Abstract
Background
Despite the critical importance of cricothyroidotomy (CCT) for patient in extremis, clinical experience with cricothyroidotomy is infrequent, and current training tools are inadequate. The long-term goal is to develop a Virtual Airway Skills Trainer (VAST) that requires a thorough task analysis to determine the critical procedural steps, learning metrics, and parameters for assessment.
Methods
Hierarchical Task Analysis (HTA) is performed to describe major tasks and subtasks for CCT. A rubric for performance scoring for each task was derived and possible operative errors were identified.
Results
Time series analyses for seven CCT videos were performed with three different observers. According to Pearson's correlation tests, three of the seven major tasks had a strong correlation between their task times and performance scores.
Conclusion
The task analysis forms the core of a proposed virtual cricothyroidotomy simulator, and highlights links between performance time and accuracy when teaching individual surgical steps of the procedure.
Keywords: Surgical Education, Surgical Simulator, Cricothyroidotomy, Cricothyroidotomy Simulator
Introduction
The first priority in the management of critically ill patients is establishment of a secure airway to ensure oxygenation and ventilation. Airway compromise represents a leading cause of preventable death in trauma patients, affects all populations, and delivers devastating consequences when not immediately rectified [1]. When challenging anatomy precludes intubation by conventional means, an emergency surgical cricothyroidotomy (CCT) is a life-saving maneuver, and often the only viable option [2][3].
Despite the life-saving role of this procedure, only one percent of all critical airways require CCT, limiting trainee experience. The Accreditation Council for Graduate Medical Education (ACGME) recommends that critical care fellows perform at least three CCT procedures during their training years to develop proficiency [4], however, emergency medicine physicians have a sufficiently high success rate for intubation (97% on fewer than two attempts) that opportunities to fulfill this quota are few [5]. This infrequency creates a dilemma, as the vital role of CCT in life-threatening scenarios mandates a strict knowledge of anatomical landmarks and a high level of surgical dexterity. Indeed, CCT can incur a high complication rate, varying from 6% to 40% [2][6]. Complications include laceration to nearby structures, vocal cord damage, vascular injury, and creation of a false lumen, all which compromise the airway and increase mortality [6].
Proficiency in CCT requires training supplemental to clinical experience, to equip practitioners with the skills to safely manage these high-stakes situations. The American College of Surgeons (ACS) has attempted to bridge this training gap through Advanced Trauma Life Support (ATLS) [7], however this course offers practice on a sporadic basis, without a graded continuum of training. Moreover, low-fidelity simulators used in courses such as ATLS are costly, and plastic mannequins lack of the realistic tactile feedback optimal for mastering this surgical procedure [4][8][10]. Concurrently, porcine and human cadavers, although more realistic, are impractical, as the CCT membrane becomes damaged with only one use [9]. Few models offer practice with procedural complications or anatomical variants.
In contrast to the aforementioned simulators, Virtual Reality (VR) simulators offer a risk-free training and assessment platform at various difficulty levels. VR simulators allow the trainers to repeatedly perform tasks and to receive quantitative feedback on their performance [10][11]. These qualities allow for improved operating room (OR) and emergency room performances[12][13][14][15].
The long-term aim of our study is the development of a virtual reality simulator for emergency CCT, with an emphasis on replication of tactile sensation and a realistic sense of proprioception using haptics technology. We seek to incorporate the multiple complex variables – cognitive and mechanical – involved in the successful performance of this life-saving procedure, to create a high-fidelity simulator ideal for systematic training. Our ultimate goal is to integrate clinical practice with technology into an elegant teaching tool, and to equip trainees with the proficiency and confidence that their patients require in the direst of circumstances. Toward this end, we performed a hierarchical task analysis of the CCT procedure, to identify key metrics of performance and assessment for use in the CCT simulator.
