Journal of Southern Medical University ›› 2025, Vol. 45 ›› Issue (5): 1056-1062.doi: 10.12122/j.issn.1673-4254.2025.05.19

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First 24-hour arterial oxygen partial pressure is correlated with mortality in ICU patients with acute kidney injury: an analysis based on MIMIC-IV database

Zihao WANG1(), Lili TAO2, Biqing ZOU1, Shengli AN1()   

  1. 1.Department of Biostatistics, School of Public Health, Southern Medical University, Guangzhou 510515, China
    2.Department of Critical Care Medicine, Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
  • Received:2024-10-25 Online:2025-05-20 Published:2025-05-23
  • Contact: Shengli AN E-mail:wangzihao0101@126.com;1069766473@qq.com

Abstract:

Objective To evaluate the correlation of mean arterial oxygen tension (PaO₂) during the first 24 h following intensive care unit (ICU) admission with mortality in critically ill patients with acute kidney injury (AKI) and determine the optimal PaO₂ threshold for devising oxygen therapy strategies for these patients. Methods We collected the clinical data of ICU patients with AKI from the MIMIC-IV database. Based on the optimal first 24-h PaO₂ threshold determined by receiver operating characteristic (ROC) curve analysis and the Youden index maximization principle, we classified the patients into hyperoxia group (with PaO₂ ≥137.029 mmHg) and hypoxemia group (PaO₂<137.029 mm Hg). Multivariable logistic regression and propensity score matching were used to evaluate the correlation of first 24-h PaO₂ levels with in-hospital mortality of the patients. Results Among the 18 335 patients, 46.7% were in the hyperoxia group, who had an overall mortality rate of 16.9%. The optimal PaO₂ threshold (137.029 mm Hg) had a sensitivity of 78.3%, a specificity of 63.7%, and an AUC of 0.76 (95% CI: 0.74=0.78). Hyperoxia within the first 24 h after ICU admission was associated with a significantly lower in-hospital mortality (OR=0.78) and 90-day mortality (OR=0.77), particularly in stage 1 AKI patients. A non-linear relationship was identified between PaO₂ and mortality of the patients (P<0.001). Kaplan-Meier survival curves indicated a significantly increased 90-day survival rate in the patients in hyperoxia group (P<0.001), who also had shorter durations of mechanical ventilation, less vasopressor use, and shorter lengths of hospital/ICU stay. Conclusion Maintenance of a PaO₂ level ≥137.029 mmHg within 24 h after ICU admission may improve clinical outcomes of critically ill AKI patients, which underscores the importance of targeted oxygen delivery in ICU care.

Key words: intensive care unit, MIMIC-IV database, acute kidney injury, arterial oxygen partial pressure, mortality, propensity score