Should we use central venous saturation to guide management in high-risk surgical patients?

Measurements of central venous oxygen saturation (ScvO₂) have been successfully used to guide haemodynamic therapy in critical care. The efficacy of this approach in the treatment of severe sepsis and septic shock has stimulated interest in the use of ScvO₂ to guide management in patients undergoing major surgery. The physiological basis of ScvO₂ measurement is complex. A number of outstanding issues will need to be resolved before incorporating ScvO₂ measurement into routine practice. First, it is not yet clear which value of ScvO₂ should be targeted. Second, there is some uncertainty as to which interventions are the most effective for achieving the desired value of ScvO₂ or how long this value should be maintained. The study by The Collaborative Study Group on Perioperative ScvO₂ Monitoring published in this edition of Critical Care may help provide answers to some of these questions. Our understanding of ScvO₂ measurement remains limited, however, and the routine use of peri-operative ScvO₂-guided goal-directed therapy cannot be recommended until a large randomised trial has confirmed the value of this approach.