Routine Evaluation of the Ventilator Circuit on a Patient in the ICU

Routine evaluation of the ventilator circuit on a patient in the ICU reveals that there are no water droplets condensed on the inner surface of the ventilator's inspiratory tube and that secretions in the endotracheal tube are thick and difficult to remove when suction is applied.The best therapy to resolve this situation is:

A) Supply artificial heat and humidity
B) Extubate the patient
C) Increase water intake to the patient
D) Change the ventilator circuit