127例大面积烧伤患者休克期高乳酸值与死亡风险关联的回顾性队列研究

Retrospective cohort study on the correlation between high value of lactic acid and risk of death in 127 patients with extensive burn during shock stage

目的分析大面积烧伤患者休克期血清乳酸值与死亡风险的关系及相关影响因素。方法回顾性分析2009年1月—2013年12月陆军军医大学第一附属医院全军烧伤研究所和2016年1月—2018年12月西南医科大学附属医院整形烧伤外科收治的符合入选标准的127例大面积烧伤患者(男111例、女16例)的临床资料,患者年龄为21~62岁,烧伤总面积>50%体表总面积,患者入院后均行抗休克治疗。(1)按照治疗结局,将患者分为存活组98例和死亡组29例。统计患者性别、年龄、烧伤总面积、Ⅱ度烧伤面积、Ⅲ度烧伤面积、简化烧伤严重指数(ABSI)、伤后入院时间、合并吸入性损伤患者数、合并急性肾衰患者数,以及入院时与入院后12、24、36、48h血清乳酸值。(2)按照入院后48h血清乳酸值最佳阳性截断值,将患者分为高乳酸组和正常乳酸组。统计患者年龄、性别、烧伤总面积,入院后48h尿素氮、肌酐、丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、血清总胆红素、碱性磷酸酶(ALP)、白蛋白、白细胞计数、血小板计数、淋巴细胞计数、凝血酶原时间(PT)、红细胞比容、氧合指数、呼吸指数、肺泡-动脉氧分压差、入院后48h平均动脉压,入院后48h内平均尿量、入院后48h内静脉补液总量、入院后第1个24h每千克体质量补液量、入院后第1个24h每1%体表面积每千克体质量补液量,入院后第1个24h每千克体质量每小时尿量、院内死亡百分比。对数据行t检验、χ^2检验、Fisher确切概率法检验,采用Cox回归分析筛选影响患者预后的独立危险因素,绘制127例患者入院后48h血清乳酸值的受试者工作特征曲线,评估其对患者死亡的预测效果,测定最佳阳性截断值。采用多因素logistic回归分析筛选导致血清乳酸升高的独立危险因素。结果(1)存活组和死亡组患者在烧伤总面积、Ⅲ度烧伤面积以及ABSI方面比较差异有统计学意义(t=6.257、4.476、5.727,P<0.01),而组间其他指标水平相近。(2)死亡组患者入院时及入院后12、24、36、48h血清乳酸值分别为(4.00±0.28)、(4.50±0.26)、(4.02±0.31)、(3.48±0.22)、(3.40±0.19)mmol/L,均显著高于存活组(3.30±0.21)、(3.20±0.19)、(2.33±0.17)、(1.85±0.18)、(1.50±0.09)mmol/L,t=14.552、29.603、38.133、40.648、74.973,P<0.05或P<0.01)。(3)Cox回归分析显示,入院后48h血清乳酸值是影响患者预后的独立危险因素,风险比=1.853,95%置信区间=1.342~2.559,P<0.01。(4)对127例患者死亡预测的入院后48h血清乳酸值的受试者工作特征曲线下总面积为0.811(95%置信区间=0.699~0.924,P<0.01),血清乳酸值的最佳阳性截断值为1.75mmol/L,其对死亡预测的敏感度达75.0%、特异度达79.5%。(5)高乳酸组34例与正常乳酸组93例患者在烧伤总面积、ALT、AST、ALP、PT、血清总胆红素、入院后48h内静脉补液总量以及入院后第1个24h每千克体质量补液量、院内死亡百分比方面比较,差异有统计学意义(t=3.592、6.797、10.367、2.089、2.880、4.517、2.984、4.044,χ^2=58.498,P<0.05或P<0.01);组间其他指标水平相近。(6)多因素logistic回归分析显示,AST和血清总胆红素是血清乳酸升高的独立危险因素,比值比=1.021、1.064,95%置信区间=1.001~1.040、1.001~1.132,P<0.05。结论入院后48h血清乳酸值能独立预测大面积烧伤患者死亡。肝脏损伤是导致烧伤休克期高乳酸血症的重要危险因素,广泛的血管通透性增加与复苏过程给予大量液体是导致腹腔脏器损伤加重的核心因素。

