Cardiac Output

Aka: Cardiac Output, Cardiac Index, Stroke Volume, Stroke Index, Clinical Assessment of Cardiac Output, Cardiac Function

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II. Definitions

  1. Cardiac Output (CO)
    1. Quantity of blood pumped per minute through the aorta and into the peripheral circulation
    2. Cardiac Output is proportional to (arterialPressure / totalPeripheralResistance)
    3. CO = SV * HR
      1. Where SV = Stroke Volume
      2. Where HR = Heart Rate
    4. Normal Adult
      1. Range: 4-8 L/min (typical 70 kg male = 5.25 L/min)
  2. Cardiac Index (CI)
    1. Average stroke output of heart per minute (Cardiac Output) adjusted for body surface area
    2. CI=CO/BSA
      1. Where CO = Cardiac Output
      2. Where BSA = Body Surface Area
    3. Normal Adult
      1. Range: 2.4 - 4 L/min/m2 (60% of csardiac output in the normal, average sized adult)
  3. Stroke Volume (SV)
    1. Volume of blood pumped from the heart in one cycle of diastole and systole
    2. Stroke Volume is affected by Preload, contractility and Afterload
    3. SV = EDV - ESV
      1. Where EDV = End-diastolic volume
      2. Where ESV = End-systolic volume
    4. Normal Adult
      1. Range: 55-100 ml (typical 70 kg male = 70 ml)
  4. Stroke Index (SI)
    1. Average stroke output of heart per cycle (Stroke Volume) adjusted for body surface area
    2. SI = CI/HR
      1. Where CI = Stroke Index
      2. Where HR = Heart Rate
    3. Normal Adult
      1. Range: 20-40 ml/m2
  5. Ejection Fraction (EF)
    1. Reflects the percentage of blood ejected from the ventricle
    2. EF = SV/EDV
      1. Where SV = Stroke Volume
      2. Where EDV = End-diastolic volume
    3. Normal Adult
      1. Left Ventricular Ejection Fraction (LVEF): 55-70%

III. Images

  1. Cardiac Cycle Volumes and Pressures (Wiggers Diagram)
    1. cvCardiacCycleWiggers.png

IV. Physiology

  1. Stroke Volume components
    1. Ventricular Preload (based on venous return of Circulatory Volume and ventricular compliance)
      1. End-diastolic volume (EDV)
      2. Increases Cardiac Output in the normal heart
      3. Results in Fluid Overload and third spacing in Congestive Heart Failure
    2. End-systolic volume (ESV) depends on ejection fraction (percentage of EDV ejected from left ventricle)
      1. Ventricular Contractality
        1. Force of ventricular contraction or inotropy
        2. Increased contractility increases Stroke Volume and Cardiac Output
      2. Ventricular Afterload (systemic Blood Pressure)
        1. Force against which the left ventricle pumps
        2. Increased Afterload decreases Stroke Volume and Cardiac Output
  2. Cardiac Output components
    1. Product of Heart Rate and Stroke Volume
    2. Heart Rate is the first compensatory mechanism to increase Oxygen Delivery to the tissues
    3. Heart is most efficient with lower Heart Rate and higher Stroke Volume
  3. Myocardial Oxygen Demand
    1. Oxygen requirements increase with venticular Muscle wall tension
    2. Ventricular Muscle wall tension is related to Ventricular Preload and Ventricular Afterload
      1. Ventricular Preload is the increasing ventricular wall tension that increases with ventricular filling
      2. Ventricular Afterload is the constant tension in ventricular Muscle as it contracts and shortens
    3. Wall tension increases with ventricular volume (ventricular radius) and ventricular pressure (Afterload)
      1. Laplace Equation = Tension (T) = Pr
      2. where P = ventricular pressure (Ventricular Afterload)
      3. where r = ventricular radius
  4. Mediators of Cardiac Output
    1. Positive Inotropes increase contractility
    2. Positive Chronotropes increase Heart Rate
    3. Positive Dromotropes increase cardiac conduction velocity