Methods
Procedure Analysis
A Hierarchical Task Analysis (HTA) is a structured and objective approach to identify and describe the procedural steps taken to achieve goals. HTA decomposes the procedure into a hierarchy of tasks and subtasks and expresses the relations among these tasks. The goal of this hierarchical expression is to objectively detail each and every step to formulate necessary or optional actions and decisions performed during the surgery. The derivation of HTA is necessary for the development of performance metrics and subsequently in depth time and performance analysis. In HTA for CCT, a total of seven videos of experts performing procedure were recorded. One CCT was performed on a hospitalized patient in an emergent setting, and six CCT procedures were performed on cadavers in the Advanced Surgical Skills for Exposure in Trauma (ASSET) course. Each cadaver-based procedure was recorded with three Go Pro cameras from different angles. Two of the three cameras were situated for capturing observer views (as seen in Figure 1) and one camera was attached to the surgeon's head to capture a first person view. All recorded videos were de-identified to remove any cadaver or surgeon-specific data prior to analysis. For completeness of the video analysis, the procedure and the tasks analysis is discussed below.
Figure 1.
Observer Camera View
Five distinct steps comprised the task analysis: (1) initiation of procedure, (2) creating incision, (3) securing airway, (4) verification and (5) suturing. Each main task had several subtasks. The list of the main tasks with their start and end time events for video analysis is listed in Table 1. The hierarchy of these tasks, their order of execution, and their relation are shown in the Figure 2.
Table 1.
Descriptions of start and end times based upon the hierarchical task tree.
| Task (CCT) | Start Time Event | End Time Event |
|---|---|---|
| Preparation | Collect necessary instruments | All instruments collected |
| Identification of Landmarks | Palpating the thyroid cartilage | Thyroid cartilage, cricoid cartilage and cricothyroid membrane locations identified |
| Incision | Start incision with scalpel | Finger or clamp placed into crichothyroidotomy |
| Dilate Cricothyroidotomy | Insertion of dilator | Insertion of ETT |
| Hook Cricothyroidotomy | Insertion of hook | Insertion of ETT |
| Insertion of ETT | Inserting tube into the incision | Airway connected to breathing circuit |
| Verification of ETT | Inspection of airway | Verbal confirmation of airway in correct location, visualization of proper CO2 reading from capnography, or auscultation of bilateral breath sounds |
| Securing ETT | Tube connected to ventilator circuit or bag mask | Tube sutured to the patient |
Figure 2.
Hierarchical decomposition tree for CCT phases. Forward arrows in the tree indicate a linear progression to the next step, and double headed arrows with underlined text indicate that either of steps can be performed. Only main tasks with bold text are used for video analysis. The correctness of this hierarchical task tree has been validated by expert surgeons with multiple iterations.
In all cases, the preparation of instruments task was already completed before the recording of the video. Furthermore, although verification of the ETT is always a required step to identify the successful oxygenation of the patient, we could not include this task in our measurements as all except one procedure were performed on cadavers. For these reasons, the verification and preparation tasks were removed from the time analysis, and are denoted as italicized tasks with ellipsoid borders in the task tree in Figure 2.
The CCT procedure starts with the equipment preparation. The necessary equipment includes; #10 or #11 scalpel to create an incision. Kelly clamp, finger, or a trousseau dilator can be used to dilate the cricothyroidotomy. A 6mm ETT is used to secure the airway in the absence of a flanged tracheostomy and ventilate the patient. Next step following the preparation of the instruments is the identification of surgical landmarks. This requires setting the patient in supine position with hyperextending the neck. This improves the physicians’ ability to palpate the thyroid cartilage and locate the cricothyroid membrane located between the thyroid and cricoid cartilage. The surgeon needs to palpate from the sternal notch to identify the cricoid cartilage to confirm the landmarks. This task is easier in male patient or male cadaver due to the larger thyroid and cricoid cartilages. During the incision task, a 4-5 cm mid-line horizontal or preferably a vertical incision is made over the cricothyroid membrane [16]. The thyroid gland is highly vascular and avoided by making an incision directly over the cricothyroid membrane [17]. Due to the fact that blood and soft tissue shifting will quickly obscure landmarks, a finger, Kelly clamp, a tracheal hook or a tracheal dilator is promptly placed through the incision into the airway. The use of tracheal hook helps to pull the thyroid cartilage out of the way during the insertion of ETT and provide traction, however the tracheal hook is optional. Dilation with or without the use of tracheal hook tasks must be completed prior to ETT placement. In ETT placement, a 6.0mm ETT is inserted and advanced far enough to ensure that the cuff is in the trachea [18]. If a boogie is used to advance ETT within trachea, it should be extracted before inflating the cuff to <20 mm hg. The task is completed when the cuff is inflated and the ETT is connected to a breathing unit. In the verification task, the tube placement is confirmed by connecting the ETT to a breathing circuit or an ambu bag and checking the lung inflation to confirm the pulmonary ventilation and using carbon dioxide detector[19]. After the ETT is verified, the tube is secured to the neck with sutures.
