Brady J P, Hasbargen J A
Department of Medicine, Indiana University Medical Center, Indianapolis, USA.
Am J Kidney Dis. 1998 Jan;31(1):35-40. doi: 10.1053/ajkd.1998.v31.pm9428449.
Serum albumin concentration has been strongly associated with risk of death in hemodialysis patients, with mortality increasing as albumin decreases. Metabolic acidosis stimulates protein catabolism and decreases protein synthesis. A study was undertaken to investigate the effect of increasing predialysis serum bicarbonate (HCO3) concentrations on the nutrition of hemodialysis patients as measured by albumin and total lymphocyte count (TLC). Metabolic acidosis was defined as a predialysis serum bicarbonate concentration of < or = 18 mEq/L. Thirty-six hemodialysis patients were enrolled in the study. Each had been stable on hemodialysis for > or = 3 months and each had a mean serum bicarbonate concentration of < or = 18 mEq/L on predialysis monthly laboratory values during the preceding 3 months. The subjects were randomized into 2 groups. The first group consisted of 18 control subjects who were dialyzed on a standard bicarbonate bath of 35 mEq/L. The second group consisted of 18 experimental patients who were dialyzed on a bicarbonate bath of 40 mEq/L. Subjects in the experimental group who had predialysis serum bicarbonate concentrations less than 22 mEq/L after 2 weeks on the higher bicarbonate bath were additionally supplemented with oral sodium bicarbonate at a dosage of 1 mEq/kg dry weight/d. Monthly predialysis laboratory values were checked for all subjects and included serum electrolytes, blood urea nitrogen, calcium, and albumin. TLCs were obtained at the initiation and at the conclusion of the study. Intact parathyroid hormone, blood pressures, and interdialytic weight gains were also followed. The study lasted 16 weeks; 32 subjects completed the study (16 in each group). There were no statistically significant differences between the two groups at the initiation of the study. The serum bicarbonate concentrations were significantly different between the two groups at the end of the study (control HCO3 17.3 +/- 3.2 mEq/L v experimental HCO3 20.2 +/- 2.9 mEq/L; P = 0.01). Serum albumin concentrations and TLCs were not statistically different (P > 0.05) between the two groups at the end of the study (control albumin 3.88 +/- 0.28 g/dL v experimental albumin 3.76 +/- 0.26 g/dL and control TLC 1,780.0 +/- 779.4/mm3 v experimental TLC 2,020.1 +/- 888.0/mm3). Potassium, intact parathyroid hormone, interdialytic weight gain, blood pressures, Kt/Vs, and protein catabolic rates did not differ. We found that the change in serum bicarbonate concentration was well-tolerated and was without any demonstrable side effects. We conclude that increasing the serum bicarbonate concentration by 3 mEq/L for 16 weeks has no effect on the indicators of nutrition that we measured (serum albumin and TLC).
血清白蛋白浓度与血液透析患者的死亡风险密切相关，随着白蛋白水平降低，死亡率上升。代谢性酸中毒会刺激蛋白质分解代谢并减少蛋白质合成。本研究旨在探讨提高透析前血清碳酸氢盐（HCO3）浓度对血液透析患者营养状况的影响，通过白蛋白和总淋巴细胞计数（TLC）来衡量。代谢性酸中毒定义为透析前血清碳酸氢盐浓度≤18 mEq/L。36名血液透析患者参与了本研究。每位患者均已接受稳定血液透析≥3个月，且在前3个月的每月透析前实验室检查中，平均血清碳酸氢盐浓度≤18 mEq/L。受试者被随机分为两组。第一组由18名对照受试者组成，他们在35 mEq/L的标准碳酸氢盐浴中进行透析。第二组由18名实验患者组成，他们在40 mEq/L的碳酸氢盐浴中进行透析。实验组中在较高碳酸氢盐浴中透析2周后透析前血清碳酸氢盐浓度低于22 mEq/L的受试者，额外补充口服碳酸氢钠，剂量为1 mEq/kg干体重/天。对所有受试者进行每月透析前实验室检查，包括血清电解质、血尿素氮、钙和白蛋白。在研究开始和结束时获取TLC。还监测了完整甲状旁腺激素、血压和透析间期体重增加情况。研究持续16周；32名受试者完成了研究（每组16名）。研究开始时两组之间无统计学显著差异。研究结束时两组血清碳酸氢盐浓度有显著差异（对照组HCO3 17.3±3.2 mEq/L，实验组HCO3 20.2±2.9 mEq/L；P = 0.01）。研究结束时两组之间血清白蛋白浓度和TLC无统计学差异（P>0.05）（对照组白蛋白3.88±0.28 g/dL，实验组白蛋白3.76±0.26 g/dL；对照组TLC 1780.0±779.4/mm³，实验组TLC 2020.1±888.0/mm³）。钾、完整甲状旁腺激素、透析间期体重增加、血压、Kt/V值和蛋白质分解代谢率无差异。我们发现血清碳酸氢盐浓度的变化耐受性良好，且无任何明显副作用。我们得出结论，将血清碳酸氢盐浓度提高3 mEq/L持续16周，对我们所测量的营养指标（血清白蛋白和TLC）没有影响。
