title: The role of atmospheric pressure variation in the development of spontaneous pneumothoraces.
abstract: It has been postulated that spontaneous pneumothoraces (SP) develop because of rupture of subpleural blebs, and that atmospheric pressure changes (delta AP) may be contributory. A 5-year retrospective analysis of SP admissions was carried out to determine if delta AP do play a role in SP development. Using a 36-yr record of hourly delta AP, a normative background for delta AP was constructed. A fall in AP below the fifth, or a rise above the ninety-fifth percentile during these time periods, was classed as "unusual." Atmospheric pressure changes in the 4 days prior to SP were analyzed. The expected frequency of SP occurring by chance, if no relationship to delta AP existed, was also calculated. A total of 192 cases of SP was analyzed. Traumatic pneumothoraces were excluded. The majority of cases (72%) had been exposed to at least one "unusual" delta AP in the 4 days prior to onset of symptoms. Among those with four or more "unusual" exposures, SP occurrence was significantly more frequent than expected by chance alone (p less than 10(-10]. A strong positive association between delta AP and SP was not found in all cases, as delta AP are unlikely to be the only causative factor for SP. This finding of a relationship with ambient pressure changes lends support to the theory that SP develop as a result of rupture of subpleural blebs.
authors.affiliation: University of Missouri-Columbia Hospital and Clinics, Department of Pulmonary, Environmental and Critical Care Medicine 65212.
authors.forename: G C
authors.initials: GC
authors.lastname: Scott
authors.forename: R
authors.initials: R
authors.lastname: Berger
authors.forename: H E
authors.initials: HE
authors.lastname: McKean
mesh_terms: D000328:Adult; D001274:Atmospheric Pressure; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000150:complications; D008297:Male; D011030:Pneumothorax / Q000209:etiology*