Does a patient with hypoxemia (oxygen saturation less than 90%) require supplemental oxygen in the absence of symptoms?

From the Guidelines

Supplemental oxygen is generally recommended for patients with oxygen saturation less than 90%, even if they are asymptomatic, to maintain saturation at or above 94-98% as suggested by the BTS guideline 1. When oxygen saturation falls below 90%, the body may not be receiving adequate oxygen to maintain normal tissue function, which can lead to hypoxic damage over time even without obvious symptoms. The standard approach is to provide supplemental oxygen to achieve target saturation. For patients with chronic respiratory conditions, a slightly lower target may be appropriate to avoid complications of hyperoxia. Even without symptoms, low oxygen levels can cause subtle cognitive impairment, increased cardiac workload, and tissue stress. The absence of symptoms doesn't necessarily indicate that the body is tolerating the low oxygen state well, as compensatory mechanisms may temporarily mask the effects of hypoxemia before more serious complications develop, as also noted in the context of acute coronary syndromes 1. Key considerations include:

• The BTS guideline suggests a desirable target saturation range of 94–98% for most acutely ill patients 1.
• Supplemental oxygen should be administered to patients with arterial oxygen saturation less than 90%, respiratory distress, or other high-risk features of hypoxemia, as recommended by the AHA/ACC guideline 1.
• Oxygen can be delivered via nasal cannula starting at 1-2 liters per minute and titrated as needed to achieve target saturation.
• For patients with specific conditions like COPD, individualized targets may apply to balance the need for adequate oxygenation with the risk of hyperoxia. Given the potential for hypoxic damage and the importance of maintaining adequate oxygenation, initiating supplemental oxygen for saturation less than 90% is a prudent approach, even in asymptomatic patients, based on the most recent and highest quality evidence available 1.

From the Research

Supplemental Oxygen Requirements

• The requirement for supplemental oxygen in patients with oxygen saturation less than 90% and no symptoms is not explicitly stated in the provided studies.
• However, according to the study 2, if peripheral oxygen saturations (SpO2) are less than 92%, supplemental oxygen should be titrated to achieve an SpO2 of greater than 92%.
• Another study 3 suggests that supplemental oxygen is recommended in patients with acute heart failure and hypoxemia (peripheral oxygen saturation <90% to 94% or partial arterial oxygen pressure <60 mm Hg).
• The study 4 found that high-flow nasal cannula oxygen therapy can effectively reduce the incidence of SpO2 < 90% during bronchoscopy in patients with hypoxemia.
• Additionally, the study 5 proposes that low flow nasal oxygen supplementation in addition to a non-rebreathing mask could be an alternative to high flow nasal cannula oxygenation for acute hypoxemic COVID-19 patients in resource-limited settings.

Clinical Guidelines

• The study 2 provides recommendations for the administration of oxygen in emergency patients, including the use of pulse oximetry and titration of supplemental oxygen to achieve an SpO2 of greater than 92%.
• The study 6 develops evidence-based recommendations regarding the use of high flow nasal cannula in various clinical settings, including hypoxemic respiratory failure and postoperative care.
• These guidelines suggest that supplemental oxygen should be used to maintain adequate oxygen saturation levels, but the specific threshold for initiating supplemental oxygen in asymptomatic patients with oxygen saturation less than 90% is not clearly defined.