Identification of Operative Errors
The operative errors most significant for patient morbidity and mortality were identified via literature review, and then confirmed through expert consensus among participating surgeons. Table 2 summarizes these possible complications.
Table 2.
Operative errors and possible occurrence phases for CCT procedure.
| Operative Error/Mistakes | Possible Occurrence/Complications | |
|---|---|---|
| Initiate procedure phase | Fail to Locate (FL) correct incision landmarks | - Caused due to misidentification of thyroid cartilage, cricoid cartilage, cricothyroid membrane. |
| Thyrohyoid Membrane (TM) Incision | - Caused due to failed identification of the
landmarks - Labeling thyrohyoid membrane as the cricothyroid membrane. - Cutting the thyroid causing major bleeding |
|
| Create incision phase | Failed Incision (FI) | - Caused due to wrong incision direction,
wrong incision size and wrong location incision. - Includes multiple incisions. |
| Cutting the anterior Jugular Veins (CJV) | - Caused due to incision at wrong location or transverse as opposed to mid-line incision. | |
| Fracture of cricoid or thyroid Cartilage (FC) | - Caused due to rough handling of tracheal hook while hook cricothyroidotomy. | |
| Excessive Bleeding/ hematoma (EB) | - Caused due to blade carried too deep while
creating the incision. - Caused due to Thyrohyoid Membrane incision |
|
| Tracheal Injury (TI) | - Caused due to incision is too deep and
excessive force is exerted. - Failure to remove tools prior to performing tasks (if used) or excessive ETT cuff inflating or removing the dilator and ETT at the same time. |
|
| Secure airway phase. | False Passage (FP) | - Caused due to loss of tract while securing the airway. |
| Retrograde Placement(RP) | - Caused due to tube angled upward while securing the airway. | |
| R Main stem Placement (MP) | - Caused due to inserting the ETT too deep while securing the airway. | |
| Loss of Tube (LT) | - Caused due to losing the manual control of ETT. | |
| Incorrect Air Pressure (IAP) for the ETT cuff. | - While not deadly immediately, too much
pressure can cause leak around the tube. - Complications can include tissue damage. |
|
| Verification phase | Failure to Validate or check successful intubation (FV). | - Caused due to failure to visualize the lungs (chest) moving, auscultate the lungs and stomach or to check oxygenation levels and CO2 is being expelled from ETT (capnography). |
| Failure to Secure the ETT (FST) | - Caused due to ETT being not secured properly or ETT being moved while suturing. | |
| Entire procedure | Lack of Oxygen (LO) | - Caused due to procedure not being completed
in within the frame. - Patient not pre-oxygenated (if appropriate) |
| Fail to intubate (FTI) | - Caused due to intubation not being completed
within the time frame or too much tissue damage/collisions. - Failing to detect incorrect intubation or unacceptable oxygen levels for a specified time. |
|
| Other Injuries (OtI) | - Injuries, in areas that are not directly
involved in the procedure, such as; esophageal damage, or cuts in
irrelevant places or hypopharyngeal laceration during CCT - Also can be caused due to the poor execution. |
Learning Objectives
We defined seven learning objectives for CCT, listed in Table 3. The objectives start with the identification of landmarks, and end with the completion of the overall procedure within a one-minute time frame. We mapped each task to at least one learning objective. Some tasks (e.g. ETT insertion) were related to more than one objective. Similarly, some of the learning objectives such as insertion of ETT tube or entering the cricothyroid membrane involve multiple tasks. The task and learning objective association is indicated with X in the Tasks-Objectives matrix in Table 3.
Table 3.
Learning objectives mapping of CCT tasks.
|
Performance Scores
We defined a scoring system for each learning objective, based on the priority of the individual task. The best/preferred action was scored as 5, an acceptable but less ideal as 3, and a failing maneuver was given a score of zero. The tasks and rubric are shown in Table 4(a) to Table 4(g).
Table 4(a).
