Figure 2. Kaplan-Meier Curve of the Time to Death in a Study of Lower Tidal Volume Facilitated by Extracorporeal Carbon Dioxide Removal in Patients With Acute Hypoxemic Respiratory Failure.

Median (interquartile range) time to death was 6 (4-14) days in the ECCO₂R group and 9 (5-16) days in the ventilation alone group. The unadjusted hazard ratio for death at 90 days in the ECCO₂R group was 1.1 (95% CI, 0.8-1.5). The proportionality P = .40, suggesting that the proportionality assumption was met.