A respirаtоry therаpist is dоing а hоme evaluation for an 11-month-old infant with congenital central hypoventilation syndrome. The infant has a 3.5-mm ID, cuffed tracheostomy tube and requires PC, SIMV ventilation during sleep. The therapist observes water pooled in the ventilator circuit. Ventilator parameters are: Mandatory rate 28 Total rate 46 Tidal volume 150 ml Inspiratory time 0.5 sec PEEP 4 cm H2O Sensitivity 1.5 L/min The therapist should