title: Low-fractional oxygen concentration continuous positive airway pressure is effective in the prehospital setting.
abstract: OBJECTIVE
  The objective of this study was to determine the effects of low-fractional concentration of inspired oxygen (FiO(2)) continuous positive airway pressure (CPAP) in prehospital noninvasive ventilation (NIV). With increasing concerns about the detrimental effects of hyperoxia, we sought to determine whether CPAP using a low FiO(2) (28%-30%) was effective in the prehospital setting.
  
  
  METHODS
  The study was a six-month prospective, nonblinded observational study conducted in a large, busy urban emergency medical services (EMS) system (Las Vegas, NV).
  
  
  RESULTS
  A total of 340 patients participated in the study. Most patients presented with symptoms consistent with a diagnosis of congestive heart failure/acute pulmonary edema (47.4%), followed by chronic obstructive pulmonary disease (COPD) (40.9%), asthma (22.7%), and pneumonia (15.9%). Improvements were seen in respiratory rate (p = 0.00) and oxygen saturation (p = 0.00). The overall CPAP discontinuation rate was 16.5%. The most common reason for CPAP discontinuation was anxiety/claustrophobia. The total number of patients requiring prehospital intubation was 5.6%. Subjective paramedic assessment of patient status at hospital delivery found that 71.5% of patients' conditions were improved, 15.1% remained unchanged, and 13.4% were worse.
  
  
  CONCLUSIONS
  CPAP using a low FiO(2) (28%-30%) was highly effective in the treatment of commonly encountered prehospital respiratory emergencies.
authors.affiliation: Department of Emergency Medicine, University of Nevada School of Medicine, Las Vegas, NV 89106, USA. bbledsoe@me.com
authors.forename: Bryan E
authors.initials: BE
authors.lastname: Bledsoe
authors.forename: Eric
authors.initials: E
authors.lastname: Anderson
authors.forename: Ryan
authors.initials: R
authors.lastname: Hodnick
authors.forename: Larry
authors.initials: L
authors.lastname: Johnson
authors.forename: Steven
authors.initials: S
authors.lastname: Johnson
authors.forename: Eric
authors.initials: E
authors.lastname: Dievendorf
mesh_terms: D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D015331:Cohort Studies; D016001:Confidence Intervals; D045422:Continuous Positive Airway Pressure / Q000009:adverse effects / Q000379:methods*; D004632:Emergency Medical Services / Q000379:methods*; D004638:Emergency Treatment / Q000379:methods; D005260:Female; D006801:Humans; D018496:Hyperoxia / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000175:diagnosis / Q000628:therapy*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D019037:Urban Health Services
chemical_list: D010100:Oxygen