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Acquisition of basic fiberoptic intubation skills with a virtual reality airway simulator
Journal of Clinical Anesthesia (2006) 18, 173 – 178
Original contribution
Acquisition of basic fiberoptic intubation skills with a virtual reality airway simulator Kai Goldmann MD (Attending Anesthesiologist)*, Thorsten Steinfeldt MD (Resident) Department of Anaesthesia and Intensive Care Therapy, Philipps University Marburg, 35033 Marburg, Germany Received 15 March 2005; accepted 11 August 2005
Keywords: Computer simulation; Fiberoptic intubation; Training in
Abstract Study Objective: To test the hypothesis that a virtual reality (VR) airway simulator (the AccuTouch Virtual Reality Bronchsocopy Simulator; Immersion Medical, Gaithersburg, MD) can be used to teach residents basic fiberoptic intubation (FOI) skills effectively. Design: Observational study. Setting: University anesthesiology department. Intervention: Supervised training was done using a VR airway simulator. Measurements: Time to intubation before and after a 4-day training period using an adult VR FOI scenario and time to intubation using a fresh human cadaver two weeks after the training experience were measured. Main Results: Residents were able to significantly improve time to intubation in the VR scenario (114 vs 75 seconds; P = 0.001). Novices differed from experienced attending anesthesiologists in time to intubation in the VR scenario, before but not after training (114 vs 79 seconds compared with 75 vs 72 seconds). Novices who had been trained with the simulator performed significantly faster in the cadaver than novices who had not (24 vs 86 seconds; P b 0.001). Furthermore, there was no difference in time to intubation in the cadaver between trained novices and experienced attending anesthesiologists (24 vs 23 seconds; P N 0.05). Conclusion: Use of a VR airway simulator enables anesthesia residents to acquire basic FOI skills comparable to those of experienced anesthesiologists in a human cadaver. D 2006 Elsevier Inc. All rights reserved.
1. Introduction Airway management is an integral part of anesthesia practice. Knowledge and skills of airway management must be acquired during training. Despite the use of alternative
* Corresponding author. Tel.: +49 6421 2862516; fax: +49 6421 2866996. E-mail address: [email protected] (K. Goldmann). 0952-8180/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.jclinane.2005.08.021
methods of training and various efforts to structure training, it remains a challenge to ensure that every anesthesia resident gains sufficient experience with core techniques of airway management that are considered essential to be able to deal with the anticipated or unanticipated difficult airway [1-3]. As less time is spent in the operating room during training [4], it becomes less likely that each trainee is exposed to an adequate number of challenging airway cases that enable him or her to practice advanced techniques of airway management under supervision.
174 One of those skills considered to be essential is fiberoptic intubation (FOI) [5,6]. Providing sufficient training in FOI, particularly hands-on experience in anesthetized patients, has always been difficult [7-9] mainly because of technical and ethical problems [10,11]. On the one hand, patients with a known difficult airway requiring awake FOI present relatively infrequently to the operating room, whereas use of elective patients with a normal airway for the teaching of FOI remains controversial. The patient has a right to be protected from the total novice [11,12]. As a consequence, it is mandatory to prepare trainees as well as possible with alternative training methods before they are allowed to attempt FOI in patients. Simple models and manikins have traditionally been used to teach residents how to manipulate the fiberoptic bronchoscope and to improve FOI skills outside the operating room before attempting FOI in patients [13-15]. In the last decade, simulation using partial-task trainers or full-scale simulators has been recognized as a tool that can be used effectively to teach complex cognitive, psychomotor, and judgment skills in medical training [16]. Fiberoptic intubation is one of those complex skills requiring intensive training for acquisition and continuous training for maintenance of the skill. Recently, a virtual reality (VR) bronchoscopy simulator that can be used to practice FOI has become available. This observational study was designed to test the hypothesis that this new simulator can be used to teach basic FOI skills to a degree comparable to those of experienced attending anesthesiologists in a human cadaver.
