Compliance Phenotypes in Early Acute Respiratory Distress Syndrome before the COVID-19 Pandemic

Rakshit Panwar; Fabiana Madotto; John G Laffey; Frank M P van Haren

doi:10.1164/rccm.202005-2046OC

Compliance Phenotypes in Early Acute Respiratory Distress Syndrome before the COVID-19 Pandemic

Am J Respir Crit Care Med. 2020 Nov 1;202(9):1244-1252. doi: 10.1164/rccm.202005-2046OC.

Authors

Rakshit Panwar^{1

2}, Fabiana Madotto³, John G Laffey^{4

5

6}, Frank M P van Haren^{7

8

9}

Affiliations

¹ ICU, John Hunter Hospital, Newcastle, New South Wales, Australia.
² School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia.
³ Scientific Institute for Research, Hospitalization and Health Care Multimedica, Sesto San Giovanni, Milan, Italy.
⁴ Anaesthesia and Intensive Care Medicine, School of Medicine, and.
⁵ Regenerative Medicine Institute, CÚRAM Centre for Research in Medical Devices, National University of Ireland Galway, Galway, Ireland.
⁶ Department of Anaesthesia, University Hospital Galway, Saolta Hospital Group, Galway, Ireland.
⁷ Medical School, Australian National University, Canberra, New South Wales, Australia.
⁸ Faculty of Health, University of Canberra, Canberra, New South Wales, Australia; and.
⁹ ICU, The Canberra Hospital, Canberra, New South Wales, Australia.

Abstract

Rationale: A novel model of phenotypes based on set thresholds of respiratory system compliance (Crs) was recently postulated in context of coronavirus disease (COVID-19) acute respiratory distress syndrome (ARDS). In particular, the dissociation between the degree of hypoxemia and Crs was characterized as a distinct ARDS phenotype.Objectives: To determine whether such Crs-based phenotypes existed among patients with ARDS before the COVID-19 pandemic and to closely examine the Crs-mortality relationship.Methods: We undertook a secondary analysis of patients with ARDS, who were invasively ventilated on controlled modes and enrolled in a large, multinational, epidemiological study. We assessed Crs, degree of hypoxemia, and associated Crs-based phenotypic patterns with their characteristics and outcomes.Measurements and Main Results: Among 1,117 patients with ARDS who met inclusion criteria, the median Crs was 30 (interquartile range, 23-40) ml/cm H₂O. One hundred thirty-six (12%) patients had preserved Crs (≥50 ml/cm H₂O; phenotype with low elastance ["phenotype L"]), and 827 (74%) patients had poor Crs (<40 ml/cm H₂O; phenotype with high elastance ["phenotype H"]). Compared with those with phenotype L, patients with phenotype H were sicker and had more comorbidities and higher hospital mortality (32% vs. 45%; P < 0.05). A near complete dissociation between Pa_O₂/Fi_O₂ and Crs was observed. Of 136 patients with phenotype L, 58 (43%) had a Pa_O₂/Fi_O₂ < 150. In a multivariable-adjusted analysis, the Crs was independently associated with hospital mortality (adjusted odds ratio per ml/cm H₂O increase, 0.988; 95% confidence interval, 0.979-0.996; P = 0.005).Conclusions: A wide range of Crs was observed in non-COVID-19 ARDS. Approximately one in eight patients had preserved Crs. Pa_O₂/Fi_O₂ and Crs were dissociated. Lower Crs was independently associated with higher mortality. The Crs-mortality relationship lacked a clear transition threshold.

Keywords: acute respiratory distress syndrome; intensive care; mechanical ventilation; phenotype; respiratory system compliance.

Publication types

Multicenter Study
Observational Study

MeSH terms

Betacoronavirus*
COVID-19
Coronavirus Infections / epidemiology*
Female
Follow-Up Studies
Humans
Intensive Care Units
Lung Compliance / physiology*
Male
Middle Aged
Pandemics*
Pneumonia, Viral / epidemiology*
Prospective Studies
Respiratory Distress Syndrome / physiopathology*
Respiratory Function Tests
SARS-CoV-2