Sustained Low-Efficiency Dialysis (SLED) with Regional Citrate Anticoagulation (RCA) and new dialysis equipment: a prospective study with serum citrate measurements and electrolyte monitoring.

Background: Sustained-Low Efficiency Dialysis (SLED) is an increasingly used Kidney Replacement Therapy (KRT) modality in critically ill patients. This study was aimed at evaluating the safety and efficacy of simplified Regional Citrate Anticoagulation (RCA) for SLED using new hemodialysis equipment.

Methods: The 8-hour SLED sessions were performed with a Surdial X Nipro^® hemodialysis machine and a cellulose triacetate filter. A concentrated citrate solution (ACD-A) was infused in predilution with a target circuit citrate concentration of 2.5-3 mmol/L. Blood recalcification in the extracorporeal circuit mainly occurred through the backfiltration phenomenon by dialysis fluid (Ca²⁺ 1.5 mmol/L). Serum citrate levels were directly measured during KRT by enzymatic methods and an extensive daily laboratory workup was performed. Changes in laboratory variables at the end of the SLED sessions were analyzed with mixed-effects linear models for repeated measures.

Results: Eighty-one SLED treatments were performed in 27 patients (APACHE II score 21 ± 6). The prescribed duration was attained for the majority of the treatments (72/81, 88%). No major bleeding episodes or side effects of citrate accumulation occurred. While calcium infusion was needed in 19/81 SLED sessions (23%), phosphate and magnesium supplementation was necessary following about 25% of all SLED sessions.

Conclusions: Our simplified regional citrate anticoagulation protocol for SLED with a new "conventional" dialysis machine resulted safe and effective, also for critically ill patients, ensuring a good match between the prescribed and delivered dialysis dose. Close electrolyte monitoring and early supplementation allowed to tailor the dialysis prescription to the patient's actual needs, while avoiding KRT-related complications.