重症患者高氧血症的发生情况和临床特征及危险因素分析

Occurrence,clinical characteristics and risk factors of hyperoxemia in critically ill patients

目的分析重症患者高氧血症的发生情况、临床特征及危险因素。方法采用回顾性研究方法。收集2017年6月至2018年10月就诊于贵州医科大学附属医院综合重症监护病房(ICU)进行常规氧疗患者的一般情况、入住ICU时和住ICU期间的血气结果、有无ICU内新发感染、有无机械通气、机械通气时间及ICU住院时间、ICU病死率等临床资料。按入住ICU 6 h后至离开ICU期间是否发生高氧血症将患者分为发生高氧血症组与未发生高氧血症组〔高氧血症的定义为动脉血氧分压(PaO_(2))≥120 mmHg(1 mmHg≈0.133 kPa)〕。比较是否发生高氧血症两组患者上述资料的差异;采用Logistic回归分析筛选出影响患者发生高氧血症的因素,并绘制受试者工作特征曲线(ROC曲线),分析各危险因素对患者发生高氧血症的预测价值。结果共纳入392例患者,入住ICU时高氧血症占34.4%(135/392);而ICU内高氧血症占56.6%(222/392)。ICU内发生高氧血症组患者较未发生高氧血症组患者年龄更小〔岁:56(39,71)比62(46,72)〕,体质量指数更低〔kg/m^(2):21.5(19.5,23.6)比22.5(20.0,25.0)〕,有更长的机械通气时间〔h:82.0(43.0,161.0)比67.5(37.8,127.0)〕和ICU住院时间〔d:6.0(4.0,11.8)比4.0(3.0,8.0)〕,机械通气比例、入住ICU时和ICU内PaO_(2)、ICU内吸入氧浓度、入住ICU时和ICU内氧合指数(PaO_(2)/FiO_(2))、入ICU时动脉血乳酸(Lac)、ICU内新发感染比例均相对更高〔机械通气比例:86.0%(191/222)比71.8%(122/170),入住ICU时PaO_(2)(mmHg):110.5(85.5)比76.0(41.8),ICU内PaO_(2)(mmHg):138.0(29.0)比76.0(22.8),ICU内吸入氧浓度:0.33(0.15)比0.30(0.15),入住ICU时PaO_(2)/FiO_(2)(mmHg):279.5(173.0,400.0)比208.0(153.0,305.0),ICU内PaO_(2)/FiO_(2)(mmHg):436.7(348.0,528.0)比249.0(190.0,331.0),入住ICU时Lac(mmol/L):2.5(2.9)比1.7(2.2),ICU内新发感染比例:45.0%(100/222)比31.2%(53/170)〕,差异均有统计学意义(均P<0.05);而发生高氧血症组与未发生高氧血症组ICU内病死率比较差异无统计学意义〔11.7%(26/222)比12.4%(21/170),P>0.05〕。多因素Logistics回归分析显示,年龄〔优势比(OR)=0.986,95%可信区间(95%CI)为0.973~0.999,P=0.032)和体质量指数(OR=0.928,95%CI为0.872~0.986,P=0.017)是重症患者发生高氧血症的保护因素,而入住ICU时PaO_(2)(OR=1.012,95%CI为1.007~1.017,P<0.001)、入住ICU时Lac(OR=1.103,95%CI为1.013~1.208,P=0.029)、ICU内吸入氧浓度(OR=1.018,95%CI为1.002~1.035,P=0.034)是影响ICU内患者发生高氧血症危险因素。ROC曲线分析显示:入住ICU时PaO_(2)和ICU内吸入氧浓度对高氧血症的发生有一定的预测价值〔ROC曲线下面积(AUC)和95%CI分别为0.684(0.635~0.729),0.617(0.567~0.665)〕;当截断值分别为82.00 mmHg、0.28时,其敏感度分别为71.2%、80.0%,特异度分别为59.54%、46.24%。结论ICU内高氧血症可能会对重症患者产生不利影响,入住ICU时PaO_(2)、Lac和ICU内吸入氧浓度是发生高氧血症的危险因素。

