不同滤过分数计算公式对连续性肾脏替代治疗体外循环寿命的影响

Effect of different filtration fraction calculation formulas on extracorporeal circulation life of continuous renal replacement therapy

目的评估不同滤过分数(filtration fraction,FF)计算公式对局部枸橼酸抗凝下连续性肾脏替代治疗(continuous renal replacement therapy,CRRT)体外循环寿命的影响。方法选择2022年6月-2023年4月在四川大学华西医院采用局部枸橼酸抗凝方式行CRRT治疗且预计CRRT时间>24 h的急性肾损伤患者。根据CRRT模式,随机将患者分为连续性静脉-静脉血液滤过(continuous veno-venous hemofiltration,CVVH)组、连续性静脉-静脉血液透析(continuous veno-venous hemodialysis,CVVHD)组、连续性静脉-静脉血液透析滤过(continuous veno-venous hemodiafiltration,CVVHDF)组,均采用Prismaflex机器。比较3组患者CRRT体外循环寿命、体外循环未使用至72 h更换的原因及通过目前国际上使用的2种FF计算公式(公式1、公式2)分别计算3组患者的FF。以2种公式得出的FF值为检验变量,是否达到体外循环寿命最长组的中位寿命为状态变量,绘制受试者操作特征曲线。结果共纳入121例患者,其中CVVH组40例、CVVHD组40例、CVVHDF组41例。CVVH组、CVVHD组、CVVHDF组体外循环寿命分别为64(46,71)、47(31.5,54)、70(65,72)h,3组比较差异有统计学意义(log-rank P=0.036)。因体外循环未使用至72 h凝血共94例,其中CVVH组30例、CVVHD组39例、CVVHDF组25例,3组比较差异有统计学意义(χ^(2)=15.83,P<0.001)。根据公式1计算,CVVH组、CVVHD组及CVVHDF组的FF分别为15.8%(15.2%,17.0%)、1.1%(0.7%,2.1%)、16.2%(14.9%,17.6%),3组比较差异有统计学意义(H=69.402,P<0.001)。根据公式2计算,CVVH组、CVVHD组及CVVHDF组滤过分数分别为33.1%(32.4%,35.7%)、4.0%(3.6%,4.9%)、19.1%(17.7%,20.7%),3组间比较,差异均有统计学意义(P<0.001)。公式1、2计算的FF对体外循环寿命影响的受试者操作特征曲线曲线下面积分别为0.539、0.668,灵敏度分别为43.18%、82.22%,特异度分别为80.65%、56.25%。结论在使用Prismaflex机器行CRRT时,CVVHD模式静脉壶凝血发生率比CVVH和CVVHDF模式更高,体外循环寿命更短。公式2计算的FF预测CRRT体外循环寿命灵敏度更高,但特异度更低。单纯使用FF作为CRRT体外循环凝血风险评估尚有局限性,特别是对于前后置换的CVVH模式。

Objective To evaluate the effects of two filtration fraction formulas on extracorporeal circulation life of continuous renal replacement therapy(CRRT)under regional citrate anticoagulation.Methods Patients with acute kidney injury who received CRRT treatment with regional citrate anticoagulation and the estimated CRRT duration was greater than 24 h at West China Hospital of Sichuan University between June 2022 and April 2023 were selected.They were randomly divided into continuous veno-venous hemofiltration(CVVH),continuous veno-venous hemodialysis(CVVHD)and continuous veno-venous hemodiafiltration(CVVHDF)groups using Prismaflex machines.The life of the CRRT extracorporeal circulation in the three groups of patients was compared,and the reasons for replacing the extracorporeal circulation after 72 h were not used,and the filtration fraction score of the three groups was calculated according to the two filtration score calculation formulas(Formula 1 and Formula 2)currently used in the world.The filtration value obtained by the two filtration fraction calculation formulas was taken as the test variable,and whether the median life of the group with the longest extracorporeal circulation life was taken as the state variable,and the receiver operating characteristic curve was drawn,and the area under the curve was calculated.Results A total of 121 patients were included,including 40 patients in the CVVH group,40 patients in the CVVHD group,and 41 patients in the CVVHDF group.The extracorporeal circulation life of CVVH group,CVVHD group and CVVHDF group was 64(46,71)h,47(31.5,54)h and 70(65,72)h,respectively,with statistical difference(log-rank P=0.036).A total of 94 cases were replaced due to filter or venous pot clotting after 72 h after the filter was not used,including 30 cases in the CVVH group,39 cases in the CVVHD group,and 25 cases in the CVVHDF group.The difference between the three groups was statistically significant(χ^(2)=15.83,P<0.001).According to Formula 1,the filtration fraction of CVVH group,CVVHD group and CVVHDF group was 15.8%(15.2%,17.0%),1.1%(0.7%,2.1%)and 16.2%(14.9%,17.6%),respectively,and the difference among the three groups was statistically significant(H=69.402,P<0.001).According to Formula 2,the filtration fraction of CVVH group,CVVHD group and CVVHDF group was 33.1%(32.4%,35.7%),4.0%(3.6%,4.9%)and 19.1%(17.7%,20.7%),respectively,and the differences among the three groups and pairwise comparison between groups were statistically significant(P<0.001).The area under the receiver operating characteristic curvec calculated by the Formula 1 and 2 for the influence of filtration fraction on extracorporeal circulation life were 0.539 and 0.668,the sensitivity were 43.18%and 82.22%,and the specificity were 80.65%and 56.25%,respectively.ConclusionsWhen using Prismaflex machine,the filter life of CVVHD is shorter than CVVH and CVVHDF modes.The filtration fraction calculated by Formula 2 is more sensitive but less specific in predicting CRRT extracorporeal circulation life.Filtration fraction as a CRRT extracorporeal circulation risk assessment has limitations,especially for the CVVH model with pre and post replacement.