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.

No abstract

Aim. This study aims to assess the association between levels of biomarkers and postoperative complications in patients after thoracic and thoracoabdominal aortic reconstruction.Material and methods. This study included 132 patients. The most of them underwent ascending aortic and aortic arch reconstruction (65 and 57, respectively).The concentrations of proadrenomedullin, presepsin, procalcitonin, troponin I and N-terminal brain natriuretic peptide were measured before induction anesthesia, at the end of the surgical operation and in 6 hours after surgery.Results. 69 patients had postoperative complications. Among them, inflammatory (27,3%) and cardiovascular complications (12,1%) prevailed. At the end of the surgical operation, the levels of the biomarkers in patients without postoperative complications and with postoperative complications were for presepsin 326 [206; 451] и 620 [332; 829] p<0,00001, tropononin I 0,77 [0,46; 1,39] and 1,49 [0,59; 3,39], p=0,01, proadrenomedullin 0,894 [0,683; 1,221] and 1,201 [0,944; 1,762], p=0,0002, procalcitonin 0,206 [0,147; 0,452] and 0,563 [0,307; 2,107], p=0,0002, respectively. According to log-linear regression model, the level of prepepsin at the end of the surgical operation >459,5 (odds ratio (OR) 6,84, 95% confidence interval (CI): 3,14-14,87) or proadrenomedullin >0,788 (OR 5,47, 95% CI: 1,52-19,68) are associated with the increased risk of postoperative complications. The level of presepsin >519,5 pg/ml at the end of the surgical operation (OR 4,55, 95% CI: 1,97-10,47) is associated with the increased risk of inflammatory complications. Regarding the prognosis of the risk of prolonged cardiotonic drug infusions, threshold values for troponin were >1,04 at the end of the surgical operation (sensitivity 75%, specificity 71,3%, AUC 0,785), >1,57 in 6 hours after surgery (sensitivity 81,3%, specificity 71,6%, AUC 0,794).Conclusion. High levels of presepsin at the end of the surgical operation may be useful to predict the postoperative complications in patients who underwent the aortic surgery however, the low levels of presepsin do not exclude the development of postoperative complications. The increased level of troponin I at the end of the surgical operation and in 6 hours after surgery can be a predictor of the need for cardiotonic support in the postoperative period.