Survival and complications of indwelling venous catheters for permanent use in hemodialysis patients.

BACKGROUND: The risk factors influencing the survival of indwelling central vein catheters and their potential complications have not been assessed in depth and on a large scale. METHODS: We investigated the general characteristics of 245 single lumen cuffed tunneled catheters and analyzed their survival by Kaplan-Meier and Cox regression analysis. Risk factors for bacteremia and thrombosis were assessed by logistic regression analysis. RESULTS: The incidence of exit-site infection, tunnel infection, bacteremia and thrombotic events was 0.35, 0.25, 1.71, and 1.94/1000 catheter days, respectively. The mean survival time per catheter was 276 days. After censoring for non catheter-related events leading to the removal of the catheter (n = 245 with 120 catheters censored and 125 events), the mean survival time of the catheter appeared to be 615 +/- 67 days (95% CI of 483-747) and the median survival time 310 +/- 50 days (95% CI of 212-408). The localization of the catheter into the right internal jugular vein results in significantly better survival as compared with other insertion sites both in Kaplan-Meier (mean survival of 650 days compared to a mean survival of 519 days, P value < 0.009) and in Cox regression analysis (relative risk of 0.537, P value < 0.001). Localization of the catheter into the right internal jugular vein seemed to increase the risk for bacteremia (relative risk of 1.798, P value of 0.063). The use of anticoagulant agents was not protective for thrombosis, although this might be due to lack of power (relative risk of 0.626, P value of 0.141). CONCLUSION: We provide evidence of a mean survival in long-term hemodialysis catheter close to 2 years with an acceptable complication rate. If a long-term hemodialysis catheter is required, it is best placed in the right internal jugular vein.

Toxicity of free p-cresol: a prospective and cross-sectional analysis.

BACKGROUND: Uremic syndrome is the consequence of the retention of solutes usually cleared by the healthy kidneys. p-Cresol can be considered a prototypic protein-bound uremic toxin. It is conceivable, analogous with drugs, that the non-protein-bound fraction of p-cresol exerts toxicity. This aspect had never been evaluated, nor have the factors influencing the free fraction of p-cresol. METHODS: In a transsectional study we evaluated the relationship between prehemodialysis free p-cresol and the ratio of free to total p-cresol (F:T) to clinical and biological factors in 44 chronic renal failure patients. The evolution of free p-cresol was assessed prospectively in 12 patients showing a change in serum albumin of at least 5 g/L over time. Hospitalization days attributable to infection and the free p-cresol concentrations were noted over a 1-year period. The impact of free p-cresol in vitro on leukocyte functional capacity was evaluated by chemiluminescence. RESULTS: We observed a correlation between total and free p-cresol (r = 0.84; P <0.001). In the multivariate analyses, free p-cresol and F:T showed a negative correlation with albumin. A shift from normal serum albumin to hypoalbumininemia in 12 patients led to an increase in free p-cresol from 5.9 +/- 3.2 to 8.2 +/- 4.5 micro mol/L (P <0.05; 0.64 +/- 0.35 to 0.89 +/- 0.49 mg/L). Free p-cresol (P <0.05) was higher in the patients hospitalized for infectious disease. In vitro, free p-cresol was higher in a 25 g/L than in a 50 g/L albumin solution (P <0.05). Leukocyte chemiluminescence production was more inhibited in the low albumin (high free p-cresol) solution (28% +/- 6% vs 21% +/- 8%; P <0.05). CONCLUSIONS: Hypoalbuminemia and total p-cresol increase the free fraction of p-cresol. Patients hospitalized for infections have higher free p-cresol. In vitro, high free p-cresol has a negative impact on leukocyte chemiluminescence production. These data demonstrate the toxicity of free p-cresol.