Anticoagulation-Free Continuous Renal Replacement Therapy Using Calcium-Free Predilution: A Single-Center Pilot Study

Aim Continuous renal replacement therapy (CRRT) usually requires systemic or regional anticoagulation to maintain circuit patency. However, in real-world intensive care settings, the use of heparin or regional citrate anticoagulation (RCA) may be limited by bleeding risk, severe coagulopathy, and technical or organizational constraints. In addition, in patients with shock and elevated lactate levels, citrate metabolism may be impaired, potentially leading to metabolic complications. In such circumstances, simplified strategies to preserve filter lifespan without formal anticoagulation are needed. Study Design This single-center observational study included ten critically ill adult patients who underwent CRRT using a calcium-free predilution solution (Prism0cal) without routine systemic heparin or RCA. The strategy aimed to reduce hemoconcentration and ionized calcium availability within the extracorporeal circuit to preserve filter function. CRRT parameters, treatment duration, filter performance, and reasons for discontinuation were recorded. Serial monitoring of ionized calcium, acid–base status, and metabolic parameters was performed, and systemic calcium and bicarbonate replacement was administered when clinically indicated. Results CRRT was successfully initiated in all patients under challenging clinical and organizational conditions. In patients with treatment durations ≥16 hours, filters were maintained without anticoagulation-related complications. Interruptions of therapy were primarily related to patient deterioration or technical factors rather than metabolic instability. Ionized calcium levels remained within a manageable range during treatment, although systemic calcium supplementation was required in selected cases. Acid–base parameters generally stabilized during CRRT with supportive bicarbonate therapy when necessary. Conclusion Anticoagulation-free CRRT using calcium-free predilution was feasible and physiologically tolerable in critically ill patients when conventional anticoagulation strategies could not be applied. With acceptable circuit performance and manageable metabolic effects, this pragmatic approach may represent a viable alternative in selected high-risk patients and real-world intensive care settings.