Alkalosis in Regional Citrate Anticoagulation during Continuous Renal Replacement Therapy—— A single-center retrospective study

Background: Metabolic alkalosis has raised concerns in patients receiving continuous renal replacement therapy (CRRT) via regional citrate anticoagulation (RCA). This study searched for alkalosis-related factors and mechanisms. Measurements: We conducted a retrospective cross-sectional study of alkalosis in patients who received CRRT for at least 12 hours with RCA at an emergency department in a tertiary hospital between April 2017 and April 2020. Main Results: The 59 patients meeting the inclusion criteria were 49% male, with a mean age of 55 ± 18 years old, and 42% had alkalosis by 12 hours after CRRT. Patients were divided into 4 groups based on whether they received NaHCO 3 and alkalosis after 12 hours of CRRT. No significant differences in demographic features or laboratory results were observed among the groups. CRRT metrics, including blood flow rate, PBP rate, replacement fluid rate and total effluent rate, were significantly different among groups (p < 0.01). Multivariable logistic regression analysis indicated that the citrate rate was a risk factor for alkalosis (OR 1.088, 95% CI 1.020–1.161, p = 0.010). In patients receiving no NaHCO3 and without alkalosis, the linear regression analysis described the relationships of citrate with replacement fluid rate (citrate rate = 0.090 × replacement fluid rate + 56.581; R 2  = 0.6918) and total effluent rate (citrate rate = 0.099 × total effluent rate + 2.449). Conclusions: This retrospective observational study demonstrated that CRRT metrics are highly associated with alkalosis after 12 hours of CRRT. Without NaHCO 3 infusion, a 10-fold linear correlation was observed between citrate and total effluent rate in patients without metabolic alkalosis.