Table 7.
Multivariable Cox Model of Morality
| Mortality |
||
|---|---|---|
| Variable a | Hazard ratio (95% CI) |
P-value |
| Plasma free hemoglobin (for each 0.1 g/L increase) | 1.01 (0.99, 1.04) | 0.389 |
| Primary ECMO indication | 0.001 | |
| Respiratory | Reference | |
| Cardiac | 1.56 (0.70, 3.44) | |
| ECPRb | 5.35 (2.15, 13.33) | |
| Heparin (0.01 units/kg/min) | 0.94 (0.92, 0.96) | <.001 |
| Red blood cells transfused (10 mL/kg) | 1.02 (1.01, 1.04) | 0.009 |
| pH in arterial blood (0.05 increase) | 0.72 (0.58, 0.90) | 0.003 |
In addition to the variables used in the model for plasma free hemoglobin, this also uses daily bleeding and thrombosis as potential predictors and forces plasma free hemoglobin in as a predictor. The population at risk consists of subjects while on ECMO and thus does not capture death occurring after the last day of ECMO.
a
Rates of missingness for all predictors considered for modeling are included in Supplemental Digital Content 3. The outcome, mortality, was never missing.
b
ECPR is extracorporeal cardiopulmonary resuscitation