The oxygen trail: the goal.

Over the last 10 years, there have been great advances in knowledge concerning changes in tissue perfusion and its prognostic implications. Has this translated into improved patient management? We review the clinical trials that have deliberately increased tissue oxygen delivery by increasing cardiac output. We have divided the studies into those that intervene early or those that intervene late in the course of a patient's illness. Although there are methodological problems limiting interpretation of the results, we show a combined odds ratio of a reduction in mortality for the early studies but not for the late studies. We conclude that a treatment policy whereby oxygen delivery is deliberately increased improves patient outcome if it is initiated early, prior to the onset of organ failure.