In closed suction group, one end of closed suction catheter was connected to ventilator and tracheal tube and the other end to suction tube. After opening the catheter valve, a nelaton catheter was inserted into the tracheal tube and secretions were suctioned (without disconnecting patient from the ventilator). In both groups, in each time of tracheal suction, suction was performed 1-3 times and the time of suction was 5-10 seconds in the both methods. To assess pneumonia, bacterial pneumonia index was used. Patients were monitored for 72 hours from admission and examined by an infection disease specialist. Bacterial pneumonia index is a standard index calculated based on body temperature, white blood cell count, airways discharges, ratio of arterial blood oxygen to inhaled oxygen, auscultation regarding infiltration development, chest X-ray, culture and smear of lung discharges (Table 1). Patient was considered to have pneumonia if scored more than 6