Using Blood Lactate to Predict Prognosis in Emergency Shock Patients

Abstract

Background. Lactic acidosis is frequently caused by systemic hypoperfusion, tissue hypoxia and the severity of shock. The purpose of this study was to investigate whether blood lactate concentration is a useful prognostic parameter in patients with shock in the emergency department (ED). Methods . The criteria for patient selection were 1) arrival at ED with shock syndrome, 2) blood lactate (BLC1) ＞ 19.6 mg/dL prior to resuscitation. All patients were monitored of blood lactate (BLC2) after resuscitation over a period of four hours prior to being sent to the operation room, intensive care unit or ordinary ward . Results. Seventy-five shock patients had abnormal blood lactate levels (BLCI ＞ 19.6 mg/dL) before resuscitation. Patients who died (mortality group) had significantly higher BLC2 levels (74.4±72.1 vs 27.0±11.1 mg/dL, p ＜ 0.0001) than patients who survived (survival group). In addition, there was a significantly higher mortality rate in patients with blood lactate concentrations (BLC1) ＞ 100 mg/dL than patients with blood lactate concentrations (BLC2) s 100 mg/dL (87%ω43%, P ＜ 0.005). Patients with blood lactate concentrations (BLC2) ＞50 mg/ dL had a higher mortality rate than patients with blood lactate concentrations (BLC2)≦50 mg/dL (100% vs 36%, P ＜ 0.0001). Patients with changes in blood lactate levels (BLC2-BLC1) ＞ 20 mg/dL had a higher rate of mortality than those with a change of ≦20 mg/ dL (n = 66) (100% us 47%, P ＜ 0.005). Conclusions. Blood lactate and its clearance may help emergency physicians predict the prognosis of shock patients in the ED. The detection of the changes in blood lactate concentrations after resuscitation is more valuable than before resuscitation.