Final answer:
The nurse's first action when suctioning a tracheostomy is to preoxygenate the patient to ensure adequate oxygenation during the procedure.
Step-by-step explanation:
When a nurse determines that a tracheostomy requires suctioning, the first action to take is to preoxygenate the patient. This step is crucial to ensure that the patient maintains adequate oxygenation during the suctioning process, which can briefly interfere with their breathing. Once the patient has been preoxygenated, the nurse should then put on clean gloves to maintain sterile technique, elevate the head of bed (HOB) to 90 degrees if not contraindicated, to provide better access and help the patient breathe easier, and then quickly insert the suction catheter to remove secretions.