{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,17]],"date-time":"2026-04-17T21:46:24Z","timestamp":1776462384979,"version":"3.51.2"},"reference-count":64,"publisher":"Wiley","issue":"7","license":[{"start":{"date-parts":[[2009,6,4]],"date-time":"2009-06-04T00:00:00Z","timestamp":1244073600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pediatric Pulmonology"],"published-print":{"date-parts":[[2009,7]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>The dynamic functional residual capacity (FRC<jats:sub>dyn<\/jats:sub>), the lung volume most routinely measured in infants, is an unreliable volume landmark. In addition to the FRC<jats:sub>dyn<\/jats:sub>, we measured the (passive) static FRC (FRC<jats:sub>st<\/jats:sub>) by inducing a brief post\u2010hyperventilation apnea (PHA) in 33 healthy infants aged 7.4\u2013127.2 weeks. A commercial system for nitrogen (N<jats:sub>2<\/jats:sub>) washout to measure FRC, and a custom made system to monitor and record flow and airway opening pressure signals in real\u2010time were used in unison. Infants were manually hyperventilated to induce a PHA. After the last passive expiration, FRC<jats:sub>st<\/jats:sub> was estimated by measuring the volume of N<jats:sub>2<\/jats:sub> expired after end\u2010passive expiratory switching of the inspired gas from room air to 100% oxygen during the post\u2010expiratory apneic pause. Repeatable intrasubject FRC<jats:sub>st<\/jats:sub> and FRC<jats:sub>dyn<\/jats:sub> measurements overlapped in most infants including the younger ones (<jats:italic>P<\/jats:italic>\u2009=\u20090.2839). Mean (95% confidence interval [CI]) FRC<jats:sub>st<\/jats:sub> was 21.1 (20.0\u201322.3), and error\u2010corrected FRC<jats:sub>dyn<\/jats:sub> was 21.4 (20.4\u201322.4) ml\/kg. Mean (washout time [<jats:italic>t<\/jats:italic>]) <jats:italic>t<\/jats:italic>FRC<jats:sub>st<\/jats:sub> was longer than <jats:italic>t<\/jats:italic>FRC<jats:sub>dyn<\/jats:sub> 60 sec (95% CI 55\u201365) versus 47 sec (95% CI 43\u201351) (<jats:italic>P<\/jats:italic>\u2009&lt;\u20090.0001). The FRC and washout time were dependent on body length, weight and age. We conclude that the FRC<jats:sub>st<\/jats:sub> is not different from the FRC<jats:sub>dyn<\/jats:sub> in infants. The FRC<jats:sub>st<\/jats:sub> is a reliable volume landmark because the PHA stabilizes the end\u2010expiratory level by potentially abolishing the sedated infant's breathing strategies. The FRC<jats:sub>st<\/jats:sub> lacks potential sources of errors and disadvantages associated with measuring the FRC<jats:sub>dyn<\/jats:sub>. The findings cast significant doubt on the traditional physiology of air trapping in healthy infants' lungs. Pediatr Pulmonol. 2009; 44:683\u2013692. \u00a9 2009 Wiley\u2010Liss, Inc.<\/jats:p>","DOI":"10.1002\/ppul.21040","type":"journal-article","created":{"date-parts":[[2009,6,4]],"date-time":"2009-06-04T18:47:37Z","timestamp":1244141257000},"page":"683-692","source":"Crossref","is-referenced-by-count":4,"title":["A novel physiological investigation of the functional residual capacity by the bias flow nitrogen washout technique in infants"],"prefix":"10.1002","volume":"44","author":[{"given":"Mohy G.","family":"Morris","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2009,6,4]]},"reference":[{"key":"e_1_2_1_2_2","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1995.78.1.179"},{"key":"e_1_2_1_3_2","first-page":"871","volume-title":"The thorax","author":"Bryan 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