2. Materials and methods 2.1. Device description The AccuTouch Bronchsocopy Simulator (Immersion Medical, Gaithersburg, MD) is a VR partial-task trainer consisting of a proxy flexible bronchoscope, a robotic interface, a computer, a monitor, and comprehensive simulation software capable of delivering different realistic bronchoscopy scenarios. The simulator bronchoscope feels like a real bronchoscope and can be steered in the same way, but actual placement of an endotracheal tube cannot be simulated. The interface device is capable of tracking the motions of the bronchoscope tip control lever and mimicking the forces and resistances felt during clinical bronchoscopy. The monitor displays computer-generated realistic anatomical images that correlate precisely with the motions of the bronchoscope and the expected anatomical position in the respiratory tract. In addition, the bvirtual patient Q is capable of displaying realistic physiologic responses to the bronchoscope. For instance, hitting the mucous membranes can cause bleeding, or if local anesthetics have been omitted, this causes bthe patient Q to cough, simulating motions of the respiratory tract that one observes in a live patient. All these features produce a training environment
K. Goldmann, T. Steinfeldt that resembles a clinical setting very realistically. The computer records various data related to the performance of the bronchoscopy, such as number of contacts with the mucous membranes, number of attempts needed to pass through the glottis, dose of local anesthetic administered, and total time of the procedure. In addition, a detailed description of the tracheal bronchial tree inspection can be obtained showing all the segments visited and time spent during a complete bronchoscopy. At the end of the case these data can be printed out and used for analysis of performance and for teaching purposes.
2.2. Training study Before we conducted the study we sought advice from the local university ethics committee. Because a formal arrangement to train trainees with noninvasive methods of airway management such as laryngeal mask insertion or FOI in cadavers had already been approved and because the study did not involve care of a patient, approval of the ethics committee was not deemed necessary.
2.3. Curriculum design and study groups All participating residents had received formal teaching in FOI during a half-day (6-hour) airway management course that consisted of formal lectures and use of the flexible bronchoscope in manikins. The course was held at our department one month before the study took place. After a formal one-hour instruction session in which the participants were allowed to familiarize themselves with the VR airway simulator device and an initial pretraining assessment of performance using the same adult FOI scenario, all participants were allowed to have as many training sessions with the VR airway simulator under the supervision of an experienced attending anesthesiologist as they wished throughout a one-week training period (Fig. 1). These training sessions happened in the afternoons and evenings on 4 consecutive working days after the regular duty hours. The same adult FOI scenario that was used for pretraining assessment was used for the final posttraining
Fig. 1
Resident using the VR airway simulator.
Training basic fiberoptic intubation skills assessment of performance on the fifth day. In addition, everybody who had used the simulator for training purposes was asked to give a subjective assessment of the quality of the VR, the handling, the usefulness of the device for training in FOI, and the improvement of their own FOI skills by filling out a short questionnaire. For definite assessment of FOI performance, all participants were asked to perform a FOI in a cadaver two weeks later. The same cadaver was used for all participants (Fig. 2). Before we conducted the study, we identified 20 residents in our department who did not have any clinical experience in FOI before the start of this study. As a consequence of clinical commitments or annual leave, 9 residents were unable to attend either the formal instruction and initial assessment at the beginning of the one-week training period or the definite assessment two weeks after the training experience, leaving 11 residents for the b novice training Q group. Four experienced attending anesthesiologists served as the bexpertsQ group for FOI performance with the adult VR FOI scenario and FOI in the cadaver. bExpert Q in our study was defined as having a minimum of 50 FOI. Four residents who were unable to use the VR airway simulator throughout the one-week training period served as the bnovice nontraining Q control group for FOI in the cadaver.
