title: Effectiveness and safety of a prehospital program of continuous positive airway pressure (CPAP) in an urban setting.
abstract: BACKGROUND
  Continuous positive airway pressure (CPAP) is commonly used in the treatment of acute cardiogenic pulmonary edema (ACPE) and acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In-hospital evidence is robust: CPAP has been shown to improve respiratory status and to reduce intubation rates. There is less evidence on prehospital CPAP, although the emergency medical services (EMS) adoption of this modality is increasing. The objectives of this study were to 1) measure the effectiveness of prehospital CPAP on morbidity, mortality, and transport times; and 2) audit the selection of patients by medics for appropriateness and safety.
  
  
  METHODS
  We conducted a before-and-after study from August 1 to October 31 in 2010 and 2011, before and after the implementation of prehospital CPAP in a city of one million people with large rural areas. Medics were trained to apply CPAP to patients with respiratory distress and a presumed diagnosis of ACPE or AECOPD. Charts were selected using the search criteria of the chief complaint of shortness of breath, emergent transport to hospital, and any patients receiving CPAP in the field. Data extracted from ambulance call reports and hospital records were analysed with appropriate univariate statistics.
  
  
  RESULTS
  A total of 373 patients enrolled (186 pre-non-invasive ventilation [NIV] and 187 post-NIV), mean age 71.5 years, female 51.4%, and final diagnoses of ACPE 18.9%, AECOPD 21.9%. In the post group of 84 patients meeting NIV criteria, 41.6% received NIV; and of 102 patients not meeting the criteria, 5.2% received NIV. There were 12 minor adverse events in 36 applications (33.3%) as per protocol. Comparing post versus pre, there were higher rates of emergency department (ED) NIV (20.0% v. 13.4%, p<0.0001) and higher overall mortality (18.8% v. 14.9%, p<0.0001). There were no differences in ED intubation (2.1% v. 2.3%, p<0.001) and length of stay (6.8 v. 8.7 days, p=0.24).
  
  
  CONCLUSIONS
  Despite the robust in-hospital data supporting its use, we could not find benefit from CPAP in our prehospital setting with respect to morbidity, mortality, and length of stay. EMS must exercise caution in making the decision to invest in the equipment and training required to implement prehospital CPAP.
authors: *Department of Emergency Medicine,University of Ottawa,Ottawa,ON.
authors: Andrew
authors: A
authors: Willmore
authors: *Department of Emergency Medicine,University of Ottawa,Ottawa,ON.
authors: Richard
authors: R
authors: Dionne
authors: *Department of Emergency Medicine,University of Ottawa,Ottawa,ON.
authors: Justin
authors: J
authors: Maloney
authors: ‡Ottawa Paramedic Service,Ottawa,ON.
authors: Ed
authors: E
authors: Ouston
authors: *Department of Emergency Medicine,University of Ottawa,Ottawa,ON.
authors: Ian
authors: I
authors: Stiell
mesh_terms: D000368:Aged; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009864:Ontario; D015397:Program Evaluation; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000628:therapy*; D011654:Pulmonary Edema / Q000453:epidemiology / Q000628:therapy*; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D019037:Urban Health Services
keywords: chronic obstructive pulmonary disease (COPD); continuous positive airway pressure (CPAP); emergency medical services (EMS); non-invasive; non-invasive ventilation (NIV); prehospital; ventilation