4. Discussion
DISEASE, COVID-19 PNEUMONIA, OXIDATIVE STRESS
The main results of the present study revealed that in NAC-treated patients, PaOIn our study, both the NAC-treated and control group patients had an altered clinical outcome on the first day of the study. Moreover, a decrease in the positive end-expiratory pressure (PEEP) and an increase in PaOThe CRP, D-dimer, and LDH responses to IV NAC were favorable in our patients. It should be noted that the decrease in D-dimer should be interpreted with caution since D-dimer levels on the initial day were significantly higher in the treated patients than in the control group. In particular, it can be seen that the D-dimer results showed high intragroup variability, therefore, quantitative difference between the first and the third day was calculated, observing statistically significant differences in the evolution in ICU (The antiviral [In our study, both groups of patients showed a decrease in total glutathione levels on the third day. This decrease could have been due to glutathione consumption because of elevated oxidative stress during the ICU stay, as previously described in the literature [Our study found a larger association between glutathione levels and clinical outcomes such as SOFA and inflammatory parameters in NAC-treated patients and none in the control group patients on the first and third days of ICU stay. It has been suggested that NAC is not an antioxidant molecule itself but that its actual role lies in the specific replenishment of GSH in deficient cells, and NAC is likely to be ineffective in GSH-replete cells [Concerning clinical outcomes, previous studies in NAC-treated patients infected by SARS-CoV-2 showed no decreased intubation rate, no improvement in oxygenation index, no shortening of ICU stay, nor reduction in mortality [However, oral administration of NAC (1200 mg/day) in patients with COVID-19 pneumonia decreases the risk of mechanical ventilation and mortality [Despite the results of the present study, this work is not without limitations. Firstly, data on patients with mild symptoms were not available because the samples were collected during the highest peak of the pandemic. Secondly, the recruited patients were from a single hospital and some potential confounding factors (sociodemographic and socioeconomic status) were not evaluated. Thus, these outcomes cannot be generalized to other populations, especially considering the wide range of COVID-19 prevalence. Thirdly, the methodology used in the determination of the glutathione molecule, despite a validated colorimetric method, may not achieve sufficient sensitivity to determine this molecule, and a chromatographic method such as HPLC may be more appropriate. Finally, the overall results may be related to the heterogeneity of the subjects and their underlying disease conditions or severity.