{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T02:19:34Z","timestamp":1787019574742,"version":"build-2736575974"},"reference-count":48,"publisher":"European Respiratory Society (ERS)","issue":"3","license":[{"start":{"date-parts":[[2020,9,24]],"date-time":"2020-09-24T00:00:00Z","timestamp":1600905600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.ersjournals.com\/user-licence"}],"funder":[{"DOI":"10.13039\/501100000024","name":"Canadian Institutes of Health Research","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000024","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000221","name":"Canadian Lung Association","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000221","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100010647","name":"Canadian Thoracic Society","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100010647","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["publications.ersnet.org"],"crossmark-restriction":true},"short-container-title":["Eur Respir J"],"accepted":{"date-parts":[[2020,9,15]]},"published-print":{"date-parts":[[2021,3]]},"abstract":"<jats:p>Many patients with severe chronic obstructive pulmonary disease (COPD) report an unpleasant respiratory sensation at rest, which is further amplified by adoption of a supine position (orthopnoea). The mechanisms of this acute symptomatic deterioration are poorly understood.<\/jats:p>\n                  <jats:p>\n                    Sixteen patients with advanced COPD and a history of orthopnoea and 16 age- and sex-matched healthy controls underwent pulmonary function tests (PFTs) and detailed sensory\u2013mechanical measurements including inspiratory neural drive (IND) assessed by diaphragm electromyography (EMG\n                    <jats:sub>di<\/jats:sub>\n                    ), oesophageal pressure (\n                    <jats:italic>P<\/jats:italic>\n                    <jats:sub>es<\/jats:sub>\n                    ) and gastric pressure (\n                    <jats:italic>P<\/jats:italic>\n                    <jats:sub>ga<\/jats:sub>\n                    ), in both sitting and supine positions.\n                  <\/jats:p>\n                  <jats:p>\n                    Patients had severe airflow obstruction (forced expiratory volume in 1\u2005s (FEV\n                    <jats:sub>1<\/jats:sub>\n                    ): 40\u00b118%\u2009pred) and lung hyperinflation. Regardless of the position, patients had lower inspiratory capacity (IC) and higher IND for a given tidal volume (\n                    <jats:italic>V<\/jats:italic>\n                    <jats:sub>T<\/jats:sub>\n                    ) (\n                    <jats:italic>i.e.<\/jats:italic>\n                    greater neuromechanical dissociation (NMD)), higher intensity of breathing discomfort, higher minute ventilation (\n                    <jats:italic>V<\/jats:italic>\n                    \u2032\n                    <jats:sub>E<\/jats:sub>\n                    ) and higher breathing frequency (\n                    <jats:italic>f<\/jats:italic>\n                    <jats:sub>B<\/jats:sub>\n                    ) compared with controls (all p&lt;0.05). For controls in a supine position, IC increased by 0.48\u2005L\n                    <jats:italic>versus<\/jats:italic>\n                    sitting erect, with a small drop in\n                    <jats:italic>V<\/jats:italic>\n                    \u2032\n                    <jats:sub>E<\/jats:sub>\n                    , mainly due to reduced\n                    <jats:italic>f<\/jats:italic>\n                    <jats:sub>B<\/jats:sub>\n                    (all p&lt;0.05). By contrast, IC remained unaltered in patients with COPD, but dynamic lung compliance (\n                    <jats:italic>C<\/jats:italic>\n                    <jats:sub>Ldyn<\/jats:sub>\n                    ) decreased (p&lt;0.05) in the supine position. Breathing discomfort, inspiratory work of breathing (WOB), inspiratory effort, IND, NMD and neuroventilatory uncoupling all increased in COPD patients in the supine position (p&lt;0.05), but not in the healthy controls. Orthopnoea was associated with acute changes in IND (r=0.65, p=0.01), neuroventilatory uncoupling (r=0.76, p=0.001) and NMD (r=0.73, p=0.002).\n                  <\/jats:p>\n                  <jats:p>In COPD, onset of orthopnoea coincided with an abrupt increase in elastic loading of the inspiratory muscles in recumbency, in association with increased IND and greater NMD of the respiratory system.<\/jats:p>","DOI":"10.1183\/13993003.00754-2020","type":"journal-article","created":{"date-parts":[[2020,9,24]],"date-time":"2020-09-24T16:50:18Z","timestamp":1600966218000},"page":"2000754","update-policy":"https:\/\/doi.org\/10.1183\/ers-crossmark-policy","source":"Crossref","is-referenced-by-count":16,"title":["Mechanisms of orthopnoea in patients with advanced COPD"],"prefix":"10.1183","volume":"57","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5180-519X","authenticated-orcid":false,"given":"Amany F.","family":"Elbehairy","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5019-7292","authenticated-orcid":false,"given":"Azmy","family":"Faisal","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hannah","family":"McIsaac","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6883-4720","authenticated-orcid":false,"given":"Nicolle J.","family":"Domnik","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7152-7016","authenticated-orcid":false,"given":"Kathryn M.","family":"Milne","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew D.","family":"James","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8019-281X","authenticated-orcid":false,"given":"J. 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Reflex compensation for changes in operational length of inspiratory muscles. In: Roussos CH , Macklem PT , eds. The thorax. Part A. Lung biology in health and disease. 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