Validity and fidelity of the upper airway in two high-fidelity patient simulators

Human patient simulators are frequently used for airway management training and research. However, little is known about their fidelity and validity. The use of these simulators as a benchmark model remains highly questionable. The objective of this study was to evaluate the validity and fidelity of two patient simulators (compared to actual patients) for anaesthesia residents performing three airway management techniques.

Endotracheal intubation, laryngeal mask airway insertion and mask ventilation were performed by anaesthesia residents on 80 patients undergoing elective surgery. The anaesthesia residents also used these three techniques to secure the airways of two human patient simulators in a randomised crossover study. The durations, difficulties, realism and success rates of the procedures were assessed.

Although the performance of endotracheal intubation was comparable in patients and both manikins, no chest rise was visible in 35% (HAL) and 32.5% (SimMan) of the manikins after inserting a laryngeal mask airway. This result was not observed in patients (P<0.001). Furthermore, effective mask ventilation was not possible in 60% of the cases using HAL, compared with 0% of cases using SimMan and 2.5% of patients (P<0.001).

Patient simulators are not a valid alternative to human patients for conducting scientific evaluations of supraglottic airway management techniques. HAL and SimMan do have adequate validity for endotracheal intubation, but the fidelity and validity are low when a laryngeal mask is used or if mask ventilation is performed. Therefore, previous simulation-based airway device evaluation studies must be interpreted with great caution.