Tracheostomy is often performed in patients after or anticipated prolonged mechanical ventilation, who are usually required oxygen therapy after discontinuation of mechanical ventilation.The high-flow tracheal (HFT) oxygen therapy in tracheostomized patients has been shown that can improve oxygenation,but can not induce positive end-expiratory pressure and elevation of end-expiratory lung volume. A modified HFT system by increasing expiratory resistance might induce PEEP and consequently elevate EELV.