Aim Noninvasive ventilation (NIV) is known to reduce intubation in patients with acute hypoxemic respiratory failure (AHRF) [ 1 ]. We aimed to assess the outcomes of NIV application in COVID-19 patients with AHRF. Materials & methods In this retrospective cohort study, patients with confirmed diagnosis of COVID-19 and AHRF receiving NIV in general wards were recruited from two university-affiliated hospitals. Demographic, clinical, and laboratory data were recorded at admission. The failure of NIV was defined as intubation or death during the hospital stay. Results Between April 8 and June 10, 2020, 61 patients were enrolled into the final cohort. NIV was successful in 44 out of 61 patients (72.1%), 17 patients who failed NIV therapy were intubated, and among them 15 died. Overall mortality rate was 24.6%. Patients who failed NIV were older, and had higher respiratory rate, PaCO 2 , D-dimer levels before NIV and higher minute ventilation and ventilatory ratio on the 1-st day of NIV. No healthcare workers were infected with SARS-CoV-2 during the study period. Conclusions NIV is feasible in patients with COVID-19 and AHRF outside the intensive care unit, and it can be considered as a valuable option for the management of AHRF in these patients.

Background Data on the lung respiratory mechanics and gas exchange in the time course of COVID-19-associated respiratory failure is limited. This study aimed to explore respiratory mechanics and gas exchange, the lung recruitability and risk of overdistension during the time course of mechanical ventilation. Methods This was a prospective observational study in critically ill mechanically ventilated patients (n = 116) with COVID-19 admitted into Intensive Care Units of Sechenov University. The primary endpoints were: «optimum» positive end-expiratory pressure (PEEP) level balanced between the lowest driving pressure and the highest SpO2 and number of patients with recruitable lung on Days 1 and 7 of mechanical ventilation. We measured driving pressure at different levels of PEEP (14, 12, 10 and 8 cmH2O) with preset tidal volume, and with the increase of tidal volume by 100 ml and 200 ml at preset PEEP level, and calculated static respiratory system compliance (CRS), PaO2/FiO2, alveolar dead space and ventilatory ratio on Days 1, 3, 5, 7, 10, 14 and 21. Results The «optimum» PEEP levels on Day 1 were 11.0 (10.0–12.8) cmH2O and 10.0 (9.0–12.0) cmH2O on Day 7. Positive response to recruitment was observed on Day 1 in 27.6% and on Day 7 in 9.2% of patients. PEEP increase from 10 to 14 cmH2O and VT increase by 100 and 200 ml led to a significant decrease in CRS from Day 1 to Day 14 (p < 0.05). Ventilatory ratio was 2.2 (1.7–2,7) in non-survivors and in 1.9 (1.6–2.6) survivors on Day 1 and decreased on Day 7 in survivors only (p < 0.01). PaO2/FiO2 was 105.5 (76.2–141.7) mmHg in non-survivors on Day 1 and 136.6 (106.7–160.8) in survivors (p = 0.002). In survivors, PaO2/FiO2 rose on Day 3 (p = 0.008) and then between Days 7 and 10 (p = 0.046). Conclusion Lung recruitability was low in COVID-19 and decreased during the course of the disease, but lung overdistension occurred at «intermediate» PEEP and VT levels. In survivors gas exchange improvements after Day 7 mismatched CRS. Trial registration ClinicalTrials.gov, NCT04445961. Registered 24 June 2020—Retrospectively registered.