V. Diagnostics: Clinical Assessment of Cardiac Output (and SV, Preload, Afterload and Contractility)

  1. Heart Rate and rhythm
    1. Palpated pulse
    2. Pulse Oximetry
    3. Telemetry or Electrocardiogram
  2. Right Ventricular Preload
    1. Central Venous Pressure
    2. IVC Ultrasound for Volume Status (Caval Aorta Index)
  3. Left Ventricular Preload
    1. Symptoms (Orthopnea or Dyspnea on exertion)
    2. Signs (Pulmonary Edema, rales)
    3. Imaging (Lung Ultrasound)
  4. Right Ventricular Afterload
    1. Mean pulmonary artery pressure or wedge pressure
  5. Left Ventricular Afterload
    1. Mean arterial pressure
  6. Cardiac Contractility
    1. Echocardiogram (ejection fraction, Stroke Volume)
  7. Cardiac Output
    1. Pulmonary artery catheter
    2. Arterial catheter (arterial waveform analysis)
    3. Esophageal doppler (descending aorta flow)

VI. Resources

  1. Wikipedia Stroke Volume
    1. http://en.wikipedia.org/wiki/Stroke_volume

VII. References

  1. Goldberg (2014) Clinical Physiology, Medmaster, Miami, p. 49-50
  2. Killu and Sarani (2016) Fundamental Critical Care Support, p. 93-114
  3. Marino (2014) ICU Book, 4th Ed Wolters-Kluwer p. 144-6

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Related Studies

Ontology: Cardiac Output (C0007165)

Definition (MSHCZE) Zkr. MOS – objem krve, který srdce, resp. levá srdeční komora, přečerpá za jednu minutu, minutový srdeční výdej. Běžně cca 5 l za minutu. (cit. Velký lékařský slovník online, 2013 http://lekarske.slovniky.cz/ )
Definition (MSH) The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).
Definition (CSP) volume of blood passing through the heart per unit of time; expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat).
Concepts Clinical Attribute (T201)
MSH D002302
SnomedCT 142252004, 82799009
LNC LP19466-9, MTHU007840
English Cardiac Output, Cardiac Outputs, Output, Cardiac, Outputs, Cardiac, heart output, cardiac output, Cardiac output, CO - Cardiac output, Cardiac output (observable entity), Cardiac output, NOS
Japanese 心拍出量, ｼﾝﾊｸｼｭﾂﾘｮｳ
Swedish Hjärtminutvolym
Spanish volumen minuto, gasto cardíaco (entidad observable), gasto cardíaco, volumen minuto (entidad observable), Gasto cardiaco, Gasto Cardíaco
Czech srdce - minutový objem, Srdeční výdej, minutový objem srdeční
Finnish Sydämen minuuttitilavuus
Russian MINUTNYI OB"EM KROVI, SERDTSA MINUTNYI OB"EM, SERDECHNYI VYBROS, MINUTNYI OB"EM SERDTSA, МИНУТНЫЙ ОБЪЕМ КРОВИ, МИНУТНЫЙ ОБЪЕМ СЕРДЦА, СЕРДЕЧНЫЙ ВЫБРОС, СЕРДЦА МИНУТНЫЙ ОБЪЕМ
Croatian SRČANI MINUTNI VOLUMEN
Polish Pojemność minutowa serca, Rzut minutowy serca, Objętość minutowa serca, CO, Rzut serca
Hungarian Perctérfogat
Norwegian Hjerteminuttvolum
Portuguese Débito cardíaco, Débito Cardíaco
Dutch hartminuutvolume, Cardiac output, Hartminuutvolume
German Herzminutenvolumen, Herzzeitvolumen
French Débit cardiaque
Italian Gittata cardiaca
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Stroke Volume (C0038455)