Identifying the key landmarks for performing a CCT and scoring.
| Proper identification of | Scoring |
|---|---|
| Thyroid notch | 5 |
| Cricoid cartilage | 5 |
| Cricothyroid window/membrane | 5 |
| Only Hyoid bone | 1 |
| Only Sternal notch | 3 |
Table 4(g).
Performing the entire procedure within 1 minute and scoring.
| Proper technique | Scoring |
|---|---|
| Perform entire procedure within 1 minute, otherwise failed | Pass/Fail |
Timing Analysis
In the timing analysis, we studied each video frame by frame using Windows and VLC media players. Time points for each subtask were measured using specific guidelines, with start and end times as listed in Table-1. Along with the task times, observers were asked to score the tasks based on the defined rubric in Tables 4 (a-g). Task times and scores from each observer, and overall average time for each task, were collected for statistical analysis. Furthermore, inter-rater reliability testing was conducted on each rated sub-task using the IBM SPSS 22 software.
Results
Three observers analyzed all the videos and identified all subtasks’ start time, end time, scores and total time spent over the procedure. All three observers are proficient in hierarchical task analysis and have solid understanding of the CCT steps. Some variability arose in the tasks performed in the videos. Out of seven videos, only two videos featured use of the tracheal hook during the procedure, while the rest used different tools such as a Kelly clamp, a finger or a Trousseau dilator to dilate the cricothyroidotomy. Finally, the ETT was secured in three cadaver videos, but not in the live-patient cricothyroidotomy.
Figure 3 shows the box plot of task times for the major CCT tasks measured by three different observers analyzing the 7 videos. Figure 4 shows the performance score data for all major CCT tasks. Pearson's correlation tests were conducted to find any correlation between the task times and scores. In the identification of landmarks task, the correlation test indicated a strong positive correlation (R=0.8809) between score and procedural time, with a statistically significant result (p=0.0204). Likewise, for the insertion task, the correlation test results showed a strong positive correlation (R=0.8992, p=0.0059). The incision task correlation test result, meanwhile, indicated a negative correlation (R=−0.7603, p=0.0473) between the task score and time. No other correlations within the data were noted.
Figure 3.
Time series results from the 7 videotaped performances for seven major tasks for the CCT procedure.
Figure 4.
Average grading points of 7 videotaped procedures for seven major tasks by 3 observers.
Among the tasks, securing ETT required the longest amount of time to complete. The average time for this task was 38.7 seconds (min: 33, max: 42). The second most time consuming task was performing the incision, which took an average of 19.9 seconds (min: 6, max: 36) seconds. The insertion task takes average 11.7 seconds (min: 2, max: 21). Identification of landmarks required 7.2 seconds (min: 2, max: 11) on average. The rest of the tasks required less time. The largest variations in time were observed in performance of the incision, insertion of ETT, securing of ETT, identification of landmarks, and hook cricothyroidotomy.
The average score acquired for the incision task was 19.3 (min: 18, max: 20). The incision task has multiple criteria and steps, each associated with points, which increases the maximum attainable score. This is also true for the identification of landmarks task, with an average score 11.2 (min: 4, max: 15). The largest variations in scores were observed in the identification of landmarks, incision, and insertion tasks. The score and time percent's can be seen in Figures 5-7. The time and point percent in figures are computed with respect to the maximum grade/maximum time for each task.
Figure 5.
Time and point comparison plot in percent values for the identification of landmarks
Figure 7.
Time and point comparison plot in percent values for the insertion task.
In order to test the inter-rater reliability for the three observers, an interclass correlation coefficient (ICC) was computed for each of the task. ICC was performed to show how items (scores/times) in the same category favor each other, by comparing variability to the total variation in all ratings and subjects. Cronbach's alpha test was used to estimate the reliability of objective testing on the same data. There was strong disagreement between the raters regarding proper incision orientation (Cronbach's alpha = 0.429, ICC = 0.286, p =0.193). There was a significant agreement among the observers for the proper identification of thyroid notch (Cronbach's alpha = 0.805, ICC = 0.767, p=0.014), which likely arose from inconsistent declaration of landmarks by surgeons in the videos. The remaining tasks showed perfect agreement (Cronbach's alpha = 1.0, ICC =1.0).
