Medicine In acute exacerbations of COPD, noninvasive positive pressure ventilation (NIPPV) is initiated when A Paco2 >45 mmHg B PaO2 <80 mmHg C FEV1 <30 D FEV1/FVC <0.7 💡 Explanation In acute exacerbations of COPD, noninvasive positive pressure ventilation (NIPPV) is initiated when ✓ Correct Answer: A. Paco2 >45 mmHg