{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T20:44:59Z","timestamp":1791146699191,"version":"4.1.0"},"reference-count":33,"publisher":"Oxford University Press (OUP)","issue":"6","license":[{"start":{"date-parts":[[1998,12,1]],"date-time":"1998-12-01T00:00:00Z","timestamp":912470400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[1998,12,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Pharyngeal occlusion during obstructive apnea is thought to be an inspiratory-related event; however, occlusion also occurs in the absence of negative intrathoracic pressure. We hypothesized that inspiratory-related pharyngeal occlusion would be preceded by significant expiratory narrowing. Eight sleeping patients with obstructive apnea were studied. Pharyngeal caliber, airflow, and esophageal pressure (Pes) were simultaneously monitored during three to four consecutive breaths preceding occlusion (between 3 and 22 events were studied per subject). Relative changes in retropalatal airway cross-sectional area (CSA) were determined from fiberoptic images (five frames per second) normalized to the maximum CSA. During inspiration, CSA was significantly reduced only during the breath immediately preceding the apnea (Group mean CSA \u00b1 SEM: 51 \u00b1 8% at the start of inspiration compared with 37 \u00b1 8% at midinspiration). During expiration, for all breaths there was an initial significant increase in CSA compared with the nadir CSA during the preceding inspiration (CSA: breath-3, 57 \u00b1 10% to 79 \u00b1 3%; breath-2, 59 \u00b1 8% to 76 \u00b1 4%; breath-1, 37 \u00b1 8% to 64 \u00b1 8%), followed by a significant narrowing at end-expiration compared with the peak CSA during that expiration (CSA: breath-3, 79 \u00b1 3% to 62 \u00b1 6%; breath-2, 76 \u00b1 4% to 50 \u00b1 10%; breath-1, 64 \u00b1 8% to 36 \u00b1 10%). Occlusion occurred at a pressure significantly less than that generated during the previous unoccluded breath (Pes: breath-1, \u2212 10.8 \u00b1 2.9 cm H2O; occlusion, \u2212 8.2 \u00b1 1.9 cm H2O). These results show that expiratory narrowing produced a significant reduction of CSA at end-expiration prior to obstructive apnea.<\/jats:p>","DOI":"10.1164\/ajrccm.158.6.9712107","type":"journal-article","created":{"date-parts":[[2013,4,4]],"date-time":"2013-04-04T13:51:12Z","timestamp":1365083472000},"page":"1974-1981","source":"Crossref","is-referenced-by-count":124,"title":["Progressive Retropalatal Narrowing Preceding Obstructive Apnea"],"prefix":"10.1093","volume":"158","author":[{"given":"MARY J.","family":"MORRELL","sequence":"first","affiliation":[{"name":"William S. Middleton Memorial Veterans Hospital, Department of Medicine, and John Rankin Laboratory of Pulmonary Medicine, Department of Preventive Medicine, University of Wisconsin Medical School, Madison, Wisconsin"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"YASEEN","family":"ARABI","sequence":"additional","affiliation":[{"name":"William S. Middleton Memorial Veterans Hospital, Department of Medicine, and John Rankin Laboratory of Pulmonary Medicine, Department of Preventive Medicine, University of Wisconsin Medical School, Madison, Wisconsin"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"BRIAN","family":"ZAHN","sequence":"additional","affiliation":[{"name":"William S. Middleton Memorial Veterans Hospital, Department of Medicine, and John Rankin Laboratory of Pulmonary Medicine, Department of Preventive Medicine, University of Wisconsin Medical School, Madison, Wisconsin"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. SAFWAN","family":"BADR","sequence":"additional","affiliation":[{"name":"William S. Middleton Memorial Veterans Hospital, Department of Medicine, and John Rankin Laboratory of Pulmonary Medicine, Department of Preventive Medicine, University of Wisconsin Medical School, Madison, Wisconsin"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[1998,12,1]]},"reference":[{"key":"2026032709062196400_B1","doi-asserted-by":"crossref","first-page":"931","DOI":"10.1152\/jappl.1978.44.6.931","article-title":"Pathogenesis of upper airway occlusion during sleep.","volume":"44","author":"Remmers","year":"1978","journal-title":"J. Appl. Physiol."},{"key":"2026032709062196400_B2","doi-asserted-by":"crossref","first-page":"772","DOI":"10.1152\/jappl.1979.46.4.772","article-title":"A neuromuscular mechanism maintaining extrathoracic airway patency.","volume":"46","author":"Brouillette","year":"1979","journal-title":"J. Appl. 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