乳酸评价急性胸痛的临床研究

目的　检验乳酸诊断急性心肌梗死(AMI)及判断危重心脏病患者预后的假说。方法　急性胸痛或其它典型AMI症状的患者检测静脉血乳酸。高于2.0mmol/L作为急性心脏疾病的预测值。同时检测心肌磷酸激酶(CK)和同工酶(CK-MB)，记录ECG。结果　全部114例患者，65例乳酸高于2.0mmol/L。25例(22%)确诊为急性心肌梗死(AMI)，其乳酸为2.7±0.7mmol/L。而Non～AMI乳酸为2.2±0.8mmol/L(P＜0.05)。乳酸诊断AMI的敏感性为96%(95%CI为89%～100%)，特异性为55%(95%CI为45%～64%)，乳酸阴性预计值为96%(95%CI为89%～100%)。胸痛患者乳酸升高的平均时间为发病3h以内。死亡或要求ICU治疗48h以上的患者其乳酸也明显升高，与不要求ICU治疗者比较其乳酸分别是5.0±4.3mmol/L比1.9±0.6mmol/L(P＜0.01)。结论　乳酸对AMI具有较高的阴性预计值，高乳酸血症与急性心脏病患者病死率及要求住院有明显的相关性。

Effect of lactate toevaluate patients with acute chest pain

Objective To test the hypothesis that ED arrival venous lactatelevels can be used to diagnose acute myocardial infarction(AMI)and to identify patients with critical cardiac illness in the triage of ED patients presenting with chest pain.Methods We enrolled a convenience sample of adult patients who had chest pain or cardial symptoms suggesting AMI that began within 24 hours of presentation.Venous lactate sample were analyzed in the ED on whole blood.An abnormal lactate level of 2.0 mmol/L or higher at the time of arrival prospectively defined as indicating the presence of acute cardiac disease.ECG findings,levels of creatine phosphokinase (CK) and CK-MB were recorded.Results Of the 114 patients included in the study,65 had an initial lactate level of 2.0 mmol/L or higher.A total of 25 patients(22%)were diagnosed with AMI and had a mean lactate of 2.7±0.7 mmol/L，compared with 2.2±0.8 mmol/L in those patients who were not diagnosed with AMI(P＜0.05).The sensitivity of this lactate level in diagnosing AMI was 96%(95% confidence interval(CI),89% to 100%),and the specificity was 55%(95% CI,45% to 64%).The negative predictive value of blood lactate was 96%(95% CI,89% to 100%).Lactate was elevated independent of the duration of chest pain symptoms,with a media time from onset to sampling of 3 hours.Lactate was elevated in patients who either died or required longer than 48 hours of ICU care,compared with survivors not requiring ICU care(5.0±4.3 mmol/L vs 1.9±0.6 mmol/L,respectively;P＜0.01).Conclusions A normal blood lactate result has a high negative predictive for AMI.Hyperlactatemia clearly correlates with mortality and the need for ICU management in the acute cardiac patient presenting to the ED.