The control scenario, where neither chest compression nor cervical stabilization was applied during intubation.

The chest compression scenario, where continuous chest compression was applied using chest compression system LUCAS-2 (Physio-Control, Redmond, WA, USA). Chest compression was provided at a rate of 100 min-1 to a depth of 5-6 cm during all intubation procedures.

The chest compression with cervical stabilization scenario, where both chest compression using Lucas-2 and cervical stabilization were applied. A correctly fitting standard cervical immobilization collar (StifNeck Select, Laerdal, Stavanger, Norway) was applied to the manikin's neck to prevent movement of the cervical spine.

Direct-Laryngoscopy

the time to intubation, defined as the time from insertion of the laryngoscope blade between the teeth to the first manual ventilation of the mannequin's lungs

success of the intubation attempt (i.e. tracheal or oesophageal placement of the tube) with was recorded when the success of the ventilation attempt was seen by the manikin's ventilation indicators.