Definition COPD’s pathology includes loss of tissue elasticity, emphysematous bullae, small airway obstruction, and destruction of lung parenchyma. Persons with COPD are typically separated into one of two catagories: “pink puffers” (normal PaCO2, PaO2 > 60 mmHg) or “blue bloaters” (PaCO2 > 45 mmHg, PaO2 < 60 mmHg). Pink puffers have severe emphysema, and characteristically […]