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

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.

Secondary pulmonary alveolar proteinosis treated by lung transplant: A case report.

BACKGROUND: Pulmonary alveolar proteinosis (PAP) is a pulmonary disease characterized by disruption of surfactant homeostasis resulting in its accumulation in the alveoli. PAP is classically classified into three categories (Table 1): 1/primary (or autoimmune) with antibodies targeting the GM-CSF pathway, 2/secondary to another disease, typically a hematologic malignancy, and 3/genetic. CASE-REPORT: A 30 year-old woman received an allogenic hematopoietic stem cell transplantation (HSCT) after treatment for acute myeloid leukemia (AML). Within the first 6 months post HSCT, she developed an ocular, oral, digestive and hepatic graft-versus-host disease associated with a mixed ventilatory defect with a very severe obstructive syndrome and a severe CO diffusion impairment. High resolution computed tomography showed a classical "crazy paving" pattern. Aspect and differential cell count of BAL were normal. All microbiological samples remained culture negative. Histo-pathological analysis of transbronchial biopsies was unremarkable. Because of the severity of the respiratory insufficiency, open-lung biopsy (OBL) could not be performed. Despite multiple immunosuppressive therapies, lung function deteriorated rapidly; the patient also developed an excavated fungal lesion unresponsive to treatment. She underwent a bilateral lung transplant 48 months after HSCT. Histo-pathological analysis of explanted lungs showed obliterative bronchiolitis (OB), diffuse PAP and invasive cavitary pulmonary aspergillosis. CONCLUSIONS: This case illustrates the simultaneous occurrence of OB, PAP and a fungal infection in a 30-year old female patient who underwent HSCT for acute myeloid leukemia (AML). To our knowledge this is the only documented case of PAP associated with OB treated by lung transplantation.

Experimental dyspnoea interferes with locomotion and cognition: a randomised trial.

BACKGROUND: Chronic respiratory diseases are associated with cognitive dysfunction, but whether dyspnoea by itself negatively impacts on cognition has not been demonstrated. Cortical networks engaged in subjects experiencing dyspnoea are also activated during other tasks that require cognitive input and this may provoke a negative impact through interference with each other. METHODS: This randomised, crossover trial investigated whether experimentally-induced dyspnoea would negatively impact on locomotion and cognitive function among 40 healthy adults. Crossover conditions were unloaded breathing or loaded breathing using an inspiratory threshold load. To evaluate locomotion, participants were assessed by the Timed Up and Go (TUG) test. Cognitive function was assessed by categorical and phonemic verbal fluency tests, the Trail Making Tests (TMTs) A and B (executive function), the CODE test from the Wechsler Adult Intelligence Scale (WAIS)-IV (processing speed) and by direct and indirect digit span (working memory). RESULTS: The mean time difference to perform the TUG test between unloaded and loaded breathing was -0.752 s (95% CI -1.012 to -0.492 s) (p<0.001). Executive function, processing speed and working memory performed better during unloaded breathing, particularly for subjects starting first with the loaded breathing condition. CONCLUSION: Our data suggest that respiratory threshold loading to elicit dyspnoea had a major impact on locomotion and cognitive function in healthy adults.

[COPD and cognitive impairment]. / BPCO et troubles cognitifs.

Patients with chronic respiratory failure, especially COPD, suffer from a multi-systemic disease with organic, behavioral and social consequences that impact largely beyond the respiratory system. Cognitive impairment is associated with decreased quality of life and increased mortality in the general population, but remains underestimated and poorly studied in chronic respiratory diseases despite their increased prevalence. However, there is growing interest in research on the association between cognitive impairment and chronic respiratory diseases. Different risk factors, some modifiable, could contribute to the early development of cognitive disorders in this population. Patients with cognitive impairment need appropriate care to promote adherence to the therapeutic project. Respiratory rehabilitation, as a multimodal intervention, seems to have a positive effect on cognitive functions.

Les sujets insuffisants respiratoires chroniques, surtout ceux atteints d'une BPCO, souffrent d'une maladie multisystémique avec des conséquences biopsychosociales qui dépassent largement le système respiratoire. Les troubles cognitifs sont associés à une diminution de la qualité de vie et à une mortalité accrue dans la population générale, mais ils demeurent sous-estimés dans les maladies respiratoires chroniques malgré leur prévalence augmentée. Différents facteurs, certains modifiables, pourraient contribuer au développement précoce de troubles cognitifs dans cette population qui ne fait pas l'objet d'un dépistage systématique. Les patients avec troubles cognitifs ont besoin de soins adaptés pour favoriser l'adhésion au projet thérapeutique. La réhabilitation respiratoire semble avoir un effet positif sur les fonctions cognitives.