Cardiac output

這是什麼

Cardiac output is the blood flow the heart delivers in one minute: cardiac output = heart rate x stroke volume. It rises when the heart makes more effective beats per minute or ejects more blood per beat, and it falls when effective beats or per-beat ejection are too low.^[1,2]

為什麼重要

For arterial pressure and organ perfusion, cardiac output is the pump-side input flow. It pushes blood into the arterial tree; outlet resistance, arterial stiffness, and tissue demand help decide how that flow becomes pressure and perfusion.^[6,1]

發生異常的根本原因

• Core relation: Cardiac output = heart rate x stroke volume; more effective beats per minute, or more blood ejected per beat, raises pump flow, while too few effective beats or too little ejected blood per beat lowers it.^[1,2]
  Heart rate and rhythmStroke volume
• Per-beat volume: Stroke volume changes with how much blood fills the ventricle, how strongly the heart muscle contracts, and how much outlet load it must push against.^[2,3]
  Stroke volumeCardiac preloadVenous returnCirculating blood volumeMyocardial contractilityCardiac afterload
• Normal context: A typical resting adult cardiac output is often around 5 L/min for a 70 kg person, but body size and metabolic demand matter; cardiac index divides cardiac output by body surface area so different-sized people can be compared.^[4,5]
  Cardiac index
• Measurement boundary: Blood pressure, pulse, or a wearable estimate does not by itself measure personal cardiac output; actual assessment depends on clinical context and hemodynamic measurement methods.^[1,5]

它會影響哪些判斷

• It connects pump flow, heart rate, stroke volume, vascular resistance, blood pressure, venous return, organ perfusion, shock, and heart-failure context.^[1]

解讀陷阱

• BioConst uses cardiac output as a mechanism node. It cannot infer a person's cardiac output from one blood-pressure or pulse reading.^[1]

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