If cardiac output doubles while CaO2 remains constant, what happens to oxygen delivery (DO2)?

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Multiple Choice

If cardiac output doubles while CaO2 remains constant, what happens to oxygen delivery (DO2)?

Oxygen delivery depends on two factors: how much blood is flowing each minute (cardiac output) and how much oxygen each milliliter of blood can carry (CaO2). If the amount of oxygen carried per unit of blood stays the same, delivering more blood per minute means more oxygen delivered per minute. So when cardiac output doubles, DO2 doubles as well, since DO2 = CO × CaO2 and CaO2 is constant. In other words, the system simply scales with flow when the oxygen content of the blood doesn’t change.

Oxygen delivery depends on two factors: how much blood is flowing each minute (cardiac output) and how much oxygen each milliliter of blood can carry (CaO2). If the amount of oxygen carried per unit of blood stays the same, delivering more blood per minute means more oxygen delivered per minute. So when cardiac output doubles, DO2 doubles as well, since DO2 = CO × CaO2 and CaO2 is constant. In other words, the system simply scales with flow when the oxygen content of the blood doesn’t change.

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