The application of combined central venous pressure and oxygen metabolism parameters monitoring in diagnosing septic shock-induced left ventricular dysfunction

Abstract

To evaluate the value of central venous pressure (CVP), central venous oxygen saturation (ScvO₂) and venous-arterial carbon dioxide partial pressure gradient (Pv-aCO₂)) in the diagnosis of septic shock-induced left ventricular dysfunction. Consecutive patients with septic shock were enrolled from September 2013 to September 2014 in ICU at Peking Union Medical College Hospital. The data of CVP, Pv-aCO₂) and ScvO₂) were recorded and analyzed. According to the left ventricular ejection fraction (LVEF) tested by bedside echocardiography, the patients were divided into two groups: new onset of left ventricular dysfunction (LVEF < 50%) group and non-left ventricular dysfunction (LVEF ≥ 50%) group. A diagnostic model was created by logistic regression. The diagnostic performance and cut-off values of CVP, Pv-aCO₂, ScvO₂) were determined using receiver operating characteristic (ROC) curve analysis. Among 93 patients enrolled, 39 were diagnosed with left ventricular dysfunction. In the new onset group, CVP [(12.5 ± 3.9) mmHg (1 mmHg = 0.133 kPa) vs (10.4 ± 2.5) mmHg; P = 0.005] and Pv-aCO₂[(7.5 ± 3.9) mmHg vs (4.5 ± 2.6) mmHg; P < 0.001] were significantly higher than those in the non-left ventricular dysfunction group, while Scv2 [(62.4 ± 10.5)% vs (72.6 ± 9.0)%; P < 0.001] was significantly lower. As far as the diagnostic value of these three parameters were concerned for left ventricular dysfunction, the sensitivity of CVP ≥ 12.5 mmHg was 46.2%, specificity 81.5% with an area under ROC curve (AUCROC) 0.674; the sensitivity of Pv-aCO₂≥ 5.0 mmHg 76.9%, specificity 37.0%, AUCROC 0.738; the sensitivity of ScvO₂≤ 65.8% 64.1%, specificity 78.6%, AUCROC 0.775. When the cut-off values were determined by ROC, the diagnostic performance of the model was ≥ 0.377 with the sensitivity, specificity and AUCROC 82.1%, 79.6% and 0.835, respectively. In patients with septic shock, the logistic regression model established by CVP, Pv-aCO₂and ScvO₂contributes to the diagnosis of septic shock-induced left ventricular dysfunction.