{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T21:24:29Z","timestamp":1790803469739,"version":"4.1.0"},"reference-count":24,"publisher":"BMJ","issue":"6","license":[{"start":{"date-parts":[[2024,6,14]],"date-time":"2024-06-14T00:00:00Z","timestamp":1718323200000},"content-version":"unspecified","delay-in-days":13,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"name":"Kantonsspital St. Gallen","award":["N\/A"],"award-info":[{"award-number":["N\/A"]}]},{"name":"Lungenliga St. Gallen - Appenzell","award":["N\/A"],"award-info":[{"award-number":["N\/A"]}]}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2024,6,2]]},"published-print":{"date-parts":[[2024,6]]},"abstract":"<jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To develop a statistical approach that provides a quantitative index measuring the magnitude of the irregularity of the breathing response to exercise for the diagnosis of dysfunctional breathing.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Cross-sectional, retrospective, real-world study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>Single-centre study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Participants<\/jats:title>\n                    <jats:p>A population of 209 patients investigated with cardiopulmonary exercise testing in our institution for unexplained or disproportionate exertional dyspnoea between January and July 2022.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Primary and secondary outcome measures<\/jats:title>\n                    <jats:p>A novel statistical approach providing a quantitative index\u2014proportional tidal volume variation (PTVV)\u2014was developed to measure the magnitude of the irregularity of the breathing response to exercise.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>PTVV provided a reliable statistical readout for the objective assessment of DB with a prediction accuracy of 78% (95% CI: 72 to 83%). The prevalence of DB in the investigated population was high with more than half of the patients affected by moderate-to-severe DB.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>PTVV can easily be implemented in the clinical routine. Our study suggests a possible further simplification for the diagnosis of DB with two objective criteria including PTVV and one single criterion for hyperventilation.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2023-083401","type":"journal-article","created":{"date-parts":[[2024,6,17]],"date-time":"2024-06-17T03:15:33Z","timestamp":1718594133000},"page":"e083401","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":8,"title":["Quantification of breathing irregularity for the diagnosis of dysfunctional breathing using proportional tidal volume variation: a cross-sectional, retrospective real-world study"],"prefix":"10.1136","volume":"14","author":[{"given":"Georg","family":"Kn\u00f6pfel","sequence":"first","affiliation":[{"name":"Pulmonary Medicine, Cantonal Hospital St. Gallen, Sankt Gallen, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1425-0428","authenticated-orcid":false,"given":"Florent","family":"Baty","sequence":"additional","affiliation":[{"name":"Pulmonary Medicine, Cantonal Hospital St. Gallen, Sankt Gallen, Switzerland"},{"name":"University of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Friedrich","family":"Uhl","sequence":"additional","affiliation":[{"name":"Pulmonary Medicine, Cantonal Hospital St. Gallen, Sankt Gallen, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lukas","family":"Kern","sequence":"additional","affiliation":[{"name":"Pulmonary Medicine, Cantonal Hospital St. Gallen, Sankt Gallen, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin","family":"Brutsche","sequence":"additional","affiliation":[{"name":"Pulmonary Medicine, Cantonal Hospital St. Gallen, Sankt Gallen, Switzerland"},{"name":"University of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2024,6,16]]},"reference":[{"key":"2025121221213267000_14.6.e083401.1","doi-asserted-by":"publisher","DOI":"10.1183\/16000617.0088-2015"},{"key":"2025121221213267000_14.6.e083401.2","doi-asserted-by":"crossref","DOI":"10.1590\/1806-3713\/e20170347","article-title":"Dysfunctional breathing: what do we know","volume":"45","author":"Vidotto","year":"2019","journal-title":"J Bras Pneumol"},{"key":"2025121221213267000_14.6.e083401.3","doi-asserted-by":"crossref","DOI":"10.1183\/16000617.0182-2020","article-title":"Minute ventilation\/carbon dioxide production in patients with dysfunctional breathing","volume":"30","author":"Watson","year":"2021","journal-title":"Eur Respir Rev"},{"key":"2025121221213267000_14.6.e083401.4","first-page":"1243","article-title":"Hyperventilation syndrome and dysfunctional breathing: update","volume":"16","author":"Du Pasquier","year":"2020","journal-title":"Rev Med Suisse"},{"key":"2025121221213267000_14.6.e083401.5","doi-asserted-by":"crossref","DOI":"10.1136\/bmjresp-2023-001770","article-title":"Dysfunctional breathing symptoms, functional impact and quality of life in patients with long COVID-19: a prospective case series","volume":"10","author":"Genecand","year":"2023","journal-title":"BMJ Open Respir Res"},{"key":"2025121221213267000_14.6.e083401.6","doi-asserted-by":"crossref","DOI":"10.31661\/gmj.v9i0.1738","article-title":"The