A 57-year-old patient with severe COPD enters the emergency…
A 57-year-old patient with severe COPD enters the emergency department with shortness of breath. Room air ABG levels are as follows: pH 7.44 PaCO2 49 mm Hg PaO2 47 mm Hg HCO3 37 mEq/L BE +12 mEq/L On the basis of this information, which of the following is the most appropriate O2 therapy?