Definition (MSH) The amount of BLOOD pumped out of the HEART per beat, not to be confused with cardiac output (volume/time). It is calculated as the difference between the end-diastolic volume and the end-systolic volume.
Definition (NCI) The difference in a cardiac ventricle's blood capacity taken at times of minimum and maximum blood content. This is end diastolic volume less end systolic volume.(Dr. Joseph A. Thie)
Concepts Clinical Attribute (T201)
MSH D013318
SnomedCT 90096001
LNC MTHU009148
English Stroke Volume, Stroke Volumes, Volume, Stroke, Volumes, Stroke, Cardiac stroke volume, cardiac stroke volume, stroke volume, SV - Stroke volume, Stroke volume, Stroke volume (observable entity)
Italian Gittata sistolica, Volume eiettivo contrattile
Japanese 一回拍出量, ｲｯｶｲﾊｸｼｭﾂﾘｮｳ
Swedish Slagvolym
Finnish Iskutilavuus
French Volume d'éjection systolique, Débit systolique, VES (Volume d'Éjection Systolique)
Russian KONECHNO-DIASTOLICHESKII OB"EM ZHELUDOCHKOV, FRAKTSIIA IZGNANIIA, SERDTSA UDARNYI OB"EM, KONECHNO-SISTOLICHESKII OB"EM ZHELUDOCHKOVYI, SISTOLICHESKII OB"EM KROVI, КРОВИ УДАРНЫЙ ОБЪЕМ, KROVI UDARNYI OB"EM, КОНЕЧНО-ДИАСТОЛИЧЕСКИЙ ОБЪЕМ ЖЕЛУДОЧКОВ, КОНЕЧНО-СИСТОЛИЧЕСКИЙ ОБЪЕМ ЖЕЛУДОЧКОВЫЙ, СЕРДЦА УДАРНЫЙ ОБЪЕМ, СИСТОЛИЧЕСКИЙ ОБЪЕМ КРОВИ, ФРАКЦИЯ ИЗГНАНИЯ
Czech Tepový objem, puls - objem, pulz - objem
Croatian MOŽDANI UDAR, VOLUMEN
Polish Objętość końcoworozkurczowa, Objętość wyrzutowa, Objętość końcowoskurczowa
Hungarian Lökéstérfogat
Norwegian Slagvolum, Hjertets slagvolum, Hjerteslagvolum
Spanish volumen de eyección, volumen sistólico (entidad observable), volumen sistólico, Volumen sistólico, Volumen Sistólico
Portuguese Volume sistólico, Volume Sistólico
Dutch slagvolume, Slagvolume, Volume, slag-
German Schlagvolumen, Herzschlagvolumen
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Cardiac function (C0232164)

Definition (ICF) Functions of pumping the blood in adequate or required amounts and pressure throughout the body.
Definition (ICF-CY) Functions of pumping the blood in adequate or required amounts and pressure throughout the body.
Definition (CSP) physiological activity and functions of the heart as a whole or of any of its parts, including the contractile activity of the myocardium and hemodynamic and electrophysiological action of the atrium and ventricles that provide for the oxygenation of blood and transportation of blood to the body.
Concepts Organ or Tissue Function (T042)
SnomedCT 86185002
English Heart functions, Heart functions, unspecified, function hearts, functions hearts, cardiac function, cardiac functioning, function heart, heart function, functions heart, cardiac functions, Cardiac function, Cardiac function (observable entity), Cardiac function, NOS, Cardiac function (function)
Spanish función cardíaca (entidad observable), función cardíaca (función), función cardíaca
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Cardiac index (C0428776)

Concepts Finding (T033)
SnomedCT 54993008
Italian Indice cardiaco
Japanese 心指数, ｼﾝｼｽｳ
Czech Srdeční index
English cardiac index, CI - Cardiac index, Cardiac index, Cardiac index (observable entity)
Hungarian Szívindex
Spanish índice cardíaco (entidad observable), índice cardíaco, Índice cardiaco
Portuguese Índice cardíaco
Dutch hartindex
French Index cardiaque
German Herzindex
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Stroke index (C0456712)

Concepts Laboratory or Test Result (T034)
SnomedCT 277381004
English SI - Stroke index, SVI - Stroke index, Stroke index, Stroke index (observable entity)
Spanish índice sistólico (entidad observable), índice sistólico
Derived from the NIH UMLS (Unified Medical Language System)

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