On admission, a patient presents as follows: pH, 7.38; respiratory rate, 24 breaths/min, regular, pursed-lip breathing; PaO2, 66 mm Hg; heart rate, 112 beats/min, sinus tachycardia; PaCO2, 52 mm Hg; blood pressure, 110/68 mm Hg; HCO3–, 24 mEq/L; and SpO2, 90% on O2 2 L/min nasal cannula. What treatment would the physician or nurse practitioner likely order for this patient?