A patient complaining of dyspnea has a heart rate of 112/min…

A patient complaining of dyspnea has a heart rate of 112/min and a respiratory rate of 28/min. The following ABG analysis results are obtained while the patient is receiving oxygen at 5 L/min by nasal cannula: ABG: pH 7.47 PCO2 33 mm Hg PO2 48 mm Hg HCO3 – 24 mEq/L BE +1 mEq/L SO2 (calc) 83% Which of the following should be done FIRST?