Laryngoscopic visualization grade predicts difficult intubations by air medical crews in the out-of-hospital setting

Abstract

Study objectives: An objective physical predictor of the difficulty of an out-of-hospital airway may be useful for rapid assessment of a patient at the start of airway management. The Cormack-Lehane laryngoscopic grading system of the glottic aperture and upper airway has been demonstrated to be associated with higher intubation failure rates with grade 3 and 4 visualizations in the anesthesia literature. We hypothesize that the Cormack-Lehane laryngoscopic grading system predicts difficult intubations in out-of-hospital procedures by air medical crews. Methods: This was a retrospective review using Golden Hour Data System's medical information management system that collects patient transport and treatment data from 13 air medical companies across the United States. Procedural data from all patients who underwent emergency intubations from 1998 to 2004 were analyzed for recorded intubation technique, medications used, and success and failure rates. The data were analyzed using χ2 statistics. Results: More than 30,000 patients were transported during the 7-year study period. A total of 2,878 patients had emergency intubation procedures recorded. Of these, 2,853 patients had oral intubation attempts, with 3,827 attempts (average 1.34 attempts per patient). More than 68% of oral intubations used rapid sequence intubation medications. There were a total of 3,171 (83%) oral intubations with laryngoscopy grades recorded. The success rates and average number of intubations attempts per patient by laryngoscopy grade are presented in the Table. Table, abstract 212 Cormack-Lehane Class (% All Patients) Total Attempts, No. Success Rate, % Average Attempts/Patient Class I (40%) 1,531 91.6 1.12 Class II (24%) 908 86.6 1.15 Class III (12%) 469 75.9 1.32 Class IV (7%) 263 73.4(P<.01) 1.38 (P<.05) Open table in a new tab Study objectives: An objective physical predictor of the difficulty of an out-of-hospital airway may be useful for rapid assessment of a patient at the start of airway management. The Cormack-Lehane laryngoscopic grading system of the glottic aperture and upper airway has been demonstrated to be associated with higher intubation failure rates with grade 3 and 4 visualizations in the anesthesia literature. We hypothesize that the Cormack-Lehane laryngoscopic grading system predicts difficult intubations in out-of-hospital procedures by air medical crews. Methods: This was a retrospective review using Golden Hour Data System's medical information management system that collects patient transport and treatment data from 13 air medical companies across the United States. Procedural data from all patients who underwent emergency intubations from 1998 to 2004 were analyzed for recorded intubation technique, medications used, and success and failure rates. The data were analyzed using χ2 statistics. Results: More than 30,000 patients were transported during the 7-year study period. A total of 2,878 patients had emergency intubation procedures recorded. Of these, 2,853 patients had oral intubation attempts, with 3,827 attempts (average 1.34 attempts per patient). More than 68% of oral intubations used rapid sequence intubation medications. There were a total of 3,171 (83%) oral intubations with laryngoscopy grades recorded. The success rates and average number of intubations attempts per patient by laryngoscopy grade are presented in the Table.