Limitations
First, the data was only collected at two sites on a single study day and a larger sample across more sites and over a longer period of time would increase the external validity and generalisability of the study results. Nonetheless, other investigators have reported that performance is variably maintained up to 3 months after teaching[4, 8,13]. Second, the participants were sequentially allocated to the different teaching methods and random allocation would have improved the internal validity of the study. Third, the method of measuring applied pressure relied on the study investigators reading the unblinded real-time values on the measuring scales which may have contributed to bias in the study results. Fourth, the airway model is not a true representation of a patient and whilst the general anatomy and size are similar, the different texture, resistance and lack of overlying soft tissue and other attached structures (i.e. head and torso) limit real-life applicability. Of note, some investigators have used cadavers instead of airway models for assessing cricoid pressure[24]. Fifth, the height of the table on which the cricoid model was placed may not be the same as the height of an intubation table. Sixth, the varying experience of the participants was not accounted for. Finally, study conditions, such as the position of the participant when applying the force, were not protocolised.
The results of our study confirm earlier reports that the biofeedback method is easy to teach and is the most effective technique for teaching the correct cricoid pressure[2,10,15–19]. Whilst we did not assess performance over time, other investigators have reported that performance is variably between one week and 3 months[4, 8,13]