探讨动脉血乳酸监测对医院获得性肺炎（HAP）患者30 d预后的判断价值。

回顾性分析陆军军医大学新桥医院2016年1月至2017年12月连续收治的71例HAP患者的病例资料，收集患者诊断为HAP后连续5 d的动脉血乳酸资料，以患者诊断为HAP后首个24 h各项指标参数行肺炎严重指数（PSI）评分，入组患者按照诊断为HAP后30 d内是否存活分为存活组（32例）和死亡组（39例）。采用重复度量分析不同预后患者乳酸值、乳酸清除量、乳酸清除率随时间的变化趋势；采用ROC曲线比较乳酸值、乳酸清除量和乳酸清除率对HAP患者30 d预后的判断价值；根据5 d内乳酸峰值分为< 2.0 mmol/L组、≥ 2.0 mmol/L组和≥ 4.0 mmol/L组，比较不同乳酸峰值患者的病死率；采用双变量线性相关性分析乳酸峰值与PSI评分的相关性。

存活组患者乳酸值随时间延长而降低，乳酸清除量、乳酸清除率随时间延长而增加；死亡组患者乳酸值随时间延长而增加，乳酸清除量、乳酸清除率随时间延长而降低。ROC曲线表明诊断为HAP后的动脉乳酸值可用来判断30 d预后，乳酸清除量、乳酸清除率则不能判断30 d预后，诊断HAP后第1天、第2天、第3天、第4天、第5天内乳酸峰值ROC曲线下面积分别为0.67、0.71、0.77、0.71、0.70和0.74。乳酸峰值< 2.0 mmol/L组、≥ 2.0 mmol/L组和≥ 4.0 mmol/L组患者30 d病死率为20.00%、64.29%和78.95%，三组差异有统计学意义（χ² = 13.27、P = 0.00）。乳酸峰值与PSI评分密切相关（r = 0.41、P = 0.00）。

不同预后HAP患者5 d内动脉乳酸值变化不同；乳酸值比乳酸清除量、乳酸清除率更适于评价预后；乳酸峰值越高，死亡风险越大，与PSI评分密切相关。

To investigate the diagnostic value of arterial lactate monitoring in predicting the prognosis of hospital acquired pneumoni (HAP) for 30 days.

The clinical data of 71 consecutive patients diagnosed as HAP admitted in Xinqiao Hospital, Army Military Medical University from January 2016 to December 2017 were analyzed, retrospectively. The arterial lactate data were collected for consecutive 5 days after diagnosis as HAP, while the pneumonia severity index (PSI) score was taken as the first 24 hours’ physiological parameters after diagnosis. According to the prognosis of survival within 30 days after diagnosis as HAP, the patients were divided into survival group (32 cases) and death group (39 cases). The change trend of arterial lactate, lactate clearance and lactate clearance rate were analyzed by repeated metric analysis. The effect of arterial lactate, lactate clearance and lactate clearance rate on the 30 days prognosis of HAP were compared by ROC curve. The difference in the mortality rates were compared according to the lactate peak within 5 days, which were divided into < 2.0 mmol/L, ≥ 2.0 mmol/L and ≥ 4.0 mmol/L groups; the correlation between lactate peak and PSI score was calculated by double variable linear correlation analysis.

In survival group, as time going on the lactate decreased, lactate clearance and lactate clearance rate increased; in death group, as time going on the lactate increased, lactate clearance and lactate clearance rate decreased. ROC curve showed that lactate could be used to evaluate the prognosis, but not the lactate clearance and lactate clearance rate. The areas under lactate ROC curve of the first day, second day, third day, fourth day, fifith day, the lactate peak within 5 days were 0.67, 0.71, 0.77, 0.71, 0.70 and 0.74, respectively. The mortality rates of the peak value of lactate within 5 days, cases in < 2.0 mmol/L group, ≥ 2.0 mmol/L group and ≥ 4.0 mmol/L group were 20.00%, 64.29% and 78.95%, respectively, with significant difference (χ² = 13.27, P = 0.00). There was a close correlation between the lactate peak and the PSI score (r = 0.41, P = 0.00).

The changes of arterial lactate were different for different prognosis of HAP patients. The value of arterial lactate was higher than that of lactate clearance and lactate clearance rate for evaluating HAP prognosis. The higher the arterial lactate, the greater risk of death. Arterial lactate peak was closely related to PSI score.