Department of Anesthesiology and Critical Care Medicine, Peking University First Hospital, Beijing, 100034, China.
Department of Database Center, Peking University First Hospital, Beijing, 100034, China.
BMC Nephrol. 2022 Jun 11;23(1):206. doi: 10.1186/s12882-022-02834-3.
Perioperative hemoglobin drop after noncardiac surgery is associated with acute kidney injury (AKI). However, opinion on the tolerable difference in postoperative hemoglobin drop in patients with different preoperative hemoglobin levels does not reach a consensus. This study aimed to identify hemoglobin drop thresholds for AKI after noncardiac surgery stratified by preoperative hemoglobin levels.
This was a single-center retrospective cohort study for elective noncardiac surgery from January 1, 2012, to December 31, 2018. The endpoint was the occurrence of AKI 7 days postoperatively in the hospital. The generalized additive model described the non-linear relationship between hemoglobin drop and AKI occurrence. The minimum P-value approach identified cut-off points of hemoglobin drop within postoperative 7 days for patients with or without preoperative anemia. Stratified by preoperative anemia, hemoglobin drop's odds ratio as continuous, quintile and dichotomous variables by various cut-off points for postoperative AKI were calculated in multivariate logistic regression models before and after propensity score weighting (PSW).
Of the 35,631 surgery, 5.9% (2105 cases) suffered postoperative AKI. Non-linearity was found between hemoglobin drop and postoperative AKI occurrence. The thresholds and corresponding odds ratio of perioperative hemoglobin drop for patients with and without preoperative anemia were 18 g/L (1.38 (95%CI 1.14 -1.62), P < .001; after PSW: 1.42 (95%CI 1.17 -1.74), P < .001) and 43 g/L (1.81 (95%CI 1.35-2.27), P < .001; after PSW: 2.88 (95%CI 1.85-4.50), P < .001) respectively. Overall thresholds and corresponding odds ratio were 43 g/L (1.82 (95%CI 1.42-2.21)), P < .001; after PSW: 3.29 (95%CI 2.00-5.40), P < .001). Sensitivity analysis showed similar results. Heterogeneity subgroup analysis showed that intraoperatively female patients undergoing intraperitoneal surgery without colloid infusion seemed to be more vulnerable to higher hemoglobin drop. Further analysis showed a possible linear relationship between preoperative hemoglobin and perioperative hemoglobin drop thresholds. Additionally, this study found that the creatinine level changed simultaneously with hemoglobin level within five postoperative days.
Heterogeneity of hemoglobin drop endurability exists after noncardiac non-kidney surgery. More care and earlier intervention should be put on patients with preoperative anemia.
非心脏手术后围手术期血红蛋白下降与急性肾损伤（AKI）有关。然而，对于不同术前血红蛋白水平的患者术后血红蛋白下降的可耐受差异，意见尚未达成一致。本研究旨在确定按术前血红蛋白水平分层的非心脏手术后 AKI 的血红蛋白下降阈值。
这是一项单中心回顾性队列研究，纳入 2012 年 1 月 1 日至 2018 年 12 月 31 日期间择期非心脏手术患者。术后 7 天内发生 AKI 为研究终点。广义加性模型描述了血红蛋白下降与 AKI 发生之间的非线性关系。最小 P 值法确定了术后 7 天内有或无术前贫血的患者血红蛋白下降的截断点。按术前贫血分层，在倾向评分匹配（PSW）前后，通过多变量逻辑回归模型计算了不同截断点的连续、五分位和二分变量的血红蛋白下降对术后 AKI 的比值比。
在 35631 例手术中，5.9%（2105 例）发生术后 AKI。血红蛋白下降与术后 AKI 发生之间存在非线性关系。有或无术前贫血患者围手术期血红蛋白下降的阈值和相应比值比分别为 18 g/L（1.38（95%CI 1.14-1.62），P<0.001；PSW 后：1.42（95%CI 1.17-1.74），P<0.001）和 43 g/L（1.81（95%CI 1.35-2.27），P<0.001；PSW 后：2.88（95%CI 1.85-4.50），P<0.001）。总体阈值和相应比值比为 43 g/L（1.82（95%CI 1.42-2.21）），P<0.001；PSW 后：3.29（95%CI 2.00-5.40），P<0.001）。敏感性分析显示出相似的结果。异质性亚组分析表明，术中女性患者接受腹腔内手术且未输注胶体似乎更容易受到较高血红蛋白下降的影响。进一步分析表明，术前血红蛋白与围手术期血红蛋白下降阈值之间可能存在线性关系。此外，本研究发现，术后 5 天内，血肌酐水平与血红蛋白水平同时发生变化。
非心脏非肾脏手术后血红蛋白下降的耐受性存在异质性。应更加关注术前贫血患者。
