Sagedal S et al. (2006) Intermittent saline flushes during haemodialysis do not alleviate coagulation and clot formation in stable patients receiving reduced doses of dalteparin. Nephrol Dial Transplant 21: 444–449

Heparin-free hemodialysis with intermittent saline flushes (ISF) has been reported to be a safe and effective method for maintenance hemodialysis in patients with increased bleeding risk; however, studies supporting these claims have failed to include appropriate controls using heparin-free dialysis without ISF.

Sagedal and colleagues assessed six dialysis sessions performed with or without ISF (100 ml every 30 min) in each of eight stable patients on chronic hemodialysis. Dalteparin was given as one bolus dose (50% of conventional dose) at the start of each session. Potential clotting in the bubble trap was evaluated and graded on a four-point scale every hour, and the dialyzer was visually inspected at the end of each session. Coagulation and platelet activation factors were measured during hemodialysis.

Dialysis was stopped because of a coagulated system in four patients; all coagulations occurred during hemodialysis with ISF. Multiple linear regression analyses showed that ISF (adjusted for dalteparin dose/kg) significantly increased mean clot in the bubble trap compared with no ISF (P = 0.0001). The coagulation marker prothrombin fragment 1+2 was significantly increased when ISF was included in hemodialysis (P = 0.001).

These results indicate that, rather than alleviating coagulation, ISF promotes clot formation in stable patients receiving reduced doses of dalteparin. Further studies are required to determine whether these results also apply to unstable patients with increased bleeding risk not receiving any anticoagulation therapy.