GSTM1 and susceptibility to pneumonia measurement: We further applied four adjusted models to clarify the effect of rehabilitation protocols, including model 1 (adjusted for sex and age), model 2 (adjusted for all variables except the APACHE score that reached statistical significance in the univariate analysis), model 3 (adjusted for all variables that reached statistical significance in the univariate analysis), and model 4 (adjusted for sex, age, DNR, ventilator type, hypotension, BUN, pneumonia, GCS, and Hb).