Editing Cardiac output (section)

==Related measurements==

===Ejection fraction===
[[Ejection fraction]] (EF) is a parameter related to SV. EF is the fraction of blood ejected by the left ventricle (LV) during the contraction or ejection phase of the cardiac cycle or [[systole]]. Prior to the start of systole, during the filling phase ([[diastole]]), the LV is filled with blood to the capacity known as end diastolic volume (EDV). During systole, the LV contracts and ejects blood until it reaches its minimum capacity known as end systolic volume (ESV). It does not completely empty. The following equations help translate the effect of EF and EDV on cardiac output Q, via SV.
{{NumBlk2|::|<math>
\begin{align}
SV &= EDV - ESV \\
EF &= \frac{SV}{EDV} \times 100\% \\
Q &= SV \times HR \\
  &= \frac{EF \times EDV \times HR}{100\%}
\end{align}
</math>|3}}

===Cardiac input===
Cardiac input (CI) is the inverse operation of cardiac output. As cardiac output implies the volumetric expression of ejection fraction, cardiac input implies the volumetric [[injection fraction]] (IF).

IF = end diastolic volume (EDV) / end systolic volume (ESV)

{{Clarify|reason = Perhaps missing a preposition|text = Cardiac input is a readily imaged mathematical model of diastole.|date=June 2015}}

=== Cardiac index ===
{{See also|Cardiac index}}
In all resting mammals of normal mass, CO value is a linear function of body mass with a slope of 0.1 L/(min kg).<ref name="milnor">WR Milnor: Hemodynamics, Williams & Wilkins, 1982{{ISBN?}}{{page?|date=August 2021}}</ref><ref name="hembook">BB Sramek: Systemic Hemodynamics and Hemodynamic Management, 2002, {{ISBN|1-59196-046-0}}{{page?|date=August 2021}}</ref> Fat has about 65% of oxygen demand per mass in comparison to other lean body tissues. As a result, the calculation of normal CO value in an obese subject is more complex; a single, common "normal" value of SV and CO for adults cannot exist. All blood flow parameters have to be indexed. It is accepted convention to index them by the body surface area, BSA [m<sup>2</sup>], by DuBois & DuBois Formula, a function of height and weight:

<math display="block">BSA_\mathrm{[m^2]} = W^{0.425}_\mathrm{[kg]} \times H^{0.725}_\mathrm{[cm]} \times 0.007184</math>

The resulting indexed parameters are stroke index (SI) and cardiac index (CI). Stroke index, measured in mL/beat/m<sup>2</sup>, is defined as

<math display="block">SI_\mathrm{[mL/beat/{m}^2]} = \frac{SV_\mathrm{[mL]}}{BSA_\mathrm{[m^2]}}</math>

Cardiac index, measured in L/(min m<sup>2</sup>), is defined as<math display="block">CI_\mathrm{[L/min/{m}^2]} = \frac{CO_\mathrm{[L/min]}}{BSA_\mathrm{[{m}^2]}}</math>

The CO equation ({{EquationNote|1}}) for indexed parameters then changes to the following.{{NumBlk2|:|<math>CI_\mathrm{[L/min/{m}^2]} = ( SI_\mathrm{[mL/beat/{m}^2]} \times HR_\mathrm{[bpm]} ) / 1000</math>|2}}The normal range for these indexed blood flow parameters are between 35 and 65 mL/beat/m<sup>2</sup> for SI and between 2.5 and 4 L/(min m<sup>2</sup>) for CI.<ref>{{Cite web|url=https://www.nursingcenter.com/ncblog/december-2016-(1)/cardiac-output-and-cardiac-index-%E2%80%93-what-s-the-diff|title=Cardiac Output and Cardiac Index – What's the difference?|date=13 December 2016|access-date=14 December 2018|archive-date=16 December 2018|archive-url=https://web.archive.org/web/20181216031953/https://www.nursingcenter.com/ncblog/december-2016-(1)/cardiac-output-and-cardiac-index-%E2%80%93-what-s-the-diff|url-status=live}}</ref>

===Combined cardiac output===
Combined cardiac output is the sum of the outputs of the right and left sides of the heart. It is a useful measurement in [[fetal circulation]], where cardiac outputs from both sides of the heart work partly in parallel by the [[Foramen ovale (heart)|foramen ovale]] and [[ductus arteriosus]], which directly supply the [[systemic circulation]].<ref name=boron1197>{{cite book | first = Walter F. | last = Boron | name-list-style = vanc |title=Medical Physiology: A Cellular And Molecular Approaoch |publisher=Elsevier/Saunders |year=2003 |page=1197 |isbn=978-1-4160-2328-9 }}{{page?|date=August 2021}}</ref>