Fig. 4

a Baseline and day 7 S1P serum levels in ARDS patients who died (n = 18), in those who were hospitalized for>28 days (n = 27) and in those who were hospitalized for ≤ 28 days (n = 49). b S1P levels were lower in non-survivors than in survivors (P < 0.001). ARDS acute respiratory distress syndrome, S1P sphingosine-1-phosphate