Objective

Acute kidney injury (AKI) is a common complication after cardiac surgery and may affect prognosis. Serum phosphate (SPh) elevation is well-known to occur after AKI but not well-documented. The aim of the present study was to describe SPh changes during AKI after cardiac surgery and to assess the accuracy for the diagnosis of AKI severity and recovery.

Design

Prospective, single center, observational study.

Setting

Intensive care unit of a tertiary university hospital.

Participants

All patients admitted consecutively to the intensive care unit between February 2015 and March 2016.

Measurements and Main Results

AKI was defined according to Kidney Disease Improving Global Outcomes criteria and classified as nonsevere (stage 1) and severe (stages 2 and 3). Receiver operating characteristic curve analysis was conducted to test reliability of SPh for AKI severity and recovery. AKI occurred in 86 of the 260 patients included (33%) in the study; 58 (67%) experienced nonsevere AKI, and 28 (33%) experienced severe AKI. A significant elevation of SPh values was observed in AKI patients, which peaked at 48 hours. At this time, an SPh of 1.33 mmol/L demonstrated a good accuracy for AKI severity, with an area under the curve of 0.91 (95% confidence interval 0.82-1.00). For kidney recovery, a 25% SPh decrease 24 hours after the peak had a positive predictive value of 100%, and a 2.5% decrease allowed for the reclassification of patients when the serum creatinine had not decreased enough.

Conclusions

The results showed that SPh changes closely follow AKI severity and kidney recovery after cardiac surgery. In addition to serum creatinine, this simple biological marker may help predict early favorable outcome.

中文翻译：

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心脏手术后急性肾脏损伤中的血清磷酸盐动力学：一项观察性研究。

目的

急性肾损伤（AKI）是心脏手术后的常见并发症，可能会影响预后。众所周知，AKI后会发生血清磷酸（SPh）升高，但文献记载不足。本研究的目的是描述心脏手术后AKI期间SPh的变化，并评估AKI严重程度和恢复的诊断准确性。

设计

前瞻性，单中心，观察性研究。

设置

三级大学医院的重症监护室。

参加者

在2015年2月至2016年3月之间，所有患者均连续进入重症监护室。

测量和主要结果

AKI是根据“肾脏疾病改善总体结果”标准定义的，分为严重程度（第1阶段）和严重程度（第2和第3阶段）。进行接收器工作特性曲线分析以测试SPh对AKI严重性和恢复的可靠性。在研究的260名患者中，有86名（33％）发生了AKI。58名（67％）患有严重AKI，28名（33％）患有严重AKI。在AKI患者中观察到SPh值显着升高，在48小时达到峰值。此时，SPh为1.33 mmol / L表现出对AKI严重程度的良好准确性，曲线下面积为0.91（95％置信区间0.82-1.00）。对于肾脏恢复，峰值后24小时SPh降低25％，具有100％的阳性预测值，而SPH则为2。

结论

结果表明，心脏手术后，SPh的变化与AKI的严重程度和肾脏的恢复密切相关。除了血清肌酐外，这种简单的生物标记物还可帮助预测早期的预后。