A 75-year-old woman was recently started on furosemide to treat pedal edema. She describes a loss of energy and a light-headed sensation when arising from a seated position. Her arterial blood gases indicate pH of 7.53 PaCO2 of 52 mmHg, HCO3- of 32 mEq/L.Serum chemistries show the following levels: Na = 129 mEq/L Cl- = 90 mEq/L K = 3.0 mEq/L Glucose = 120 mg/dL These findings are suggestive of