ABSTRACT
Background: Continuous positive airway pressure (CPAP) can improve oxygenation in severe COVID-19 pneumonia. Objective(s): To assess whether CPAP-associated improvements in oxygenation can inform clinical outcomes in patients with severe COVID-19 pneumonia. Method(s): Retrospective study in patients with severe COVID-19 pneumonia treated with CPAP in three academic respiratory units in Milan, Italy. Arterial gas analysis obtained before and 1 hour after starting CPAP. CPAP failure defined as either death in the respiratory units while on CPAP or need for intubation. Result(s): 211 patients (mean age 64 years, 74% males) were included. Baseline median PaO2was 68 (57-83) mmHg, PaO2/FiO2(P/F) ratio was 129 (91-179) mmHg and alveolar-arterial (A-a) O2 gradient was 310 (177-559) mmHg. On CPAP, PaO2and P/F increased to 100 (79-141) (p<0.001) and 195 (132-257;p<0.001) mmHg and A-a gradient decreased to 240 (188-308;p<0.001) mmHg. 42 (19.9%) patients died in the respiratory units while on CPAP and 51 (24.2%) required intubation. There was a substantial overlap of baseline and CPAP-associated values of PaO2, P/F ratio and A-a gradient in CPAP failures and successes (Figure). CPAP-associated changes in PaO2, P/F ratio and A-a gradient in both groups were similar. Conclusion(s): CPAP-associated improvements in oxygenation cannot be used to inform clinical outcomes of the individual patient with severe COVID-19 pneumonia.
ABSTRACT
This article explores current evidence on the role of oxidative stress in viral infections, and on the use of antioxidant drugs as adjunctive treatment. MEDLINE/PubMed was searched for appropriate keywords, and preclinical and clinical studies with reviews were retrieved and examined by authors. Old and current evidence shows that GSH content reduction is the main mechanism of redox imbalance in viral-infected cells. Clinical studies found that GSH levels are depleted in patients with viral infections such as HIV and SARS-CoV. Viral infections activate inflammation through different pathways, and several of these mechanisms are related to oxidative stress. NAC is a precursor of GSH, and many of its intracellular effects are mediated by GSH replenishment, but it also activates some anti-inflammatory mechanisms. NAC has an excellent safety profile and better oral and topical bioavailability than GSH. These characteristics make NAC a suitable option as a repurposed drug. Adjunctive antioxidant treatment may improve the outcomes of antiviral therapies. Current evidence supports the rationale for this practice and some clinical experience showed encouraging results.