Final answer:
The nurse's first action is to assess the client's respiratory status.
Step-by-step explanation:
The nurse's first action when caring for a client who is intubated with an endotracheal tube and on a mechanical ventilator and able to make sounds is to Assess the client's respiratory status.
Assessing the client's respiratory status is crucial to monitor the effectiveness of the mechanical ventilation and ensure the client's oxygenation and ventilation needs are met. This includes assessing the client's oxygen saturation levels, breath sounds, and respiratory rate.
Administering pain medication, notifying the healthcare provider, and documenting the findings are important actions in the overall care of the client but are not the nurse's first priority in this situation.