PO067 – REGIONAL ANTICOAGULATION IN CONTINUOUS VENOVENOUS HEMODIAFILTRATION COMBINING A LOW CITRATE DOSE WITH A PHOSPHATE-CONTAINING SOLUTION

Autori: Di Mario F (1), Pistolesi V (1), Zeppilli L (1), Sacco MI (1), Polistena F (1), Regolisti G (2), Fiaccadori E (2), Morabito S (1)
Affiliazioni:  (1) UOD Dialisi, Policlinico Umberto I, Sapienza, Università di Roma; (2) Unità Fisiopatologia dell’Insufficienza Renale, Università degli Studi di Parma

Introduction: Regional citrate anticoagulation (RCA) is increasingly used to minimize CRRT related bleeding risk and a citrate dose ranging from 3 to 4 mmol/l is usually adopted. Hypophosphatemia is reported in up to 80% of cases when standard solutions are used and may negatively impact on respiratory, central nervous and cardiovascular systems.

The aim of the study was to evaluate the efficacy and safety of an RCA protocol characterized by a lower than conventional citrate dose and by the use of a phosphate-containing solution.

Methods: In heart surgery patients undergoing CRRT for AKI we adopted RCA as standard anticoagulation strategy. RCA in CVVHDF modality was performed by using an 18 mmol/l citrate solution combined with a calcium and phosphate-containing replacement fluid acting as dialysate and replacement fluid (Figure 1).The citrate solution rate was initially set to obtain an estimated circuit citrate concentration of 2.5-3 mmol/l, calculated in plasma water. Hypophosphatemia was defined as mild (<0.81 mmol/l), moderate (<0.61 mmol/l) and severe (<0.32 mmol/l). Potassium, phosphate and magnesium losses with CRRT were replaced, when needed, respectively with potassium chloride, d-fructose-1,6-diphosphate (FDP; Esafosfina® 5 g/50 ml) and magnesium sulphate. FDP administration was scheduled in case of phosphate levels <0.9 mmol/l.

Results: Over a four-years period 75 patients were treated with RCA-CVVHDF for at least 72 hours. RCA-CVVHDF initial parameters are showed in Table 1 while patient’s characteristics at the start of the treatment are reported in Table 2. Three hundred sixty-nine RCA circuits were used with a mean filter life of 53.9±33.6 hours (median 48, IQR 24-78, total running time 19.891 hours). Main parameters during RCA-CVVHDF are reported in Table 3.

Circuits running at 24, 48, 72 hours (%): 75, 51, 49.
RCA stopping causes: 56.7% scheduled, 22.2% CVC malfunction, 8.9% alarm handling/technical issues, 7.3% medical procedures, 4.9% circuit clotting.
No patients had clinically relevant bleeding complications and transfusion rate was 0.28 units/day. RCA has been stopped for signs of citrate accumulation in only 1 patient (calcium ratio >2.5). Regardless of base-line levels, phosphoremia was progressively corrected and maintained in a narrow normality range throughout CRRT days (after 72 hours: 1.14±0.25 mmol/l). Considering the whole CRRT period, 45 out of 975 (4.6%) serum phosphorus determinations met the criteria for mild (<0.81 mmol/l) or moderate (<0.61 mmol/l) hypophosphatemia; severe hypophosphatemia (<0.32 mmol/l) never occurred. After 72 hours, 88% of patients were normophosphatemic, 9% hyperphosphatemic and 3% hypophosphatemic (Figure 2). At some time during CRRT, only 15 out of 75 patients (20%) received a low amount of phosphate supplementation (d-fructose-1,6-diphosphate 0.79±1.83 g/day).
Conclusions

  • The RCA protocol adopted in our study, characterized by a lower than conventional citrate dose, aimed at reducing citrate load in patients with high illness severity, appeared safe and at the same time effective in preventing circuit clotting, thus minimizing CRRT down-time.
  • RCA allowed to ensure an adequate filter life and to maintain a low transfusion rate in high bleeding risk heart surgery patients with AKI and MODS.
  • During a prolonged RCA-CVVHDF treatment period, hypophosphatemia was effectively prevented or corrected in most patients throughout CRRT days.

Bibliografia:

Lascia un commento