output3) Cardiac Output- measured by observer using ultrasonic cardiac- measured by observer using ultrasonic c...
5) SM Inotropy Index5) SM Inotropy Index- Retrospectively calculated from the USCOM- Retrospectively calculated from the U...
Exit Criteria.Exit Criteria.Data collection ceased when patient judged toData collection ceased when patient judged tobe a...
Data AnalysisData AnalysisThe dataThe data were analysed using SPSS v16 softwarewere analysed using SPSS v16 softwareusing...
HypovolaemiaHypovolaemia21 Patients were judged to have absolute hypovolaemia.21 Patients were judged to have absolute hyp...
Successful Outcome.Successful Outcome.Positive response to volume resuscitationPositive response to volume resuscitationwa...
Hypovolaemia (n = 21)Hypovolaemia (n = 21)+ve response+ve response -ve response-ve responseBlood lossBlood loss 66 00Fluid...
Septicaemia (n = 12)Septicaemia (n = 12)+ve response+ve response -ve response-ve responseN =N = 44 88Mean SMIIMean SMII 1....
Mixed Pattern (n = 8)Mixed Pattern (n = 8)+ve response+ve response -ve response-ve responseN =N = 44 44Mean SMIIMean SMII ...
All Patients (n = 41)All Patients (n = 41)n =n = +ve+ve -ve-veSMII > 1.1SMII > 1.1 2424 2222 22SMII <1.1SMII <1.1 1717 11 ...
First SMIIFirst SMII%%ΔΔCOCO
ConclusionsConclusionsInitial SMII measurement accurately predicts patientInitial SMII measurement accurately predicts pat...
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Inotropy Index and Volume responsiveness

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Inotropy Index accurately predicts fluid responsiveness in volume resuscitation.
Brendan E. Smith and Veronica M. Madigan
School of Biomedical Science,
Charles Sturt University, Bathurst, NSW, Australia.
Specialist in Anaesthesia and Intensive Care,
Bathurst Base Hospital, Bathurst, NSW, Australia.

Published in: Health & Medicine, Technology
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Inotropy Index and Volume responsiveness

  1. 1. Inotropy Index accurately predictsInotropy Index accurately predictsfluid responsiveness in volumefluid responsiveness in volumeresuscitation.resuscitation.Brendan E. SmithBrendan E. Smith1,21,2and Veronica M. Madiganand Veronica M. Madigan1111School of Biomedical Science,School of Biomedical Science,Charles Sturt University, Bathurst, NSW, Australia.Charles Sturt University, Bathurst, NSW, Australia.22Specialist in Anaesthesia and Intensive Care,Specialist in Anaesthesia and Intensive Care,Bathurst Base Hospital, Bathurst, NSW, Australia.Bathurst Base Hospital, Bathurst, NSW, Australia.
  2. 2. Introduction.Introduction.Inotropy (myocardial contractility) as aInotropy (myocardial contractility) as a conceptconcept is wellis wellknown to all clinicians but not as aknown to all clinicians but not as a discrete quantitydiscrete quantity..Depressed inotropy is an important feature of many EDDepressed inotropy is an important feature of many EDpresentations –presentations –11ooCardiac Conditions – AMI, LVF, CardiomyopathyCardiac Conditions – AMI, LVF, Cardiomyopathy22ooMyocardial Depression – Septicaemia, Pancreatitis,Myocardial Depression – Septicaemia, Pancreatitis,Pneumonia, DKA, Burns, Hypoxia, Crush Injury,Pneumonia, DKA, Burns, Hypoxia, Crush Injury,Hypovolaemia, Anaemia, Thyroid Disorders,Hypovolaemia, Anaemia, Thyroid Disorders,Hyper + Hypothermia, Poisoning,Hyper + Hypothermia, Poisoning, Evenomation,Evenomation,Iatrogenic e.g. Antihypertensives, Chemotherapy,Iatrogenic e.g. Antihypertensives, Chemotherapy,Electrolyte Disorders, Steroids, ……Electrolyte Disorders, Steroids, ……
  3. 3. Volume ResuscitationVolume ResuscitationIs practiced every day in every ED in the worldIs practiced every day in every ED in the worldin a wide range of conditions!in a wide range of conditions!What they all have in common is that whatWhat they all have in common is that whatwe are trying to do is either :-we are trying to do is either :-1)1) Increase Blood PressureIncrease Blood Pressure2) Increase Cardiac Output2) Increase Cardiac Outputi.e. increase Blood Flowi.e. increase Blood Flow
  4. 4. Preload Inotropy AfterloadPreload Inotropy AfterloadWhy is inotropy so important?Why is inotropy so important?BP = SVR x HR x SV : SV x HR = COBP = SVR x HR x SV : SV x HR = COFluid loadingFluid loading
  5. 5. Initially, a fall in SVR or in CO can be compensated by anInitially, a fall in SVR or in CO can be compensated by anincreased Cardiac Output or SVR which maintains BP,increased Cardiac Output or SVR which maintains BP,thethe compensated phasecompensated phase..But this process cannot go on forever! Eventually, the heartBut this process cannot go on forever! Eventually, the heartcannot increase CO further or the circulation cannot increasecannot increase CO further or the circulation cannot increaseSVR further and BP will fall.SVR further and BP will fall.This is theThis is the decompensated phasedecompensated phase..The point at which this occurs depends on theThe point at which this occurs depends on the cardiaccardiacreservereserve, which in turn depends on, which in turn depends on preloadpreload availability and onavailability and oninotropyinotropy..
