Low-fractional oxygen concentration continuous positive airway pressure is effective in the prehospital setting

Prehosp Emerg Care. 2012 Apr-Jun;16(2):217-21. doi: 10.3109/10903127.2011.640765. Epub 2011 Dec 22.


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.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Blood Gas Analysis
  • Cohort Studies
  • Confidence Intervals
  • Continuous Positive Airway Pressure / adverse effects
  • Continuous Positive Airway Pressure / methods*
  • Emergency Medical Services / methods*
  • Emergency Treatment / methods
  • Female
  • Humans
  • Hyperoxia / prevention & control
  • Male
  • Middle Aged
  • Oxygen / blood*
  • Prospective Studies
  • Respiratory Insufficiency / diagnosis
  • Respiratory Insufficiency / therapy*
  • Risk Assessment
  • Sensitivity and Specificity
  • Treatment Outcome
  • Urban Health Services


  • Oxygen