ABSTRACT
Background The goal of this study was to determine whether an awake prone position (aPP) reduces the global inhomogeneity (GI) index of ventilation measured by electrical impedance tomography (EIT) in COVID-19 patients with acute respiratory failure (ARF). Methods This prospective crossover study included COVID-19 patients with COVID-19 and ARF defined by PaO2:FiO2 of 100–300 mmHg. After baseline evaluation and 30 min EIT recording in the supine position (SP), patients were randomized into one of two sequences: SP-aPP or aPP-SP. At the end of each 2 h step, oxygenation, respiratory rate, Borg scale, and 30 min EIT were recorded. Results Ten patients were randomized in each group. The GI index did not change in the SP-aPP group (baseline 74±20%, end of SP 78±23% and end of aPP 72±20%, p=0.85) or in the aPP-SP group (baseline 59±14%, end of aPP 59±15% and end of SP 54±13%, p=0.67). In the whole cohort, PaO2:FiO2 increased from 133±44 mmHg at baseline to 183±66 mmHg in aPP (p=0.003) and decreased to 129±49 mmHg in SP (p=0.03). Conclusion In spontaneously breathing non-intubated COVID-19 patients with acute respiratory failure, aPP was not associated with a decrease of lung ventilation inhomogeneity assessed by EIT, despite an improvement in oxygenation.
ABSTRACT
To determine the effect of the awake prone position (APP) on gas exchange and the work of breathing in spontaneously breathing patients with COVID-19-associated acute hypoxemic respiratory failure (AHRF) supported by high-flow nasal oxygen. DESIGN: Prospective randomized physiologic crossover multicenter trial. SETTINGS: Four ICUs in Marseille, France. PATIENTS: Seventeen patients with laboratory-confirmed COVID-19 pneumonia and Pao2/Fio2 less than or equal to 300 mm Hg while treated with high-flow nasal cannula oxygen therapy. INTERVENTIONS: Periods of APP and semirecumbent position (SRP) were randomly applied for 2 hours and separated by a 2-hour washout period. MEASUREMENTS AND MAIN RESULTS: Arterial blood gases, end-tidal CO2. and esophageal pressure were recorded prior to and at the end of each period. Inspiratory muscle effort was assessed by measuring the esophageal pressure swing (∆PES) and the simplified esophageal pressure-time product (sPTPES). The other endpoints included physiologic dead space to tidal volume ratio (VD/VT) and the transpulmonary pressure swing. The APP increased the Pao2/Fio2 from 84 Torr (61-137 Torr) to 208 Torr (114-226 Torr) (p = 0.0007) and decreased both the VD/VT and the respiratory rate from 0.54 (0.47-0.57) to 0.49 (0.45-0.53) (p = 0.012) and from 26 breaths/min (21-30 breaths/min) to 21 breaths/min (19-22 breaths/min), respectively (p = 0.002). These variables remained unchanged during the SRP. The ∆PES and sPTPES per breath were unaffected by the position. However, the APP reduced the sPTPES per minute from 225 cm H2O.s.m-1 (176-332 cm H2O.s.m-1) to 174 cm H2O.s.m-1 (161-254 cm H2O.s.m-1) (p = 0.049). CONCLUSIONS: In spontaneously breathing patients with COVID-19-associated AHRF supported by high-flow nasal oxygen, the APP improves oxygenation and reduces the physiologic dead space, respiratory rate, and work of breathing per minute.
Subject(s)
Anticoagulants/adverse effects , Coronavirus Infections/pathology , Heparin/adverse effects , Pneumonia, Viral/pathology , Thrombocytopenia/etiology , Adult , Aged , Antibodies/blood , Antibodies/immunology , Anticoagulants/therapeutic use , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/virology , Extracorporeal Membrane Oxygenation , Female , Heparin/chemistry , Heparin/therapeutic use , Humans , Immunoassay , Male , Middle Aged , Pandemics , Platelet Factor 4/chemistry , Platelet Factor 4/immunology , Pneumonia, Viral/virology , SARS-CoV-2 , Severity of Illness Index , Thrombocytopenia/diagnosis , Venous Thrombosis/drug therapyABSTRACT
BACKGROUND: Data on respiratory mechanics of COVID-19 ARDS patients are scarce. Respiratory mechanics and response to positive expiratory pressure (PEEP) may be different in obese and non-obese patients. METHODS: We investigated esophageal pressure allowing determination of transpulmonary pressures (PL ) and elastances (EL) during a decremental PEEP trial from 20 to 6 cm H2O in a cohort of COVID-19 ARDS patients. RESULTS: Fifteen patients were investigated, 8 obese and 7 non-obese patients. PEEP ≥ 16 cm H2O for obese patients and PEEP ≥10 cm H2O for non-obese patients were necessary to obtain positive expiratory PL. Change of PEEP did not alter significantly ΔPL or elastances in obese patients. However, in non-obese patients lung EL and ΔPL increased significantly with PEEP increase. Chest wall EL was not affected by PEEP variations in both groups.