2.4. Measurements Primary end point for assessment of FOI performance was time to reach the carina in both the VR simulator and the cadaver. The number of training sessions and the total time of training were recorded for each participant. At the end of the study, all participants were asked to answer the following 4 questions using a numeric analogue scale (NAS) ranging from 0, indicating the worst, to 10, indicating the best: Do you think the opportunity to use a VR airway simulator for training FOI is in general bnot useful Q (0) or bvery usefulQ (10)? Do you think your FOI skills have bnot improved at allQ (0) or bimproved a lotQ (10)?
175 Table 1 Comparison of time to intubation in the adult VR scenario separated by groups Initial assessment; duration of FOI (s) Final assessment; duration of FOI (s)
Experts
Novices training
79 F 18.2 (50-108)* 72 F 18.0 (43-101)*
114 F 32.3 (93-136)** 75 F 18.8 (62-87)**
* P N 0.05, experts’ initial vs final assessment. ** P b 0.001, novices’ initial vs final assessment.
Do you think the VR simulation has a bvery low degreeQ (0) or a bvery high degreeQ of reality (10)? Do you think the handling of the VR airway simulator is bvery badQ (0) or bvery goodQ (10)?
2.5. Statistics Results were analyzed using the SPSS (SPSS Inc, Chicago, IL) computer program. Unless otherwise stated, data are expressed as mean F SD (95% confidence intervals) or median values (ranges). The paired t test was used for comparison between pre- and posttraining performance using the adult FOI scenario of the virtual VR simulator. Student t test was used for comparison between the novice training group, the expert group, and the novice nontraining control group. Results were considered statistically significant for a P value of less than 0.05.
3. Results Nineteen anesthesiologists, 15 residents, and 4 attending physicians, participated in the study. They used the simulator in 4 training sessions (range, 1-14) for 50 minutes (range, 15-115 minutes). Time to intubation using the adult FOI VR scenario and the cadaver are presented in Tables 1 and 2, respectively. Both novices from the training group and attending physicians from the experts control group were able to improve time to intubation in the adult FOI VR scenario, but the values were only significant for novices ( P = 0.001). There was a difference between novices and experts before, but not after, training. In the cadaver, novices of the training group were able to perform FOI as fast as attending physicians of the experts group, but novices from the nontraining group required significantly longer ( P b 0.001). The users (n = 19) found the simulator very Table 2 Comparison of time to intubation in the cadaver separated by groups
Duration of FOI (s) Fig. 2
Residents performing FOI in a fresh cadaver.
Experts
Novices training
Novices nontraining
23 F 4.6 (16-30)*
24 F 5.3 (20-27)*,**
86 F 38 (25-147)**
* P N 0.05, novices training vs experts. ** P b 0.001, novices training vs novices nontraining.
176 useful (NAS = 10; range, 7-10) for training FOI and felt that their FOI skills had improved a lot (NAS = 8; range, 2-10). They assessed the degree of reality as very high (NAS = 9; range, 7-10) and handling of the VR airway simulator as very good (NAS = 9; range, 2-10).
