Editing Cardiac output (section)

=== 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>