Abstract: Objective:To investigate the significance of the application value of lactic（Lac） and central venous oxygen saturation(ScvO2 )in shock patients . Methods: Selection the shock patients that stay in the department of emergency intensive care unit(EICU) in our hospital fron January 2013 to April 2015.Monitoring the lactic and ScvO2 at arrive hospital,After 6 hours moniting lactic again to calculate the lactate clearance rate(6h-LCR). Calculate acate physicalogy and chronic health evalauation Ⅱ(APACHE Ⅱ) score within 24 hours .The 28 days after stay hospital is the end ling of study.Patients are divided into generation group and death group. Comparing the difference of Lac/ScvO2 between the two groups , Analyse the correlation of Lac/ScvO2 with death, Lac level , APACHE Ⅱ score. Draw the receiver operating characteristic curve (ROC curve) analysis the ability of Lac/ScvO2 , Lac, 6h-LCR, ScvO2, APACHE Ⅱ score to judge happen derth with shock patients. The end compares the advantages of them. Results: The gender and age of two groups are no statistical difference (P > 0.05).The Lac/ScvO2 of Survival group is lower than the death group (P < 0.05). Lac, ScvO2, 6h-LCR, APACHE Ⅱ score have obvious difference (P < 0.05). Lac/ScvO2 with Lac and APACHE Ⅱ scores were positively correlated, (r = 0.901, r = 0.659, P < 0.01), Lac/ScvO2 related to happen death (r = 0.512, P < 0.01). The AUC of Lac/ScvO2 is 0.844 (0.751, 0.751), The cutoff value is 5.91, Sensitivity is 86.70%, Specificity is 67.60%, OR value is 16.25. Relative to the Lac, ScvO2, 6h-LCR, APACHE Ⅱ score ,The AUC and sensitivity of Lac/ScvO2 is the highest. Conclusions: Lac/ScvO2 is a better indicators for shock patients to evaluation the degree of the severity of illness and prognosis. Lac/ScvO2 is the best than Lac, ScvO2, 6h-LCR and APACHE Ⅱ score to judge prognosis in shock patients.

Key words: shock, lactic acid；diagnosis, differential, ROC curve, APACHE Ⅱ score, central venous oxygen saturation