Clin Nephrol. 2022 Jul;98(1):26-32. doi: 10.5414/CN110735.
We aimed to evaluate daily variability of bicarbonate in hemodialysis (HD) patients and identify the factors which affect that issue.
Blood samples of 41 patients for bicarbonate (total carbon dioxide (CO)) and blood gas analysis (pH, bicarbonate (HCO)) were obtained, pre-dialysis and post-dialysis, on the first, second, and third session of the week. Those with pre-dialysis HCO < 22 mmol/L in all sessions were classified as acidotic. Demographic and laboratory data of acidotic and non-acidotic groups were compared, and the factors related to HCO level were identified.
pH, tCO, HCO of the first HD session were significantly lower than those of short inter-dialytic intervals (p < 0.001, respectively). Using Blant Altman analysis, pre- and post-dialysis tCO did not show good agreement with HCO. Acidotic patients had higher levels of serum albumin and phosphorus (p < 0.01 and p = 0.02, respectively) and were more likely to use sevelamer (p = 0.04). Also, the value of HCO was inversely correlated with dialysis vintage (r = -0.432, p = 0.005) and serum albumin (r = -0.427, p = 0.005).
Since tCO did not show good agreement with HCO, relying solely on the pre-dialysis tCO values to define metabolic acidosis may increase misclassification rate. More work is needed for optimal assessment of acid-base status. Also, understanding the determinants of HCO may guide physicians for individualized HCO prescription.
评估血液透析（HD）患者碳酸氢盐的日变异性，并确定影响该问题的因素。
采集 41 例患者的血液样本，进行碳酸氢盐（总二氧化碳（CO））和血气分析（pH、碳酸氢盐（HCO）），分别在每周的第一次、第二次和第三次透析前和透析后采集。所有透析前 HCO < 22 mmol/L 的患者均被归类为酸中毒。比较酸中毒和非酸中毒组的人口统计学和实验室数据，并确定与 HCO 水平相关的因素。
首次 HD 治疗时的 pH、tCO、HCO 明显低于短间隔透析时的水平（p < 0.001）。使用 Bland-Altman 分析，透析前和透析后的 tCO 与 HCO 无良好一致性。酸中毒患者的血清白蛋白和磷水平较高（p < 0.01 和 p = 0.02），且更有可能使用司维拉姆（p = 0.04）。此外，HCO 值与透析时间呈负相关（r = -0.432，p = 0.005）和血清白蛋白（r = -0.427，p = 0.005）。
由于 tCO 与 HCO 无良好一致性，仅依靠透析前 tCO 值来定义代谢性酸中毒可能会增加错误分类率。需要进一步研究以优化酸碱状态评估。此外，了解 HCO 的决定因素可能有助于医生为患者个体化制定 HCO 处方。
