What is the target FiO2 (fraction of inspired oxygen) for COPD (Chronic Obstructive Pulmonary Disease) patients?

Target FiO2 in COPD

The target oxygen saturation range for patients with COPD should be 88-92% to minimize the risk of hypercapnic respiratory failure and mortality.1

Rationale for Lower Oxygen Targets in COPD

• COPD patients are at significant risk of hypercapnic respiratory failure when given excessive oxygen therapy, which can lead to respiratory acidosis, coma, and increased mortality 1
• The mechanisms for carbon dioxide retention in COPD are complex and not simply due to loss of hypoxic drive, but oxygen-induced hypercapnia can be avoided by using targeted lower concentration oxygen therapy 1
• A randomized controlled trial demonstrated significantly lower mortality in COPD patients receiving titrated oxygen to maintain SpO2 88-92% compared to those receiving high-concentration oxygen in the prehospital setting 1
• Even modest elevations in oxygen saturations above the recommended range (93-96%) were associated with an increased risk of death compared to the 88-92% target range 2

Initial Oxygen Therapy Recommendations

• For patients with known COPD or risk factors for hypercapnic respiratory failure, start with:

  • 24% Venturi mask at 2-3 L/min, or
  • 28% Venturi mask at 4 L/min, or
  • Nasal cannulae at 1-2 L/min 1

• Always aim for the target saturation of 88-92% pending blood gas results 1

• Check arterial blood gases after 30-60 minutes of oxygen therapy (or sooner if clinical deterioration occurs) to assess for hypercapnia and acidosis 1

Management Based on Blood Gas Results

• If pH and PCO2 are normal, continue to aim for oxygen saturation of 88-92% unless there is no history of previous hypercapnic respiratory failure 1
• If PCO2 is raised but pH is ≥7.35 (or bicarbonate >28 mmol/L), the patient likely has chronic hypercapnia; maintain target range of 88-92% 1
• If the patient is hypercapnic (PCO2 >6 kPa) and acidotic (pH <7.35), consider non-invasive ventilation (NIV) if respiratory acidosis persists for more than 30 minutes after standard medical management 1

Common Pitfalls to Avoid

• Avoid high-flow oxygen therapy in COPD patients, which is a common error in pre-hospital and emergency department care 3
• Never suddenly discontinue oxygen therapy in hypercapnic patients as this can cause life-threatening rebound hypoxemia 1
• Do not set different target saturations based on carbon dioxide levels, as research shows similar mortality trends in both hypercapnic and normocapnic patients with oxygen saturations above 92% 2
• Be aware that COPD is often unrecognized in emergency settings (only identified in 53% of cases in one study), leading to inappropriate high-flow oxygen administration 3

Special Considerations

• For patients who use long-term home oxygen therapy (LTOT) for severe COPD, a senior clinician should consider setting a patient-specific target range if the standard range would require inappropriate adjustment of their usual oxygen therapy 1
• When monitoring oxygen saturation with pulse oximetry, be aware that SpO2 may overestimate actual arterial oxygenation, especially in active smokers 4
• Consider arterial blood gas analysis for all COPD patients with SpO2 ≤94% to accurately assess for severe hypoxemia and avoid false negatives 4

By maintaining the target oxygen saturation of 88-92% in COPD patients, clinicians can reduce the risk of hypercapnic respiratory failure, respiratory acidosis, and mortality while still providing adequate oxygenation 1, 5, 2.