According to the grading rubric (4a-g), learners fail in their performance of CCT via one of two pathways. Either 1) the CCT tasks are performed correctly, but the user takes longer than one minute to complete the entire procedure, or 2) the tasks are completed within one minute, but one or more of the tasks is not performed correctly. One minute was selected given the time-sensitive nature of the procedure, and the immediacy with which an airway must be established in an emergency. In the recorded videos, the total procedure time often exceeded one minute due to instructive narration given by the performing surgeons. To account for this confounder, the total time was calculated by summing the times for each individual task, excluding commentary. In all scenarios, this total time was less than one minute.
Although the procedures were performed by expert surgeons, observers noted several of the errors listed in Table 2. One error was (FL), i.e., failure to locate a key landmark such as the cricothyroid membrane following a skin incision. Expectedly, such errors were associated with prolonged procedure time, and decreased task score. Furthermore, in multiple videos the securing ETT was not completed, which were noted as FST errors. Finally, in multiple recordings, the subjects did not cut the suture after securing the ETT. This was not considered an error, however it prolonged the overall time.
Discussion
The experts used in this study was a group of 7 fellowship trained trauma and acute care surgeons. Each expert has performed over 15 cricothyroidotomies in the last 5 years and regularly trained residents on cadaver models.
In this preliminary phase of development of a VR cricothyroidotomy training simulator, we present a task analysis tree outlining the entire CCT procedure into five main stages, each with several tasks and subtasks. This task analysis allows CCT to be compartmentalized into distinct segments, which can be used for quantitative measurements and feedback in a VR simulator. Since each phase, task, and subtask can be individually mapped to learning objectives for surgical performance, they can be used for monitoring CCT skills training and assessment.
Several features of our task analysis warrant further investigation. As noted in results section, there is a positive linear correlation between times and scores for identification of landmarks and insertion of ETT tasks. In plain terminology, surgeons who did not rush these step had higher degrees of performance accuracy. There was a negative correlation, however, between time and score for the incision task. Although one could postulate that more confident and skilled surgeons perform the incision with greater speed, the correlation itself was weak. Further studies using a greater number of analyzed performances are required to elucidate the significance of this finding.
Additionally, the inter-reliability test results showed sizeable disagreement among observers in grading the orientation of the incision. The orientation was not accurately identifiable from the videos in all circumstances, and the multiple camera angles created dissimilar scores due to the quality of the videotaping. This rubric will require fine-tuning as the simulator development progresses.
In the videos provided an ETT was chosen over a flanged tracheostomy due to the physicians performing the emergent cricothyroidotomy are often in situations where a flanged #6 tracheostomy is not available. Therefore it was felt that one should be trained to use an endotracheal tube, although the option to use a flanged tracheostomy is possible.
Under the identification of operative errors, transverse incision was noted as a cause for CJV in the incision phase. Although not a mistake in the model, the vertical mid-line incision is preferred given the avoidance of cutting the anterior jugular veins. In an emergent cricothyroidotomy a large mid-line incision provides ample access to the cricothyroid membrane. The expert group decided this was the preferred approach.
Conclusion
We present a hierarchical task analysis for CCT, as a preliminary phase in the development of a VR CCT training simulator. The resultant task tree serves as a tool not only for our simulator, but also potentially in the implementation of other teaching modules focused on the infrequent, but high-stakes CCT procedure.
In future work, we plan to integrate our findings with haptic data, using gloves fused with sensors to monitor movements, force and pressure exerted during the CCT maneuvers. Using our hierarchical task tree as a guide, we will incorporate these metrics with statistical analysis to create a final rubric for performance assessment in a VR CCT simulator.
Figure 6.
Time and point comparison plot in percent values for the incision task.
Table 4(b).
Performing an appropriate skin incision and scoring.
| Technique | Scoring |
|---|---|
| Length of incision | |
| Greater than 5 cm | 3 |
| 3-5 cm | 5 |
| Less than 2 cm (will require additional cut, FI) | 0 (fail) |
| Depth of incision | |
| Pierces skin | 5 |
| Orientation of incision | |
| Vertical incision | 5 |
| Non vertical incision | 3 |
| Location of incision | |
| Midline of the neck starting overlying the thyroid cartilage extending inferior to the cricoid cartilage | 5 |
| Midline of the neck starting superior to the thyroid cartilage but extends down to approximately 3 cm | 3 |
| Incision is not made over the cricoid cartilage | 0 |
Table 4(c).
