{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T12:30:03Z","timestamp":1791203403841,"version":"4.2.0"},"reference-count":40,"publisher":"European Respiratory Society (ERS)","issue":"1","license":[{"start":{"date-parts":[[2019,4,18]],"date-time":"2019-04-18T00:00:00Z","timestamp":1555545600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.ersjournals.com\/user-licence"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["R01HL128658"],"award-info":[{"award-number":["R01HL128658"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000968","name":"American Heart Association","doi-asserted-by":"publisher","award":["15SDG25890059"],"award-info":[{"award-number":["15SDG25890059"]}],"id":[{"id":"10.13039\/100000968","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000925","name":"National Health and Medical Research Council","doi-asserted-by":"publisher","award":["1064163"],"award-info":[{"award-number":["1064163"]}],"id":[{"id":"10.13039\/501100000925","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["publications.ersnet.org"],"crossmark-restriction":true},"short-container-title":["Eur Respir J"],"accepted":{"date-parts":[[2019,4,3]]},"published-print":{"date-parts":[[2019,7]]},"abstract":"<jats:sec><jats:title>Rationale and objectives<\/jats:title><jats:p>Non-invasive quantification of the severity of pharyngeal airflow obstruction would enable recognition of obstructive<jats:italic>versus<\/jats:italic>central manifestation of sleep apnoea, and identification of symptomatic individuals with severe airflow obstruction despite a low apnoea\u2013hypopnoea index (AHI). Here we provide a novel method that uses simple airflow-<jats:italic>versus<\/jats:italic>-time (\u201cshape\u201d) features from individual breaths on an overnight sleep study to automatically and non-invasively quantify the severity of airflow obstruction without oesophageal catheterisation.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>41 individuals with suspected\/diagnosed obstructive sleep apnoea (AHI range 0\u201391\u2005events\u00b7h<jats:sup>\u22121<\/jats:sup>) underwent overnight polysomnography with gold-standard measures of airflow (oronasal pneumotach: \u201cflow\u201d) and ventilatory drive (calibrated intraoesophageal diaphragm electromyogram: \u201cdrive\u201d). Obstruction severity was defined as a continuous variable (flow:drive ratio). Multivariable regression used airflow shape features (inspiratory\/expiratory timing, flatness, scooping, fluttering) to estimate flow:drive ratio in 136\u200a264 breaths (performance based on leave-one-patient-out cross-validation). Analysis was repeated using simultaneous nasal pressure recordings in a subset (n=17).<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Gold-standard obstruction severity (flow:drive ratio) varied widely across individuals independently of AHI. A multivariable model (25 features) estimated obstruction severity breath-by-breath (R<jats:sup>2<\/jats:sup>=0.58<jats:italic>versus<\/jats:italic>gold-standard, p&lt;0.00001; mean absolute error 22%) and the median obstruction severity across individual patients (R<jats:sup>2<\/jats:sup>=0.69, p&lt;0.00001; error 10%). Similar performance was achieved using nasal pressure.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>The severity of pharyngeal obstruction can be quantified non-invasively using readily available airflow shape information. Our work overcomes a major hurdle necessary for the recognition and phenotyping of patients with obstructive sleep disordered breathing.<\/jats:p><\/jats:sec>","DOI":"10.1183\/13993003.02262-2018","type":"journal-article","created":{"date-parts":[[2019,4,18]],"date-time":"2019-04-18T12:16:19Z","timestamp":1555589779000},"page":"1802262","update-policy":"https:\/\/doi.org\/10.1183\/ers-crossmark-policy","source":"Crossref","is-referenced-by-count":61,"title":["Quantifying the magnitude of pharyngeal obstruction during sleep using airflow shape"],"prefix":"10.1183","volume":"54","author":[{"given":"Dwayne L.","family":"Mann","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Philip 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