Objective To analyze the relationship between serum lactic acid value and risk of death in patients with extensive burn during shock stage and the related influencing factors.Methods Clinical data of 127 patients(111 males and 16 females)with extensive burn admitted to Institute of Burn Research of the First Affiliated Hospital of Army Medical University from January 2009 to December 2013 and Department of Plastic Surgery and Burns of the Affiliated Hospital of Southwest Medical University from January 2016 to December 2018,who met the admission criteria,were retrospectively analyzed.The patients aged 21 to 62 years,with total burn area more than 50% total body surface area.All patients were treated with antishock therapy after admission.(1)According to the treatment outcome,the patients were divided into survival group(n=98)and death group(n=29).The gender,age,total burn area,partial-thickness burn area,full-thickness burn area,abbreviated burn severity index(ABSI),admission time after injury,number of patients with inhalation injury,number of patients with acute renal failure,and serum lactic acid values on admission and at post admission hour(PAH)12,24,36,and 48 were recorded.(2)According to the optimal positive cut-off value of serum lactic acid 48 hours after admission,the patients were divided into high lactic acid group and normal lactic acid group.Age,gender,total burn area,indexes at PAH 48 including urea nitrogen,creatinine,alanine aminotransferase(ALT),aspartate aminotransferase(AST),total serum bilirubin,alkaline phosphatase(ALP),albumin,white blood cell count,platelet count,lymphocyte count,prothrombin time(PT),hematocrit value,oxygenation index,respiratory index(RI),the alveolar-arterial oxygen partial pressure difference,mean arterial pressure(MAP)at PAH 48,the average urine volume within 48 hours after admission,the total volume of intravenous fluid infusion within 48 hours after admission,the volume of fluid infusion per kilogram of body mass within the first 24 hours after admission,the volume of fluid infusion per one percent of body surface area per kilogram of body mass within the first 24 hours after admission,the volume of urine per kilogram of body mass per hour within the first 24 hours after admission,and the percentage of hospital death were recorded.Data were processed with t test,chi-square test,and Fisher's exact probability test.Cox regression analysis was used to screen independent risk factors affecting the prognosis of patients.Receiver operating characteristic curve(ROC)of serum lactic acid value at PAH 48 of 127 patients was drawn to predict patients'death and determine the optimal positive cut-off value.Multivariate logistic regression analysis was used to screen independent risk factors causing increase of serum lactic acid.Results(1)There were significantly statistical differences in total burn area,full-thickness burn area,and ABSI of patients between survival group and death group(t=6.257,4.476,5.727,P<0.01),while other indexes between the two groups were close.(2)The serum values of lactic acid of patients in death group on admission and at PAH 12,24,36,and 48 were(4.00±0.28),(4.50±0.26),(4.02±0.31),(3.48±0.22),(3.40±0.19)mmol/L,respectively,which were significantly higher than those in survival group[(3.30±0.21),(3.20±0.19),(2.33±0.17),(1.85±0.18),(1.50±0.09)mmol/L,t=14.552,29.603,38.133,40.648,74.973,P<0.05 or P<0.01].(3)Cox regression analysis showed that the serum value of lactic acid at PAH 48 was the independent risk factor affecting the prognosis of patients,with risk ratio of 1.853 and 95% confidence interval of 1.342-2.559,P<0.01.(4)The total area under ROC of serum value of lactic acid at PAH 48 to predict death of 127 patients was 0.811,with 95% confidence interval of 0.699-0.924,P<0.01.The optimal positive cut-off value of serum value of lactic acid was 1.75 mmol/L,with sensitivity of 75.0% and specificity of 79.5% for predicting death.(5)There were significantly statistical differences in total burn area,ALT,AST,ALP,PT,total serum bilirubin,total volume of intravenous fluid infusion within 48 hours after admission,volume of fluid infusion per kilogram of body mass within the first 24 hours after admission,and percentage of hospital deaths of patients between high lactic acid group(n=34)and normal lactic acid group(n=93),t=3.592,6.797,10.367,2.089,2.880,4.517,2.984,4.044,χ^2=58.498,P<0.05 or P<0.01,while other indexes were close between the two groups.(6)Multivariate logistic regression analysis showed that AST and total serum bilirubin were independent risk factors for increase of serum lactic acid,with odds ratios of 1.021 and 1.064 and 95% confidence intervals of 1.001-1.040 and 1.001-1.132,P<0.05.Conclusions Serum value of lactic acid at PAH 48 can independently predict the death of patients with extensive burns.Liver injury is an important risk factor causing hyperlacticemia during burn shock stage.Widespread increase of vascular permeability and large amount of fluid resuscitation are the core factors leading to aggravation of abdominal organ injury.