An elderly man with chronic obstructive pulmonary disease presents with severe respiratory distress, cyanosis, drowsiness, abundant upper‑airway secretions, hypotension, tachycardia, hypoxemia (SpO2 74%), arterial PaCO₂ 8 kPa, HCO₃⁻ 36 mmol/L, and pH 7.24. What is the best immediate management: nasal continuous positive airway pressure, invasive mechanical ventilation, aminophylline infusion, or face‑mask oxygen?

Invasive Mechanical Ventilation is Required

This patient requires immediate invasive mechanical ventilation (Option B) due to severe respiratory acidosis (pH 7.24), extreme hypercapnia (PCO₂ 7.99 kPa), impaired mental status (drowsiness), copious secretions, and hemodynamic instability (hypotension 90/60 mmHg). 1

Why Invasive Ventilation is Mandatory

Critical Contraindications to Non-Invasive Ventilation Present

This patient meets multiple absolute contraindications to non-invasive positive pressure ventilation (NPPV) or CPAP:

• Impaired mental status/somnolence/drowsiness – explicitly listed as a contraindication to NPPV 1
• Copious and/or viscous secretions with high aspiration risk – another absolute contraindication 1
• Cardiovascular instability (hypotension) – blood pressure 90/60 mmHg constitutes hemodynamic instability 1
• Severe acidosis (pH < 7.25) with hypercapnia (PCO₂ > 8 kPa/60 mmHg) – these values mandate consideration for immediate intubation 1

Guideline-Based Thresholds Met for Invasive Ventilation

The ATS/ERS guidelines explicitly state that intubation should be considered in patients with severe acidosis (pH < 7.25) and hypercapnia (PCO₂ > 8 kPa or 60 mmHg), which this patient meets precisely (pH 7.24, PCO₂ 7.99 kPa ≈ 60 mmHg). 1

When pH is < 7.25, even if NPPV were attempted, it should only be in the ICU with intubation readily available, but given the multiple contraindications present, proceeding directly to intubation is appropriate. 1

Why Other Options Are Inappropriate

Option A (Nasal CPAP) is Contraindicated

• CPAP alone provides no ventilatory support, only positive end-expiratory pressure 1
• This patient needs active ventilatory assistance to reduce PCO₂, not just oxygenation support 1
• The patient's drowsiness, copious secretions, and hypotension are absolute contraindications to any form of non-invasive ventilation 1
• Recent evidence suggests high failure rates with NIV in patients with copious secretions, and failure of NIV with delayed intubation worsens outcomes 1, 2

Option C (Aminophylline Infusion) is Inadequate

• Aminophylline has no proven benefit on ventilation-perfusion matching or blood gases in acute COPD exacerbations 3
• This patient requires immediate ventilatory support, not bronchodilation alone 1
• Medical therapy (bronchodilators, steroids, antibiotics) should be given concurrently with mechanical ventilation, not as a substitute 2

Option D (Face Mask Oxygen) is Dangerous

• Simple oxygen administration will worsen hypercapnia in this severely acidotic patient 4, 2
• The patient already has severe respiratory acidosis; increasing oxygen delivery without ventilatory support will further suppress respiratory drive 2
• Target SpO₂ in COPD should be 88-92%, but this patient needs ventilatory support to clear CO₂, not just oxygen 4, 2, 5

Immediate Management Algorithm

1. Prepare for immediate endotracheal intubation with experienced personnel 1
2. Airway clearance – suction copious secretions before and after intubation 1
3. Initial ventilator settings after intubation 5:
   • Assist-control mode initially
   • Tidal volume 6 ml/kg predicted body weight (may increase to 8 ml/kg if not tolerated)
   • PEEP 4-8 cmH₂O to offset intrinsic PEEP
   • Respiratory rate 10-14 breaths/min
   • FiO₂ titrated to SpO₂ 88-92%
   • I:E ratio 1:2 or 1:3 to allow adequate expiratory time
4. Concurrent medical therapy: bronchodilators, systemic corticosteroids, antibiotics if infection suspected 2
5. Recheck ABG in 30-60 minutes and adjust ventilator settings 5

Critical Pitfalls to Avoid

• Do not delay intubation by attempting NPPV in a patient with contraindications – this increases mortality 1, 2
• Do not administer high-flow oxygen without ventilatory support – this will worsen hypercapnia 4, 2
• Do not use excessive tidal volumes – maintain lung-protective ventilation to prevent barotrauma 5
• Do not ignore the copious secretions – these require aggressive airway management that only invasive ventilation can provide 1