Background Data on the efficacy of non-invasive ventilation (NIV) after progression of respiratory failure in patients who have already received oxygen therapy, or CPAP outside ICU is limited. The study aimed to find predictors of NIV failure based on breathing pattern, gas exchange, and accessory respiratory muscles evaluation in patients who progressed to moderate-to-severe COVID-19 ARDS. Methods This was a prospective observational study in patients with moderate-to-severe COVID-19-ARDS on NIV (n = 80) admitted to COVID-ICU of Sechenov University. The combined success rate for conventional oxygen and CPAP outside ICU was 78.6% (440 of 560 patients). The primary endpoints were intubation rate and mortality. We measured respiratory rate, exhaled tidal volume (Vte), mean peak inspiratory flow (PIF), inspiratory time (Ti), PaO2, SpO2, end-tidal carbon dioxide (PETCO2), and Patrick score, and calculated ROX index, PaO2/FiO2, ventilatory ratio, and alveolar dead space (Vdalv/Vt) on Days 1, 3, 5, 7, 10, and 14. For all significant differences between NIV success and failure groups in measured data, we performed ROC analysis. Results NIV failure rate in ICU after deterioration of respiratory failure outside ICU was 71.3% (n = 57). Patients with the subsequent NIV failure were older at inclusion, more frail, had longer duration of disease before ICU admission, and higher rate of CPAP use outside ICU. ROC-analysis revealed that the following respiratory parameters after 48 h of NIV can serve as a predictors for NIV failure in moderate-to-severe COVID-19-associated ARDS: PaO2/FiO2 < 112 mmHg (AUROC 0.90 (0.93–0.97), p < 0.0001); PETCO2 < 19.5 mmHg (AUROC 0.84 (0.73–0.94), p < 0.0001); VDalv/VT > 0.43 (AUROC 0.78 (0.68–0.90), p < 0.0001); ROX-index < 5.02 (AUROC 0.89 (0.81–0.97), p < 0.0001); Patrick score > 2 points (AUROC 0.87 (0.78–0.96), p = 0.006). Conclusion In patients who progressed to moderate-to-severe COVID-19-ARDS probability of NIV success rate was about 1/3. Prediction of the NIV failure can be made after 48 h based on ROX index < 5.02, PaO2/FiO2 < 112 mmHg, PETCO2 < 19.5 mmHg, and Patrick score >  = 2. Trial registration ClinicalTrials.gov identifier: NCT04667923, registered on 16/12/2020.

The novel coronavirus infection caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome-relate CoronaVirus 2) is a serious disease often associated with cardiovascular complications. The combination of acute respiratory distress syndrome, invasive ventilation, thromboembolic complications, and direct myocardial injury creates conditions that increase likelihood of right ventricular (RV) dysfunction due to pulmonary hypertension (PH). The aim of the work was to search for literature sources in the PubMed, Google Scholar and eLibrary databases and analyze these sources to elucidate the main pathophysiological mechanisms that underly the onset and progression of PH in COVID-19 (COronaVIrus Disease 2019). Viral damage to the myocardium and pulmonary vascular endothelium in hospitalized patients with COVID-19 may contribute to the development of PH, which is associated with signs of a more severe course of the disease and the development of RV failure in the future. Results. It was concluded that the routine echocardiography protocol should be expanded with additional indicators of the right ventricular function, since these data can be used can be used to predict course of the disease. Conclusion. Based on the literature data, COVID-19 can lead to the development of clinically significant PH in some cases.

Obesity is a rapidly growing social problem that affects more than 650 million people worldwide. It has been proven that obesity is associated with diabetes mellitus, dyslipidemia, hypertension, cardiovascular diseases, obstructive sleep apnea (OSA) syndrome. However, one of the most serious and least reported complications is obesity-hypoventilation syndrome, characterized by obesity (body mass index ≥ 30 kg/m2), hypercapnia (PaCO2 > 45 mmHg), as well as respiratory disorders during sleep (AHI > 5h). The prevalence of OHS is estimated at 10–20% in obese patients. The basis of the pathogenesis of OHS is low compliance of the chest and lungs due to excessive weight load. An effective method of treatment is to change the life-style in order to reduce body weight, however, there are frequent cases of acute respiratory failure (ARF), for the correction of which respiratory support is necessary, in particular with the help of non-invasive ventilation (NVL). For this purpose, an artificial ventilation device is used with various modes of operation: continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP), average volume-assured pressure support (AVAPS). At the same time, obstructive phenomena are not attributed to the main causes of OHS, which is why CPAP is not conceptually a method of treating OHS, however, it was found that more than 90% of patients with OHS have concomitant OSA. In such patients, most of the pathophysiological links can be safely corrected using CPAP therapy, since with this method the stability of the upper respiratory tract lumen is achieved. BiPAP and AVAPS regimens affect the pathogenetic mechanisms of OHS, which is why they demonstrate high effectiveness both in the short term (ARF) and in the long term (long-term treatment with respiratory support).