A 75-yeаr-оld wоmаn is brоught to the emergency depаrtment by her daughter because of a 2-day history of malaise and new-onset confusion. The patient has been hemiplegic and bedridden following an ischemic stroke 4 months ago. She has type 2diabetes mellitus and hypertension. Current medications include metformin, lisinopril, atorvastatin, and aspirin. She is oriented to person but not to place or time. Her temperature is 37.6°C (99.7°F), pulse is 102/min, respirations are 31/min, and blood pressure is 88/59 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 95%. Examination of the sacrum reveals an ulcer with exposed subcutaneous tissue and necrotic areas. The skin is warm and well-perfused. Arterial blood gas analysis shows a pH of 7.25, pCO2 of 30 mm Hg, and HCO3- of 14 mEq/L. Which of the following is the most appropriate next step in management?