Efecto agudo del baño con citrato sobre la alcalemia postdiálisis

Abstract

Introduction: Correcting metabolic acidosis provoked by renal failure is achieved by supplying bicarbonate during dialysis. To prevent the precipitation of calcium and magnesium carbonate produced in the dialysis fluid (DF) when bicarbonate is added, it is necessary to add an acid (normally acetate), which involves secondary effects. Consequently, citrate is presented as an advantageous alternative to acetate, although its acute effects are not known with precision.Objective: Our objective was to assess the acute effect of using a DF with citrate instead of acetate on the parameters of acid-base balance and of phosphorus-calcium metabolism.Material and methods: We carried out a prospective, cross-over study on 24 patients (15 males and 9 females). All the patients were dialysed using an AK 200 ULTRA-S monitor with SoftPac® DF, prepared with 3 mmol/l of acetate, and with SelectBag Citrate®, with 1 mmol/l of acetate-free citrate. Before and after dialysis we extracted: venous blood gases, calcium (Ca), ionized calcium (Cai), phosphorus (P) and parathyroid hormone (PTH).Results: We found differences (P<.05) when we used a dialysate with citrate (C) compared with using acetate (A) in the post-dialysis values of pH (C: 7.43 [0.04] vs A: 7.47 [0.05]), bicarbonate (C: 24.7 [2.7] vs A: 27.3 [2.1] mmol/L), base excess of extracellular fluid (BEecf) (C: 0.4 [3.1] vs A: 3.7 [2.4] mmol/L), corrected calcium (cCa) (C: 9.8 [0.8] vs A: 10.1 [0.7] mg/dl) and Cai (C: 1.16 [0.05] vs A: 1.27 [0.06] mmol/L). We found no differences in any of the parameters measured before dialysis.Conclusion: Dialysis with citrate achieves better post-dialysis acid-base balance, lowering/avoiding post-dialysis alkalemia and producing a lower increase in corrected calcium (Cac) and Cai. This finding is of special interest for patients with predisposing factors to arrhythmia and patients with respiratory failure, carbon dioxide retention, calcifications or advanced hepatopathy.