Evaluation of the Relationship between FeNO and Clinical Risk Stratification for Early Mortality in Pulmonary Embolism.

BACKGROUND: Pulmonary embolism (PE) is a common complication of deep vein thrombosis that causes high mortality and morbidity. This study aimed to determine the relationship between clinical risk scoring for early mortality and fractional exhaled nitric oxide (FeNO) in PE patients. METHODS: The study included a total of 98 subjects, 68 patients diagnosed with PE in the emergency department, and 30 healthy controls. Patients with PE were grouped according to clinical scoring of early mortality risk as low (n = 20), moderate-low (n = 24), and moderate-high (n = 24) risk. FeNO levels were measured after diagnosis. RESULTS: FeNO levels were significantly higher in patients with moderate-high risk PE compared to the other three groups and in those with moderate-low risk PE compared to the control group (p < 0.001 for all). Moderate to strong positive correlations were observed between FeNO level and mean pulmonary artery pressure (r = 0.818, p = 0.01), troponin-I (r = 0.67, p = 0.01), pro-BNP (r = 0.762, p = 0.01), and D-dimer levels (r = 0.652, p = 0.01). A FeNO cutoff value of 7.5 ppb had 84% sensitivity and 78% specificity in differentiating moderate-high risk PE from moderate-low risk PE. CONCLUSIONS: FeNO may be as reliable, noninvasive, and easily accessible as cardiac biomarkers in clinical risk scoring for early mortality in PE patients.

Evaluation of the value of exhaled carbon monoxide in the differentiation of viral and bacterial pneumonia.

Aim: This study compared exhaled carbon monoxide (CO) levels in patients hospitalized for bacterial and COVID-19-related viral community-acquired pneumonia. Materials & methods: The study included a total of 150 patients: 50 patients hospitalized for COVID-19 between February 2021 and March 2022, 50 patients with bacterial community-acquired pneumonia and 50 healthy controls. Results: In comparisons of exhaled CO levels among the groups, there was no significant difference between patients with bacterial pneumonia and controls, whereas patients with COVID-19 pneumonia had significantly higher exhaled CO levels compared with both the bacterial pneumonia and control groups (p < 0.001). Conclusion: Viral agents can directly affect the heme oxygenase system of the lower respiratory tract, leading to greater increases in ferritin and exhaled CO levels compared with bacterial pneumonia.

Infections in the lung tissue cause stress in the body. Several mechanisms are activated in the body to balance this stress. The heme oxygenase system plays a role in suppressing inflammation, and its overactivation can cause an increase in the amount of carbon monoxide (CO) we exhale. This study examined exhaled CO levels in patients with bacterial lung infection and COVID-19 viral lung infection in comparison with the healthy population. We found that patients with COVID-19 lung infection had higher levels of CO in their breath than patients with bacterial lung infection and healthy control subjects. These findings suggest that measurements of exhaled CO levels in people with signs and symptoms of lung infection might be used to differentiate patients with viral and bacterial lung infections.