Dynamics of the oxygenation index in PP group and non-PP group
We conducted a comparative analysis of the changes in oxygenation indices between the PP group and the non-PP group over a 13-day duration. Among the 74 cases in the PP group, their first PP occurred within (3.2±2.8) day on ICU admission, and the termination of PP was observed within (8.0±5.1) day . Notably, the increase in oxygenation index was more pronounced in the PP group compared to the non-PP group (48 vs 32 mmHg)(Fig 2).(It is worth mentioning that patient number E28 in the PP group initiated PP on day 25, while E32, E59, and E66 commenced on day 16.)