What is the recommended first‑line treatment for an adult presenting with an acute COPD exacerbation, including oxygen therapy target, bronchodilator regimen, systemic corticosteroid dosing, antibiotic choice, and indications for non‑invasive ventilation such as respiratory acidosis, hypercapnia, or altered mental status?

Acute COPD Exacerbation Management

Immediate Oxygen Therapy

Target oxygen saturation of 88–92% using controlled-delivery devices (Venturi mask 24–28% or nasal cannula 1–2 L/min) to correct life-threatening hypoxemia while preventing CO₂ retention and worsening respiratory acidosis. 1, 2

• Obtain arterial blood gas within 60 minutes of starting oxygen to detect hypercapnia (PaCO₂ >45 mmHg) or acidosis (pH <7.35) 1, 2, 3
• Repeat ABG at 30–60 minutes if clinical deterioration occurs or if initial pH <7.35 1, 2
• If initial ABG shows normal pH and PaCO₂, you may increase target to 94–98% only if the patient has no prior history of hypercapnic failure requiring NIV and their usual stable saturation is ≥94% 1
• High-flow oxygen (>28% FiO₂ or >4 L/min) without blood gas monitoring worsens hypercapnic respiratory failure and increases mortality by 78% 1, 2

Bronchodilator Therapy

Administer combined short-acting β₂-agonist (salbutamol 2.5–5 mg) plus short-acting anticholinergic (ipratropium 0.25–0.5 mg) via nebulizer every 4–6 hours during the acute phase, providing superior bronchodilation lasting 4–6 hours compared to either agent alone. 1, 2, 3

• Power nebulizers with compressed air (not oxygen) when PaCO₂ is elevated or respiratory acidosis is present; provide supplemental oxygen via separate nasal cannula at 1–2 L/min 2, 3
• Continue every 4–6 hours for 24–48 hours until clinical improvement occurs 2
• Metered-dose inhalers with spacer are equally effective for outpatients who can coordinate inhalation 1, 2
• Never use intravenous methylxanthines (theophylline/aminophylline)—they increase adverse effects without clinical benefit 1, 2, 3

Systemic Corticosteroid Protocol

Give oral prednisone 30–40 mg once daily for exactly 5 days starting immediately upon presentation; this short course is as effective as 14-day regimens while reducing cumulative steroid exposure by >50%. 1, 2, 4

• Oral administration is equally effective to intravenous and should be the default route unless the patient cannot tolerate oral intake 1, 2, 4
• If unable to take oral medications, use intravenous hydrocortisone 100 mg daily as the equivalent alternative 4
• This regimen improves lung function and oxygenation, shortens recovery time and hospital stay, reduces treatment failure by >50%, and lowers rehospitalization risk within 30 days 1, 2
• Do not extend systemic corticosteroids beyond 5–7 days unless another indication exists, as prolonged courses increase adverse effects without additional benefit 1, 2, 4

Antibiotic Therapy

Prescribe antibiotics for 5–7 days when increased sputum purulence is present together with either increased dyspnea or increased sputum volume (two of three cardinal symptoms, with purulence required). 1, 2

• This strategy reduces short-term mortality by ~77%, treatment failure by ~53%, and sputum purulence by ~44% 1, 2
• First-line agents (based on local resistance patterns): amoxicillin-clavulanate 875/125 mg twice daily, doxycycline 100 mg twice daily, or macrolides (azithromycin, clarithromycin) 1, 2
• Most common organisms are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis 1, 2

Non-Invasive Ventilation (NIV)

Initiate NIV immediately as first-line therapy when acute hypercapnic respiratory failure (PaCO₂ >45 mmHg) with acidosis (pH <7.35) persists for >30 minutes after standard medical treatment. 1, 2, 3

Indications for NIV:

• pH <7.35 with PaCO₂ >45 mmHg persisting >30 minutes after initial therapy 1, 2, 3
• Persistent hypoxemia despite supplemental oxygen 2, 3
• Severe dyspnea with respiratory muscle fatigue or use of accessory muscles 2, 3
• Respiratory rate ≥25–30 breaths/min 1, 3

NIV Benefits:

• Improves gas exchange and reduces work of breathing 1, 2
• Decreases intubation rates by ~50% 1, 2
• Shortens hospital stay and improves survival 1, 2
• Success rate of 80–85% in appropriately selected patients 2

Contraindications to NIV (require invasive mechanical ventilation):

• Altered mental status with inability to protect airway 2, 3
• Large-volume secretions 2
• Hemodynamic instability 2
• Recent facial or upper-airway surgery 2

ICU Transfer Criteria:

• pH <7.26 despite NIV 1, 3
• Exhaustion, confusion, or decreased level of consciousness 3
• Inability to tolerate or failure of NIV 3
• Hemodynamic instability or life-threatening arrhythmias 3

Hospitalization Criteria

Admit to hospital or evaluate in emergency department when any of the following are present: 1, 2

• Marked increase in dyspnea unresponsive to outpatient therapy 1, 2
• Respiratory rate >30 breaths/min 1, 2
• Inability to eat or sleep because of respiratory symptoms 1, 2
• New or worsening hypoxemia (SpO₂ <90% on room air) 1, 2
• New or worsening hypercapnia (PaCO₂ >45 mmHg) 1, 2
• Altered mental status or loss of alertness 1, 2
• Persistent rhonchi after initial treatment requiring continued nebulization 2
• High-risk comorbidities (pneumonia, cardiac arrhythmia, heart failure, diabetes, renal or liver failure) 1, 2
• Inability to care for self at home 1, 2

Discharge Planning

Schedule pulmonary rehabilitation within 3 weeks after discharge to reduce hospital readmissions and improve quality of life; do not initiate during hospitalization as this increases mortality. 1, 2

• Initiate or optimize long-acting bronchodilator therapy (LAMA, LABA, or combinations) before discharge 1, 2
• Do not step down from triple therapy (LAMA/LABA/ICS) during or immediately after an exacerbation, as ICS withdrawal increases recurrent exacerbation risk 1, 2
• Verify proper inhaler technique at discharge 1, 2
• Provide smoking cessation counseling with nicotine replacement therapy and behavioral intervention for current smokers 1, 2

Common Pitfalls to Avoid

• Never power nebulizers with oxygen in hypercapnic patients—use compressed air for nebulization and provide supplemental oxygen via separate nasal cannula 2, 3
• Never delay NIV when criteria for acute hypercapnic respiratory failure are met (pH <7.35, PaCO₂ >45 mmHg persisting >30 minutes) 1, 2
• Never use methylxanthines (theophylline/aminophylline) in acute exacerbations—they add toxicity without benefit 1, 2, 3
• Never continue systemic corticosteroids beyond 5–7 days for a single exacerbation unless another indication exists 1, 2, 4
• Never administer high-flow oxygen without arterial blood gas monitoring—this can worsen hypercapnic respiratory failure and increase mortality 1, 2