Factors affecting the safety of infusing recirculated saline or blood in hemodialysis.

It is not surprising that there is no documented evidence supporting a standard for safe infusion of recirculated saline or blood in hemodialysis. A number of factors affect the bacteriologic and pyrogenic quality of recirculated saline and how individuals will physiologically respond to the final product. Attention to strict asepsis when preparing the dialysis circuit, bacterial quality of the dialysate, characteristics of the dialyzer used, and individual physiological response to the presence of endotoxins all play a part in whether individuals being dialyzed experience a pyrogenic response. Those who depend on chronic hemodialysis utilizing catheter access may be especially vulnerable due to the possibility of continued bacterial growth in the catheter lumen. Unit policy regarding the length of time a primed dialysis system can be considered safe for use should consider all of these factors. It may not be possible to create experimental situations in which all relevant factors leading to high quality of primed saline can replicate any one actual experience in a hemodialysis unit. However, practices that decrease the probability of bacterial contamination of priming saline or dialysate can help prevent adverse patient responses. Considering the limited evidence about reasons for thrombosis of blood in dialysis systems, very few conclusions can be drawn about the safety of infusing recirculated blood. The possible interactions of the dialysis system and individual physiological factors are limitless and are probably impossible to predict. The available literature identifies that the coagulation process begins immediately as blood interacts with the dialyzer and can be exacerbated if complement is activated. Combining this probability with the effects of possible pyrogen exposure, it is safe to say that considerable risk may exist the longer blood in the extracorporeal system is recirculated. Weighing these risks with the possible benefits of returning recirculated blood to a person on hemodialysis must be an individual decision each time the situation presents itself.