OPTIMAL PAO 2 IS 130-160 MMHG IN THE FIRST WEEK FOR SEPSIS PATIENTS IN ICU: A RETROSPECTIVE COHORT STUDY BASED ON MIMIC-IV DATABASE.

Background: The relationship between the partial pressure of oxygen in arterial blood (PaO 2 ) and the prognosis of sepsis patients, and its potential variation over time, remains unclear. The optimal PaO 2 range for sepsis patients has always been a contentious issue, with no consensus. We aimed to explore the association between different levels of PaO 2 exposure over time and the 28-day mortality of sepsis patients, and to identify the optimal PaO 2 range for sepsis patients within a specific time frame. Methods: We retrieved data on adult patients diagnosed with sepsis within 24 h before or after intensive care unit (ICU) admission from the Medical Information Mart for Intensive Care IV (MIMIC-IV, version 2.2) database. We excluded patients who were not admitted to the ICU for the first time, those with ICU stay <24 h, and those without PaO 2 results during their ICU stay. We calculated the time-weighted average (TWA) of PaO 2 and used piece-wise exponential additive mixed models (PAMMs) to estimate the time-dependent changes in the association between TWA-PaO 2 and patient prognosis. Results: A total of 16,880 sepsis patients were included in the MIMIC cohort. Results indicated that patients' TWA-PaO 2 correlates with increased 28-day mortality after ICU admission in sepsis patients, and this association was mainly manifested in the early course of the disease. With a time window of the first 1-7 days after ICU admission, the optimal TWA-PaO 2 range for sepsis patients was ≥130 mmHg and ≤160 mmHg. Increased exposure time, proportion of exposure time, and exposure dose of high-risk PaO 2 outside the range were all associated with an increased risk of 28-day mortality. Conclusion: PaO 2 in sepsis patients should be closely monitored. During the first 1-7 days of ICU admission, PaO 2 should be maintained within the range of ≥130 mmHg and ≤160 mmHg. A dose-dependent relationship exists between high-risk PaO 2 outside the range and patient outcome.