Clark W R, Mueller B A, Kraus M A, Macias W L
Renal Division, Baxter Healthcare Corp., McGaw Park, Illinois, USA.
Kidney Int. 1998 Aug;54(2):554-60. doi: 10.1046/j.1523-1755.1998.00016.x.
Urea kinetic modeling (UKM) and creatinine (Cr) kinetic modeling (CKM) are used in the nutritional evaluation of end-stage renal disease (ESRD) patients. Both the UKM-derived normalized protein catabolic rate (nPCR) and the CKM-derived estimate of lean body mass (LBM) may also provide important information in critically ill acute renal failure (ARF) patients. Estimation of LBM may be particularly useful as previous data demonstrate that malnutrition adversely influences outcome in ARF patients.
Eleven critically ill ARF patients (age 52 +/- 21 years; mean +/- SD) treated with continuous venovenous hemofiltration (CVVH) were the study group. They were analyzed at steady state with a single-pool variable-volume model that determined the creatinine generation rate (GCr) by a methodology that we have previously described.
The CVVH ultrafiltrate production rate was 913 +/- 49 ml/hr, yielding a blood Cr clearance of 15.2 +/- 0.9 ml/min and a steady state serum Cr of 3.4 +/- 1.7 mg/dl. Daily creatinine generation normalized to body wt (creatinine index: CI) was 6.3 +/- 0.8 and 10.6 +/- 3.0 mg/kg/day for females (N = 4) and males (N = 7), respectively (P < 0.05). Estimated mean LBM was 30.0 +/- 2.0 and 41.2 +/- 7.0 kg in females and males, respectively (P < 0.05), while the same parameter normalized to body wt was 0.50 +/- 0.05 and 0.52 +/- 0.10, respectively. These values are substantially lower than those previously reported for both normal and ESRD patients. Regression analysis demonstrated both GCr (r2 = 0.96; P < 0.001) and LBM (r2 = 0.96; P < 0.001) were significantly correlated with steady state serum Cr in a linear manner. However, no significant correlation (r2 = 0.06; P = 0.24) between nPCR and CI was observed.
These data suggest critically ill ARF patients have severe somatic protein depletion. This malnourished state is likely due to deficits established prior to the development of ARF, such as those secondary to underlying chronic illnesses or prolonged hospitalization, and deficits related to acute hypercatabolism. Quantitative assessment of malnutrition in ARF patients with this CKM-based methodology may permit a better understanding of predisposing factors and, consequently, facilitate the development of interventions designed to prevent malnutrition in these patients.
尿素动力学模型（UKM）和肌酐（Cr）动力学模型（CKM）用于终末期肾病（ESRD）患者的营养评估。UKM得出的标准化蛋白分解代谢率（nPCR）和CKM得出的瘦体重（LBM）估计值也可能为重症急性肾衰竭（ARF）患者提供重要信息。LBM的估计可能特别有用，因为先前的数据表明营养不良会对ARF患者的预后产生不利影响。
11例接受持续静静脉血液滤过（CVVH）治疗的重症ARF患者（年龄52±21岁；均值±标准差）为研究组。使用单池可变容积模型在稳态下对他们进行分析，该模型通过我们先前描述的方法确定肌酐生成率（GCr）。
CVVH超滤率为913±49 ml/小时，血Cr清除率为15.2±0.9 ml/分钟，稳态血清Cr为3.4±1.7 mg/dl。女性（N = 4）和男性（N = 7）每日肌酐生成量按体重标准化（肌酐指数：CI）分别为6.3±0.8和10.6±3.0 mg/kg/天（P < 0.05）。女性和男性的估计平均LBM分别为30.0±2.0和41.2±7.0 kg（P < 0.05），而同一参数按体重标准化后分别为0.50±0.05和0.52±0.10。这些值显著低于先前报道的正常人和ESRD患者的值。回归分析表明，GCr（r2 = 0.96；P < 0.001）和LBM（r2 = 0.96；P < 0.001）均与稳态血清Cr呈显著线性相关。然而，未观察到nPCR与CI之间存在显著相关性（r2 = 0.06；P = 0.24）。
这些数据表明重症ARF患者存在严重的躯体蛋白消耗。这种营养不良状态可能是由于ARF发生之前就已存在的缺陷，例如继发于潜在慢性疾病或长期住院的缺陷，以及与急性高分解代谢相关的缺陷。使用这种基于CKM的方法对ARF患者的营养不良进行定量评估，可能有助于更好地理解易感因素，从而促进制定旨在预防这些患者营养不良的干预措施。
