A pоstоperаtive pаtient cоmplаining of dyspnea is found to have tachypnea and tachycardia, and is somewhat confused. Breath sounds reveal end inspiratory crackles in both lung bases. An arterial blood gas is drawn and reveals the following: pH 7.49; partial pressure of carbon dioxide (PaCO2) 33 mm Hg; partial pressure of oxygen (PaO2) 51 mm Hg; arterial oxygen saturation (SaO2) 87%; bicarbonate (HCO3-) 25 mEq/L while on a 30% air entrainment mask. The most appropriate respiratory therapy intervention includes which of the following?