Respiratory physiology of COVID-19-induced respiratory failure compared to ARDS of other etiologies

• Published in: Critical care (London, England) Vol. 24; no. 1; p. 529
• Main Authors: Grieco, Domenico Luca, Bongiovanni, Filippo, Chen, Lu, Menga, Luca S, Cutuli, Salvatore Lucio, Pintaudi, Gabriele, Carelli, Simone, Michi, Teresa, Torrini, Flava, Lombardi, Gianmarco, Anzellotti, Gian Marco, De Pascale, Gennaro, Urbani, Andrea, Bocci, Maria Grazia, Tanzarella, Eloisa S, Bello, Giuseppe, Dell'Anna, Antonio M, Maggiore, Salvatore M, Brochard, Laurent, Antonelli, Massimo
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 28.08.2020; BioMed Central; BMC
• Subjects: Adult respiratory distress syndrome; Aged; Alveolar recruitment; ARDS; Betacoronavirus; Clinical outcomes; Comparative analysis; Coronavirus Infections - physiopathology; Coronavirus Infections - therapy; Coronaviruses; COVID-19; Critical care; Demographics; Development and progression; Etiology; Female; Hemodynamics; Humans; Intensive Care Units; Intubation; Italy; Male; Mechanics; Middle Aged; Pandemics; PEEP; Physiological aspects; Pneumonia, Viral - physiopathology; Pneumonia, Viral - therapy; Positive-Pressure Respiration; Respiratory Distress Syndrome - physiopathology; Respiratory Distress Syndrome - therapy; Respiratory failure; Respiratory Function Tests; Respiratory insufficiency; Respiratory mechanics; Respiratory Mechanics - physiology; Respiratory system; SARS-CoV-2; Statistical analysis; Ventilators; Italy; United States > US; COVID-19; Alveolar recruitment; Respiratory mechanics; PEEP; ARDS
• ISSN: 1364-8535; 1466-609X; 1364-8535; 1366-609X
• DOI: 10.1186/s13054-020-03253-2

Whether respiratory physiology of COVID-19-induced respiratory failure is different from acute respiratory distress syndrome (ARDS) of other etiologies is unclear. We conducted a single-center study to describe respiratory mechanics and response to positive end-expiratory pressure (PEEP) in COVID-19 ARDS and to compare COVID-19 patients to matched-control subjects with ARDS from other causes. Thirty consecutive COVID-19 patients admitted to an intensive care unit in Rome, Italy, and fulfilling moderate-to-severe ARDS criteria were enrolled within 24 h from endotracheal intubation. Gas exchange, respiratory mechanics, and ventilatory ratio were measured at PEEP of 15 and 5 cmH O. A single-breath derecruitment maneuver was performed to assess recruitability. After 1:1 matching based on PaO /FiO , FiO , PEEP, and tidal volume, COVID-19 patients were compared to subjects affected by ARDS of other etiologies who underwent the same procedures in a previous study. Thirty COVID-19 patients were successfully matched with 30 ARDS from other etiologies. At low PEEP, median [25th-75th percentiles] PaO /FiO in the two groups was 119 mmHg [101-142] and 116 mmHg [87-154]. Average compliance (41 ml/cmH O [32-52] vs. 36 ml/cmH O [27-42], p = 0.045) and ventilatory ratio (2.1 [1.7-2.3] vs. 1.6 [1.4-2.1], p = 0.032) were slightly higher in COVID-19 patients. Inter-individual variability (ratio of standard deviation to mean) of compliance was 36% in COVID-19 patients and 31% in other ARDS. In COVID-19 patients, PaO /FiO was linearly correlated with respiratory system compliance (r = 0.52 p = 0.003). High PEEP improved PaO /FiO in both cohorts, but more remarkably in COVID-19 patients (p = 0.005). Recruitability was not different between cohorts (p = 0.39) and was highly inter-individually variable (72% in COVID-19 patients and 64% in ARDS from other causes). In COVID-19 patients, recruitability was independent from oxygenation and respiratory mechanics changes due to PEEP. Early after establishment of mechanical ventilation, COVID-19 patients follow ARDS physiology, with compliance reduction related to the degree of hypoxemia, and inter-individually variable respiratory mechanics and recruitability. Physiological differences between ARDS from COVID-19 and other causes appear small.