Entering the cricothyroid membrane and scoring.
| Possible Outcomes | Scoring |
|---|---|
| Incision enters cricothyroid membrane only | 5 |
| Incision enters cricothyroid membrane and penetrates esophagus or Incision enters cricothyroid membrane and penetrates the trachea a second time or Incision enters proximal trachea or Incision doesn't enter the cricothyroid membrane | 0 |
| Incision doesn't enter cricothyroid membrane, which the learner notices and makes a second incision that enters the cricothyroid membrane | 3 |
Table 4(d).
Dilating the cricothyroidotomy with appropriate tool and scoring.
| Technique | Scoring |
|---|---|
| Insert one of the following into the site of incision: scalpel handle, trousseau dilator, Kelly clamp, hemostat, finger | 5 |
| Amount of dilation achieved with selected device | |
| Proper (large enough to fit ETT) | 5 |
| Insufficient (not large enough to fit ETT) | 1 |
Table 4(e).
Inserting ETT into cricothyroidotomy, confirming placement and scoring
| Technique | Scoring |
|---|---|
| Insert small cuffed tracheostomy tube | |
| Proper insertion | 5 |
| Improper or no insertion | 0 |
| Inflate cuff | |
| Proper inflation | 5 |
| Improper or no inflation | 0 |
| Check for proper amount of inflation | 5 |
| Attach ambu bag | 5 |
| Evaluate airway: | |
| Auscultate lungs and stomach or Capnography | 5 |
| All of the previous events have been performed in the correct order | 5 |
Table 4(f).
Securing ETT and scoring.
| Proper technique | Scoring |
|---|---|
| The ETT needs to be secured in position using tape or 2 anchoring suture such that it will not be dislodged without the use of excessive force | 5 |
| suture(typically 0-2.0 silk or nylon suture) - loosely applied to ETT or suture - applies pressure that extrudes ETT | 0 |
| 2 anchoring sutures +− tape | 5 |
| Just tape | 3 |
| 1 anchoring suture +− tape | 2 |
Acknowledgement
Authors would like to thank Adam Ryason and Alexander Yu for their contributions in the study. This project was supported by National Institutes of Health (NIH) Grant NIH/NHLBI 1R01HL119248-01A1, NIH/NIBIB 2R01EB005807, 5R01EB010037, 1R01EB009362 and 1R01EB014305.
Footnotes
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References
- 1.Mayglothling J, Duane TM, Gibbs M, McCunn M, Legome E, Eastman AL, Whelan J, Shah KH. Emergency tracheal intubation immediately following traumatic injury: an Eastern Association for the Surgery of Trauma practice management guideline. J. Trauma Acute Care Surg. 2012;73(5):S333–S340. doi: 10.1097/TA.0b013e31827018a5. [DOI] [PubMed] [Google Scholar]
- 2.Davis DP, Bramwell KJ, Vilke GM, Cardall TY, Yoshida E, Rosen P. Cricothyrotomy technique: standard versus the rapid four-step technique. J. Emerg. Med. 1999;17(1):17–21. doi: 10.1016/s0736-4679(98)00118-8. [DOI] [PubMed] [Google Scholar]
- 3.Hart KL, Thompson SH. Emergency cricothyrotomy. Atlas Oral Maxillofac. Surg. Clin. 2010;18(1):29–38. doi: 10.1016/j.cxom.2009.11.002. [DOI] [PubMed] [Google Scholar]
- 4.Wang EE, Vozenilek JA, Flaherty J, Kharasch M, Aitchison P, Berg A. An innovative and inexpensive model for teaching cricothyrotomy. Simul. Healthc. 2007;2(1):25–29. doi: 10.1097/SIH.0b013e3180302124. [DOI] [PubMed] [Google Scholar]
- 5.Tayal VS, Riggs RW, Marx JA, Tomaszewski CA, Schneider RE. Rapid-sequence Intubation at an Emergency Medicine Residency: Success Rate and Adverse Events during a Two-year Period. Acad. Emerg. Med. 1999;6(1):31–37. doi: 10.1111/j.1553-2712.1999.tb00091.x. [DOI] [PubMed] [Google Scholar]
