H K Tan1, S Uchino, R Bellomo. 1. Department of Intensive Care, Austin & Repatriation Medical Centre, Heidelberg, Victoria, Australia.
Abstract
OBJECTIVE: To evaluate, quantify and compare the effects of continuous veno-venous hemofiltration (CVVH) with lactate or bicarbonate-buffered replacement fluids on acid-base balance. DESIGN: Randomized double crossover study. SETTING:Intensive Care Unit of Tertiary Medical Center. PARTICIPANTS: Eight patients with severe acute renal failure. INTERVENTIONS: 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). MEASUREMENTS AND RESULTS: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). CONCLUSIONS:CVVH with lactate-buffered replacement fluids induces iatrogenic hyperlactatemia. Such hyperlactatemia is associated with an acidifying effect despite a positive buffer-base balance.
RCT Entities:
OBJECTIVE: To evaluate, quantify and compare the effects of continuous veno-venous hemofiltration (CVVH) with lactate or bicarbonate-buffered replacement fluids on acid-base balance. DESIGN: Randomized double crossover study. SETTING: Intensive Care Unit of Tertiary Medical Center. PARTICIPANTS: Eight patients with severe acute renal failure. INTERVENTIONS: 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). MEASUREMENTS AND RESULTS: 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). CONCLUSIONS: CVVH with lactate-buffered replacement fluids induces iatrogenic hyperlactatemia. Such hyperlactatemia is associated with an acidifying effect despite a positive buffer-base balance.
Authors: Andrew S Allegretti; Jennifer E Flythe; Vinod Benda; Emily S Robinson; David M Charytan Journal: Biomed Res Int Date: 2015-01-08 Impact factor: 3.411