4. Discussion Fiberoptic intubation plays a central role in difficult airway management [17-19]. It is believed that awake FOI offers the highest degree of safety in a patient with an anticipated difficult airway [19]. As a consequence, it is considered one of the core techniques of airway management [5,6]. If something is considered a core skill, then all residents must receive sufficient training during residency in this particular technique. Apparently, this is not the case. Various recent surveys from different countries revealed that the prevalence of sufficient FOI skills is still low [20-24]. Although the value of bench models, manikins, and simple simulators for training FOI has been shown in several studies [13-15], they do not imitate a realistic clinical scenario. In our own experience, simple bench models and manikins carry the limitation that the trainees often know the tasks to be performed after a short period and then stop using these training tools because they do not feel they could gain any more than they have already learned. The fact that patients with a known difficult airway requiring awake FOI present relatively infrequently to the operating theater is the reason [7] why trainees and attending anesthesiologists still lack sufficient experience in FOI, despite efforts to structure training and to use alternative methods of training outside the operating room [1-3]. A VR airway simulator could help to overcome the existing lack of appropriate clinical and nonclinical training opportunities for FOI. One advantage of modern VR simulators is that the computer software can provide a large number of ever changing tasks, can give immediate feedback, and mimic breal patients.Q All these features help to produce very realistic clinical scenarios and thereby make VR simulators very attractive to trainees as is shown by the very positive assessment of the VR airway simulator by the participants of this study. However, the question that remains is how effective VR simulators are in terms of the transfer of skills learned and practiced outside the operating room into clinical practice. The results of this study indicate that this VR airway simulator can be used very effectively to teach basic FOI skills to novices. Residents with no clinical FOI experience were able to acquire a degree of dexterity with the flexible bronchoscope that enabled them to perform a FOI in a cadaver as fast as experienced attending physicians would, whereas residents who did not use the airway simulator for training needed significantly longer. This confirms the results of the study by Rowe and colleagues, who showed that residents who practiced FOI with this airway simulator were able to improve their FOI skills significantly in
K. Goldmann, T. Steinfeldt comparison to trainees who did not use the airway simulator [25]. In contrast to the study by Rowe, we chose to use a cadaver instead of live pediatric patients for definite assessment of FOI performance for several reasons. First, use of cadavers for the training of airway management techniques has been recommended and practiced for a long time [26-28]. In our own practice we have found use of cadavers not only valuable for training purposes, but also for assessing whether a trainee can be considered bready Q for performing FOI under supervision in the operating room. Second, assessment of performance in live patients would have carried the limitation that each participant would have been assessed in a different patient with anatomical differences of the airway. Third, because of the limited number of patients requiring FOI, definite assessment of performance could not have been achieved on the same day for all participants if we had chosen to use live patients. Some residents would have been assessed shortly after their training experience, whereas others would have been assessed a considerable time after their training experience. Both aspects would have made it difficult to compare the performance of all participants. Another difference between the study by Rowe et al. and our study is that we included a group of consultants who were experienced in FOI. The main reason to include an bexpert groupQ was to compare the performance of trainees who were newly trained outside the operating room using this VR airway simulator with clinicians who had been trained by traditional methods and were now, as a consequence of their clinical experience, considered competent in performing FOI. The results indicate that residents can be taught basic FOI skills to a degree that compares to physicians who have been trained using traditional methods. The fact that residents with training using the VR airway simulator improved their skills in contrast to residents who did not have this training proves that this improvement can be attributed to the training with this VR airway simulator. In contrast, time to intubation in the after-training assessment did not differ much from the initial assessment in the group of attending anesthesiologists. This shows that experts with advanced FOI skills are unlikely to improve their performance significantly using this VR airway simulator. This is not surprising because these physicians have gained advanced FOI skills over a long period and are experienced in performing FOI in clinical cases whose level of difficulty can be far more complex than what a VR scenario can display. It is reasonable to assume that these attending anesthesiologists had already reached a level of basic FOI skills that could hardly be improved. Furthermore, in this study, novices with training performed as well as attending anesthesiologists both in their final simulator assessment and in the cadaver. This indicates that simulator assessment could be used to compare novices’ performance with experts’ performance in the same way that cadaver assessment is used. This seems
