Monard Céline, Tebib Nicolas, Trächsel Bastien, Kelevina Tatiana, Schneider Antoine Guillaume
Adult Intensive Care Unit, Centre Hospitalier Universitaire Vaudois, University Hospital of Lausanne, 1011, Lausanne, Switzerland.
Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
Crit Care. 2024 Dec 19;28(1):425. doi: 10.1186/s13054-024-05200-x.
Oliguria diagnosis includes the normalization of urine output (UO) by body weight. However, the rational and the method to apply to normalize UO to body weight are unclear. We aimed to explore the impact of the method applied to normalize UO on oliguria incidence and association with outcomes.
We included all adult patients admitted to a Swiss (derivation cohort) and a US (MIMIC-IV database, validation cohort) ICU, except those on maintenance hemodialysis, who declined consent or had < 6 consecutive UO measurements. Among a panel of candidate variables (ideal body weight, body mass index, body surface area and adjusted body weight), we identified the best predictor for UO (i.e. the variable that was most closely associated with mean UO during ICU stay). We then compared oliguria incidence and association with 90-day mortality and acute kidney disease (AKD) at hospital discharge, according to whether UO was normalized by actual body weight (ABW) or the identified best UO predictor.
The derivation and validation cohorts included respectively 15 322 and 28 610 patients. Those in the validation cohort were heavier (mean ABW 81 versus 75 kg) older (65 versus 62 years) and had a lower SAPS-II score (38 versus 43). The best UO predictor was ideal body weight (IBW). Oliguria incidence increased almost linearly across weight categories with ABW normalization but remained constant with IBW normalization. Using IBW for UO normalization rather than ABW improved the association between oliguria and 90-day mortality and AKD. It increased the proportion of patients correctly classified from 37.6 to 48.3% (mortality) and from 37.8 to 47% (AKD). All findings persisted after correction for sex and SAPS-II score and were confirmed in sensitivity analyses.
UO normalization by IBW lead to a stable incidence of oliguria across categories of weight and improved the association between oliguria and outcomes. IBW should be preferred to normalize UO in critically ill patients.
少尿的诊断包括根据体重使尿量（UO）正常化。然而，使尿量按体重正常化的合理方法尚不清楚。我们旨在探讨使尿量正常化的方法对少尿发生率及与预后相关性的影响。
我们纳入了所有入住瑞士（推导队列）和美国（MIMIC-IV数据库，验证队列）重症监护病房的成年患者，但不包括接受维持性血液透析、拒绝同意或连续尿量测量少于6次的患者。在一组候选变量（理想体重、体重指数、体表面积和校正体重）中，我们确定了尿量的最佳预测指标（即与重症监护病房住院期间平均尿量最密切相关的变量）。然后，根据尿量是按实际体重（ABW）还是按确定的最佳尿量预测指标进行正常化，比较少尿发生率以及与90天死亡率和出院时急性肾损伤（AKD）的相关性。
推导队列和验证队列分别包括15322例和28610例患者。验证队列中的患者体重更重（平均实际体重81对75kg）、年龄更大（65对62岁）且急性生理与慢性健康状况评分系统II（SAPS-II）得分更低（38对43）。尿量的最佳预测指标是理想体重（IBW）。按实际体重进行尿量正常化时，少尿发生率几乎随体重类别呈线性增加，但按理想体重进行尿量正常化时则保持不变。使用理想体重而非实际体重进行尿量正常化改善了少尿与90天死亡率及急性肾损伤之间的相关性。它将正确分类的患者比例从37.6%提高到了48.3%（死亡率），从37.8%提高到了47%（急性肾损伤）。在校正性别和急性生理与慢性健康状况评分系统II得分后，所有结果均持续存在，并在敏感性分析中得到证实。
按理想体重进行尿量正常化可使各体重类别少尿发生率稳定，并改善少尿与预后之间的相关性。在危重症患者中，应首选理想体重来使尿量正常化。
