And the rate of aminophylline use was 0,0 and 10.3 % respectively ( P = 0.025 and P = 0.038 ) ; the airway tract spasm-free duration within 6 days after extubation was 5.8 ( 5.5-6 .2 ) , 5.8 ( 5.5-6 .2 ) and 5.3 ( 4.8-5 .9 ) days ( P = 0.028 ) ; the overall incidence of pulmonary complications was 70.0 % , 71.0 % and 75.9 % ( P = 0.865 ) .