Regional Citrate Anticoagulation in Predilution Continuous Venovenous Hemofiltration Using Prismocitrate 10/2 Solution

Abstract

Regional citrate anticoagulation (RCA) for continuous renal replacement therapy (CRRT) is associated with a longer filter life and fewer bleeding events. Complexity of the regimen is the major hurdle preventing widespread application. This study describes a simple predilution continuous venovenous hemofiltration (CVVH) protocol utilizing a commercially prepared replacement solution containing citrate (Prismocitrate 10/2). Ten patients with acute renal failure were evaluated. The Prismaflex system was used for predilution CVVH, with Prismocitrate 10/2 running at 2500 mL/h as the main predilution replacement. An 8.4% sodium bicarbonate solution was infused at 50 mL/h in the first 2 h followed by 30 mL/h; 10% calcium gluconate was given to achieve an ionized calcium (iCa) level of 1-1.2 mmol/L. The circuit was run for 72 h unless there was filter clotting, transportation was required, or the patient did not require further CRRT. Total treatment duration was 504.5 h. The post-dilution equivalent ultrafiltration rate was 32.9 mL/kg/h (interquartile range [IQR] 31.6-38.2) and the median circuit life was 50.3 h (IQR 25.5-72.0). None of the circuit was changed due to circuit clotting. The median systemic iCa was 0.98 mmol/L (IQR 0.91-1.08). The total calcium-to-iCa ratio was 2.33 (IQR 2.21-2.45). None of the patients developed hypernatremia (Na ≥ 150 mmol/L) or citrate toxicity (total Ca-to-iCa ratio > 2.5 plus increasing metabolic acidosis), and metabolic alkalosis (pH ≥ 7.5) occurred in one patient. This simple RCA CVVH protocol using commercially-prepared solution could be a feasible, relatively safe, and effective alternative to the conventional regimen for patients with a body weight up to 80 kg.

Regional Citrate Anticoagulation for RRTs in Critically Ill Patients with AKI

“…The physiologic sodium content of isotonic solutions allows RCA CVVH or RCA CVVHDF without the need of a low-sodium replacement fluid and/ or dialysate (Table 1). In protocols using citrate-buffered replacement solutions, the buffer supply derives from citrate (predilution CVVH) or citrate and bicarbonate in various proportions (predilution and postdilution CVVH and CVVHDF) in relation to the composition and the combination of the solutions that are used (14,19,50,62,(64)(65)(66)(67). A simplification on the basis of the use of solutions with an appropriately low citrate concentration allows RCA CRRT as CVVH in the predilution-only modality (19,50).…”

“…An appropriate matching of citrate and CRRT solutions is also required with the use of isotonic solutions. In a comparison between two different low-concentration citrate solutions in RCA CVVHDF, the use of a citrate concentration of 23 mmol/L was frequently associated with metabolic alkalosis, whereas a lower citrate concentration (18 mmol/L) provided more appropriate acid-base balance (19,64) or combined with postdilution conventional replacement fluid (predilution and postdilution CVVH) (14) may be associated with a suboptimal buffer supply, which is not easily balanced through the optimization of RCA settings and frequently requires additional bicarbonate supplementation directly to the patient. Abnormalities of parathyroid hormone (PTH) release during RCA have been reported (93,94) and seem to be mainly related to calcium balance during RRT.…”

A New Type of Double-Lumen Catheter to Replace Current One in RCA

“…Potassium was added to the pre-replacement fluid for those patients who required supplementation. Rates of hemofilter clotting, significant bleeding events, metabolic alkalosis (defined as pH > 7.50 [1]) and evidence of citrate toxicity were observed (Table 2).…”

“…Regional citrate anticoagulation (RCA) for CRRT is associated with a longer filter life span and fewer bleeding events. However, the complexity of the regimen is the major hurdle preventing widespread application [1] [2] for example, frequent peripheral vein puncture for blood sampling. In order to simplify the cumbersome operating procedures of blood sampling, a new type of double lumen catheter was located in the patient's femoral vein, in which the minimum distance from the inner venous port to the inner arterial port was lengthened to 6 cm long, then, extracorporeal circulation connected via arterial and return lines.…”

Risks and benefits of citrate anticoagulation for continuous renal replacement therapy

“…Alternatively, normonatraemic citrate solution may be used, for instance, Prismocitrate 18/0 or Prismocitrate 10/2 (Gambro Hospal, Stockholm, Sweden), which serves as both an anticoagulant and a source of buffer for predilutional treatment. 28,29 The drawback of this method is that it does not guarantee a fixed relationship between citrate and blood flow. This is due to the fact that the amount of replacement fluid entering the circuit is dependent on filtrate flow and the desired amount of fluid removal, which are prone to variations.…”