Things We Do for No Reason™: Supplemental Oxygen for Patients without Hypoxemia

Importantly, the above discussion pertains to normoxemic patients receiving supplemental oxygen. There is no dispute that significantly hypoxemic patients should receive supplemental oxygen. There are also instances where the use of supplemental oxygen in normoxemic patients may be beneficial, such as in carbon monoxide poisoning, decompression injury, gas embolism, cluster headaches, sickle cell crisis, and pneumothorax.¹⁷

Like any other drug, oxygen should be administered after assessment of its indications, intended benefits, and possible harms. Both significant hypoxemia and hyperoxemia should be avoided. In patients with neither hypoxemia nor the indications above, clinicians should not administer supplemental oxygen. Recent society guidelines can be applied in various clinical contexts. In patients with suspected MI, oxygen should be administered if SpO₂ is <90%.¹⁰ For most other acutely ill patients, clinicians should administer supplemental oxygen if SpO₂ <90%-92% and target an SpO₂ of no higher than 94%-96%,^18-19 as meta-analyses found evidence of harm above this level.¹³ Results of randomized trials currently underway should add supporting evidence for more specific oxygenation targets in different patient populations. With respect to implementation, it must be noted that factors beyond physician decision influence the use of supplemental oxygen. Appropriate institutional policies, standards of care, and educational efforts to all hospital providers must be enacted in order to reduce the unnecessary use of supplemental oxygen.

• For most acutely ill patients, do not administer supplemental oxygen when SpO₂ >92%. If supplemental oxygen is used, the SpO₂ should not exceed 94%-96%.
• For patients with suspected MI, only start supplemental oxygen for SpO₂ <90%.
• For patients at risk for hypercapnic respiratory failure (eg, COPD patients), target SpO₂ of 88%-92%.
• Provide supplemental oxygen to normoxemic patients with carbon monoxide poisoning, decompression injury, gas embolism, cluster headache, sickle cell crisis, and pneumothorax.
• Review and revise institutional practices and policies that contribute to unnecessary use of supplemental oxygen.

In the opening case, the patient is acutely ill and requires further workup. Her current SpO₂ of 99% puts her at risk for adverse events and death, and supplemental oxygen should be titrated down or stopped to avoid SpO₂ greater than 94%-96%. For years, clinicians have erred on the side of using supplemental oxygen, without recognizing its dangers. However, over a century of evidence from pathophysiologic experiments and randomized trials across multiple clinical settings have associated hyperoxemia with adverse outcomes and increased mortality. Professional societies are adopting this evidence into their guideline recommendations, and clinicians should use supplemental oxygen judiciously in their daily practice.

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