title: Predictors of intubation success and therapeutic value of paramedic airway management in a large, urban EMS system.
abstract: BACKGROUND
  Endotracheal intubation (ETI) is commonly used by paramedics for definitive airway management. The predictors of success and therapeutic value with regard to oxygenation are not well studied.
  
  
  OBJECTIVE
  1) To explore the relationship between intubation success and perfusion status, Glasgow Coma Scale (GCS) score, and end-tidal carbon dioxide (EtCO2); 2) to describe the incidence of unrecognized esophageal intubations with use of continuous capnometry; and 3) to document the incremental benefit of invasive versus noninvasive airway management techniques in correcting hypoxemia.
  
  
  METHODS
  This was a prospective, observational study conducted in a large urban emergency medical services system. Paramedics completed a telephone debriefing interview with quality assurance personnel following delivery of all patients in whom invasive airway management had been attempted. Continuous capnometry was used for confirmation of tube position in all patients. Descriptive statistics were used to document airway management performance, including first-attempt ETI success, overall ETI success, and Combitube insertion (CTI) success. In addition, the incidence of unrecognized esophageal intubation was recorded. The relationship between intubation success and perfusion status, GCS score, and initial EtCO2 value was explored using logistic regression. Finally, recorded SpO2 values and the incidence of hypoxemia (SpO2 < 90%) at baseline, following noninvasive airway maneuvers, and after invasive airway management were compared for perfusing patients.
  
  
  RESULTS
  A total of 703 patients were enrolled over 12 months. First-attempt ETI success was 61%, and overall ETI success was 81%; invasive airway management (ETI or CTI) was unsuccessful in 11% of patients. A single unrecognized esophageal intubation was observed (0.1%). A clear relationship between airway management success and perfusion status, GCS score, and initial EtCO2 value was observed. Only EtCO2 demonstrated an independent association with ETI success after adjusting for the other variables. Significant improvements in mean SpO2 and the incidence of hypoxemia over baseline were observed with both noninvasive and invasive airway management techniques in 168 perfusing patients.
  
  
  CONCLUSIONS
  A relationship between intubation success and perfusion status, GCS score, and initial EtCO2 value was observed. Capnometry was effective in eliminating unrecognized esophageal intubations. Both noninvasive and invasive airway management strategies were effective in increasing SpO2 values and decreasing the incidence of hypoxemia, with additional benefit observed with invasive airway maneuvers in some patients.
authors.affiliation: Department of Emergency Medicine, UC San Diego, San Diego, CA 92103-8676, USA. davismd@cox.net
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Davis
authors.forename: Roger
authors.initials: R
authors.lastname: Fisher
authors.forename: Colleen
authors.initials: C
authors.lastname: Buono
authors.forename: Criss
authors.initials: C
authors.lastname: Brainard
authors.forename: Susan
authors.initials: S
authors.lastname: Smith
authors.forename: Ginger
authors.initials: G
authors.lastname: Ochs
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Poste
authors.forename: James V
authors.initials: JV
authors.lastname: Dunford
mesh_terms: D002140:California; D004632:Emergency Medical Services; D015600:Glasgow Coma Scale; D006801:Humans; D007407:Interviews as Topic; D007442:Intubation, Intratracheal / Q000706:statistics & numerical data*; D016015:Logistic Models; D010477:Perfusion; D011446:Prospective Studies; D016896:Treatment Outcome; D014505:Urban Population