“…Similarly, Calvo and colleagues set an exemplar of proof-of-concept study, combining 3D printed trachea model, air pump, blood pad, and pork belly to enhance realism and human physiology at low costs [ 26 ]. With demonstration by 11 Intensive care trainees, airway surgical experts were satisfied with tactile fidelity, whereas “resistance or friction” on intubation process were high [ 26 ]. However, sample size of the study was small, without investigation on training effectiveness at higher level, in terms of learning effect and its transfer to clinical setting.…”