Oxygen transport goals in the resuscitation of critically ill patients

OBJECTIVE: To discuss the limitations of conventional monitoring techniques of shock and examine more recent monitoring techniques that are used to titrate therapies to attain supranormal oxygen transport goals. DATA SOURCES: Review articles and investigations published since 1973. STUDY SELECTION: Articles were selected if they examined the monitoring or treatment of shock. Emphasis was placed on finding investigations involving humans that used innovative methods to assess and treat inadequate tissue perfusion. DATA EXTRACTION: Data were extracted primarily from original investigations and review articles published in or translated into English. DATA SYNTHESIS: The conventional monitoring of shock often fails to detect inadequate tissue perfusion, which may lead to inadequate resuscitation of patients, resulting in increased morbidity and mortality. Attainment of supranormal values for oxygen transport variables has been associated with improved outcomes, especially in patients with hypovolemic shock or septic shock. Additionally, interventions used to increase these variables to supranormal values have resulted in improved survival in high-risk preoperative patients with hypovolemic or septic shock, but not in severely ill postoperative patients with multiple complications. CONCLUSIONS: Efforts to increase oxygen transport variables to supranormal values cannot be recommended routinely for all critically ill patients. Preoperative patients in early stages of hypovolemic or septic shock may benefit from therapies titrated to achieve supranormal goals, but patients in later stages of illnesses may be harmed by such attempts. Questions remain regarding how quickly and how long the oxygen transport variables should be elevated. The most effective and least toxic therapeutic interventions for increasing the variables need to be determined.