The relationship between oxygen support levels and oxidative stress levels of patients taking oxygen support due to severe COVID-19 pneumonia

Introduction-Aim: There are studies observing that while oxidative stress markers increase in lung damage due to oxygen toxicity, antioxidant markers decrease. Studies investigating the risk of developing pulmonary toxicity due to high-flow O2 therapy, which is widely used in severe patients in the COVID-19 pandemic, are needed. In this study; We aimed to compare malondialdehyde (MDA) as an oxidative stress marker and glutathione (GSH) as an antioxidant and glutathione and malonadialdehyde levels while receiving low flow and high flow oxygen during the recovery period of the same patients. Material-Method: To work; 50 patients diagnosed with COVID-19 pneumonia who received 15 lt/min oxygen therapy with a reservoir mask, high flow oxygen therapy (HFNO) 60 lt/min, non-invasive mechanical ventilation (NIMV) with ≥ 60% FiO2 oxygen therapy were included. GSH and MDA levels were measured 48 hours after starting high flow and 48 hours after oxygen therapy was reduced to 4-5 lt/min. Control GSH and MDA levels could not be measured because 20 patients died. Results: Of the patients 60% (n= 30) were male and 40% (n=20) were female. The mean age of the patients was 66.0 ± 15.2 (min: 40, max: 93). Underlying diseases, in order of frequency; DM 32% (n=16), HT 26% (n=13), ischemic heart disease 26% (n=13), congestive heart failure 12% (n=6), prostatic hypertrophy 10% (n=5), hypothyroidism was 10% (n=5) and chronic renal failure was 8% (n=4). The O2 saturation of the patients under high-flow O2 therapy was around 93%, the breath rate was 23/min, while the mean LDH, ferritin, d-Dimer and CRP values were above the normal reference values. In patients with underlying disease HT, MDA levels, which were higher during the high-flow O2 treatment period, were significantly decreased during the low-flow O2 treatment periods (from 0.62 to 0.54, p=0.043). In patients with underlying disease hypertension, higher MDA levels during the high-flow O₂ treatment period, although not significantly, decreased during the low-flow O₂ treatment period (from 6.26 to 5.57, p=0.064). In patients with underlying disease DM, GSH levels, which were higher during the high-flow O₂ treatment period, were significantly decreased during the low-flow O₂ treatment periods (from 3.95 to 3.05, p=0.021). In patients with severe radiological involvement, GSH levels, which were higher during the high-flow O₂ treatment period, were significantly decreased during the low-flow O₂ treatment periods (from 3.61 to 2.94, p=0.039). No significant difference was observed in MDA and GSH levels during high-flow and low-flow O₂ treatment periods according to gender, age category, smoking, presence of COPD, and mild and moderate radiological involvement levels. However; Although not statistically significant in those under 60 years of age, significant decrease in MDA (from 7.42 to 6.23, p=0.117), significant decrease in GSH in non-smokers (4.93 from 3.09, p=0.093), significant decrease in GSH in those without COPD diagnosis (4.98 to 4.30, p=0.153), significant GSH reduction (5.53 to 4.58, p=136) was observed in those without HT. Control tests for ex were performed in 30 of the 50 patients. Mean MDA levels of patients who died were significantly higher than those who survived (10.12 vs. 6.65). Although the GSH levels of the deceased were lower than those of the survivors, the difference was not significant (2.91 vs 4.56). Conclusion: Oxidative stress has an important role in viral infections, especially in COVID-19 infection. Understanding the role of oxidative stress in COVID-19 infection, including the roles of antioxidants and redox proteins, can help guide potential therapeutics. Keywords: COVID-19 infection; glutathione; malondialdehyde; high flow oxygen therapy