The dynamics of the metabolism of acetate and bicarbonate associated with use of hemodialysates in the ABChD trial: a phase IV, prospective, single center, single blind, randomized, cross-over, two week investigation

Abstract

BackgroundIn the United States, hemodialysis (HD) is generally performed via a bicarbonate dialysate. It is not known if small amounts of acid used in dialysate to buffer the bicarbonate can meaningfully contribute to overall buffering administered during HD. We aimed to investigate the metabolism of acetate with use of two different acid buffer concentrates and determine if it effects blood bicarbonate concentrations in HD patients.MethodsThe Acid-Base Composition with use of hemoDialysates (ABChD) trial was a Phase IV, prospective, single blind, randomized, cross-over, 2 week investigation of peridialytic dynamics of acetate and bicarbonate associated with use of acid buffer concentrates. Eleven prevalent HD patients participated from November 2014 to February 2015. Patients received two HD treatments, with NaturaLyte® and GranuFlo® acid concentrates containing 4 and 8 mEq/L of acetate, respectively. Dialysate order was chosen in a random fashion. The endpoint was to characterize the dynamics of acetate received and metabolized during hemodialysis, and how it effects overall bicarbonate concentrations in the blood and dialysate. Acetate and bicarbonate concentrations were assessed before, at 8 time points during, and 6 time points after the completion of HD.ResultsData from 20 HD treatments for 11 patients (10 NaturaLyte® and 10 GranuFlo®) was analyzed. Cumulative trajectories of arterialized acetate were unique between NaturaLyte® and GranuFlo® (p = 0.003), yet individual time points demonstrated overlap without remarkable differences. Arterialized and venous blood bicarbonate concentrations were similar at HD initiation, but by 240 min into dialysis, mean arterialized bicarbonate concentrations were 30.2 (SD ± 4.16) mEq/L in GranuFlo® and 28.8 (SD ± 4.26) mEq/L in NaturaLyte®. Regardless of acid buffer concentrate, arterial blood bicarbonate was primarily dictated by the prescribed bicarbonate level. Subjects tolerated HD with both acid buffer concentrates without experiencing any related adverse events.ConclusionsA small fraction of acetate was delivered to HD patients with use of NaturaLyte® and GranuFlo® acid buffers; the majority of acetate received was observed to be rapidly metabolized and cleared from the circulation. Blood bicarbonate concentrations appear to be determined mainly by the prescribed concentration of bicarbonate.Trial registrationThis trial was registered on ClinicalTrials.gov on 11 Dec 2014 (NCT02334267).Electronic supplementary materialThe online version of this article (doi:10.1186/s12882-017-0683-6) contains supplementary material, which is available to authorized users.

Nouveaux dialysats : quel acide dans le bain de dialyse ?

“…La généralisation de l'hémodialyse au bicarbonate dans les années 1980 s'est accompagnée d'une nette amélioration de la tolérance des séances, notamment hémodynamique [3,10,11,16]. Il semble persister malgré tout une augmentation significative de l'acétatémie après les séances d'hémodialyse, bien que les études ne soient pas toutes concordantes : une étude récente a trouvé une concentration normale d'acétate [17], à l'inverse de travaux antérieurs qui montraient une élévation de la concentration d'acétate de 10 à 70 fois la limite supérieure de la normale [18,19].…”

Alkali delivery in chronic hemodialysis: Would more acetate be helpful?

“…Although some hemodialysis patients may have exceptionally low rate of acetate metabolism, most patients on hemodialysis metabolize acetate rapidly. Indeed, according to a recent paper, arterial acetate concentrations did not differ between patients treated with 4 mmol/L and 8 mmol/L of sodium acetate in their dialysate. With a dialysate acetate concentration of 8 mmol/L, the average concentration of acetate in blood leaving the dialyzer was about 2 mmol/L, while blood entering the dialyzer was markedly reduced at about 0.5 mmol/L.…”

“…Although some hemodialysis patients may have exceptionally low rate of acetate metabolism, most patients on hemodialysis metabolize acetate rapidly. Indeed, according to a recent paper, 7 per minute in patients receiving acetate dialysis and similar rates in normal volunteers 8,9 . This calculation (0.5 mmol/min) is based on the assumption that the blood flow through the dialyzer is 400 mL per minute, hematocrit is 33%, concentration of acetate in the red blood cell is about 2/3 the concentration in plasma, and red blood cell water content is 62% of red blood cell mass.…”

Citric Acid–Containing Dialysate and Survival Rate in the Dialysis Outcomes and Practice Patterns Study

“…Several beneficial effects have been attributed to the use of citric acid-containing dialysate including fewer episodes of intradialytic arterial hypotension (6), improved dialysis performance (8), better control of metabolic acidosis (9), reduced dose of anticoagulation (10), improved calcification propensity score or T50 (11,12), and improved nutritional status (13). However, some negative effects have also been described such as muscular cramps (14), negative calcium balance, and the exacerbation of secondary hyperparathyroidism (15), and most importantly an increased risk of mortality (16).…”