[The clinical value of atrial natriuretic peptide in early diagnosis of sepsis].

OBJECTIVE: To evaluate the clinical value and specificity of atrial natriuretic peptide (ANP) in early diagnosis of sepsis.

METHODS: A prospective study was performed. Data of patients with sepsis were consecutively collected from September 2007 to December 2012 according to the international criteria for the diagnosis of sepsis, and that of 114 patients admitted to intensive care unit (ICU) and the cadre health care ward were divided into three groups: systemic inflammatory response syndrome (SIRS) group (n=37), sepsis group (n=41) and severe sepsis group (including severe sepsis and septic shock, n=36). Venous blood of each patient was drawn instantly when admitted to ICU. The concentration of plasma ANP in each group was determined on the 1st day using a new type of sandwich immunofluorescence assay, and other biomarkers, such as procalcitonin (PCT, detected with double antibody immunochemi luminometry), blood lactic acid (detected with electrode meter), and C-reactive protein (CRP, detected with immunonephelometric analysis), and the acute physiology and chronic health evaluation II (APACHEII) score was recorded. APACHEII score and biomarkers were compared among three groups. The risk factor for severity was confirmed with stepwise regression, and the value of each index in early diagnosis of sepsis was analyzed with receiver operating characteristic (ROC) curve.

RESULTS: The plasma concentration of ANP exhibited a gradual increase with the aggravation of the disease, and the median ANP value was found to be highest in the severe sepsis group compared with SIRS group and sepsis group [μg/L: 0.26 (0.22) vs. 0.19 (0.05), 0.21 (0.08), P<0.01 and P<0.05]. The regression equation was established at y=0.69 + 0.66APACHEIIscore + 1.285 ANP value, with group as independent variable, and APACHEII score, ANP, PCT, CRP and blood lactic acid value as dependent variables. It could be concluded that APACHEII score and ANP value were correlated with severity of sepsis, and accordingly they were regarded as the independent predictors of severity of sepsis. It was found through the ROC curve analysis of ANP in the sepsis patients, that the area under the ROC curve for ANP [0.805, P=0.000, 95% confidence interval (95%CI) 0.726-0.883, sensitivity 75.8%, specificity 78.4%] was similar with the area under the APACHEII score (0.820, P=0.000, 95%CI 0.742-0.897, sensitivity 68.4%, specificity 78.4%), and it was apparently higher than AUCs of PCT (0.716, P=0.000, 95%CI 0.622-0.810, sensitivity 67.1%, specificity 62.2%), CRP (0.569, P=0.236, 95%CI 0.463-0.675, sensitivity 76.3%, specificity 41.5%), or blood lactic acid (0.566, P=0.254, 95%CI 0.453-0.679, sensitivity 75.0%, specificity 48.6%).

CONCLUSIONS: Plasma ANP concentration is clinically valuable in early diagnosis and severity assessment of sepsis, and it is more specific and sensitive than biomarkers PCT and CRP.