{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T14:14:05Z","timestamp":1790864045511,"version":"4.1.0"},"reference-count":40,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"6","license":[{"start":{"date-parts":[[2024,8,23]],"date-time":"2024-08-23T00:00:00Z","timestamp":1724371200000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2025,6]]},"abstract":"\n BACKGROUND:<\/jats:title>\n \n Pulmonary atelectasis is present even before surgery in patients with obesity. We aimed to estimate the prevalence and extension of preoperative atelectasis in patients with obesity undergoing bariatric surgery and to determine if variation in preoperative Sp\n o<\/jats:sc>\n 2<\/jats:sub>\n values in the seated position at room air is explained by the extent of atelectasis coverage in the supine position.\n <\/jats:p>\n <\/jats:sec>\n \n METHODS:<\/jats:title>\n \n This was a cross-sectional study in a single center specialized in laparoscopic bariatric surgery. Preoperative chest computed tomographies were reassessed by a senior radiologist to quantify the extent of atelectasis coverage as a percentage of total lung volume. Patients were classified as having atelectasis when the affection was \u22652.5%, to estimate the prevalence of atelectasis. Crude and adjusted prevalence ratios (aPRs) and odds ratios (aORs) were obtained to assess the relative prevalence of atelectasis and percentage coverage, respectively, with increasing obesity category. Inverse probability weighting was used to assess the total, direct (not mediated), and indirect (mediated through atelectasis) effects of body mass index (BMI) on preoperative Sp\n o<\/jats:sc>\n 2<\/jats:sub>\n , and to quantify the magnitude of mediation (proportion mediated). E-values were calculated, to represent the minimum magnitude of association that an unmeasured confounder with the same directionality of the effect should have to drive the observed point estimates or lower confidence intervals (CIs) to 1, respectively.\n <\/jats:p>\n <\/jats:sec>\n \n RESULTS:<\/jats:title>\n \n In 236 patients with a median BMI of 40.3 kg\/m\n 2<\/jats:sup>\n (interquartile range [IQR], 34.6\u201346.0, range: 30.0\u201377.3), the overall prevalence of atelectasis was 32.6% (95% CI, 27.0\u201338.9) and by BMI category: 30 to 35 kg\/m\n 2<\/jats:sup>\n , 12.7% (95% CI, 6.1\u201324.4); 35 to 40 kg\/m\n 2<\/jats:sup>\n , 28.3% (95% CI, 17.2\u201342.6); 40 to 45 kg\/m\n 2<\/jats:sup>\n , 12.3% (95% CI, 5.5\u201324.3); 45 to 50 kg\/m\n 2<\/jats:sup>\n , 48.4% (95% CI, 30.6\u201366.6); and \u226550 units, 100% (95% CI, 86.7\u2013100). Compared to the 30 to 35 kg\/m\n 2<\/jats:sup>\n group, only the categories with BMI \u226545 kg\/m\n 2<\/jats:sup>\n had significantly higher relative prevalence of atelectasis\u201445 to 50 kg\/m\n 2<\/jats:sup>\n , aPR = 3.52 (95% CI, 1.63\u20137.61, E-value lower bound: 2.64) and \u226550 kg\/m\n 2<\/jats:sup>\n , aPR = 8.0 (95% CI, 4.22\u201315.2, E-value lower bound: 7.91)\u2014and higher odds of greater atelectasis percentage coverage: 45\u201350 kg\/m\n 2<\/jats:sup>\n , aOR = 7.5 (95% CI, 2.7\u201320.9) and \u226550 kg\/m\n 2<\/jats:sup>\n , aOR = 91.5 (95% CI, 30.0\u2013279.3). Atelectasis percent alone explained 70.2% of the variation in preoperative Sp\n o<\/jats:sc>\n 2<\/jats:sub>\n . The proportion of the effect of BMI on preoperative Sp\n o<\/jats:sc>\n 2<\/jats:sub>\n values <96% mediated through atelectasis was 81.5% (95% CI, 56.0\u2013100).\n <\/jats:p>\n <\/jats:sec>\n \n CONCLUSIONS:<\/jats:title>\n \n The prevalence and extension of atelectasis increased with higher BMI, being significantly higher at BMI \u226545 kg\/m\n 2<\/jats:sup>\n . Preoperative atelectasis mediated the effect of BMI on Sp\n o<\/jats:sc>\n 2<\/jats:sub>\n at room air in the seated position.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.1213\/ane.0000000000007166","type":"journal-article","created":{"date-parts":[[2024,8,23]],"date-time":"2024-08-23T21:43:00Z","timestamp":1724449380000},"page":"1450-1460","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":5,"title":["Preoperative Atelectasis in Patients with Obesity Undergoing Bariatric Surgery: A Cross-Sectional Study"],"prefix":"10.1213","volume":"140","author":[{"given":"Javier","family":"Mancilla-Galindo","sequence":"first","affiliation":[{"name":"Department of Bariatric Anesthesia, Baja Hospital and Medical Center, Tijuana, Mexico."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jesus Elias","family":"Ortiz-Gomez","sequence":"additional","affiliation":[{"name":"Department of Bariatric Surgery, Baja Hospital and Medical Center, Tijuana, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Orlando Rub\u00e9n","family":"P\u00e9rez-Nieto","sequence":"additional","affiliation":[{"name":"Department of Intensive Care Medicine, Hospital General San Juan del Rio, Queretaro, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Audrey","family":"De Jong","sequence":"additional","affiliation":[{"name":"Department of Anesthesia and Intensive Care Unit, Regional University Hospital of Montpellier, St-Eloi Hospital, University of Montpellier, Montpellier, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Diego","family":"Escarram\u00e1n-Mart\u00ednez","sequence":"additional","affiliation":[{"name":"Department of Anesthesia, National Medical Center \u201cLa Raza,\u201d Mexico City, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ashuin","family":"Kammar-Garc\u00eda","sequence":"additional","affiliation":[{"name":"Direcci\u00f3n de Investigaci\u00f3n, Instituto Nacional de Geriatr\u00eda, Mexico City, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luis Carlos","family":"Ram\u00edrez Mata","sequence":"additional","affiliation":[{"name":"Department of Radiology, Baja Hospital and Medical Center, Tijuana, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adriana Mendez","family":"D\u00edaz","sequence":"additional","affiliation":[{"name":"Department of Bariatric Anesthesia, Baja Hospital and Medical Center, Tijuana, Mexico."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Manuel Alberto","family":"Guerrero-Guti\u00e9rrez","sequence":"additional","affiliation":[{"name":"Department of Bariatric Anesthesia, Baja Hospital and Medical Center, Tijuana, Mexico."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2024,8,23]]},"reference":[{"key":"R1-20251003","article-title":"Prevalence of obesity in the U.S. Population, 2017-2018. 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