Intensive Care, UZ Brussel, Laarbeeklaan 101, Jette, Brussel, 1090, Belgium.
Intensive Care, UZ Brussel, Laarbeeklaan 101, Jette, Brussel, 1090, Belgium; Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
Clin Nutr. 2020 Feb;39(2):353-357. doi: 10.1016/j.clnu.2019.02.034. Epub 2019 Feb 23.
Indirect calorimetry (IC) is the gold standard for measuring energy expenditure in critically ill patients However, continuous renal replacement therapy (CRRT) is a formal contraindication for IC use.
To discuss specific issues that hamper or preclude an IC-based assessment of energy expenditure and correct caloric prescription in CRRT-treated patients.
Narrative review of current literature.
Several relevant pitfalls for validation of IC during CRRT were identified. First, IC measures CO production (VCO) and O consumption to calculate resting energy expenditure (REE) with the Weir equation. VCO measurements are influenced by CRRT because CO is exchanged during the blood purification process. CO exchange also depends on type of pre- and/or postdilution fluid(s). CO dissolves in different forms with dynamic but unpredictable impact on VCO. Second, the effect of immunologic activation and heat loss on REE caused by extracorporeal circulation during CRRT is poorly documented. Third, caloric prescription should be adapted to CRRT-induced in- and efflux of different nutrients. Finally, citrate, which is the preferred anticoagulant for CRRT, is a caloric source that may influence IC measurements and REE.
Better understanding of CRRT-related processes is needed to assess REE and provide individualized nutritional therapy in this condition.
间接热量测定法（IC）是测量危重症患者能量消耗的金标准。然而，连续肾脏替代疗法（CRRT）是 IC 使用的正式禁忌。
讨论妨碍或排除基于 IC 的能量消耗评估和 CRRT 治疗患者正确热量处方的具体问题。
对当前文献进行叙述性综述。
确定了在 CRRT 期间验证 IC 的几个相关问题。首先，IC 通过 Weir 方程测量 CO 产量（VCO）和 O 消耗来计算静息能量消耗（REE）。VCO 的测量受到 CRRT 的影响，因为 CO 在血液净化过程中进行交换。CO 交换还取决于预稀释和/或后稀释液体的类型。CO 以不同的形式溶解，对 VCO 的影响具有动态但不可预测性。其次，CRRT 期间体外循环引起的免疫激活和热量损失对 REE 的影响记录甚少。第三，应根据 CRRT 引起的不同营养素的进出流量来调整热量处方。最后，枸橼酸盐是 CRRT 的首选抗凝剂，它是一种热量来源，可能会影响 IC 测量和 REE。
需要更好地了解 CRRT 相关过程，以评估 REE 并在这种情况下提供个体化营养治疗。
