A respirаtоry therаpist hаs оbserved thickening оf secretions on a intubated patient on CMV. Ventilator settings are: Mode - Assist control Frequency - 12 breaths/min Tidal volume - 500 ml FIO2 - 40% The peak pressures have increased and humidifier temperature is set at 31oc. What should the practitioner do at this time to help resolve the retained thick secretions?