Background and objectives
Patients suffering from severe COVID-19 pneumonia frequently encounter difficulties that necessitate high concentrations of supplemental oxygen, a treatment essential for improving their respiratory function. However, the delivery of such high levels of oxygen poses a risk of oxidative stress and resultant lung damage. This research study focused on examining the effects of various oxygen therapy modalities on oxidative stress indicators. Specifically, it aimed to compare the levels of malondialdehyde (MDA), a recognized marker for oxidative stress, alongside glutathione (GSH), an important antioxidant marker, in individuals diagnosed with severe COVID-19 pneumonia.
Methods
In this carefully structured study, 50 patients diagnosed with COVID-19 pneumonia were enrolled, all of whom received differing forms of oxygen therapy. Patients were treated using reservoir masks with a flow rate of ≥15 L/m, high-flow oxygen therapy at the more aggressive rate of 60 L/m, or through noninvasive mechanical ventilation administering oxygen at fraction of inspired O2 (FiO2) levels of at least 60%. The biochemical markers, GSH and MDA, were meticulously measured 48 hours post-initiation of oxygen therapy at FiO2 ≥ 60% and again 48 hours after transitioning to nasal cannula oxygen therapy, which delivered a more moderate flow of 2–4 L/m.
Results
The demographic analysis revealed that a significant portion of the enrolled patients, specifically 60% (n = 30), were male, while the remaining 40% (n = 20) were female. Among those with pre-existing hypertension, a noteworthy observation was made: MDA levels, which were considerably elevated during high oxygen flow therapy at FiO2 ≥ 60%, exhibited a marked decrease once the treatment shifted to nasal cannula oxygen therapy at 2–4 L/m (p = 0.046). Furthermore, despite testing, a significant variation in MDA levels was not recorded after the transition to reduced oxygen flow in patients also diagnosed with diabetes mellitus (p = 0.064). For the subset of patients with diabetes, GSH levels were notably higher while undergoing oxygen therapy at FiO2 ≥ 60%, but also demonstrated a significant decline after switching to nasal cannula therapy at 2–4 L/m (p = 0.021).
Conclusions
This comprehensive study provided a comparative analysis of MDA and GSH levels among patients undergoing oxygen therapy at both heightened and reduced concentrations for severe COVID-19 pneumonia. The findings indicated that individuals who succumbed to COVID-19 pneumonia harbored substantially higher average MDA levels in comparison to their surviving counterparts. Notably, in patients with an underlying condition of hypertension, MDA levels — initially elevated during oxygen therapy at FiO2 ≥ 60% — showed a significant reduction during the transition to nasal oxygen therapy at 2–4 L/m. These observations highlight a compelling correlation between an increase in serum MDA levels during high-flow oxygen therapy and a decrease experienced with low-flow therapy in patients suffering from COVID-19 pneumonia, particularly those with hypertension, underscoring the potential oxidative stress risk attributed to hyperoxia.
Source:
Journal reference:
Özenç, S., et al. (2024). Relationship between Concentrations of Oxygen and Levels of Oxidative Stress in Patients Receiving Oxygen Therapy for Severe COVID-19 Pneumonia. Exploratory Research and Hypothesis in Medicine. doi.org/10.14218/erhm.2024.00015.
What are the potential side effects of high-flow oxygen therapy in patients with severe COVID-19 pneumonia?
**Interview with Dr. Emily Zhang, Lead Researcher on Oxygen Therapy and COVID-19 Pneumonia Study**
**Editor:** Thank you for joining us, Dr. Zhang. To start, could you explain the main objective of your research study on oxygen therapy?
**Dr. Zhang:** Thank you for having me. The main goal of our research was to investigate the impact of different oxygen therapy modalities on oxidative stress in patients suffering from severe COVID-19 pneumonia. Specifically, we aimed to compare the levels of malondialdehyde (MDA), a marker of oxidative stress, and glutathione (GSH), an important antioxidant, in these patients.
**Editor:** That sounds crucial, especially considering the challenges faced by COVID-19 patients. Can you briefly describe the methods you used in your study?
**Dr. Zhang:** Certainly! We enrolled 50 patients diagnosed with severe COVID-19 pneumonia, who were treated with various oxygen therapies. These included high-flow oxygen via reservoir masks, noninvasive mechanical ventilation, and then transitioning to nasal cannula therapy. We measured MDA and GSH levels 48 hours after the initiation of the high-flow therapies and again after switching to nasal cannula therapy, which provides a lower flow of oxygen.
**Editor:** What were some of your key findings regarding MDA levels in relation to the oxygen therapy provided?
**Dr. Zhang:** Our findings revealed that MDA levels were significantly elevated during high oxygen flow therapy (FiO2 ≥ 60%), particularly in patients with pre-existing hypertension. However, we observed a marked decrease in MDA levels once we transitioned these patients to nasal cannula therapy at a lower flow rate of 2-4 L/m. This suggests that high concentrations of oxygen, while necessary, can lead to oxidative stress and potential lung damage.
**Editor:** That’s a significant observation. What are the implications of your research for the treatment of severe COVID-19 pneumonia going forward?
**Dr. Zhang:** The implications are quite substantial. Our study indicates that while high-flow oxygen therapy is essential for respiratory support in severe cases, the associated oxidative stress and potential lung damage must be carefully managed. This may involve transitioning to less aggressive oxygen delivery methods once patients stabilize, in order to minimize oxidative stress and improve overall outcomes.
**Editor:** Thank you, Dr. Zhang. As we continue to navigate the complexities of COVID-19 treatment, your research provides valuable insights into optimizing oxygen therapy for better patient care.
**Dr. Zhang:** Thank you for the opportunity to discuss our work. It’s important that we continue to refine treatment strategies to support the health and recovery of our patients.
