Department of Intensive Care, Austin Hospital, Melbourne, VIC, Australia.
Department of Intensive Care, Faculty of Medicine, Mahidol University, Bangkok, Thailand.
Crit Care Med. 2020 Oct;48(10):e934-e942. doi: 10.1097/CCM.0000000000004508.
During continuous renal replacement therapy, a high net ultrafiltration rate has been associated with increased mortality. However, it is unknown what might mediate its putative effect on mortality. In this study, we investigated whether the relationship between early (first 48 hr) net ultrafiltration and mortality is mediated by fluid balance, hemodynamic instability, or low potassium or phosphate blood levels using mediation analysis and the primary outcome was hospital mortality.
Retrospective, observational study.
Mixed medical and surgical ICUs at Austin hospital, Melbourne, Australia.
Critically ill patients treated with continuous renal replacement therapy within 14 days of ICU admission who survived greater than 48 hours.
None.
We studied 347 patients (median [interquartile range] age: 64 yr [53-71 yr] and Acute Physiology and Chronic Health Evaluation III score: 73 (54-90)]. After adjustment for confounders, compared with a net ultrafiltration less than 1.01 mL/kg/hr, a net ultrafiltration rate greater than 1.75 mL/kg/hr was associated with significantly greater mortality (adjusted odds ratio, 1.15; 95% CI, 1.03-1.29; p = 0.011). Adjusted univariable mediation analysis found no suggestion of a causal mediation pathway for this effect by blood pressure, vasopressor therapy, or potassium levels, but identified a possible mediation effect for fluid balance (average causal mediation effect, 0.95; 95% CI, 0.89-1.00; p = 0.060) and percentage of phosphate measurements with hypophosphatemia (average causal mediation effect, 0.96; 95% CI, 0.92-1.00; p = 0.055). However, on multiple mediator analyses, these two variables showed no significant effect. In contrast, a high net ultrafiltration rate had an average direct effect of 1.24 (95% CI, 1.11-1.40; p < 0.001).
An early net ultrafiltration greater than 1.75 mL/kg/hr was independently associated with increased hospital mortality. Its putative effect on mortality was direct and not mediated by a causal pathway that included fluid balance, low blood pressure, vasopressor use, hypokalemia, or hypophosphatemia.
在持续肾脏替代治疗过程中，较高的净超滤率与死亡率增加相关。然而，其对死亡率的潜在作用的中介因素尚不清楚。在这项研究中，我们通过中介分析来探讨早期（前 48 小时）净超滤与死亡率之间的关系是否由液体平衡、血流动力学不稳定或低钾或低磷血症介导，主要结局为住院死亡率。
回顾性观察性研究。
澳大利亚墨尔本奥克斯丁医院的混合内科和外科 ICU。
入住 ICU 14 天内接受持续肾脏替代治疗且存活时间超过 48 小时的危重症患者。
无。
我们研究了 347 名患者（中位[四分位间距]年龄：64 岁[53-71 岁]和急性生理学和慢性健康评估 III 评分：73[54-90]）。在校正混杂因素后，与净超滤率＜1.01 mL/kg/hr 相比，净超滤率＞1.75 mL/kg/hr 与死亡率显著增加相关（校正优势比，1.15；95%CI，1.03-1.29；p=0.011）。校正单变量中介分析发现，血压、血管加压药治疗或钾水平对此无因果中介途径提示，但发现液体平衡（平均因果中介效应，0.95；95%CI，0.89-1.00；p=0.060）和低磷血症的磷酸盐测量百分比（平均因果中介效应，0.96；95%CI，0.92-1.00；p=0.055）可能存在中介作用。然而，在多中介分析中，这两个变量均无显著作用。相反，高净超滤率有 1.24 的直接平均效应（95%CI，1.11-1.40；p＜0.001）。
早期净超滤率＞1.75 mL/kg/hr 与住院死亡率增加独立相关。其对死亡率的潜在作用是直接的，而不是通过包括液体平衡、低血压、血管加压药使用、低钾血症或低磷血症的因果途径介导的。
