Page 62 - Journal of Special Operations Medicine - Summer 2016

Multiple studies found an initial improvement in perfor- various sources. 72–80 These studies had more stringent cri-
mance (up to 3 to 4 weeks) after training on cadaver, LT, teria defining “failure” (often following one or two ETI
or synthetic models, usually with testing occurring on attempts) when compared with studies with medical and
the same model used for training. 33,56–58 However, when paramedic students (which often allowed at least three
reassessing performance at 6 months, the skill was not attempts, and, often, unlimited attempts). 72–80 With these
retained in learners with minimal experience with, or more lenient criteria, the medical/paramedic students
exposure to, the procedure during that time period. 57 reached a higher success rate more quickly (90% success
after 11–30 attempts); however, they still were not per-
Endotracheal Intubation Using Direct Laryngoscopy forming a “good” ETI (judged on metrics such as ETI in
The literature search retrieved 53 articles that were ap- less than 30 seconds) nor were they able to intubate on
propriate for in-depth review of ETI using direct laryn- the first or second attempt successfully until performing
goscopy; 22 informed at least one key question. There a greater number of ETIs. 76–80 Kovacs et al. found that
were five relevant studies investigating translational ETI skills deteriorated after approximately 4 months in
outcomes on future success with ETI when various novices without any ongoing practice or training, but
hands-on training methods were used, including manne- independent practice with periodic feedback resulted in
quins, LT, cadavers, and anesthetized patients. For adult maintained skill performance at 9 months. 81
patients, simulation training or training on anesthetized
patients increased future success with ETI in both oper- Cricothyrotomy
ating room (OR) and prehospital environments. 59–62 No We retrieved 44 articles that were appropriate for in-
studies investigated LT in isolation as a training modal- depth review of cricothyrotomy (open surgical tech-
ity, and one found that adding limited cadaver ETI at- nique). Of these, one was unable to be located, and
tempts (n = 3) to a robust simulator curriculum made seven solely focused on percutaneous cricothyrotomy
no difference. Two studies investigating transfer of and, therefore, will not be discussed. Eleven informed
63
skills between various synthetic training models demon- at least one key question. Three studies compared open
strated that although using different models could seem- surgical cricothyrotomy on LT models to a simulator
ingly slow skill acquisition, it may improve retention (TraumaMan). 23,27,28 Only one study investigated ac-
23
and transfer of skills to new settings. 64,65 tual performance outcomes following training on LT
versus a simulator (TraumaMan), finding no difference
The translational outcomes observed in adult patients between the two training arms with nonphysician mili-
following training on simulators may not be generaliz- tary learners. The study was underpowered and only
able to the neonatal population. Some pediatric sim- one-quarter of the requisite cadavers for testing were
66
ulators have been shown not to accurately reflect the obtained. Conflicting results have been found regard-
23
airway dimensions of actual patients; if this is also true ing learner preference of LT versus synthetic models;
of neonatal simulators, this could be one reason why however, participants training on either or both models
neonatal intubation success rates did not improve fol- rated their self-efficacy similarly. 27,28
lowing simulation training in one study. 66,67 Similar inac-
curacies of airway dimensions have been found in adult The anesthetized porcine and caprine models and the
mannequins as well; however, success rates on two of TraumaMan simulator seemed to demonstrate accept-
these mannequins remain concordant with the success ability and face validity; however, difficulties obtaining
rates in actual patients. 61,68 sufficient numbers of donor bodies reduced the accept-
ability/usability of the cadaver model. More errors were
Acceptability seems to be sufficient regarding use of LT observed in placing a cricothyrotomy in the canine
and synthetic models for training ETI. There were three model compared with the human model. This suggests
studies comparing or assessing the realism of simula- lack of anatomic equivalence and raises questions about
tors or cadavers that revealed acceptability as well as training transfer from the canine to the human model.
20
face and content validity for fresh frozen cadavers. 69–71 Discriminant validity was shown for an assessment tool
The simulators used in these studies were the Laerdal developed for use with the caprine model. Training
22
Airway Trainer (Laerdal Medical; http://www.laerdal on the porcine and TraumaMan models seemed to be
.com/), SimMan (Laerdal), and TruCorp AirSim (Tru- predictive of effective performance on a cadaver model.
Corp; http://www.trucorp.com). 69–71 However, model limitations, such as the TraumaMan
not having a hyoid bone, were hypothesized to have led
Nine studies examined learning curves determined by to the thyrohyoid misplacement of the cricothyrotomy,
performance on actual patients and one examined skill which seems indicative of poor anatomic fidelity. 23
decay. For anesthesia residents, the number of intuba-
tions required to achieve greater than a 90% success No studies investigated learning curves or retention fol-
rate was approximately 30–60 intubations, according to lowing training on open cricothyrotomy. One study did

48 Journal of Special Operations Medicine Volume 16, Edition 2/Summer 2016