Predictors of Intubation Success andTherapeutic 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 andtherapeutic value with regard to oxygenation are not well studied. Objectives. 1) To explore the relationship between intubation success andperfusion status, Glasgow Coma Scale (GCS) score, andend-tidal carbon dioxide (EtCO₂); 2) to describe the incidence of unrecognized esophageal intubations with use of continuous capnometry; and3) 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, andCombitube insertion (CTI) success. In addition, the incidence of unrecognized esophageal intubation was recorded. The relationship between intubation success andperfusion status, GCS score, andinitial EtCO₂ value was explored using logistic regression. Finally, recorded SpO₂ values andthe incidence of hypoxemia (SpO₂ < 90%) at baseline, following noninvasive airway maneuvers, andafter 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%, andoverall 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 andperfusion status, GCS score, andinitial EtCO₂ value was observed. Only EtCO₂ demonstrated an independent association with ETI success after adjusting for the other variables. Significant improvements in mean SpO₂ andthe incidence of hypoxemia over baseline were observed with both noninvasive andinvasive airway management techniques in 168 perfusing patients. Conclusions. A relationship between intubation success andperfusion status, GCS score, andinitial EtCO₂ value was observed. Capnometry was effective in eliminating unrecognized esophageal intubations. Both noninvasive andinvasive airway management strategies were effective in increasing SpO₂ values anddecreasing the incidence of hypoxemia, with additional benefit observed with invasive airway maneuvers in some patients.

Key words:

• endotracheal intubation
• emergency medical services
• end-tidal carbon dioxide.