Our study found significant and large improvements in knowledge of the tracheobronchial anatomy after a short bronchoscopic simulator training. We did not observe any significant differences in this effect between modes of instructions, i.e. between simulator guided and tutor guided groups. Gains in anatomical performance were accompanied by significant and relevant drops in handling of the bronchoscope. Trainees spend less time in the mid lumen and had substantially more wall contacts. Again, this effect was independent of the mode of instruction.
There are at least two potential reasons why we did not find significant differences between modes of instruction. There either simply may be no relevant difference between the two groups, or our sample size may be too small to detect a difference of relevance. Indeed, the tutor guided groups shows larger gains between pre- and post-assessment than the simulator guided group, with medium effect sizes ranging between 0.46 and 0.63. The effects by the training per se however are at least 3.5fold larger than those of the mode of instruction. This, together with the fact that in clinical practice providing a tutor requires much more resources, may justify the use of simulator-guided instruction only.
The slightly larger gain in anatomical knowledge in the tutor-guided group comes at the expense of slightly worse navigational skills. Students in the tutor-guided group had slightly more scope wall contacts in post-assessment than those in the simulator-guided group (d = 0.37, a medium effect size). However, again, the effect of training per se is larger than the effect of the mode of instruction. In contrast to other studies (5, 10), that showed an improvement of navigational skills after a bronchoscopy simulator self-training, our results show the opposite. One possible reason is the short training time in our trial. Another aspect might be, that the students concentrated more on the identification of the bronchial segments to the disadvantage of the scope manipulation.
Training time in published bronchoscopy simulation studies range from a single 1-hour-session to 10 repetitive training sessions (13). For example, participants of an 8-hour simulator training session improved their navigational skills and missed fewer segments in the post-training assessment (10). Because physician and student workload is generally high, it is difficult to provide time slots for regular simulator training within existing curricula. Our study could achieve improvement of anatomical knowledge and accuracy of tracheobronchial inspection after only a 1-hour-simulator training, admittedly at the expense of navigational precision. An implication of our finding might be, that shorter training sessions should focus on only one or few objectives, e.g. either scope manipulation or identification of the anatomical structures.
Another point to discuss is the fact, that body posture, body language and movements, and the correct technique of advancing the scope without distortion cannot be observed by a simulator without a supervisor. Nevertheless these are important aspects of FB, that are frequently not intuitive for novice bronchoscopists and an accurate scope handling technique is mandatory for the performance of a high quality FB. Furthermore, 84.6% of our participants of the simulator-guided group would have appreciated the presence of an instructor for provision of guidance in handling of the scope. There may be a solution for that problem, as Collela et al. investigated a motion analysis system, that is able to provide automated feedback on correct movements during self-directed training on simulators. The authors commented that this approach opens the opportunity for trainees in bronchoscopy to receive automated feedback on their scope handling during training, without the need of an instructor being present (14).
Either way, feedback is frequently rated as one of the cornerstones of medical education (15), whereas the source of feedback seems to be less important (3). In our study, the SIM group received feedback solely from the simulator, the TUT group from the simulator and the supervisor. Although not significant, but the TUT group had a slightly better performance in identifying the endobronchial segments. That is in line with Lee et al, who demonstrated that a trainee group with additional personal mentoring in robotic surgery training achieved significant better learning outcomes compared to self-directed, mentor-free learning (12). This result is reflected in our finding, that 22 (84.6%) of the participants in the simulator guided group would have preferred an additional person-to-person mentoring.
However, this approach is again conflicting with limited availability of supervisors due to their workload and thus shortage of training time (12). Being aware that additional supervision can enhance the learning experience and outcome, several studies, including ours, have shown a certain efficiency of self-directed simulator training compared to no training (16). Thus, one can argue, that, in place of not offering simulator training due to lack of a tutor, self-directed training can be a feasible compromise.
Earlier trials have frequently used the Bronchoscopy Skills and Tasks Assessment Tool (BSTAT) to evaluate proficiency in FB (3, 17). We intentionally decided to use the built-in assessment tool of the simulator, to again avoid the dependency of the presence of a human supervisor/assessor.
Our study has several limitations. First, the duration of the training session was short, with approximately 1 hour. However, this conforms to reality where time for simulator training is limited. Second, our study consisted of only one single training session with immediate assessment afterwards and did not assess long-term retention. However, we primarily aimed to assess the presence and extent of a difference in learning between the tutor-guided and the simulator-guided group. Additionally, simulator training cannot completely replace clinical practice in real patients. When basic proficiency in FB is achieved through simulator training, parallel performance of “real bronchoscopy” will take place. This would interfere with any results of “long-term-skills-retainment-assessment of simulator training between the two groups. Furthermore it is known, that the learning curve is most effective in novices and then a certain plateau will be reached (5, 18, 19). Thus, it can be assumed that in case of a difference between simulator and tutor guided simulation training, it would most likely be apparent in the early training stages.
Third, in real life, all bronchial segments have to be investigated and procedural performance is more likely to be reflected by the time needed for this procedure than by the number of segments skipped. However, we intentionally limited the time available for the examination to 5 minutes per assessment, so that the outcomes of interest could be measured on a single scale (i.e. number of segments identified or skipped) rather than having to adjust for two different scales (i.e. number of segments and time for the procedure). Earlier trials indeed found a reduction in procedure time after BST (5). A shorter procedure time may result in better patient comfort (20), and less complications (5, 21). However, despite the advantages of a short procedure time, we argue that the patient benefits even more from a cautious and atraumatic scope manipulation and a precise and complete inspection of the bronchial system.
Despite these limitations and the necessity of further research, in times of high physician workload, scarcity of time, money and availability of educators, our study is an important step on the way to determine the ideal teaching approach for basic FB.