Eur J Anaesthesiol. 2019;Epub ahead of print

# Necessity to depict difficult neck anatomy for training of cricothyroidotomy: A pilot study evaluating two surgical devices on a new hybrid training model.

Hossfeld B, Mahler O, Mayer B, Kulla M, Helm M

BACKGROUND: Everyone dealing with airway emergencies must be able to accomplish cricothyroidotomy, which cannot be trained in real patients. Training models are necessary.

OBJECTIVE: To evaluate the suitability of a hybrid training model combining synthetic and porcine parts to depict variable neck anatomy.

DESIGN: Model-based comparative trial.

SETTING: Armed Forces Hospital Ulm, Germany, August 2018.

INTERVENTION: On four anatomical neck variations (long slim/long obese/short slim/short obese) we performed two surgical approaches to cricothyroidotomy (SurgiCric II vs. ControlCric).

PARTICIPANTS: Forty-eight volunteers divided into two groups based on their personal skill level: beginners group and proficient performers group.

MAIN OUTCOME MEASURES: Time to completion was recorded for each procedure. Once the operator had indicated completion, the correct anatomical tube placement was confirmed by dissection and structures were inspected for complications. Primary outcomes were successful tracheal placement of an airway tube and time needed to achieve a patent airway. Secondary outcome was assessment of complications.

RESULTS: Overall, 384 procedures were performed. Median time to completion was 74 s. In total, 284 procedures (74%) resulted in successful ventilation. Time to completion was longer in short obese than in long slim and the risk of unsuccessful procedures was increased in short obese compared with long slim. Even if ControlCric resulted in faster completion of the procedure, its use was less successful and had an increased risk of complications compared with SurgiCric II. Proficient performers group performed faster but had an increased risk of injuring the tracheal wall compared with beginners group.

CONCLUSION: Participants had difficulties in performing cricothyroidotomy in obese models, but various and difficult anatomical situations must be expected in airway management and therefore must be taught. A new hybrid model combining porcine and synthetic materials offers the necessary conditions for the next step in training of surgical airway procedures.

TRIAL REGISTRATION: The study was performed without human tissue or living animals, and was therefore exempted from ethical review by the University of Ulm Ethical Committee, Germany (Chairperson Prof Dr C. Lenk) on 9 August 2018. Hence a protocol number was not attributed.