Oxygen delivery in the pediatric surgical patient

Support of oxygen delivery (DO2) is central to the care of the critically ill. Whether through interventions designed to correct deviations in cardiac output, oxygenation, or hemoglobin content, the overall therapeutic goal is to maintain perfusion and oxygen delivery to the tissues. In normal animals and humans, there is a biphasic relationship between oxygen consumption (VO2) and delivery in which VO2 remains stable as long as sufficient oxygen is delivered. If oxygen delivery is reduced below a critical value (DO2 crit), then oxygen consumption decreases. The mixed venous oxygen saturation serves as an excellent monitor of the adequacy of oxygen delivery in relation to oxygen consumption. As discussed in this review, controversy exists as to whether such VO2/DO2 relationships exist in patients with sepsis or the adult respiratory distress syndrome.