COPD Management

In a patient with COPD and acute exacerbation, which of the following is the most appropriate initial antibiotic choice for community-acquired infection in the absence of severe disease or recent hospitalization?

A 68-year-old male with COPD (GOLD Stage 3, FEV₁ 38% predicted) on ICS/LABA therapy presents to the emergency department with acute dyspnea, increased sputum purulence, and fever (38.2°C) for 2 days. Chest X-ray shows no focal consolidation. Arterial blood gas: pH 7.32, PaCO₂ 58 mmHg, HCO₃⁻ 28 mEq/L, PaO₂ 62 mmHg on room air. Which of the following is the most appropriate initial management?

A 62-year-old male smoker with COPD GOLD stage 3 (FEV₁ 35% predicted) and chronic bronchitis presents for routine follow-up. He is currently on tiotropium and salbutamol as needed. Regarding pharmacological management of stable COPD, all of the following statements are correct EXCEPT:

Which clinical feature best distinguishes COPD with emphysema-predominant phenotype from COPD with chronic bronchitis phenotype?

A 58-year-old man with COPD GOLD Stage III presents with acute exacerbation. Which is the most common cause of acute exacerbation in COPD patients in India?