title: Nasal continuous positive airway pressure with heliox versus air oxygen in infants with acute bronchiolitis: a crossover study.
abstract: OBJECTIVE
  The purpose of this work was to evaluate the effects of administering either heliox or air oxygen in combination with nasal continuous positive airway pressure in infants with refractory bronchiolitis.
  
  
  METHODS
  We conducted a prospective, interventional, single-center, crossover study in a teaching hospital including infants 1 month to 2 years of age, consecutively admitted to the PICU from February 2004 to February 2005 for treatment of severe acute bronchiolitis unresponsive to therapy. Patients with a clinical score (Modified Wood's Clinical Asthma Score) of >5, arterial oxygen saturation of <92%, or transcutaneous CO(2) pressure of >50 mmHg despite supportive therapy, nebulized L-epinephrine, and heliox therapy through a nonrebreathing reservoir face mask were eligible. During the study period, 40 infants with bronchiolitis were admitted to the PICU; 12 fulfilled inclusion criteria. A predetermined balanced sequential allocation to either 30 minutes of treatment with nasal continuous positive airway pressure with heliox or to air-oxygen nasal continuous positive airway pressure was performed. Measurements were taken at baseline and after 30 minutes of each treatment.
  
  
  RESULTS
  Baseline mean values were as follows: nasal continuous positive airway pressure of 7.2 cmH(2)O; clinical score of 7.7 points; transcutaneous CO(2) pressure of 61.6 mmHg; and arterial oxygen saturation of 88.6%, with the fraction of inspired oxygen at 35.4%. Clinical score, transcutaneous CO(2) pressure, and arterial oxygen saturation improved during the study time with both heliox-nasal continuous positive airway pressure and air-oxygen-nasal continuous positive airway pressure: after 1 hour, the clinical score fell 1.7 points, transcutaneous CO(2) pressure decreased 8.2 mmHg, and arterial oxygen saturation increased by 7.7%. Improvement in clinical score was double with heliox-nasal continuous positive airway pressure compared with the air-oxygen-nasal continuous positive airway pressure (2.12 vs 1.08 points), and the fall in the transcutaneous CO(2) pressure was greater with heliox-nasal continuous positive airway pressure compared with air-oxygen-nasal continuous positive airway pressure (9.7 vs 5.4 mm Hg). There was no difference in arterial oxygen saturation between groups. No patients required endotracheal intubation. No adverse effects attributable to either of the study interventions were detected.
  
  
  CONCLUSIONS
  Nasal continuous positive airway pressure improves the clinical score and the CO(2) elimination of infants with refractory bronchiolitis. These positive effects are significantly enhanced when nasal continuous positive airway pressure is combined with heliox instead of air oxygen. Both techniques are noninvasive, seem safe, and may reduce the need for endotracheal intubation.
authors.affiliation: Pediatric Emergency and Critical Care Division, Department of Pediatrics, Complejo Hospitalario Universitario de Santiago, Santiago de Compostela, Spain. federico.martinon.torres@sergas.es
authors.forename: Federico
authors.initials: F
authors.lastname: Martinón-Torres
authors.forename: Antonio
authors.initials: A
authors.lastname: Rodríguez-Núñez
authors.forename: Jose María
authors.initials: JM
authors.lastname: Martinón-Sánchez
mesh_terms: D000208:Acute Disease; D001785:Blood Gas Monitoring, Transcutaneous; D001990:Bronchiolitis, Viral / Q000503:physiopathology / Q000628:therapy*; D045422:Continuous Positive Airway Pressure; D018592:Cross-Over Studies; D005260:Female; D006371:Helium / Q000008:administration & dosage*; D006801:Humans; D007223:Infant; D008297:Male; D010100:Oxygen / Q000008:administration & dosage*; D018357:Respiratory Syncytial Virus Infections / Q000503:physiopathology / Q000628:therapy*
chemical_list: D006371:Helium; C038949:heliox; D010100:Oxygen