Final answer:
The essential step when suctioning the airway through an endotracheal tube is to ensure proper suction pressure and technique.
Step-by-step explanation:
The essential step when suctioning the airway through an endotracheal tube is to ensure proper suction pressure and technique. It is important to use a sterile, disposable suction catheter and to maintain aseptic technique to prevent infection. The suction catheter should be inserted gently and advanced only as far as necessary to clear the airway. Suction should be applied intermittently while withdrawing the catheter to prevent tissue damage and promote effective clearance of secretions or debris.