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Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery

BACKGROUND: Pathological evidence suggests that coronavirus disease 2019 (COVID-19) pulmonary infection involves both alveolar damage (causing shunt) and diffuse microvascular thrombus formation (causing alveolar dead space). We propose that measuring respiratory gas exchange enables detection and q...

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Autores principales: Harbut, Piotr, Prisk, G. Kim, Lindwall, Robert, Hamzei, Sarah, Palmgren, Jenny, Farrow, Catherine E., Hedenstierna, Goran, Amis, Terence C., Malhotra, Atul, Wagner, Peter D., Kairaitis, Kristina
Formato: Online Artículo Texto
Lenguaje:English
Publicado: European Respiratory Society 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9515481/
https://www.ncbi.nlm.nih.gov/pubmed/36137595
http://dx.doi.org/10.1183/13993003.01117-2022
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author Harbut, Piotr
Prisk, G. Kim
Lindwall, Robert
Hamzei, Sarah
Palmgren, Jenny
Farrow, Catherine E.
Hedenstierna, Goran
Amis, Terence C.
Malhotra, Atul
Wagner, Peter D.
Kairaitis, Kristina
author_facet Harbut, Piotr
Prisk, G. Kim
Lindwall, Robert
Hamzei, Sarah
Palmgren, Jenny
Farrow, Catherine E.
Hedenstierna, Goran
Amis, Terence C.
Malhotra, Atul
Wagner, Peter D.
Kairaitis, Kristina
author_sort Harbut, Piotr
collection PubMed
description BACKGROUND: Pathological evidence suggests that coronavirus disease 2019 (COVID-19) pulmonary infection involves both alveolar damage (causing shunt) and diffuse microvascular thrombus formation (causing alveolar dead space). We propose that measuring respiratory gas exchange enables detection and quantification of these abnormalities. We aimed to measure shunt and alveolar dead space in moderate COVID-19 during acute illness and recovery. METHODS: We studied 30 patients (22 males; mean±sd age 49.9±13.5 years) 3–15 days from symptom onset and again during recovery, 55±10 days later (n=17). Arterial blood (breathing ambient air) was collected while exhaled oxygen and carbon dioxide concentrations were measured, yielding alveolar–arterial differences for each gas (P(A−aO(2)) and P(a−ACO(2)), respectively) from which shunt and alveolar dead space were computed. RESULTS: For acute COVID-19 patients, group mean (range) for P(A−aO(2)) was 41.4 (−3.5–69.3) mmHg and for P(a−ACO(2)) was 6.0 (−2.3–13.4) mmHg. Both shunt (% cardiac output) at 10.4% (0–22.0%) and alveolar dead space (% tidal volume) at 14.9% (0–32.3%) were elevated (normal: <5% and <10%, respectively), but not correlated (p=0.27). At recovery, shunt was 2.4% (0–6.1%) and alveolar dead space was 8.5% (0–22.4%) (both p<0.05 versus acute). Shunt was marginally elevated for two patients; however, five patients (30%) had elevated alveolar dead space. CONCLUSIONS: We speculate impaired pulmonary gas exchange in early COVID-19 pneumonitis arises from two concurrent, independent and variable processes (alveolar filling and pulmonary vascular obstruction). For most patients these resolve within weeks; however, high alveolar dead space in ∼30% of recovered patients suggests persistent pulmonary vascular pathology.
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spelling pubmed-95154812022-11-14 Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery Harbut, Piotr Prisk, G. Kim Lindwall, Robert Hamzei, Sarah Palmgren, Jenny Farrow, Catherine E. Hedenstierna, Goran Amis, Terence C. Malhotra, Atul Wagner, Peter D. Kairaitis, Kristina Eur Respir J Original Research Articles BACKGROUND: Pathological evidence suggests that coronavirus disease 2019 (COVID-19) pulmonary infection involves both alveolar damage (causing shunt) and diffuse microvascular thrombus formation (causing alveolar dead space). We propose that measuring respiratory gas exchange enables detection and quantification of these abnormalities. We aimed to measure shunt and alveolar dead space in moderate COVID-19 during acute illness and recovery. METHODS: We studied 30 patients (22 males; mean±sd age 49.9±13.5 years) 3–15 days from symptom onset and again during recovery, 55±10 days later (n=17). Arterial blood (breathing ambient air) was collected while exhaled oxygen and carbon dioxide concentrations were measured, yielding alveolar–arterial differences for each gas (P(A−aO(2)) and P(a−ACO(2)), respectively) from which shunt and alveolar dead space were computed. RESULTS: For acute COVID-19 patients, group mean (range) for P(A−aO(2)) was 41.4 (−3.5–69.3) mmHg and for P(a−ACO(2)) was 6.0 (−2.3–13.4) mmHg. Both shunt (% cardiac output) at 10.4% (0–22.0%) and alveolar dead space (% tidal volume) at 14.9% (0–32.3%) were elevated (normal: <5% and <10%, respectively), but not correlated (p=0.27). At recovery, shunt was 2.4% (0–6.1%) and alveolar dead space was 8.5% (0–22.4%) (both p<0.05 versus acute). Shunt was marginally elevated for two patients; however, five patients (30%) had elevated alveolar dead space. CONCLUSIONS: We speculate impaired pulmonary gas exchange in early COVID-19 pneumonitis arises from two concurrent, independent and variable processes (alveolar filling and pulmonary vascular obstruction). For most patients these resolve within weeks; however, high alveolar dead space in ∼30% of recovered patients suggests persistent pulmonary vascular pathology. European Respiratory Society 2023-01-26 /pmc/articles/PMC9515481/ /pubmed/36137595 http://dx.doi.org/10.1183/13993003.01117-2022 Text en Copyright ©The authors 2023. https://creativecommons.org/licenses/by-nc/4.0/This version is distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0. For commercial reproduction rights and permissions contact permissions@ersnet.org (mailto:permissions@ersnet.org)
spellingShingle Original Research Articles
Harbut, Piotr
Prisk, G. Kim
Lindwall, Robert
Hamzei, Sarah
Palmgren, Jenny
Farrow, Catherine E.
Hedenstierna, Goran
Amis, Terence C.
Malhotra, Atul
Wagner, Peter D.
Kairaitis, Kristina
Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery
title Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery
title_full Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery
title_fullStr Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery
title_full_unstemmed Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery
title_short Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery
title_sort intrapulmonary shunt and alveolar dead space in a cohort of patients with acute covid-19 pneumonitis and early recovery
topic Original Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9515481/
https://www.ncbi.nlm.nih.gov/pubmed/36137595
http://dx.doi.org/10.1183/13993003.01117-2022
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