title: Effect of intubation and mechanical ventilation on exhaled nitric oxide in preterm infants with and without bronchopulmonary dysplasia measured at a median postmenstrual age of 49 weeks.
abstract: BACKGROUND
  Exhaled nitric oxide (eNO) is a marker of established airway inflammation in adults and children, but conflicting results have been reported in preterm infants when postnatal eNO is measured during tidal breathing. This study investigated the extent to which intubation and mechanical ventilation (MV) affect eNO and NO production (V'NO) in preterm infants with and without bronchopulmonary dysplasia (BPD).
  
  
  METHODS
  A total of 176 very low birth weight (VLBW) infants (birth weight <1500 g), including 74 (42%) with and 102 (58%) without BPD, were examined at a median postmenstrual age of 49 weeks. Of the 176 infants, 84 (48%) did not require MV, 47 (27%) required MV for <7 days and 45 (26%) required MV for ≥7 days. Exhaled NO and tidal breathing parameters were measured in sleeping infants during tidal breathing, respiratory mechanics were assessed by occlusion tests, and arterialized capillary blood gas was analyzed.
  
  
  RESULTS
  eNO was significantly correlated with tidal breathing parameters, while V'NO was correlated with growth parameters, including age and body length (p < 0.001 each). Infants who were intubated and received MV for <7 days had significantly lower eNO (p < 0.01) and V'NO (p < 0.01) than non-ventilated infants. In contrast, eNO and V'NO did not differ significantly in non-ventilated infants and those receiving MV for ≥7 days. Multivariate analysis showed that independent on the duration of MV eNO (p = 0.003) and V'NO (p = 0.018) were significantly increased in BPD infants comparable with the effects of intubation and MV on eNO (p = 0.002) and V'NO (p = 0.017).
  
  
  CONCLUSIONS
  Preterm infants with BPD show only weak postnatal increases in eNO and V'NO, but these changes may be obscured by the distinct influences of breathing pattern and invasive respiratory support. This limits the diagnostic value of postnatal eNO measurements in the follow-up of BPD infants.
authors: Department of Neonatology, Charité University Medicine, Charitéplatz 1, D - 10117 Berlin, Germany. gerd.schmalisch@charite.de.
authors: Gerd
authors: G
authors: Schmalisch
authors: Silke
authors: S
authors: Wilitzki
authors: Hendrik S
authors: HS
authors: Fischer
authors: Christoph
authors: C
authors: Bührer
mesh_terms: D001997:Bronchopulmonary Dysplasia / Q000378:metabolism / Q000503:physiopathology*; D045853:Exhalation; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000378:metabolism / Q000502:physiology*; D019102:Infant, Very Low Birth Weight / Q000378:metabolism / Q000502:physiology; D007440:Intubation / Q000379:methods*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D012119:Respiration; D012121:Respiration, Artificial / Q000379:methods*; D012129:Respiratory Function Tests / Q000379:methods; D015656:Respiratory Mechanics / Q000502:physiology; D012189:Retrospective Studies; D012890:Sleep / Q000502:physiology; D013990:Tidal Volume / Q000502:physiology
chemical_list: D009569:Nitric Oxide