Table 2.
Univariate and multivariate analyses of risk factors that may prolong mechanical ventilation
| Variables | Cox model | p value | Hazard ratio (95.0% CI for HR) |
|---|---|---|---|
| Alcohol statusb | Univariate analysis | 0.040 | 0.524 (0.283–0.970) |
| Multivariate analysisa | 0.049 | 0.517 (0.267–0.998) | |
| MGFA classification | Univariate analysis | 0.001 | 0.789 (0.685–0.908) |
| Multivariate analysisa | 0.007 | 0.811 (0.697–0.944) | |
| Clavien-Dindo classification | Univariate analysis | 0.003 | 0.748 (0.617–0.907) |
| Multivariate analysisa | 0.013 | 0.783 (0.645–0.950) | |
| Osserman’s classification | Univariate analysis | 0.006 | 0.680 (0.515–0.897) |
| QMG score | Univariate analysis | 0.010 | 0.948 (0.910–0.987) |
| Preoperative crisisb | Univariate analysis | 0.036 | 0.550 (0.314–0.963) |
| Preoperative max pyridostigmine | Univariate analysis | 0.025 | 0.998 (0.996–1.000) |
| Lung function | Univariate analysis | 0.005 | 0.738 (0.597–0.912) |
We defined “status = 1” as tracheal extubation and “time” as the duration of mechanical ventilation in the analysis of Cox proportional hazard regression analyse
aMultivariate Cox analysis by forward step
bAlcohol status is defined as (1) never, (2) occasional, (3) excessive, and (4) dependence. Preoperative crisis is defined as the times of myasthenic crisis before surgery