What conditions require 24/7 oxygen supplementation, particularly in older adults or those with a history of smoking, such as chronic obstructive pulmonary disease (COPD), severe pneumonia, heart failure, or neuromuscular diseases like muscular dystrophy?

Conditions Requiring 24/7 Oxygen Supplementation

Continuous oxygen therapy for at least 15-18 hours per day (effectively 24/7) is indicated for patients with chronic obstructive pulmonary disease (COPD) who have severe resting hypoxemia with PaO2 ≤55 mmHg or oxygen saturation ≤88%, as this is the only oxygen therapy proven to prolong survival. 1, 2

Primary Indication: COPD with Severe Chronic Hypoxemia

Long-term oxygen therapy (LTOT) is specifically indicated when:

• PaO2 ≤55 mmHg (or SpO2 ≤88%) at rest while clinically stable and on optimal medical therapy 1, 2
• PaO2 56-59 mmHg with evidence of: 1, 3
  • Pulmonary hypertension
  • Peripheral edema suggesting heart failure
  • Polycythemia (hematocrit >55%)

Critical requirements before prescribing LTOT:

• Patient must be clinically stable (not during acute exacerbation) 1, 3
• Optimal pharmacological treatment must be established 3, 4
• Smoking cessation is mandatory 1, 2
• Measurements should be repeated after 8 weeks of stability before confirming long-term need 1, 5

Duration Requirements for Survival Benefit

Oxygen must be used for at least 15-18 hours daily to achieve mortality reduction, with 24-hour use potentially providing greater benefit 1, 3. The survival benefit in COPD is dose-dependent—shorter durations do not improve mortality 1, 2.

Other Conditions Potentially Requiring Continuous Oxygen

While LTOT criteria are primarily established for COPD, similar principles apply to:

Severe Heart Failure

• Continuous oxygen may be considered for severe heart failure patients with resting hypoxemia (PaO2 ≤55 mmHg) who meet LTOT criteria 1
• Nocturnal-only oxygen can be considered for severe heart failure with sleep-disordered breathing causing daytime symptoms, at low flow rates (1-2 L/min) 1

Interstitial Lung Disease (ILD)

• LTOT indicated when meeting same PaO2 criteria as COPD (≤55 mmHg at rest) 1
• Nocturnal oxygen alone is NOT recommended for ILD patients with only nighttime desaturation 1

Cystic Fibrosis

• LTOT indicated when meeting standard criteria (PaO2 ≤55 mmHg) 1
• Nocturnal oxygen alone should NOT be given for nighttime hypoxemia without established ventilatory failure 1

Neuromuscular Disease and Chest Wall Deformities

• These patients are at high risk for hypercapnic respiratory failure 1
• Oxygen alone is often insufficient and potentially dangerous—these patients typically require non-invasive ventilation (NIV) rather than oxygen alone 1
• If hypoxemic with established ventilatory failure, oxygen should be given WITH NIV support, not alone 1

Critical Safety Considerations

Common pitfall: Patients with conditions causing hypercapnic respiratory failure (moderate-to-severe COPD, morbid obesity, neuromuscular disease, chest wall deformities, cystic fibrosis, bronchiectasis) require controlled oxygen therapy with target SpO2 of 88-92%, not the standard 94-98% 1, 6

Never suddenly discontinue oxygen in patients on LTOT, as this causes life-threatening rebound hypoxemia with rapid falls below baseline saturation 1, 5

Conditions That Do NOT Require Continuous Oxygen

The following scenarios do NOT meet criteria for 24/7 oxygen:

• Moderate hypoxemia alone (PaO2 56-69 mmHg without complications) 7, 3
• Exercise-induced desaturation only without resting hypoxemia 1, 7
• Nocturnal desaturation only without meeting LTOT criteria 1
• Dyspnea without hypoxemia—"palliative oxygen" does not improve breathlessness in non-hypoxemic patients 7

Follow-Up Requirements

Patients initiated on LTOT require:

• Blood gas reassessment at 3 months to confirm ongoing need and therapeutic adequacy 1
• Subsequent follow-up every 6-12 months 1
• Home visit within 4 weeks by specialist nurse to assess compliance, safety, and therapeutic effect 1
• Oxygen may be discontinued if reassessment shows clinical improvement 1