  6. 6. Total Inotropy = PE + KE( = blood pressure + blood flow)Inotropy = BPm x SV x 10Inotropy = BPm x SV x 10-3-3++ 1 x SV x 101 x SV x 10-6-6xx ρρ x Vx V227.5 x FT7.5 x FT 2 x FT2 x FT(The Smith-Madigan Formula)(The Smith-Madigan Formula)The SI unit of inotropy is the WattThe SI unit of inotropy is the Watt
  7. 7. Inotropy IndexInotropy IndexBut how do we judge inotropy in patients of varying size,But how do we judge inotropy in patients of varying size,e.g. large and small adults, children, infants?e.g. large and small adults, children, infants?By analogy to cardiac index which is –By analogy to cardiac index which is –Cardiac Index = Cardiac OutputCardiac Index = Cardiac OutputBody Surface AreaBody Surface AreaSmith-Madigan Inotropy Index = InotropySmith-Madigan Inotropy Index = InotropyBSABSAThe SI unit of SMII is therefore W/mThe SI unit of SMII is therefore W/m22
  8. 8. Clinical ObservationClinical ObservationThe response of patients to volume loading isThe response of patients to volume loading isvariable, from a good response to littlevariable, from a good response to littleor even no response at all.or even no response at all.Why is this so?Why is this so?Could it be due to variations in inotropy indexCould it be due to variations in inotropy indexaffecting volume responsiveness?affecting volume responsiveness?
  9. 9. Starling Curves and Inotropy IndexStarling Curves and Inotropy IndexLeft ventricular end diastolic volumeLeft ventricular end diastolic volumeStrokeStrokeVolumeVolumeΔΔSVSVinotropyinotropySMII = 0.8SMII = 0.8
  10. 10. Patient Selection.Patient Selection.Convenience sample of 41 adult patientsConvenience sample of 41 adult patientsadmitted to ED with diagnosis of non-admitted to ED with diagnosis of non-cardiogenic shock where volume expansioncardiogenic shock where volume expansionwas to be used.was to be used.
  11. 11. Shock Criteria – any 3 ofShock Criteria – any 3 ofHypotensionHypotensionTachycardiaTachycardiaImpaired Cerebral FunctionImpaired Cerebral FunctionPoor Peripheral PerfusionPoor Peripheral PerfusionCold and Clammy SkinCold and Clammy Skin
  12. 12. ObserverObserverObserver was not involved in clinicalObserver was not involved in clinicaldecision making – collected data only.decision making – collected data only.
