[Risk analysis and validation of the process for producing the substitution fluid for online hemodiafiltration]. / Analyse des risques et validation du procédé de production du liquide de substitution de la technique d'hémodiafiltration en ligne.

INTRODUCTION: Online hemodiafiltration is a technique of dialysis with many advantages, but its use is limited because of the lack of control of microbiological risks. This work conducts a risk analysis of the process for producing substitution liquid for online hemodiafiltration and validates this process from a microbiological point of view. MATERIAL AND METHOD: The risk analysis was carried out following the approach of analysing failure modes, their effects and their criticalities. It identified the "worst case" of the production process being studied. For the validation of this process, we used the limulus amoebocytes lysate assay for bacterial endotoxins and the membrane filtration test for sterility control. RESULTS: We identified 17 failure modes, 13 of which were acceptable. Failure modes that exceeded the acceptability threshold were defined as "worst cases". Sterility monitoring and endotoxin testing, conducted in the "worst case", verified the microbiological quality of the liquid produced to the required standards and subsequently validated the process used. DISCUSSION: This approach has resulted in the identification of as many failure modes as possible. Validating in "worst case" is an extreme challenge to the process and its success provides a sufficient basis to conclude that the technique is safe and, therefore, to validate the process. CONCLUSION: This work has enabled us to validate our production process in extreme cases to promote safer use of the technique.

Role of thrombophilia in vascular access thrombosis among chronic hemodialysis patients in Tunisia.

Vascular access thrombosis represents a serious and common problem in hemodialysis patients. Therefore, identification of relevant thrombotic risk factors could lead to an improved antithrombotic therapy. This case control study was performed to evaluate the relationship between some thrombophilias and vascular access thrombosis in hemodialysis patients. Seventy-eight patients undergoing dialysis (between May 2007 and September 2009) were selected as subjects. This sample was divided into two groups; a case group of 28 patients who had sustained one or more thrombotic events that resulted in vascular access failure and a control group of 50 patients, who had never had a thrombotic occlusion of a functioning permanent dialysis access. Antithrombin, protein C and protein S levels were measured. Also, both groups were tested for the factor V Leiden mutation, the prothrombin G20210A mutation, the methylene tetrahydrofolate reductase C677T and A1298C mutations. Among genetic mutations of factor V Leiden, prothrombin G20210A and methylene tetrahydrofolate reductase genes, the C677T methylene tetrahydrofolate reductase mutation was the only significant genetic cause of vascular access thrombosis (P=0.005). Our data demonstrated a significantly increased risk of vascular access thrombosis in carriers of the C677T methylene tetrahydrofolate reductase mutation.