High Oxygen Flow Linked to Increased Oxidative Stress in Severe COVID-19 Patients

A recent study published by Xia & He Publishing Inc. explores the relationship between oxygen therapy levels and oxidative stress markers in patients with severe COVID-19 pneumonia. By analyzing the levels of malondialdehyde (MDA), a marker of oxidative stress, and glutathione (GSH), an antioxidant, the study provides critical insights into how oxygen delivery methods affect physiological responses. These findings offer guidance for optimizing oxygen therapy in critically ill patients, especially those with underlying conditions such as hypertension or diabetes.

New Findings on Oxidative Stress and Oxygen Therapy

The study evaluated 50 patients (60% male and 40% female) with severe COVID-19 pneumonia who received oxygen therapy through modalities such as reservoir masks (≥15 L/min), high-flow oxygen therapy (60 L/min), and noninvasive mechanical ventilation with a fraction of inspired oxygen (FiO2) ≥ 60%. Researchers measured MDA and GSH levels 48 hours after initiating high-concentration oxygen therapy and again after switching to nasal cannula therapy at 2–4 L/min.

In patients with hypertension, MDA levels, which were elevated during FiO2 ≥ 60% oxygen therapy, significantly decreased after transitioning to nasal cannula therapy (p = 0.046). Patients with underlying diabetes mellitus exhibited higher GSH levels during FiO2 ≥ 60% oxygen therapy. However, these levels significantly declined after switching to lower oxygen flow (p = 0.021). 

Elevated MDA levels were associated with higher mortality among COVID-19 patients, highlighting the critical role of oxidative stress in influencing clinical outcomes Interestingly, no significant changes in MDA levels were observed in diabetic patients after transitioning to lower oxygen flow therapy (p = 0.064).

Impacts on Patient Care

The study underscores the potential risks of hyperoxia in severe COVID-19 cases, particularly for patients with comorbidities such as hypertension or diabetes. While high oxygen flow is necessary to address severe respiratory distress, it appears to exacerbate oxidative stress, as reflected by increased MDA levels. Conversely, transitioning to lower oxygen flow via nasal cannula reduced oxidative stress markers, emphasizing the need for careful oxygen titration to minimize lung injury.

For clinicians managing severe COVID-19 pneumonia, these findings highlight the importance of balancing the therapeutic benefits of high-flow oxygen with the risks of oxidative damage. Tailoring oxygen therapy protocols to individual patients' needs, particularly those with underlying conditions, is essential to optimize outcomes and prevent hyperoxia-induced complications.