title: Factors associated with failure of noninvasive positive pressure ventilation in the emergency department.
abstract: OBJECTIVE
  To determine the factors associated with failure of noninvasive positive pressure ventilation (NPPV) in patients presenting with acute respiratory failure to the emergency department (ED).
  
  
  METHODS
  The authors retrospectively analyzed patients admitted to the ED for acute respiratory failure (defined as a PaCO2 level >45 mm Hg, and pH < or = 7.35 or a PaO2/FiO2 ratio < 250 mm Hg) and who were treated with NPPV. NPPV was delivered routinely according to an institutional protocol. Failure of NPPV was defined as the requirement of endotracheal intubation at any time.
  
  
  RESULTS
  A total of 104 patients were included. NPPV failed in 31% (32/104), and the mortality was significantly higher in this group (12/32 [44%]) compared with patients who were not intubated (2/72 [3%]) (p < 0.0001). Factors associated with failure of NPPV were Glasgow Coma Scale score < 13 at ED admission (odds ratio [OR], 3.67; 95% confidence interval [CI] = 1.33 to 10.07), pH < or = 7.35 (OR, 3.23; 95% CI = 1.25 to 8.31), and respiratory rate (RR) > or =20 min(-1) (OR, 3.86; 95% CI = 1.33 to 11.17) after one hour of NPPV. The negative predictive value for NPPV failure was 86% (95% CI = 70% to 95%) for RR > or =20 min(-1). In the multivariate analysis, pH < or = 7.35 and RR > or =20 min(-1) after one hour of NPPV were independently associated with NPPV failure (adjusted ORs, 3.51; 95% CI = 1.29 to 9.62 and 3.55; 95% CI = 1.13 to 11.20, respectively).
  
  
  CONCLUSIONS
  Patients with pH < or = 7.35 and an RR > or =20 min(-1) after one hour of NPPV had an increased risk of subsequent endotracheal intubation.
authors.affiliation: Division of Surgical Intensive Care, Department of Anesthesiology, Pharmacology, and Surgical Intensive Care, University of Geneva Hospital, Geneva, Switzerland. paolo.merlani@hcuge.ch
authors.forename: Paolo G
authors.initials: PG
authors.lastname: Merlani
authors.forename: Patrick
authors.initials: P
authors.lastname: Pasquina
authors.forename: Jean Max
authors.initials: JM
authors.lastname: Granier
authors.forename: Miriam
authors.initials: M
authors.lastname: Treggiari
authors.forename: Olivier
authors.initials: O
authors.lastname: Rutschmann
authors.forename: Bara
authors.initials: B
authors.lastname: Ricou
mesh_terms: D000368:Aged; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007442:Intubation, Intratracheal / Q000706:statistics & numerical data; D008297:Male; D015999:Multivariate Analysis; D010043:Outcome and Process Assessment, Health Care; D011175:Positive-Pressure Respiration / Q000706:statistics & numerical data*; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D013557:Switzerland; D017211:Treatment Failure