The study was performed between September 2019 – November 2019 at the Acibadem Mehmet Ali Aydınlar University Simulation Center, Turkey. On a volunteer basis, the study included 89 final-year medical students studying at the Acıbadem Mehmet Ali Aydınlar University. The study protocol was approved by the Acıbadem Mehmet Ali Aydinlar University Medical Research Ethical Committee (ATADEK-2019/14).
We used an effective and low-cost simulation model, which was done, using styrofoam, a sheep trachea, and a double-layer of chicken skin. Sterile gloves, a scalpel, a scalpel handle, a hook, an endotracheal tube, and a syringe were used in carrying out the procedure. The sheep trachea was placed in the cavity made in the styrofoam, and two layers of chicken skin were then fixed over the trachea (Figure 1). Skins were replaced after every 3 or 4 cricothyroidotomy applications.
Two emergency medicine assistant professors and an emergency medicine resident recorded a best practice video of the cricothyroidotomy procedure (15). The video was shown three times to trainees following a PowerPoint presentation regarding the cricothyroidotomy procedure. During the presentation, trainees were informed about cricothyroidotomy indications, complications, and how the procedure should be performed.
Trainees were randomized into two groups after the presentation and the best practice video. One was self video-feedback group (SVFG); trainees review their performance alone for 15 minutes with a checklist of procedure steps (Appendix A). And the other was expert assisted video-feedback group (EVFG); trainees review their performance while an emergency physician provides additional feedback.
Nine of the trainees were quitted before the practical session of the study. 80 trainees subsequently performed the cricothyroidotomy procedure and all performances were recorded using a dome camera (2 Megapixel, 4.8 - 120 mm) positioned to record an optimal view of the application site. Trainees received no instruction or feedback during the procedure. An emergency physician evaluated students’ live performance skills and assessed them based on the cricothyroidotomy steps checklist (Appendix A). Each step on the checklist was scored separately. Any step that was applied incorrectly or missed was scored as “1”. Steps including a pause after the previous step but performed properly and at the correct time, scored as “2". In contrast, those performed at the proper way and time, and without hesitation, scored as “3”. The last step was about total procedure time. We used a threshold of 40 seconds to define success as Wong et al. (16). Failure and success were scored “1,2” respectively. After the feedback (SVFG or EVFG), trainees performed the procedure, recorded it onto video, and scored again. Scores gained for each step were added, and the total score was obtained.
On the other hand, video recordings of pre- and post- feedback performances were also watched and scored by another emergency physician based on the same checklist. The mean total score was calculated from the assessment results of the two physicians. Also, trainees’ age, sex, and the duration of applications were recorded.
We additionally evaluated the mean scores of the 1st and the 4th steps because they are the most critical.
Statistical analysis was performed using the MedCalc Statistical Software version 12.7.7 (MedCalc Software bvba, Ostend, Belgium; http://www.medcalc.org; 2013). Descriptive statistics were presented using mean, standard deviation, median, minimum, maximum scale variables. For comparison of two non-normally distributed independent groups, Mann Whitney U test was used. For comparison of two normally distributed independent groups, Student t-test was used. For comparison of two non-normally distributed dependent groups, the Wilcoxon test was used. For comparison of two normally distributed dependent groups, Paired Samples t-test was used. Statistical significance was accepted when the two-sided p-value was lower than 0.05.