A Comparative Study Of Two Different Anticoagulation Methods In Continuous Renal Replacement Therapy CRRT To Critically Ill Patients

Objective: Continuous renal replacement therapy(CRRT) is a great progress in the therapeutic areas of critically ill patients, which can remove inflammatory mediators, maintain a stable internal environment, and replace renal function. But the safe and effective anticoagulation is an important guarantee for the smooth progress of CRRT. The purpose of this study is to make a comparative study of low molecular weight heparin and regional citrate these two kinds of anticoagulation methods, in order to provide a better basis and methods for anticoagulation therapy of CRRT.Methods: The critically ill patients under CRRT treatment were randomly divided into low molecular weight heparin group(Group A) and sodium citrate group(Group B), both of which chose continuous veno-venous hemofiltration(CVVH) model, and the vascular accesses of which used 12 F 16cm double lumen central venous catheter inserted through femoral veins. PRISMA FLEX hemofiltration apparatus(GAMBRO) and AN69 filter(M100 Membrane area of 0.9m2) were applied into CRRT, with the displacement liquid of 3000ml/h, pre displacement of 75%, post displacement of 25%, and blood flow rate of 100-150ml/min. Filters and catheters were pre rinsed with 2L physiological saline which contained 12500 units of heparin sodium before the start of hemofiltration, and the pre rinsing liquid which contained heparin sodium was released when the blood was led. Low molecular weight heparin group(Group A): The low molecular weight heparin load was 40IU/kg, then a dose of 4IU/kg/h was continuously pumped into. Citrate group(Group B): The initial pump speed(ml/h) of sodium citrate was set 1.2-1.5 times of blood flow rate, and the pump speed of 10% calcium gluconate was 8.8-11.1ml/h(6.1% of that of citrate). The dose of citrate was adjusted according to the filtered calcium ions, while the dose of calcium gluconate was adjusted according to the calcium ions in vivo. The service life of filters, hematological indexes before and after CRRT treatment, coagulation indexes, liver and kidney functions and metabolic indexes were monitored, and the efficacy and safety of anticoagulation were evaluated.Results: 67 patients were included into this study, of which there were 34 patients in Group A, and 33 patients in Group B, before the CRRT treatment, there was no obvious statistical significance in ages, weights, APACHE II scores and creatinine clearance rate of the two groups(P>0.05). Before the CRRT treatment, a comparison of white blood cells(WBC), hemoglobin(HGB), platelets(PLT), coagulation functions, renal functions and liver functions between the two groups were made, and there was no obvious statistical significance(P>0.05). In Group A, there was a decrease in HGB after the treatment than before(P<0.05), the activated partial thromboplastin time(APTT) was prolonged after the treatment than before(P<0.05), while in Group B, there were no significant changes in HGB and APTT before and after the treatment(P>0.05), but the PLT of both two groups of patients significantly decreased than before(P<0.05). The BUN and Cr of both two groups of patients significantly decreased than before(P<0.05), There was no significant differences in the comparison between the two groups of patients(P>0.05).There was no statistically significance in the comparisons of ion indexes within each group or between the two groups of patients at each time point(P>0.05), but there was significant differences between the blood gas indexes(P<0.05). The service lives of the filters(mean±standard deviation) were respectively as Group A of 33.76±13.56 h, Group B of 41.36±20.85 h, which proved that the filters lives of citrate group was longer than that of low molecular weight heparin group, the P value after the comparison between the two groups was 0.081(P>0.05), there were no obvious statistical differences.Conclusions:1 The filers service lives of regional citrate anticoagulation group is longer than that of low molecular weight heparin anticoagulation group, but the statistical comparison shows there is no statistical significance, therefore, analysis of large samples and multi center study may still be needed.2 Both these two kinds of anticoagulation methods can make the hemofiltration effectively remove serum creatinine and blood urea nitrogen.