Objective To analyze the incidence,clinical characteristics and risk factors of hyperoxemia in crtically ill patients.Methods A retrospective study was conducted.Clinical data of patients admitted to the department of comprehensive intensive care unit(ICU)of the Affiliated Hospital of Guizhou Medical University from June 2017 to October 2018 were collected,including general conditions of routine oxygen therapy,blood gas results at ICU admission and during ICU stay,new infections in ICU,mechanical ventilation,mechanical ventilation duration and length of ICU stay.Patients were divided into a hyperoxemia group and a non-hyperoxemia group according to whether hyperoxemia occurred from 6 hours after ICU admission until ICU discharge[defined as arterial partial pressure of oxygen(PaO_(2))≥120 mmHg(1 mmHg≈0.133 kPa)].The differences in clinical data between the two groups were compared.Logistic regression analysis was used to screen for factors that affected the occurrence of hyperoxemia in patient;receiver operator characteristic curve(ROC curve)was plotted to analyze the predictive value of each risk factor for the occurrence of hyperoxemia in patients.Results A total of 392 patients were included,among whom 34.4%(135/392)experienced hyperoxemia upon admission to the ICU,while 56.6%(222/392)developed hyperoxemia during the ICU.Compared with non-hyperoxemia group,patients in hyperoxemia group in the ICU were younger[years:56(39,71)vs.62(46,72)],had lower body mass index[kg/m^(2):21.5(19.5,23.6)vs.22.5(20.0,25.0)],longer mechanical ventilation times[hours:82.0(43.0,161.0)vs.67.5(37.8,127.0)],and longer length of ICU stay[days:6.0(4.0,11.8)vs.4.0(3.0,8.0)],the proportions of mechanical ventilation,PaO_(2)upon admission to ICU and during the ICU,during the ICU stay and oxygenation index(PaO_(2)/FiO_(2))upon admission to the ICU and during the ICU stay,blood lactic acid(Lac)upon admission to the ICU and the incidence of new infections during the ICU stay were higher in the hyperoxemia group than those in non-hyperoxemia group[mechanical ventilation ratio:86.0%(191/222)vs.71.8%(122/170),PaO_(2)upon admission to the ICU(mmHg):110.5(85.5)vs.76.0(41.8),PaO_(2)during the ICU stay(mmHg):138.0(29.0)vs.76.0(22.8),fractional of inspired oxygen during the ICU stay:0.33(0.15)vs.0.30(0.15),PaO_(2)/FiO_(2)upon admission to the ICU(mmHg):279.5(173.0,400.0)vs.208.0(153.0,305.0),PaO_(2)/FiO_(2)during the ICU stay(mmHg):436.7(348.0,528.0)vs.249.0(190.0,331.0),Lac upon admission to the ICU(mmol/L):2.5(2.9)vs.1.7(2.2),the incidence of new infections during the ICU stay:45.0%(100/222)vs.31.2%(53/170)],all differences were statistically significant(all P<0.05).However,there was no significant difference in mortality in ICU between the hyperoxemia group and non-hyperoxemia group[11.7%(26/222)vs.12.4%(21/170),P>0.05].Multivariate Logistic regression analysis showed that age[odds ratio(OR)=0.986,95%confidence interval(95%CI)was 0.973-0.999,P=0.032]and body mass index[odds ratio(OR=0.928,95%CI was 0.872-0.986,P=0.017)were protective factors for the occurrence of hyperoxemia in critically ill patients,while PaO_(2)upon admission to the ICU(OR=1.012,95%CI was 1.007-1.017,P<0.001),Lac at admission(OR=1.103,95%CI was 1.013-1.208,P=0.029)and fractional of inspired oxygen during the ICU stay(OR=1.018,95%CI was 1.002-1.035,P=0.034)were risk factors for hyperoxemia in the ICU.ROC curve analysis showed that the PaO_(2)upon admission to the ICU and inspired oxygen concentration during the ICU stay had predictive value for the occurrence of hyperoxemia[the area under ROC curve(AUC)and 95%CI were 0.684(0.635-0.729)and 0.617(0.567-0.665),respectively].When the cut-off values were 82.00 mmHg and 0.28,the sensitivity was 71.2%and 80.0%,and the specificity was 59.54%and 46.24%,respectively.Conclusion Hyperoxemia in the ICU may have adverse effects on critically ill patients,PaO_(2)and artery blood lactate upon admission to the ICU and fractional of inspired oxygen during the ICU stay are risk factors for hyperoxemia in the ICU.