Training basic fiberoptic intubation skills particularly helpful when one wants to determine whether trainees have reached a level of skill that is sufficient to allow them to perform a FOI in a live patient. Until now there has been no method of assessment outside the operating theater that comes close to the clinical situation that trainees will experience in the operating theater when they perform their first FOI. In most institutions, current practice is to allow trainees to perform their first FOI under supervision in anesthetized patients after they have had basic FOI training in models or manikins in the absence of any reliable standardized assessment. This can result in a very unpleasant training experience when it turns out that the trainee has not acquired sufficient FOI skills to succeed in a complex clinical situation. Training and evaluation using this VR airway simulator could make clinical teaching safer for the patient and the learning experience more comfortable for the trainee by providing an effective training tool and a reliable method to determine the level of acquired FOI skills. However, the validity of any such evaluation using a VR airway simulator would have to be determined in a separate study because the main objective of our study was to investigate the value of this device for training. Nevertheless, our results indicate that VR airway simulator assessment can be used for assessment of FOI performance. The improvement of performance in the VR scenario in the trainees to a level that was similar to the experts’ level explains why the level of performance in the cadaver was also similar in both groups. The main limitation of our study is that we did not assess the participants’ performance during an awake FOI in a live patient; placing the fiberscope is only half of a FOI, the other half is placing the endotracheal tube into the trachea. Therefore, our study does not give any data on how the trainees would have performed in a clinical case. However, our aim was to investigate into basic and not advanced FOI skill training and to have comparable conditions at the same time for all participants. We choose the cadaver over live patients for final assessment of FOI skills. No doubt, a VR airway simulator assessment would still have to be considered a substitute for a clinical FOI assessment. However, under medicolegal aspects, we feel that using a patient for such an initial assessment is debatable and, to date, VR assessment is the closest one can get to a clinical assessment. In conclusion, this VR airway simulator offers an effective tool for training basic FOI skills in an environment that comes closer to reality than any other FOI training modality outside the operating room. Another value of this tool is that it can be used for assessment of performance before allowing trainees to attempt FOI in a live patient.
Acknowledgments The AccuTouch Bronchoscopy Simulator was provided free of charge for the study by Immersion Medical
177 (Gaithersburg, MD). The authors thank Dr John Henderson for reviewing the manuscript critically.
References [1] Koppel JN, Reed AP. Formal instruction in difficult airway management. A survey of anesthesiology residency programs. Anesthesiology 1995;83:151 - 6. [2] Hagberg CA, Greger J, Chelly JE, Saad-Eddin HE. Instruction of airway management skills during anesthesiology residency training. J Clin Anesth 2003;15:149 - 53. [3] Popat M. The airway. Anaesthesia 2003;58:1166 - 71. [4] Tomlinson A. Effects of the EWTD on anaesthetic training in the UK. Anaesthesia 2005;60:96 - 7. [5] Royal College of Anaesthetists. The CCST in Anaesthesia II. Competency based specialist registrar years 1 and 2 training and assessment. A manual for trainees and trainers. London7 Royal College of Anaesthetists; 2000. [6] Braun U, Goldmann K, Hempel V, Krier C. Airway Management. Leitlinie der Deutschen Gesellschaft fqr Anaesthesiologie und Intensivmedizin. Anaesth Intensivmed 2004;45:302 - 6. [7] Wood PR, Dressner M, Lawler PGP. Training in fiberoptic tracheal intubation in the North of England. Br J Anaesth 1992; 69:202 - 3. [8] Schaefer HG, Marsch SC, Keller HL, Strebel S, Anselmi L, Drewe J. Teaching fiberoptic intubation in anaesthetized patients. Anaesthesia 1994;49:331 - 4. [9] Randell T, Hakala P. Fiberoptic intubation and brochofibroscopy in anaesthesia and intensive care. Acta Anaesthesiol Scand 1995;39:3 - 16. [10] Bray JK, Yentis SM. Attitudes of patients and anaesthetists to informed consent for specialist airway techniques. Anaesthesia 2002;57:1012 - 5. [11] Mason RA. Education and training in airway management. Br J Anaesth 1998;81:305 - 79. [12] Stringer KR, Bajenov S, Yentis SM. Training in airway management. Anaesthesia 2002;57:967 - 83. [13] Ovassapian A, Dykes MH, Golmon ME. A training programme for fiberoptic nasotracheal intubation. Use of model and live patients. Anaesthesia 1983;38:795 - 8. [14] Ovassapian A, Yelich SJ, Dykes MH, Golman ME. Learning fibreoptic intubation: use of simulators v. traditional teaching. Br J Anaesth 1988;61:217 - 20. [15] Naik VN, Matsumoto ED, Houston PL, et al. Fiberoptic orotracheal intubation on anesthetized patients. Do manipulation skills learned on a simple model transfer into the operating room? Anesthesiology 2001;95:343 - 8. [16] Schaefer JJ. Simulators and difficult airway management skills. Paediatr Anaesth 2004;14:28 - 37. [17] Benumof JL. Management of the difficult adult airway. With special emphasis on awake tracheal intubation. Anesthesiology 1991;75: 1087 - 110. [18] Practice guidelines for the management of the difficult airway. A report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 1993;78: 597 - 602. [19] Practice guidelines for management of the difficult airway. An updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 2003; 98:1269 - 77. [20] Popat MT, Srivastava M, Russel R. Awake fibreoptic skills in obstetric patients: a survey of anaesthetists in the Oxford region. Int J Obstet Anesth 2000;9:78 - 82. [21] Kirstensen MS, Mbller J. Airway management behaviour, experience and knowledge among Danish anaesthesiologists—room for improvement. Acta Anaesthesiol Scand 2001;45:1181 - 5.
