Low bicarbonate replacement fluid normalizes metabolic alkalosis during continuous veno-venous hemofiltration with regional citrate anticoagulation

Paul Köglberger; Sebastian J Klein; Georg Franz Lehner; Romuald Bellmann; Andreas Peer; Daniel Schwärzler; Michael Joannidis

doi:10.1186/s13613-021-00850-4

Low bicarbonate replacement fluid normalizes metabolic alkalosis during continuous veno-venous hemofiltration with regional citrate anticoagulation

Ann Intensive Care. 2021 Apr 23;11(1):62. doi: 10.1186/s13613-021-00850-4.

Authors

Paul Köglberger¹, Sebastian J Klein¹, Georg Franz Lehner¹, Romuald Bellmann¹, Andreas Peer¹, Daniel Schwärzler¹, Michael Joannidis²

Affiliations

¹ Division of Intensive Care and Emergency Medicine, Department of Internal Medicine, Medical University Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria.
² Division of Intensive Care and Emergency Medicine, Department of Internal Medicine, Medical University Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria. Michael.joannidis@i-med.ac.at.

Abstract

Background: Metabolic alkalosis is a frequently occurring problem during continuous veno-venous hemofiltration (CVVH) with regional citrate anticoagulation (RCA). This study aimed to evaluate the effectiveness of switching from high to low bicarbonate (HCO₃^-) replacement fluid in alkalotic critically ill patients with acute kidney injury treated by CVVH and RCA.

Methods: A retrospective-comparative study design was applied. Patients who underwent CVVH with RCA in the ICU between 09/2016 and 11/2017 were evaluated. Data were available from the clinical routine. A switch of the replacement fluid Phoxilium^® (30 mmol/l HCO₃^-) to Biphozyl^® (22 mmol/l HCO₃^-) was performed as blood HCO₃^- concentration persisted ≥ 26 mmol/l despite adjustments of citrate dose and blood flow. Data were collected from 72 h before the switch of the replacement solutions until 72 h afterwards.

Results: Of 153 patients treated with CVVH during that period, 45 patients were switched from Phoxilium^® to Biphozyl^®. Forty-two patients (42 circuits) were available for statistical analysis. After switching the replacement fluid from Phoxilium^® to Biphozyl^® the serum HCO₃^- concentration decreased significantly from 27.7 mmol/l (IQR 26.9-28.9) to 25.8 mmol/l (IQR 24.6-27.7) within 24 h (p < 0.001). Base excess (BE) decreased significantly from 4.0 mmol/l (IQR 3.1-5.1) to 1.8 mmol/l (IQR 0.2-3.4) within 24 h (p < 0.001). HCO₃^- and BE concentration remained stable from 24 h till the end of observation at 72 h after the replacement fluid change (p = 0.225). pH and PaCO₂ did not change significantly after the switch of the replacement fluid until 72 h.

Conclusions: This retrospective analysis suggests that for patients developing refractory metabolic alkalosis during CVVH with RCA the use of Biphozyl^® reduces external HCO₃^- load and sustainably corrects intracorporeal HCO₃^- and BE concentrations. Future studies have to prove whether correcting metabolic alkalosis during CVVH with RCA in critically ill patients is of relevance in terms of clinical outcome.

Keywords: Acute kidney injury; Biphozyl®; Continuous veno-venous hemofiltration; Metabolic alkalosis; Phoxilium®; Regional citrate anticoagulation.