Prognostic value of central venous-to-arterial carbon dioxide difference in patients with bloodstream infection.

Bloodstream infection (BSI) are prone to circulation disorders, which portend poor outcome. The central venous-to-arterial carbon dioxide difference (Pcv-aCO) is a biomarker for circulation disorders, but the prognostic value of Pcv-aCO in BSI patients remains unclear. This study was to investigate the association of Pcv-aCO with adverse events in BSI patients. The patients with BSI between August 2014 and August 2017 were prospectively enrolled. Clinical characteristic and laboratory results were collected. We analyzed the association of the level of Pcv-aCO with clinical variables and 28-day mortality. A total of 152 patients were enrolled. The Pcv-aCO was positively correlated with white blood cell count (r=0.241, p=0.003), procalcitonin (r=0.471, p<0.001), C-reactive protein (r=0.192, p=0.018), lactate (r=0.179, p=0.027), Sequential Organ Failure Assessment (r=0.318, p<0.001) and Acute Physiology And Chronic Health Evaluation II score (r=0.377, p<0.001), while that was negatively correlated with central venous oxygen saturation (r=-0.242, p<0.001) and platelet (r=-0.205, p=0.011). Kaplan-Meier curves demonstrated that patients with Pcv-aCO >6mmHg had a worse prognosis than those without (log rank=32.10, p<0.001). Multivariate analysis showed Level of Pcv-aCO was an independent risk factor for 28-day mortality (HR: 3.10, 95% CI: 1.43-6.74, p=0.004). The area under the receiver operating characteristic curve of Pcv-aCO for prediction of 28-day mortality in patients with BSI was 0.794. Pcv-aCO>6 mmHg had 81.1% sensitivity and 78.8% specificity for predicting 28-day mortality. Pcv-aCO may be a simple and valuable biomarker to assessment of 28-day mortality in patients with BSI.