Objective: To determine if circuit life is influenced by a higher pre- dilution volume used in CVVH when compared with a lower pre- dilution volume approach in CVVHDF.Design: A comparative crossover study. Cases were randomized to receive either CVVH or CVVHDF followed by the alternative treatment.Subjects: All patients >= 18 yrs of age who required CRRT while in ICU were eligible to participate, but excluded if coagulopathic, thrombocytopenic or unable to receive heparin. Based on an intention- to- treat, 45 patients were randomized to receive either CVVH or CVVHDF followed by the alternative treatment. Setting: A 24- bed, tertiary, medical and surgical adult intensive care unit ( ICU).Intervention: Blood flow rate, vascular access device and insertion site, hemofilter, anticoagulation and machine hardware were standardized. An ultrafiltrate dose of 35 ml/ kg/ h delivered pre- filter was used for CVVH. A fixed pre- dilution volume of 600 mls/ h with a dialysate dose of 1 L was used for CVVHDF. Results: Thirty- one patients received CVVH or CVVHDF out of 45 participants followed by the alternative technique. There was a significant increase in circuit life in favor of CVVHDF ( median= 16 h 5 min, range= 40 h 23 min) compared with CVVH ( median= 6 h 35 min, range= 30 h 45 min). A Mann- Whitney U test was performed to compare circuit life between the two different CRRT modes ( Z=- 3.478, p< 0.001). Measurements of circuit life on the 93 circuits which survived to clotting ( 50 CVVH and 43 CVVHDF) were log transformed prior to under taking a standard multiple regression analysis. None of the independent variables - activated prothrombin time ( aPTT), platelet count, heparin dose, patient hematocrit or urea - had a coefficient partial correlation > 0.09 ( coefficient of the determination= 0.117) or a linear relationship which could be associated with circuit life ( p= 0.228).Conclusion: Pre- diluted CVVHDF appeared to have a longer circuit life when compared to high volume pre- diluted CVVH. The choice of CRRT mode may be an important independent determinant of circuit life. ( Int J Artif Organs 2008; 31: 221- 7).
|Journal||International Journal of Artificial Organs|
|Publication status||Published - 2008|