title: Thoracoabdominal Asynchrony Is Not Associated with Oxyhemoglobin Saturation in Recovering Premature Infants.
abstract: Recovering premature infants are at risk for hypoxemia and lack of synchrony between their rib cage and abdomen due to airflow obstruction and poor respiratory compliance. Thoracoabdominal asynchrony (TAA) is a useful marker of resistive and elastic lung properties. Whether TAA predicts oxygenation is unknown.
  
  
  
  We investigated oxyhemoglobin saturation (SpO2%) and TAA (phase angle, φ) in preterm infants with/without high-humidity nasal cannula (HHNC).
  
  
  
  A cross-sectional observational study was conducted in 92 infants at 32 weeks' postmenstrual age. We measured SpO2% with pulse oximetry and TAA with φ via respiratory inductance plethysmography in infants (mean gestational age: 26.4 + 1.3 weeks) who required room air (n = 18) or HHNC with/without supplemental oxygen (1-5 liters per minute, FiO2 0.21-0.33, n = 74). We calculated median SpO2% from 24.7 + 10.0 min of quiet sleep and median φ from up to 60 breaths.
  
  
  
  Infants breathing room air alone had marked TAA (φ = 83.6 + 32.9°, range: 10.9-148.5) as did those receiving varying degrees of ventilatory and oxygen support via HHNC (range of group means, φ = 47.0-90.0°). Infants breathing room air had statically greater median SpO2% than those receiving support (96.3 + 0.6% vs. 91.3 + 0.6%; ANOVA p = 0.001). SpO2% was not associated with TAA in either group (r2 = 0.09).
  
  
  
  Recovering premature infants exhibited TAA regardless of need for ventilatory support and supplemental oxygen. TAA was not associated with SpO2% in either group. Maintenance of SpO2% does not require correction of TAA.
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA.
authors.forename: Colleen
authors.initials: C
authors.lastname: Brennan
authors.forename: Lara
authors.initials: L
authors.lastname: Ulm
authors.forename: Samuel
authors.initials: S
authors.lastname: Julian
authors.forename: Aaron
authors.initials: A
authors.lastname: Hamvas
authors.forename: Thomas
authors.initials: T
authors.lastname: Ferkol
authors.forename: Julie
authors.initials: J
authors.lastname: Hoffman
authors.forename: Laura
authors.initials: L
authors.lastname: Linneman
authors.forename: James
authors.initials: J
authors.lastname: Kemp
mesh_terms: D000005:Abdomen / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology* / Q000628:therapy; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D008297:Male; D008923:Missouri; D063087:Noninvasive Ventilation / Q000379:methods; D010092:Oximetry; D010100:Oxygen / Q000008:administration & dosage*; D010108:Oxyhemoglobins / Q000032:analysis*; D010991:Plethysmography; D012044:Regression Analysis; D015656:Respiratory Mechanics; D013909:Thorax / Q000503:physiopathology*
chemical_list: D010108:Oxyhemoglobins; D010100:Oxygen
keywords: High-humidity nasal cannula; Hypoxemia; Prematurity; Respiratory inductance plethysmography