26 Regional Citrate Anticoagulation During Hemodialysis: Our Experiences
Authors: Buturović‐Ponikvar J , Čatak S , Benedik M , Varl J , Knap B , Pernat A Marn , Kandus A , Guček A , Premru V , Malovrh M , Gubenšek J , Škofic N , Gaber L , Bren A F , Ponikvar R 
Published: February 2005

Background  Regional citrate anticoagulation (RCA) during hemodialysis is alternative to heparin in patients at high risk of bleeding. It enables excellent antithrombotic effect in the circuit, but requires strict monitoring during the procedure. The aim of our retrospective clinical study is to evaluate safety and efficacy of RCA performed according to our unit protocol.

Methods  Data from 40 protocols for RCA performed between April and June 2004 were analyzed. Double‐needle vascular access was obtained via either arteriovenous fistula or hemodialysis catheter. Hollow‐fiber dialyzer Polyflux 14 S (Gambro, Lund, Sweden) was used in all dialysis sessions. Calcium‐free dialysate was used and set to: Na 137 mEq/L, bicarbonate 28 mEq/L, magnesium 0.5 mEq/L, potassium 2.0 mEq/L, glucose 0 mEq/L. Potassium and glucose were added into the dialysate or intravenously if needed, respectively. Blood flow rate was maintained between 250–300 mL/min. 4% trisodium citrate was infused in the arterial line of the circuit, proximally from the arterial bubble trap, at the initial rate 300 mL/hour and adjusted accordingly to the blood flow rate and targeted clotting time (15–20 minutes in the circuit). One molar CaCl2 was infused in the venous line (distally from the venous bubble trap) at the initial rate 13 mL/h and was adjusted to maintain ionized calcium concentration (iCa) within normal range. Clotting time, iCa, Na, and bicarbonate were measured during hemodialysis. Clot formation in the dialyzer was estimated by counting the number of clotted fibers and assessment of clot presence in bubble traps.

Results   (see Table A26)

preHD
At 60 min
At 120 min
At 180 min
Post HD

Clotting time (min)
–
11.0 ± 3.4
11.0 ± 3.3
11.2 ± 3.0
 11.2 ± 2.7

iCa (mmol/L)
1.15 ± 0.31
 1.0 ± 0.12
1.03 ± 0.09
1.04 ± 0.10
 1.07 ± 0.20

Sodium (mmol/L)
 137 ± 4
 139 ± 3
 139 ± 4
 140 ± 3
  140 ± 3

Bicarbonate (mmol/L)
21.4 ± 3.0
–
–
–
25.02 ± 3.3

pH
7.39 ± 0.04
–
–
–
 7.45 ± 0.07

At 60 min
At 120 min
At 180 min
At 240 min

Blood flow rate (mL/min)
268 ± 24
 266 ± 25
267 ± 23
 267 ± 23

Citrate infusion rate (mL/h)
297 ± 11
 298 ± 23
297 ± 22
 300 ± 15

1M CaCl2 inf. rate (mL/h)
12.95 ± 0.45
13.12 ± 1.4
13.17 ± 1.55
13.35 ± 1.1

Assessment of clotting in the circuit   23/40 dialyzers (57.5%) were estimated as excellent (<10 clotted fibers), 14/40 (35%) as very good (11–20 clotted fibers), 2/40 (5%) as good (21–50 clotted fibers) and one dialyzer (2.5%) was full of small thrombi (50–100 clotted fibers capillaries). We noted significant clots in the venous bubble trap in two dialysis sessions. In addition, significant clots in the arterial bubble trap was noted in two dialysis sessions. No dialysis session was terminated prematurely because of technical or clinical problems.

Conclusion  Regional citrate anticoagulation performed according to our protocol was safe and effective. Clotting time was lower than targeted, but excellent macroscopic antithrombotic activity in the circuit was achieved.