In recent years, high flow nasal cannula (HFNC) is a respiratory support system that has become prominent in the treatment of respiratory failure. HFNC provides higher concentration and flow of oxygen, resulting in decreasing anatomic dead space by preventing rebreathing and ensure positive end-expiratory. However, in COVID-19, the usage of HFNC is much controversial due to concerns about the benefits and risk of aerosol-dispersion. Considering the debates about the use of HFNC, we reviewed the literature related to the usage of HFNC in COVID-19. The available reports suggest that HFNC provides high concentrations of oxygen to the patients, who can not reach with conventional devices. HFNC can reduce the requiring of intubation in patients with COVID-19, and it can decrease the length of intensive care unit stay, and complications related to mechanical ventilation. Also HFNC can in achieving apneic oxygenation in patients during airway management. Besides that, the use of high-flow oxygen cannulas can produce aerosols. So, HFNC treatment should be carried out in a negative pressure room; when it is not possible, devices should be undertaken in a single room.

Introduction Guidelines recommend using a pulse oximeter rather than arterial blood gas (ABG) for COVID-19 patients. However, significant differences can be observed between oxygen saturation measured by pulse oximetry (SpO₂) and arterial oxygen saturation (SaO₂) in some clinical conditions. We aimed to assess the reliability of pulse oximeter in patients with COVID-19 Methods We retrospectively reviewed ABG analyses and SpO₂ levels measured simultaneously with ABG in patients hospitalized in COVID-19 wards. Results We categorized total 117 patients into two groups; in whom the difference between SpO₂ and SaO₂ was ≤4% (acceptable difference) and >4% (large difference). Large difference group exhibited higher neutrophil count, C-reactive protein, ferritin, fibrinogen, D-dimer and lower lymphocyte count. Multivariate analyses revealed that increased fibrinogen, increased ferritin and decreased lymphocyte count were independent risk factors for large difference between SpO₂ and SaO₂. The total study group demonstrated the negative bias of 4.02% with the limits of agreement of −9.22% to 1.17%. The bias became significantly higher in patients with higher ferritin, fibrinogen levels and lower lymphocyte count. Conclusion Pulse oximeters may not be sufficient to assess actual oxygen saturation especially in COVID-19 patients with high ferritin and fibrinogen levels and low lymphocyte count low SpO₂ measurements.

Prone positioning is a well-known supportive maneuver to improve oxygenation for patients with moderate to severe acute respiratory distress syndrome (ARDS). Although this technique is usually performed to sedated patients on invasive mechanical ventilation, it has been used in non-intubated patients frequently during the coronavirus diseases-2019 (COVID-19) pandemic. Favorable outcomes have been reported mainly in combining the prone positioning with high flow nasal cannula (HFNC) or non-invasive ventilation (NIV). Due to limited data, a standard approach for the awake prone positioning has not yet been defined. In this manuscript, we reviewed the literature data about prone positioning in non-intubated patients with COVID-19. According to available literature data, we concluded that prone positioning in non-intubated COVID-19 patients may improve oxygenation and prevent the need for invasive mechanical ventilation. But the efficacy is still controversial in the early stage of the disease due to pulmonary mechanics. Further studies are needed to the defined optimal approach of awake prone positioning in COVID-19 patients with hypoxemic respiratory failure.

Acute pulmonary thromboembolism (PTE) is a common cause of cardiovascular mortality. Right ventricular (RV) dysfunction is the most important cause of mortality. Computed Tomography Pulmonary Angiography (CTPA) can detect right ventricular enlargement which is an indicator of RV dysfunction at the time of diagnosis. This study aimed to determine the parameters indicating RV dysfunction in CTPA and correlation of early mortality findings. In this retrospective study, electronic files of patients diagnosed PTE with CTPA between January 2012 and December 2017 were evaluated. Measurements of heart chambers, IVC reflux, and IVS morphology were calculated. In-hospital mortality of the patients after acute PTE diagnosis was evaluated. There were 206 eligible patients. Among the evaluated radiological parameters, right atrium (RA) size (p= 0.002), PA size (p= 0.003), Ao size (p= 0.006), and the presence of IVC reflux (p= 0.001) were associated with mortality. No significant relationship was found between RV/LV ≥1 and mortality (p= 0.908). All patients with PTE-related mortality had RV/LV ratio ≥1 in CTPA and had IVC reflux. Patients with an RV/LV ratio of ≥1 had statistically significantly higher troponin levels (p= 0.004) and IVC reflux (p= 0.025) compared to patients with an RV/LV ratio of <1. In conclusion, RV/LV ratio should be evaluated together with cardiac biomarkers to define mortality risk.

Objective: The red cell distribution width (RDW) is an inexpensive, readily available prognostic indicator of several diseases. RDW has been assessed as a prognostic biomarker in patients with idiopathic pulmonary fibrosis (IPF) in only one study; furthermore, the relationship between the RDW and combined pulmonary fibrosis emphysema (CPFE) has yet to be reported. Subjects and Methods: This single-center study was conducted between January 2015 and December 2018 in the Atatürk Chest Diseases and Chest Surgery Education and Research Hospital. Baseline characteristics, laboratory results, and survival status of patients were recorded. Results: The RDW value was significantly higher in the CPFE group than in the IPF group (median [IQR 25–75]; 16.8 [15.5–19] vs. 15.3 [13.7–16.8], p = 0.028). High RDW values were correlated with carbon monoxide diffusion capacity (DLCO) (r: −0.653 p = 0.001), 6-minute walking test (6MWT) distance (r: −0.361 p = 0.017), arterial partial oxygen pressure (PaO₂) (r: −0.692 p < 0.001), and systolic pulmonary arterial pressure (SPAP) (r: 0.349 p = 0.022) in patients with fibrotic lung disease. The RDW value was significantly higher in the exitus group than in the survivors (median [IQR 25–75]; 18.4 [15.4–19] vs. 15.2 [13.5–17.2], p = 0.016). A univariate Cox regression analysis identified DLCO, SPAP, PaO₂, and RDW as potential covariates of mortality. In a multivariate analysis, the DLCO (HR 1.21, 95% CI 1.11–1.47, p = 0.012) and RDW level (HR 1.65, 95% CI 1.09–2.47, p = 0.023) remained independent predictors of mortality. Conclusion: High RDW values appear to be a simple prognostic factor in patients with IPF or CPFE.