J Korean Soc Emerg Med.  2020 Dec;31(6):534-542.

Comparison of tracheal intubation with direct laryngoscope using an assistive technique for novice: a manikin study

• Won JH
• Kang IH
• Kim YH
• Kim YH
• Lee JH
• Cho KW
• Hwang SY
• Lee DW

Abstract

Objective
Tracheal intubation is an essential procedure in many emergencies. Direct laryngoscopy is the best method of intubation, but its success is not assured in a difficult airway. This study was designed to compare the performance of two intubation-assisted maneuvers that can help an unskilled person to perform a successful intubation.
Methods
A randomized crossover trial for intubation was conducted in three airway scenarios: normal airway, tongue edema (TE) and cervical immobilization (CI). Sixty paramedic students performed intubation on a manikin using single operator intubation (SM), external laryngeal manipulation (ELM), and colleague assisted laryngoscopic maneuver (CALM). The degree of the visual field, intubation success rate, time to ventilation (TTV), tooth fracture, and difficulty of intubation were measured.
Results
There was no statistically significant difference in success rates between the three intubation methods, except in CI, where CALM had a significantly higher success rate (91.7%) as compared to ELM (78.3%) and SM (71.7%). There was no significant difference in TTV between the three intubation methods in all scenarios. However, with an improvement in the degree of visual field with ELM and CALM, evaluated using the Cormack-Lehane classification system, there was a statistically significant improvement in both TE and CI. Tooth fractures were lowest when CALM was used. The degree of difficulty felt by operators during intubation also tended to be lower in CALM than other methods, particularly, in CI.
Conclusion
For a novice, intubation using CALM was on par or better than ELM in the manikin study. And CALM was a more effective assistive method, specifically in CI cases.

Keyword

Intubation; Direct laryngoscopy; External laryngeal manipulation; Colleague assisted laryngoscopic maneuver