Scientific article
Open access

Dysfunctional breathing diagnosed by cardiopulmonary exercise testing in 'long COVID' patients with persistent dyspnoea

Published inBMJ open respiratory research, vol. 9, no. 1, e001126
First online date2022-03-30

Background: 'Long COVID'-associated dyspnoea may persist for months after SARS-CoV-2 infection. Among the causes of persistent dyspnoea, dysfunctional breathing (DB), defined as an erratic or inappropriate ventilation at rest or exercise, has been observed, but little is known about its occurrence and pathophysiology among individuals with 'long COVID'. We aimed to describe the occurrence and identify clinical predictors of DB among patients following SARS-CoV-2 infection.

Methods: Cardiopulmonary exercise testing (CPET) was performed in 51 SARS-CoV-2 patients (median age, 64 years (IQR, 15)); male, 66.7%) living with 'long COVID' and persistent dyspnoea. CPET was classified into three dominant patterns: respiratory limitation with gas exchange abnormalities (RL); normal CPET or O2 delivery/utilisation impairment (D); and DB. Non-parametric and χ2 tests were applied to analyse the association between CPET dominant patterns and demographics, pulmonary function tests and SARS-CoV-2 severity.

Results: Among 51 patients, DB mostly without hyperventilation was found in 29.4% (n=15), RL in 54.9% (n=28) and D in 15.7% (n=8). When compared with RL individuals, patients with DB were younger, had significantly less severe initial infection, a better transfer capacity for carbon monoxide (median 85% (IQR, 28)), higher oxygen consumption (22.9 mL/min/kg (IQR, 5.5)), a better ventilatory efficiency slope (31.6 (IQR, 12.8)), and a higher SpO2 (95% (IQR, 3)).

Conclusions: Our findings suggest that DB without hyperventilation could be an important pathophysiological mechanism of disabling dyspnoea in younger outpatients following SARS-CoV-2 infection, which appears to be a feature of COVID-19 not described in other viral diseases.

  • COVID-19
  • Viral infection
  • COVID-19 / complications
  • COVID-19 / diagnosis
  • Dyspnea / diagnosis
  • Dyspnea / etiology
  • Exercise Test
  • Exercise Tolerance / physiology
  • Humans
  • Male
  • Middle Aged
  • Respiration
  • SARS-CoV-2
  • Post-Acute COVID-19 Syndrome
Citation (ISO format)
FRESARD MORAND, Isabelle et al. Dysfunctional breathing diagnosed by cardiopulmonary exercise testing in “long COVID” patients with persistent dyspnoea. In: BMJ open respiratory research, 2022, vol. 9, n° 1, p. e001126. doi: 10.1136/bmjresp-2021-001126
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Article (Published version)
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ISSN of the journal2052-4439

Technical informations

Creation03/10/2023 10:18:27 AM
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Update time09/21/2023 11:48:36 AM
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