optimal cut-off score of the Nijmegen questionnaire for diagnosing Hyperventilation syndrome using a Bayesian model in the absence of a gold standard","volume":"9","author":"Azizmohammad Looha","year":"2020","journal-title":"Galen Med J"},{"key":"2025121221213267000_14.6.e083401.7","doi-asserted-by":"publisher","DOI":"10.1007\/s10484-008-9052-3"},{"key":"2025121221213267000_14.6.e083401.8","doi-asserted-by":"publisher","DOI":"10.1007\/s10484-015-9316-7"},{"key":"2025121221213267000_14.6.e083401.9","doi-asserted-by":"crossref","first-page":"6482","DOI":"10.3390\/jcm11216482","article-title":"Kinetics during the Hyperventilation provocation test in the diagnosis of idiopathic Hyperventilation syndrome","volume":"11","author":"Pauwen","year":"2022","journal-title":"JCM"},{"key":"2025121221213267000_14.6.e083401.10","doi-asserted-by":"publisher","DOI":"10.1111\/j.1752-699X.2007.00036.x"},{"key":"2025121221213267000_14.6.e083401.11","doi-asserted-by":"crossref","first-page":"916","DOI":"10.1111\/j.1440-1843.2007.01197.x","article-title":"Design and validation of an interpretative strategy for cardiopulmonary exercise tests","volume":"12","author":"Schmid","year":"2007","journal-title":"Respirology"},{"key":"2025121221213267000_14.6.e083401.12","doi-asserted-by":"crossref","DOI":"10.1183\/13993003.02036-2016","article-title":"Physiological and clinical relevance of exercise ventilatory efficiency in COPD","volume":"49","author":"Neder","year":"2017","journal-title":"Eur Respir J"},{"key":"2025121221213267000_14.6.e083401.13","doi-asserted-by":"crossref","DOI":"10.3389\/fphys.2020.620955","article-title":"Cardiopulmonary exercise testing in the assessment of dysfunctional breathing","volume":"11","author":"Ionescu","year":"2020","journal-title":"Front Physiol"},{"key":"2025121221213267000_14.6.e083401.14","doi-asserted-by":"crossref","unstructured":"Palange P , Laveneziana P , Neder JA , et al ., eds. Clinical exercise testing . European Respiratory Society. Sheffield, United Kingdom, 2018:320.Available: http:\/\/erspublications.com\/lookup\/doi\/10.1183\/2312508X.erm8018","DOI":"10.1183\/2312508X.erm8018"},{"key":"2025121221213267000_14.6.e083401.15","doi-asserted-by":"crossref","DOI":"10.1136\/bmjresp-2021-001126","article-title":"Dysfunctional breathing diagnosed by cardiopulmonary exercise testing in \u2019long COVID\u2019 patients with persistent dyspnoea","volume":"9","author":"Fr\u00e9sard","year":"2022","journal-title":"BMJ Open Respir Res"},{"key":"2025121221213267000_14.6.e083401.16","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.resp.2018.05.002","article-title":"Exercise ventilatory irregularity can be quantified by approximate entropy to detect breathing pattern disorder","volume":"255","author":"Bansal","year":"2018","journal-title":"Respir Physiol Neurobiol"},{"key":"2025121221213267000_14.6.e083401.17","doi-asserted-by":"crossref","DOI":"10.1183\/23120541.00117-2023","article-title":"Chaotic breathing in post-COVID-19 Breathlessness: a key feature of dysfunctional breathing can be characterised objectively by approximate entropy","volume":"9","author":"Samaranayake","year":"2023","journal-title":"ERJ Open Res"},{"key":"2025121221213267000_14.6.e083401.18","doi-asserted-by":"publisher","DOI":"10.1164\/rccm.201908-1590ST"},{"key":"2025121221213267000_14.6.e083401.19","doi-asserted-by":"publisher","DOI":"10.1164\/rccm.167.2.211"},{"key":"2025121221213267000_14.6.e083401.20","unstructured":"R Core Team . R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing, 2023. Available: https:\/\/www.R-project.org\/"},{"key":"2025121221213267000_14.6.e083401.21","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0146021","article-title":"Dose-response analysis using R","volume":"10","author":"Ritz","year":"2015","journal-title":"PLOS ONE"},{"key":"2025121221213267000_14.6.e083401.22","unstructured":"Otto SA , Plonus R , Funk S , et al . INDperform: Evaluation of indicator performances for assessing ecosystem states, 2023. Available: https:\/\/saskiaotto.github.io\/INDperform\/"},{"key":"2025121221213267000_14.6.e083401.23","doi-asserted-by":"crossref","unstructured":"Khan MRA , Brandenburger T . ROCit: Performance assessment of binary classifier with visualization, 2020. Available: https:\/\/CRAN.R-project.org\/package=ROCit","DOI":"10.32614\/CRAN.package.ROCit"},{"key":"2025121221213267000_14.6.e083401.24","doi-asserted-by":"publisher","DOI":"10.1378\/chest.84.2.202"}],"container-title":["BMJ Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bmjopen-2023-083401","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,13]],"date-time":"2025-12-13T05:21:40Z","timestamp":1765603300000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmjopen.bmj.com\/lookup\/doi\/10.1136\/bmjopen-2023-083401"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,6]]},"references-count":24,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2024,6,16]]},"published-print":{"date-parts":[[2024,6]]}},"alternative-id":["10.1136\/bmjopen-2023-083401"],"URL":"https:\/\/doi.org\/10.1136\/bmjopen-2023-083401","relation":{},"ISSN":["2044-6055","2044-6055"],"issn-type":[{"value":"2044-6055","type":"print"},{"value":"2044-6055","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,6]]}}}