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

Abstract

BACKGROUND:

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.

METHODS:

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 cmH2O. A single-breath derecruitment maneuver was performed to assess recruitability. After 1:1 matching based on PaO2/FiO2, FiO2, 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.

RESULTS:

Thirty COVID-19 patients were successfully matched with 30 ARDS from other etiologies. At low PEEP, median [25th-75th percentiles] PaO2/FiO2 in the two groups was 119 mmHg [101-142] and 116 mmHg [87-154]. Average compliance (41 ml/cmH2O [32-52] vs. 36 ml/cmH2O [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, PaO2/FiO2 was linearly correlated with respiratory system compliance (r = 0.52 p = 0.003). High PEEP improved PaO2/FiO2 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.

CONCLUSIONS:

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.

• Authors: Domenico Luca Grieco, Filippo Bongiovanni, Lu Chen, Luca S Menga, Salvatore Lucio Cutuli, Gabriele Pintaudi, Simone Carelli, Teresa Michi, Flava Torrini, Gianmarco Lombardi, Gian Marco Anzellotti, Gennaro De Pascale, Andrea Urbani, Maria Grazia Bocci, Eloisa S Tanzarella, Giuseppe Bello, Antonio M Dell'Anna, Salvatore M Maggiore, Laurent Brochard, Massimo Antonelli
• Journal: Critical care (London, England) (Crit Care) Vol. 24 Issue 1 Pg. 529 (08 28 2020) ISSN: 1466-609X [Electronic] England
• PMID: 32859264 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Aged
• Betacoronavirus
• COVID-19
• Coronavirus Infections (physiopathology, therapy)
• Female
• Humans
• Intensive Care Units
• Italy
• Male
• Middle Aged
• Pandemics
• Pneumonia, Viral (physiopathology, therapy)
• Positive-Pressure Respiration
• Respiratory Distress Syndrome (physiopathology, therapy)
• Respiratory Function Tests
• Respiratory Mechanics (physiology)
• SARS-CoV-2