Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Jul 16;10(1):95.
doi: 10.1186/s13613-020-00716-1.

Respiratory mechanics and gas exchanges in the early course of COVID-19 ARDS: a hypothesis-generating study

J-L Diehl  1   2 , N Peron  3 , R Chocron  4   5 , B Debuc  6 , E Guerot  3 , C Hauw-Berlemont  3 , B Hermann  3 , J L Augy  3 , R Younan  3 , A Novara  3 , J Langlais  3 , L Khider  7 , N Gendron  8   9 , G Goudot  5 , J-F Fagon  3 , T Mirault  4   10 , D M Smadja  8   9
Affiliations

Respiratory mechanics and gas exchanges in the early course of COVID-19 ARDS: a hypothesis-generating study

J-L Diehl et al. Ann Intensive Care. .

Abstract

Rationale: COVID-19 ARDS could differ from typical forms of the syndrome.

Objective: Pulmonary microvascular injury and thrombosis are increasingly reported as constitutive features of COVID-19 respiratory failure. Our aim was to study pulmonary mechanics and gas exchanges in COVID-2019 ARDS patients studied early after initiating protective invasive mechanical ventilation, seeking after corresponding pathophysiological and biological characteristics.

Methods: Between March 22 and March 30, 2020 respiratory mechanics, gas exchanges, circulating endothelial cells (CEC) as markers of endothelial damage, and D-dimers were studied in 22 moderate-to-severe COVID-19 ARDS patients, 1 [1-4] day after intubation (median [IQR]).

Measurements and main results: Thirteen moderate and 9 severe COVID-19 ARDS patients were studied after initiation of high PEEP protective mechanical ventilation. We observed moderately decreased respiratory system compliance: 39.5 [33.1-44.7] mL/cmH2O and end-expiratory lung volume: 2100 [1721-2434] mL. Gas exchanges were characterized by hypercapnia 55 [44-62] mmHg, high physiological dead-space (VD/VT): 75 [69-85.5] % and ventilatory ratio (VR): 2.9 [2.2-3.4]. VD/VT and VR were significantly correlated: r2 = 0.24, p = 0.014. No pulmonary embolism was suspected at the time of measurements. CECs and D-dimers were elevated as compared to normal values: 24 [12-46] cells per mL and 1483 [999-2217] ng/mL, respectively.

Conclusions: We observed early in the course of COVID-19 ARDS high VD/VT in association with biological markers of endothelial damage and thrombosis. High VD/VT can be explained by high PEEP settings and added instrumental dead space, with a possible associated role of COVID-19-triggered pulmonary microvascular endothelial damage and microthrombotic process.

Keywords: ARDS; COVID-19; Physiological dead-space; Ventilatory ratio.

PubMed Disclaimer

Conflict of interest statement

All the authors have nothing to disclose.

Figures

Fig. 1
Fig. 1
Correlations between different respiratory parameters. a Correlation between physiological dead space and ventilatory ratio in 22 COVID-19 ARDS patients studied early after intubation and initiation of protective ventilation. b Correlation between CO2 total body production and ventilatory ratio
See this image and copyright information in PMC

References

    1. Gattinoni L, Coppola S, Cressoni M, Busana M, Chiumello D. Covid-19 does not lead to a « typical » Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med. 2020 doi: 10.1164/rccm.202003-0817LE. - DOI - PMC - PubMed
    1. Liu X, Liu X, Xu Y, Xu Z, Huang Y, Chen S, et al. Ventilatory Ratio in hypercapnic mechanically ventilated patients with COVID-19 associated ARDS. Am J Respir Crit Care Med. 2020 doi: 10.1164/rccm.202002-0373LE. - DOI - PMC - PubMed
    1. Pan C, Chen L, Lu C, Zhang W, Xia J-A, Sklar MC, et al. Lung recruitability in SARS-CoV-2 associated Acute Respiratory Distress Syndrome: a single-center, observational study. Am J Respir Crit Care Med. 2020 doi: 10.1164/rccm.202003-0527LE. - DOI - PMC - PubMed
    1. Beloncle FM, Pavlovsky B, Desprez C, Fage N, Olivier P-Y, Asfar P, et al. Recruitability and effect of PEEP in SARS-Cov-2-associated acute respiratory distress syndrome. Ann Intensive Care. 2020;10(1):55. doi: 10.1186/s13613-020-00675-7. - DOI - PMC - PubMed
    1. Mauri T, Spinelli E, Scotti E, Colussi G, Basile MC, Crotti S, et al. Potential for lung recruitment and ventilation-perfusion mismatch in patients with the acute respiratory distress syndrome from coronavirus disease. Crit Care Med. 2020 doi: 10.1097/CCM.0000000000004386. - DOI - PMC - PubMed

LinkOut - more resources