- 6.Vissers RJ, Gibbs MA. The high-risk airway. Emerg. Med. Clin. North Am. 2010;28(1):203–217. doi: 10.1016/j.emc.2009.10.004. [DOI] [PubMed] [Google Scholar]
- 7.Simulation in trauma education: beyond ATLS. Injury. 2014 May;45(5):817–818. doi: 10.1016/j.injury.2014.01.010. [DOI] [PubMed] [Google Scholar]
- 8.Pettineo CM, Vozenilek JA, Wang E, Flaherty J, Kharasch M, Aitchison P. Simulated emergency department procedures with minimal monetary investment: cricothyrotomy simulator. Simul. Healthc. 2009;4(1):60–64. doi: 10.1097/SIH.0b013e31817b9572. [DOI] [PubMed] [Google Scholar]
- 9.Cho J, Kang GH, Kim EC, Oh YM, Choi HJ, Im TH, Yang JH, Cho YS, Chung HS. Comparison of manikin versus porcine models in cricothyrotomy procedure training. Emerg. Med. J. 2008;25(11):732–734. doi: 10.1136/emj.2008.059014. [DOI] [PubMed] [Google Scholar]
- 10.Aggarwal R, Ward J, Balasundaram I, Sains P, Athanasiou T, Darzi A. Proving the effectiveness of virtual reality simulation for training in laparoscopic surgery. Ann. Surg. 2007;246(5):771–779. doi: 10.1097/SLA.0b013e3180f61b09. [DOI] [PubMed] [Google Scholar]
- 11.Rosser Jr JC, Rosser LE, Savalgi RS. Objective evaluation of a laparoscopic surgical skill program for residents and senior surgeons. Arch. Surg. 1998;133(6):657–661. doi: 10.1001/archsurg.133.6.657. [DOI] [PubMed] [Google Scholar]
- 12.Fried MP, Satava R, Weghorst S, Gallagher A, Sasaki C, Ross D, Sinanan M, Cuellar H, Uribe JI, Zeltsan M, Arora H. The Use of Surgical Simulators to Reduce Errors,” in Advances in Patient Safety: From Research to Implementation (Volume 4: Programs, Tools, and Products) In: Henriksen K, Battles JB, Marks ES, Lewin DI, editors. Agency for Healthcare Research and Quality (US); Rockville (MD): 2005. [Google Scholar]
- 13.Seymour NE, Gallagher AG, Roman SA, O'Brien MK, Bansal VK, Andersen DK, Satava RM. Virtual Reality Training Improves Operating Room Performance. Ann. Surg. 2002 Oct;236(4):458–464. doi: 10.1097/00000658-200210000-00008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Grantcharov TP, Kristiansen VB, Bendix J, Bardram L, Rosenberg J, Funch-Jensen P. Randomized clinical trial of virtual reality simulation for laparoscopic skills training. Br. J. Surg. 2004;91(2):146–150. doi: 10.1002/bjs.4407. [DOI] [PubMed] [Google Scholar]
- 15.Rosser JC, Rosser LE, Savalgi RS. Skill acquisition and assessment for laparoscopic surgery. Arch. Surg. 1997;132(2):200–204. doi: 10.1001/archsurg.1997.01430260098021. [DOI] [PubMed] [Google Scholar]
- 16.Cannon-Bowers J, Bowers C, Stout R, Ricci K, Hildabrand A. Using Cognitive Task Analysis to Develop Simulation-Based Training for Medical Tasks. Mil. Med. 2013;178(10S):15–21. doi: 10.7205/MILMED-D-13-00211. [DOI] [PubMed] [Google Scholar]
- 17.Cricothyroidotomy. Am. Med. Assoc. Complete Med. Encycl. 2003 Jan;:419–420. [Google Scholar]
- 18.Paix BR, Griggs WM. Emergency surgical cricothyroidotomy: 24 successful cases leading to a simple ‘scalpel–finger–tube'method. Emerg. Med. Australas. 2012;24(1):23–30. doi: 10.1111/j.1742-6723.2011.01510.x. [DOI] [PubMed] [Google Scholar]
- 19.Hamaekers AE, Henderson JJ. Equipment and strategies for emergency tracheal access in the adult patient. Anaesthesia. 2011;66(s2):65–80. doi: 10.1111/j.1365-2044.2011.06936.x. [DOI] [PubMed] [Google Scholar]