Improvement in glottic visualisation by using the C-MAC PM video laryngoscope as a first-line device for out-of-hospital emergency tracheal intubation An observational study

BACKGROUND Out-of-hospital tracheal intubation is associated with life-threatening complications. To date, no study has compared direct and video laryngoscopic views simultaneously in the same patients in an out-of-hospital setting. OBJECTIVES The aim of this study was to determine the effect of C-MAC PM video laryngoscope on laryngeal view, compared with direct laryngoscopy, and to estimate possible consequences for patient safety. DESIGN An observational, single-centre study. SETTING Helicopter Emergency Medical Service (HEMS) 'CHRISTOPH 22', Ulm, Germany. PATIENTS Two-hundrend and twenty-eight emergency patients undergoing airway management out of hospital. INTERVENTIONS Laryngoscopy and tracheal intubation using C-MAC PM video laryngoscope. For all intubations, the HEMS physician used CMAC PM as the first-line device and performed an initial direct laryngoscopy followed by a video laryngoscopy, without changing the laryngoscope blade. MAIN OUTCOME MEASURES The difference in laryngeal view was recorded as well as the number of intubation attempts along with the success rate and difficulties in airway management. Improvement in glottic visualisation from Cormack and Lehane grade III/IV to I/II was rated as being clinically relevant. RESULTS During a 20-month study period, a total of 228 out-of-hospital emergency patients requiring tracheal intubation were included. The overall success rate in securing the airway was 100%. For 226 patients (99.1%), tracheal intubation was successful with two or fewer attempts. For comparison of direct and indirect laryngoscopic views, five patients were excluded because of the use of an indirect laryngoscope blade. Of 223 patients, 120 had a glottic view rated as Cormack and Lehane grade II to IV with direct laryngoscopy; in these patients, visualisation of the glottis was significantly improved with the C-MAC PM video laryngoscope (P< 0.001). In 56 patients (25.1%), improvement of glottic visualisation was clinically relevant (P< 0.001). CONCLUSION Use of the C-MAC PM video laryngoscope is associated with improved visualisation of the glottis according to the Cormack and Lehane grading system and an excellent success rate for out-of-hospital tracheal intubation. These results suggest that the use of C-MAC PM as a first-line device for tracheal intubation by out-of-hospital emergency medical services is a safe procedure.