A client admitted with chronic pulmonary obstruction disease (COPD) exacerbation is receiving assisted ventilation with continuous positive airway pressure (CPAP). The clients vital signs are an oral temperature 98.8 °F (37.1 °C), a heart rate of 118 beats/minute, a respiratory rate of 46 breaths/minute, and a blood pressure of 176/92 mm Hg. While completing the pulmonary assessment, the client's oxygen saturation reading is 78% and he is difficult to arouse. Which action should the nurse implement?