Which of the following statements about delivery-dependent oxygen consumption are true?

B. D(overdot)O 2crit may be increased in patients with sepsis.

C. A desirable goal in the treatment of shock is to achieve delivery-independent oxygen consumption

DISCUSSION: Oxygen consumption is said to be delivery dependent below a critical point, D(overdot)O 2crit, at which anaerobic metabolism supervenes. Above this point, oxygen consumption is relatively independent of oxygen delivery because the body's cells can compensate for falls in oxygen delivery by extracting more oxygen. In the delivery-dependent region, if cellular hypoxia is present, the lactate-pyruvate ratio rises, owing to the switch to anaerobic metabolism. Generally, it is desirable to achieve delivery-independent oxygen consumption, to avoid ongoing tissue hypoxia. There is considerable debate, however, about the nature of the oxygen consumption–oxygen delivery relationship in cases of established sepsis or multiple organ dysfunction syndrome. In such cases, D(overdot)O 2crit may be increased, although the therapeutic benefit of trying to achieve “supranormal” oxygen delivery has not been firmly established.