title: Comparison of lung area by chest radiograph, with estimation of lung volume by helium dilution during prone and supine positioning in mechanically ventilated preterm infants: a pilot study.
abstract: Measurement of lung volume may be useful in determining the degree of lung disease and for optimizing an infant's mechanical ventilator settings. A chest radiograph (CXR) is often used to estimate lung volume, because direct measurement, e.g., functional residual capacity (FRC), is neither practical nor possible in the neonatal intensive care unit. In supinely positioned infants, good correlation was found between lung area determined by CXR and lung volume, e.g., functional residual capacity (FRC). Whether this is true for the prone position is unknown. Since positioning may affect oxygenation and pulmonary function, we studied the relationship between lung area measured from CXR and FRC during both supine and prone positioning in 14 mechanically ventilated preterm infants. Lung area was determined from CXRs using computed radiography and FRCs obtained by helium dilution at end-expiration in both supine and prone positions. Reproducibility of lung area measurements was demonstrated by high correlations between two observers (R2 = 0.92 and 0.99 for supine and prone, respectively). When supine, lung area was 15.4 +/- 3.1 cm2, and FRC was 19.5 +/- 7.3 ml. In prone position, lung area was 16.7 +/- 4.2 cm2, and FRC 23.0 +/- 9.4 ml. There was a moderate to strong positive correlation between lung area and FRC for both positions (supine: r = 0.57, P < 0.03; prone: r = 0.63, P < 0.02). Lung area measured by computed radiography is a reproducible and practical method for estimating lung volume from routine chest X-rays in both supine and prone positions in mechanically ventilated preterm infants.
authors.affiliation: Division of Neonatal-Perinatal Medicine, Schneider Children's Hospital, North-Shore Long Island Jewish Health System, Long Island Campus for Albert Einstein College of Medicine, New Hyde Park, New York 11040, USA.
authors.forename: Pankaj
authors.initials: P
authors.lastname: Kumar
authors.forename: John C
authors.initials: JC
authors.lastname: Leonidas
authors.forename: Manzar
authors.initials: M
authors.lastname: Ashtari
authors.forename: Barbara
authors.initials: B
authors.lastname: Napolitano
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Steele
mesh_terms: D005260:Female; D006371:Helium; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008168:Lung / Q000000981:diagnostic imaging*; D008176:Lung Volume Measurements / Q000379:methods; D008297:Male; D016684:Prone Position; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D012121:Respiration, Artificial; D012127:Respiratory Distress Syndrome, Newborn / Q000000981:diagnostic imaging* / Q000628:therapy; D016683:Supine Position
chemical_list: D006371:Helium