  13. 13. Data collectedData collected1) Blood pressure1) Blood pressure- prior to any iv fluid then at 15 minute intervals using- prior to any iv fluid then at 15 minute intervals usingautomated oscillotonometry or arterial line when presentautomated oscillotonometry or arterial line when present2) Heart Rate2) Heart Rate- prior to any iv fluid then at 15 minute intervals from ECG- prior to any iv fluid then at 15 minute intervals from ECG
  14. 14. 3) Cardiac Output3) Cardiac Output- measured by observer using ultrasonic cardiac- measured by observer using ultrasonic cardiacoutput monitor (USCOM) from suprasternal notchoutput monitor (USCOM) from suprasternal notchprior to iv fluid and then every 15 minutesprior to iv fluid and then every 15 minutes4) Cerebral Function - On four point scale4) Cerebral Function - On four point scalea) Normal (A = “alert”)a) Normal (A = “alert”)b) Slightly impaired (B = “blunted”)b) Slightly impaired (B = “blunted”)c) Confused (C = “confused”)c) Confused (C = “confused”)d) Insensible (D = “doolally”)d) Insensible (D = “doolally”)
  15. 15. 5) SM Inotropy Index5) SM Inotropy Index- Retrospectively calculated from the USCOM- Retrospectively calculated from the USCOMreadings, BP and Hb from the Smith-Madigan Formulareadings, BP and Hb from the Smith-Madigan Formulafor each 15 minute observation.for each 15 minute observation.
  16. 16. Exit Criteria.Exit Criteria.Data collection ceased when patient judged toData collection ceased when patient judged tobe adequately resuscitated by ED staff orbe adequately resuscitated by ED staff orwhen transferred to ICU or other facility.when transferred to ICU or other facility.
  17. 17. Data AnalysisData AnalysisThe dataThe data were analysed using SPSS v16 softwarewere analysed using SPSS v16 softwareusing Analysis of Variance, Chi square, Fisher’s exactusing Analysis of Variance, Chi square, Fisher’s exacttest, Regression Analysis and Pearson and Spearmantest, Regression Analysis and Pearson and SpearmanCorrelations.Correlations.
  18. 18. HypovolaemiaHypovolaemia21 Patients were judged to have absolute hypovolaemia.21 Patients were judged to have absolute hypovolaemia.6 due to whole blood loss6 due to whole blood loss15 due to fluid loss / dehydration15 due to fluid loss / dehydration12 Patients had relative hypovolaemia due to septicaemia.12 Patients had relative hypovolaemia due to septicaemia.8 Patients had a mixed pattern of hypovolaemia.8 Patients had a mixed pattern of hypovolaemia.
  19. 19. Successful Outcome.Successful Outcome.Positive response to volume resuscitationPositive response to volume resuscitationwas taken as an increase in mean arterialwas taken as an increase in mean arterialpressure or cardiac output of 10% or morepressure or cardiac output of 10% or morefollowing =>20ml/kg of fluid.following =>20ml/kg of fluid.
  20. 20. Hypovolaemia (n = 21)Hypovolaemia (n = 21)+ve response+ve response -ve response-ve responseBlood lossBlood loss 66 00Fluid loss /Fluid loss / 99 66DehydrationDehydrationMean SMIIMean SMII 1.481.48 0.840.84RangeRange (1.28 – 1.72)(1.28 – 1.72) (0.68 – 1.15)(0.68 – 1.15)p =p = 0.0020.002
  21. 21. Septicaemia (n = 12)Septicaemia (n = 12)+ve response+ve response -ve response-ve responseN =N = 44 88Mean SMIIMean SMII 1.361.36 0.970.97RangeRange (1.21 – 1.49)(1.21 – 1.49) (0.63 –(0.63 –1.04)1.04)p =p = 0.020.02
  22. 22. Mixed Pattern (n = 8)Mixed Pattern (n = 8)+ve response+ve response -ve response-ve responseN =N = 44 44Mean SMIIMean SMII 1.311.31 0.910.91RangeRange (1.07 – 1.52)(1.07 – 1.52) (0.73 –(0.73 –1.15)1.15)p =p = 0.0650.065
  23. 23. All Patients (n = 41)All Patients (n = 41)n =n = +ve+ve -ve-veSMII > 1.1SMII > 1.1 2424 2222 22SMII <1.1SMII <1.1 1717 11 1616p =p = <0.001<0.001
  24. 24. First SMIIFirst SMII%%ΔΔCOCO
  25. 25. ConclusionsConclusionsInitial SMII measurement accurately predicts patientInitial SMII measurement accurately predicts patientresponsiveness in volume resuscitation.responsiveness in volume resuscitation.Initial SMII values below 1.1 W/mInitial SMII values below 1.1 W/m22are associated withare associated witha poor response to iv fluid in 94% of cases.a poor response to iv fluid in 94% of cases.Initial SMII values below 1.1 W/mInitial SMII values below 1.1 W/m22may indicate themay indicate theearly use of inotropes in volume resuscitation.early use of inotropes in volume resuscitation.

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