A Comparison of Bicarbonate Kinetics and Acid-base Status in High Flux Hemodialysis and On-Line Post-Dilution Hemodiafiltration

Morel, Hélène; Jaffrin, Michel Y.; Lux, Clément; Renou, Marianne; Fessier, Claire; Petit, A; Morinière, P; Legallais, Cécile

doi:10.5301/ijao.5000082

Cited by 20 publications

(18 citation statements)

References 15 publications

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“…Our acid‐base measurements are consistent with previous studies, demonstrating little further change in blood [HCO 3 − ] after 2 hours of treatment . Blood pH rises gradually throughout the treatment, from a predialysis value of 7.38 to an end treatment value of 7.50.…”

Section: Measurement Resultssupporting

confidence: 91%

“…Because blood [HCO 3 − ] remains essentially constant during the last hour or so of dialysis despite a continued driving force for its entry from the bath, a quasi‐steady state develops in which base addition is matched or exceeded by H + generation. Our results and those of others suggest that this dysequilibrium persists even when the duration of dialysis is extended to 4 full hours …”

Section: Model Analysissupporting

confidence: 84%

“…Only a few studies have reported the pattern of rise in blood [HCO 3 − ] during a single hemodialysis treatment . These studies have uniformly shown that almost all the increase occurs during the first two hours, with little change thereafter despite a continued gradient for HCO 3 − entry from the bath solution.…”

Section: Introductionmentioning

confidence: 99%

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Acid‐base homeostasis during hemodialysis: New insights into the mystery of bicarbonate disappearance during treatment

Sargent

Marano²,

Maranò

et al. 2018

Seminars in Dialysis

130

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In patients receiving hemodialysis, it has long been recognized that much more bicarbonate is delivered during treatment than ultimately appears in the blood. To gain insight into this mystery, we developed a model that allows a quantitative analysis of the patient's response to rapid alkalinization during hemodialysis. Our model is unique in that it is based on the distribution of bicarbonate in the extracellular fluid and assesses its removal from this compartment by mobilization of protons (H ) from buffers and other sources. The model was used to analyze the pattern of rise in blood bicarbonate concentration ([HCO ]), calculated from measurements of pH and PCO , in patients receiving standard bicarbonate hemodialysis. Model analysis demonstrated two striking findings: (1) 35% of the bicarbonate added during hemodialysis was due to influx and metabolism of acetate, despite its low concentration in the bath solution, because of the rapidly collapsing gradient for bicarbonate influx. (2) Almost 90% of the bicarbonate delivered to the patients was neutralized by H generation. Virtually all the new H came from intracellular sources and included both buffering and organic acid production. The small amount of added bicarbonate retained in the extracellular fluid increased blood [HCO ], on average, by 6 mEq/L in our patients. Almost all this rise occurred during the first 2 hours. Thereafter, blood [HCO ] changed minimally and always remained less than bath [HCO ]. This lack of equilibrium was due to the continued production of organic acid. Release of H from buffers is a reversible physiological response, restoring body alkali stores. By contrast, organic acid production is an irreversible process during hemodialysis and is metabolically inefficient and potentially catabolic. Our analysis underscores the need to develop new approaches for alkali repletion during hemodialysis that minimize organic acid production.

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Section: Measurement Resultssupporting

confidence: 91%

Section: Model Analysissupporting

confidence: 84%

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Acid‐base homeostasis during hemodialysis: New insights into the mystery of bicarbonate disappearance during treatment

Sargent

Marano²,

Maranò

et al. 2018

Seminars in Dialysis

130

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“…These data confirm the in vitro data obtained by the same group . Thus, BIC dialysance behaves very differently from urea clearance, even though both solutes have a similar molecular weight …”

Section: Acid‐base Balance In Patients Undergoing Hdsupporting

confidence: 90%

“…When comparing bicarbonate kinetics and acid‐base status in high‐flux HD and on‐line postdilution hemodiafiltration (D BIC was 38 mmol/L in both treatments; the mean reinjected volume was 21 L in hemodiafiltration), no significant differences were observed between acid‐base parameters at the end of HD and hemodiafiltration sessions. An unexpected result was the continuous decay of BIC dialysance both in HD and hemodiafiltration runs . These data confirm the in vitro data obtained by the same group .…”

Section: Acid‐base Balance In Patients Undergoing Hdsupporting

confidence: 85%

Dialysate bicarbonate concentration: Too much of a good thing?

Basile

Rossi

Lomonte

2018

Seminars in Dialysis

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Acid-base equilibrium is a complex and vital system whose regulation is impaired in chronic kidney disease (CKD). Metabolic acidosis is a common complication of CKD. It is typically due to the accumulation of sulfate, phosphorus, and organic anions. Metabolic acidosis is correlated with several adverse outcomes, such as morbidity, hospitalization and mortality. In patients undergoing hemodialysis, acid-base homeostasis depends on many factors: net acid production, amount of alkali given by the dialysate bath, duration of interdialytic period, as well as residual diuresis, if any. Recent literature data suggest that the development of postdialysis metabolic alkalosis may contribute to adverse clinical outcomes. Unfortunately, no randomized studies exist about the effect of different dialysate bicarbonate concentrations on hard outcomes, such as mortality. Like everything else in dialysis, the quest for the "ideal" dialysate bicarbonate concentration is far from over. The Latin aphorism "ne quid nimis" ie "nothing in excess" (excess of neither acid nor base) probably best summarizes our current state of knowledge in this field. For the present, the clinician should understand that target values for predialysis serum bicarbonate concentrations have been established primarily based on observational studies and expert opinion. On the basis of this information, we should keep predialysis serum bicarbonate concentrations at least at 22 mEq/L. Furthermore, a specific focus should be addressed to the clinical and nutritional status of the major outliers on both the acid and alkaline sides of the curve.

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Integrated Model of Cardiovascular System, Body Fluids and Haemodialysis Treatment: Structure, Equations and Parameters

Pstras

Waniewski

2019

Mathematical Modelling of Haemodialysis

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A Comparison of Bicarbonate Kinetics and Acid-base Status in High Flux Hemodialysis and On-Line Post-Dilution Hemodiafiltration

Abstract: Uremic acidosis was well corrected without risk of alkalosis. An unexpected result was the continuous decay of bicarbonate dialysance both in HD and HDF during runs.

Cited by 20 publications

References 15 publications

Acid‐base homeostasis during hemodialysis: New insights into the mystery of bicarbonate disappearance during treatment

Acid‐base homeostasis during hemodialysis: New insights into the mystery of bicarbonate disappearance during treatment

Dialysate bicarbonate concentration: Too much of a good thing?

Integrated Model of Cardiovascular System, Body Fluids and Haemodialysis Treatment: Structure, Equations and Parameters

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