Skill trainer
At present, to the best of our knowledge, there is no commercial system allowing to judge pressure during intubation training. In our study, we used a skill trainer equipped with force sensors for the retraining of expert medical professionals in intubation procedures. Considering a sample with experience in neonatal intensive care, our aim was to investigate its potential use as an instrument for procedure optimization. We do not exclude its utilization in less expert hands (for example, in pediatric residents), but in our opinion this should follow practice on commercial intubation models, to acquire basic technique. Our novel manikin allowed for accurate feedback of pressures applied, in order to safe soft tissues when operators perform the procedure in vivo. A correct execution of intubations is very important in reducing potential damage on oral and airway structures. This issue is often underestimated in clinical practice, especially in emergencies, where more importance is attributed to a rapid completion of the maneuver. Moreover, we demonstrated operator improvement in terms of time to intubation with reduced applied forces.
In our opinion, offering skill training on a high-difficulty model allows the optimization of the procedure, achieving an automated execution of gentler gestures in easier clinical situations. Moreover, it encourages a deeper reflection on the procedure by the participants. Our opinion about skill trainer is shared by most of our participants, as demonstrated by the results of the second interview.
Moreover, real time feedback of our skill trainer allows a playful approach to the issue, which guarantees a serene and motivated participation in the sessions, according to simulation principles.
We received a good feedback about our skill trainer and its fidelity. Consistently with literature, skill trainer rigidity due to not suitable material represents an issue for the majority of participants, with potential impact on skill trainer fidelity levels and procedure execution. In addition to stiffness related to the commercial model, we believe the allocation of force sensors on external side of the device has a role on this issue. Five operators indicated stiffness as the main problem which forced them to apply greater pressures than in clinical practice. However, the analysis of video-recordings of the attempts demonstrated that these operators strived to obtain a better view of the glottis in order to complete intubations. After debriefing about the difficulties of intubation maneuvers in our skill trainer, we obtained a significant pressure reduction on all critical points. One operator asserted that the applied force level was higher than in clinical practice during the first session, but lower in the second one. After debriefing, the majority of the operators gave a positive feedback about the use of our skill trainer as difficult intubation model, which is consistent with our aim.
In addition to the stiffness of the skill trainer, the method used for attached the sensors to the manikin potentially affected the precision of their location on dental arches. We believe that this issue could underestimate the pressure values recorded in these sites. Anyway, this still proved to be a better solution, if compared with glue as in the previous work [
12].
Moreover, we contend that the system accounting for time pacing is inefficient. The majority of participants, especially during the first session, did not pay attention to the 30s and following sound signals, continuing the attempt until success or, eventually, failure. In our opinion, this system lacks fidelity. Its substitution with a more realistic saturation digital monitor, similar to that normally present in NICU, would increase setting fidelity and induce participants to pay increasing attention to decision making and non-technical skills.
We collected opinions about device fidelity as well as any suggestions for potential improvements. Among the latter, the possibility to monitor pressure on the cricoid cartilage, normally considered in clinical practice, would considerably improve glottis view in case of difficult intubation. According to our operators feeling, obtaining a better epiglottis and tongue mobility also needs to be carefully considered. A future perspective of our research could be the realization of a new airway model in which the integration of force sensors ab initio would be envisioned, in order to solve the allocation problems described above. In addition, we should also consider more sophisticated measurement methods, to obtain a continuous force plot on the tissues, rather than punctual force values as in this study (e.g. we need to integrate superficial sensors).
We compared our skill trainer with other devices described in the literature. In a recent study by Doreswamy et al. [
14],
Neonatal Intubation Trainer was employed to evaluate pressure levels accomplished by NICU professionals (included nurses) during intubation procedures. They analyzed forces on the superior dental arch using Prescale Ultra Low, a pressure-sensitive film by Fujifilm. They reported a mean pressure of about 568 kPa, which was considered cause of potential damage. They also recorded mean time of procedure (14.7 s) and mean area under pressure (142mm
2). These variables were then compared between different health professional categories and different procedure experience (more or less than 2 intubations per year). This study only carried out a comparison between health categories, observing almost no significant differences between groups except for procedure time, which was lower in expert participants. The issue of retraining, however, was not addressed.
To the best of our knowledge, no sensorized skill trainer device for neonatal intubation has been previously described. An active skill trainer for adult intubation
(©Difficult Airway Management Simulator MW11 by
©Kyoto Kagaku) has been recently released, and is equipped with several kinds of sensors: force sensors on dental arches and tongue (not on epiglottis), position sensors for head and neck, tension sensors for airway. There are actuators which respond to operator’s actions, determining high fidelity. The realization of this device was conducted starting from robotic prototypes, which underwent clinical validation [
15]. In a recent study by Nakanishi et al. [
16], this device was used to compare different performances by novel physicians with direct laryngoscope and video-laryngoscope. They evidence how video-laryngoscope guarantees a lower pressure on tongue during intubation; on the other hand, in contrast with other studies [
17] on adult patients, they find a higher pressure on dental arches during video-laryngoscope intubation, probably due to the lack of clinical experience of their participants.
Study structure
A familiarization phase is necessary before the beginning of the sessions according to most participants. We did not envision this phase as we aimed to make our settings as similar as possible to routine clinical practice, where a difficult intubation case is an unexpected event which increases failure chances. The surprise effect of such a situation would have been eliminated by a familiarization phase.
Our analysis firstly focused on time and pressure trends. We verified a progressive decrease in procedure time and in pressures on epiglottis and inferior dental arch. In our opinion, these functions can be reasonably considered as learning trends. Our results are in keeping with the impressions of our participants, who noticed a significant performance improvement in the second session. They also gave importance to the debriefing phase, aimed at clarifying our setting and device features. We confirmed again the role of an expert debriefer as learning facilitator in simulation scenarios. Indeed, it is well known that debriefing is a key point in training by simulation, since it substantially contributes to improve trainees’ performances.
The epiglottis sensor was the most stressed during intubation attempts. This data is consistent with gesture features. In our opinion, the attempt of obtaining a better glottis view during intubation explains these findings, considered that most participants declare not to intubate a newborn without a sufficient visualization of the glottis. In this case, debriefing allowed a progressive decrease of pressure values, lowering damage possibility. Active instruction giving by a debriefer may also explain the better correlation between pressure values and decrease of procedure time during the second session.
Although our sample size was limited, we found significant differences among participant groups in our study, related to their years of NICU work experience. In particular, pressures of the younger participants are higher on the inferior arch and lower on the epiglottis if compared with the other groups. This could be explained by a more evident forward traction maneuver executed by the younger personnel, and by the fact that nobody in the younger group loads the epiglottis during intubation attempts.
We believe that the analysis of these differences during debriefing allowed for an effective explanation of intubation gesture. Therefore, our skill trainer could be a valid instrument to achieve an optimization of intubation procedures. Our skill trainer could also represent a starting point for the realization of retraining in intubation procedures for expert medical professionals. Intubation procedure retraining should indeed be carried out as, in its absence, procedural competence regarding airway management has been documented to decrease rapidly [
18]. Thus, the maintenance throughout continuing medical education of medical procedural competences has to be emphasized, as strongly as their primary acquisition. In the United States, maintenance programs started in 2000, with the institution of Maintenance of Certification (MOC) by the American Board of Medical Specialties (ABMS). Several studies demonstrated how MOC participants significantly increase selected competences and how simulation is necessary to optimization of clinical practice [
19]. In Italy, no similar programs have been officially scheduled so far.