High central venous saturation after cardiac surgery is associated with increased organ failure and long-term mortality: an observational cross-sectional study

Felix Balzer, Michael Sander, Mark Simon, Claudia Spies, Marit Habicher, Sascha Treskatsch, Viktor Mezger, Uwe Schirmer, Matthias Heringlake, Klaus-Dieter Wernecke, Herko Grubitzsch, Christian von Heymann

Central venous saturation (ScvO2) monitoring has been suggested to address the issue of adequate cardiocirculatory function in the context of cardiac surgery. Aim of this study was to determine the impact of low (<60%), normal (60-80%) and high (>80%) ScvO2 measured on ICU admission after cardiac surgery. Retrospective, cross-sectional, observational study at three intensive care units of a university hospital department for anaesthesiology and intensive care. Electronic patient records of all adults that underwent cardiac surgery between 2006 and 2013 and available admission measurements of ScvO2 were examined. Patients were allocated to one of three groups according to first ScvO2 measurement after ICU admission (group L <60%, group N 60-80%, group H >80%). Primary end-points were in-hospital and three-year follow-up survival. Data from 4,447 patients was included in analysis. Low and high initial measurements of ScvO2 were associated with increased in-hospital mortality (L: 5.6%, N: 3.3%, H: 6.8%), three-year follow-up mortality (L: 21.6%, N: 19.3%, H: 25.8%), incidence of post-operative haemodialysis (L: 11.5%, N: 7.8%, H: 15.3%) and prolonged hospital length of stay (L: 13d [9;22], N: 12d [9;19], H: 14d [9;21]). Adjusting for possible confounding variables, an initial ScvO2 above 80% was associated with an adjusted hazard ratio of 2.79 (95% CI: 1.565-4.964, p < 0.001) for in-hospital survival and 1.31 (95% CI: 1.033-1.672, p = 0.026) for three-year follow-up survival. Patients with high ScvO2 were particularly affected by unfavourable outcomes. Advanced haemodynamic monitoring may help to identify patients with high ScvO2 that developed extraction dysfunction to establish treatment algorithms in these patients to improve patient outcome.