Tan H K, Uchino S, Bellomo R
Department of Intensive Care, Austin & Repatriation Medical Centre, Heidelberg, Victoria, Australia.
Int J Artif Organs. 2003 Jun;26(6):477-83. doi: 10.1177/039139880302600605.
To evaluate, quantify and compare the effects of continuous veno-venous hemofiltration (CVVH) with lactate or bicarbonate-buffered replacement fluids on acid-base balance.
Randomized double crossover study.
Intensive Care Unit of Tertiary Medical Center.
Eight patients with severe acute renal failure.
Random allocation to either 2 hours of isovolemic lactate-buffered (treatment A) CVVH or 2 hours of bicarbonate-buffered (treatment B) CVVH with cross over and with same procedure repeated the following day (double cross over).
Timed collections of arterial blood and ultrafiltrate (UF), measurement of blood and UF gases and lactate concentrations and calculation of buffer-base mass balance. At baseline, both groups of patients had a similar, slight metabolic alkalosis (pH: 7.45 vs. 7.45; BE 3.9 mEq/L for treatment A and 4.0 for treatment B) and a serum bicarbonate of 28.1 mmol/L for treatment A vs. 28.3 mmol/L for treatment B; all NS. This alkalosis was present despite slight hyperlactatemia in both groups (A: 2.4 mmol/L vs. B 2.8 mmol/; NS). Within 60 minutes of treatment, however, treatment A led to a significantly higher lactate concentration (3.9 vs 2.5 mmol/L; p = 0.0011), a significantly lower BE (2.3 vs 4.1 mEq/L; p = 0.0019) and a significantly lower bicarbonate concentration (26.7 vs. 28.3 mmol/L; p = 0.0038) in the presence of an unchanged PaCO2. These differences persisted during the study period. The UF of patients receiving treatment A contained more lactate (10.2 vs 2.9 mmol/L; p < 0.0001) and less bicarbonate (25.6 vs. 30.8 mmol/L; p < 0.0001) than treatment B resulting in a mean buffer-base balance of +20.4 mEq/h compared to -2.6 mEq/h for treatment B; p < 0.0001).
CVVH with lactate-buffered replacement fluids induces iatrogenic hyperlactatemia. Such hyperlactatemia is associated with an acidifying effect despite a positive buffer-base balance.
评估、量化并比较使用乳酸盐或碳酸氢盐缓冲置换液的连续性静脉-静脉血液滤过（CVVH）对酸碱平衡的影响。
随机双交叉研究。
三级医疗中心重症监护病房。
8例严重急性肾衰竭患者。
随机分配接受2小时等容乳酸盐缓冲（治疗A）的CVVH或2小时碳酸氢盐缓冲（治疗B）的CVVH，进行交叉，并在次日重复相同程序（双交叉）。
定时采集动脉血和超滤液（UF），测量血液和UF中的气体及乳酸浓度，并计算缓冲碱质量平衡。基线时，两组患者均有相似的轻度代谢性碱中毒（pH：7.45对7.45；治疗A的碱剩余为3.9 mEq/L，治疗B为4.0；均无统计学差异），治疗A的血清碳酸氢盐为28.1 mmol/L，治疗B为28.3 mmol/L；均无统计学差异。尽管两组均有轻度高乳酸血症（A组：每升2.4毫摩尔对B组每升2.8毫摩尔；无统计学差异），但仍存在碱中毒。然而，在治疗60分钟内，治疗A导致乳酸浓度显著升高（3.9对2.5毫摩尔/升；p = 0.0011），碱剩余显著降低（2.3对4.1 mEq/L；p = 0.0019），碳酸氢盐浓度显著降低（26.7对28.3 mmol/L；p = 0.0038），而动脉血二氧化碳分压未变。这些差异在研究期间持续存在。接受治疗A的患者的超滤液中乳酸含量更高（10.2对2.9毫摩尔/升；p < 0.0001），碳酸氢盐含量更低（25.6对30.8 mmol/L；p < 0.0001），与治疗B相比，导致平均缓冲碱平衡为每小时+20.4 mEq，而治疗B为每小时-2.6 mEq；p < 0.0001）。
使用乳酸盐缓冲置换液的CVVH会引发医源性高乳酸血症。尽管缓冲碱平衡为正值，但这种高乳酸血症具有酸化作用。
