Vascular reactivity during combined ultrafiltration-hemodialysis: influence of dialysate-derived contaminants.

It has been suggested that hemodynamic instability and impaired vascular reactivity during combined ultrafiltration-hemodialysis are related to bioincompatibility factors such as dialysate-derived contaminants or the dialyzer. The study presented here investigated whether vascular reactivity could be improved by the use of sterile dialysate. Forearm vascular resistance and venous tone (measured by strain-gauge plethysmography) as well as arterial blood pressure (by Dinamap) and heart rate (by electrocardiogram) were measured in ten stable dialysis patients (age range, 28 to 71 yr) during 2 h of combined ultrafiltration-hemodialysis (bicarbonate; ultrafiltration rate 1.0 L/h). In addition, a dialysate sample was obtained for culture and limulus amebocyte lysate testing while blood was withdrawn for the estimation of plasma bactericidal/permeability increasing factor (measured by ELISA) and the soluble tumor necrosis factor receptor p75 (measured by ELISA). Patients served as their own control, comparing dialysis with nonsterile and sterile dialysate. No bacterial growth was observed in sterile dialysate, whereas all samples were positive for Pseudomonas in culture in nonsterile dialysis. All limulus amebocyte lysate tests were negative. Bactericidal/permeability increasing factor tended to increase during nonsterile dialysis (P = 0.063) and remained unchanged during sterile dialysis. In both treatments, tumor necrosis factor receptor p75 increased significantly (P < 0.01). There were no significant differences in hemodynamic parameters between the treatment modalities. Despite use of sterile dialysate, forearm vascular resistance remained unchanged whereas venous tone decreased significantly. These results indicate that vascular reactivity during combined ultrafiltration-hemodialysis is not improved by the use of sterile dialysate.