title: [What is the role of monitoring of mixed venous blood saturation in cardiac surgery?].
abstract: The equipment available for mixed venous blood saturation (Svo2) monitoring is now accurate. SvO2 is not a direct measure of cardiac output, because it depends on the balance between oxygen delivery (TaO2) and consumption (VO2). As haemoglobin affinity for oxygen increases during cardio-pulmonary bypass (CPB), the optimal level of SvO2 after CPB should be above 65-70%. There is a critical level of TaO2 below which VO2 is dependent on TaO2. Below this level, SvO2 has no clinical value as it no longer depends on TaO2. Similarly, SvO2 has no clinical value during lactic acidosis. When these limitations are taken into account, SvO2 monitoring is useful for the interpretation of intra- and post-operative haemodynamic alterations occurring during cardiac surgery. It is particularly indicated in patients with preoperative NYHA class III or IV congestive heart failure.
authors.affiliation: Service d'Anesthésie et Réanimation Chirurgicale, Hôpital R. et G. Laënnec, CHRU de Nantes.
authors.forename: M
authors.initials: M
authors.lastname: Videcoq
authors.forename: J M
authors.initials: JM
authors.lastname: Desmonts
mesh_terms: D006348:Cardiac Surgical Procedures; D005112:Extracorporeal Circulation; D006439:Hemodynamics; D006801:Humans; D007432:Intraoperative Period; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D011184:Postoperative Period
chemical_list: D010100:Oxygen
vernacular_title: Quelle est la place du monitorage de la saturation du sang veineux mêlé en chirurgie cardiaque?