P1056SUSTAINED LOW EFFICIENCY DIALYSIS (SLED) WITH STANDARD HEMODIALYSIS MACHINE AND CITRATE AS CIRCUIT ANTICOAGULANT IN CRITICALLY ILL PATIENTS WITH ACUTE KIDNEY INJURY
Authors: Di Mario Francesca , Fani Filippo , Greco Paolo , Maccari Caterina , Farina Maria Teresa , Di motta Tommaso , Parenti Elisabetta , Regolisti Giuseppe , Fiaccadori Enrico 
Published: June 2020

Abstract

Background and Aims
Sustained-Low Efficiency Dialysis (SLED) is a Renal Replacement Therapy (RRT) modality characterized by excellent efficiency and hemodynamic stability that is increasingly used in critically patients with Acute Kidney Injury (AKI). SLED can be performed with either continuous RRT or conventional hemodialysis machines. Even in the case of SLED, avoiding extracorporeal circuit clotting is a mainstay of treatment, and a rational approach to this issue is represented by regional citrate anticoagulation. The present pilot study is aimed at a preliminary evaluation of safety and efficacy of a simplified regional anticoagulation protocol based on ACD-A for SLED performed by using a conventional hemodialysis machine in critically ill patients with AKI in the ICU.

Method
SLED was performed for 8-12 hours (daily or every other day) with a Surdial X Nipro® hemodialysis machine, with a standard hemodialysis circuit, and a triacetate of cellulose filter (Sureflux-19L, 1.9 m2, KUF 19 ml/mmHg/h). Blood flow was set at 200 ml/min and dialysis fluid flow at 100 ml/min. The citrate was infused in pre-dilution as ACD-A solution (citrate 2.2%, 112.9 mmol/L) at rates ranging from 200 to 400 ml/h, to obtain an estimated pre-filter citrate concentration between 2 and 4 mmol/L. The treatment was monitored by serial evaluations of ionized calcium (Ca ++) and ACT (Hemochron Jr) at the following times: at the beginning of the SLED (sampling at the arterial line representative of patient’s blood), at the 2nd hour (arterial line and post-filter) and at the end of SLED (arterial line). Laboratory targets for monitoring were as follows: normal values of ACT and calcium ionized (Ca++) not less than 0.9 mmol/L in the patient blood (systemic circulation), ionized calcium values not less than 0.6 mmol/L in the post-filter blood. The blood of the extracorporeal circuit was then recalcified in the filter by dialysis fluid itself (Ca ++ 1.5 mmol/L) through Ca backfiltration. The protocol does not request routine calcium infusion to the patient until Ca++ values in the post-filter blood at the 2nd hour is &lt; 0.6 mmol/L.

Results
A total of 41 SLED sessions were performed in 12 patients (mean age 69 + 18 SD, 7 males and 5 females, mean APACHE II 22); 6 patients were on mechanical ventilation, and 6 had severe hemodynamic instability requiring high-dose vasoactive drugs. Patients had an average fluid overload of 6 Kg, as estimated by the usual weight values reported. Average pre-SLED urea was 94 mg/dL, and 32 mg/dL at the end of treatment. Most of the sessions were completed for elapsed prescribed time. Only in three cases a premature interruption was observed for clotting of circuit or of the filter (in all cases after at least 6 hours of treatment); in one case only blood restitution was not complete. No statistically significant differences were observed between systemic ACT values during SLED as compared to baseline values of the patients. Calcium infusion (calcium gluconate at fixed rate, 5 ml/h) was started in 10 treatments (10/42, 23.8%). No new cardiac arrhythmia episode or hemorrhagic events were observed during treatments or shortly after.

Conclusion
Our preliminary data suggests that a simplified citrate-based SLED protocol using a conventional dialysis machine is easy and safe, also ensuring a good match between prescribed and actual dialysis dose administered.