In the NPPV group , the re-intubation rate was 18.8 % , tracheotomy rate was 12.5 % , VAP incidence was 0 , and the in-hospital mortality was 18.8 % , significantly lower than in the control group 80.9 % , 29.8 % , 17.0 % and 38.3 % respectively , P < 0.05 or P < 0.01 .