Review
Clinical review: use of venous oxygen saturations as a goal - a yet unfinished puzzle
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* Corresponding author: Paul van Beest p.van.beest@anest.umcg.nl
1 Department of Anaesthesiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen 9700 RB, the Netherlands
2 Department of Intensive Care Medicine, Gelre Hospital Apeldoorn, Albert Schweitzerlaan 31, Apeldoorn 7300 DS, the Netherlands
3 Department of Intensive Care Medicine, Academic Medical Center, Meibergdreef 9, Amsterdam 1105 AZ, the Netherlands
4 HERMES Critical Care Group, Schweitzerlaan 31, Apeldoorn 7300 DS, the Netherlands
5 Department of Intensive Care Medicine, Medical Center Leeuwarden, Henri Dunantweg 2, Leeuwarden 8901 BR, the Netherlands
Critical Care 2011, 15:232 doi:10.1186/cc10351
Published: 24 October 2011Abstract
Shock is defined as global tissue hypoxia secondary to an imbalance between systemic oxygen delivery and oxygen demand. Venous oxygen saturations represent this relationship between oxygen delivery and oxygen demand and can therefore be used as an additional parameter to detect an impaired cardiorespiratory reserve. Before appropriate use of venous oxygen saturations, however, one should be aware of the physiology. Although venous oxygen saturation has been the subject of research for many years, increasing interest arose especially in the past decade for its use as a therapeutic goal in critically ill patients and during the perioperative period. Also, there has been debate on differnces between mixed and central venous oxygen saturation and their interchangeability. Both mixed and central venous oxygen saturation are clinically useful but both variables should be used with insightful knowledge and caution. In general, low values warn the clinician about cardiocirculatory or metabolic impairment and should urge further diagnostics and appropriate action, whereas normal or high values do not rule out persistent tissue hypoxia. The use of venous oxygen saturations seems especially useful in the early phase of disease or injury. Whether venous oxygen saturations should be measured continuously remains unclear. Especially, continuous measurement of central venous oxygen saturation as part of the treatment protocol has been shown a valuable strategy in the emergency department and in cardiac surgery. In clinical practice, venous oxygen saturations should always be used in combination with vital signs and other relevant endpoints.