Endotracheal Aspiration. Sterile suction catheters of 53 cm length (model GS 2006 Romsons, Agra, India) of sizes appropriate for the different sized endotracheal tubes were used. The catheter connected to mucus trap unit (model GS 51800, Romson, Agra, India) was advanced through the ETT till some resistance was encountered and after withdrawing about 1-2 cm, suctioning was performed and the aspirate collected in a sterile mucus trap. During this procedure the patient was temporarily disconnected from the ventilator with mean duration of 10 seconds.