178 [22] Rosenstock C, astergaard D, Kristensen MS, Lippert A, Ruhnau B, Rasmussen LS. Trainees lack knowledge and practical skills in handling the difficult airway. Acta Anaesthesiol Scand 2004;48: 1014 - 8. [23] Ezri T, Konichezky S, Geva D, Warters RD, Szmuk P, Hagberg C. Difficult airway management patterns among attending anaesthetists practicing in Israel. Eur J Anaesthesiol 2003;20:619 - 23. [24] Ezri T, Szmuk P, Warters RD, Katz J, Hagberg C. Difficult airway management practice patterns among anesthesiologists practicing in the United States: have we made any progress? J Clin Anesth 2003; 15:418 - 22.
K. Goldmann, T. Steinfeldt [25] Rowe R, Cohen RA. An evaluation of a virtual reality airway simulator. Anesth Analg 2002;95:62 - 6. [26] Morhaim DK, Heller MB. The practice of teaching endotracheal intubation on recently deceased patients. J Emerg Med 1991;9:515. [27] Keller C, Brimacombe J. The intubating laryngeal mask airway in fresh cadavers vs. paralysed anesthetized patients. Can J Anaesth 1999;46:1067 - 9. [28] Brimacombe J, Keller C. The laryngeal mask airway in fresh cadavers versus paralysed anaesthetized patients: ease of insertion, airway sealing pressure, intracuff pressures and anatomic position. Eur J Anaesthesiol 1999;16:600 - 701.
Original contribution
Acquisition of basic fiberoptic intubation skills with a virtual reality airway simulator Kai Goldmann MD (Attending Anesthesiologist)*, Thorsten Steinfeldt MD (Resident) Department of Anaesthesia and Intensive Care Therapy, Philipps University Marburg, 35033 Marburg, Germany Received 15 March 2005; accepted 11 August 2005
Keywords: Computer simulation; Fiberoptic intubation; Training in
Abstract Study Objective: To test the hypothesis that a virtual reality (VR) airway simulator (the AccuTouch Virtual Reality Bronchsocopy Simulator; Immersion Medical, Gaithersburg, MD) can be used to teach residents basic fiberoptic intubation (FOI) skills effectively. Design: Observational study. Setting: University anesthesiology department. Intervention: Supervised training was done using a VR airway simulator. Measurements: Time to intubation before and after a 4-day training period using an adult VR FOI scenario and time to intubation using a fresh human cadaver two weeks after the training experience were measured. Main Results: Residents were able to significantly improve time to intubation in the VR scenario (114 vs 75 seconds; P = 0.001). Novices differed from experienced attending anesthesiologists in time to intubation in the VR scenario, before but not after training (114 vs 79 seconds compared with 75 vs 72 seconds). Novices who had been trained with the simulator performed significantly faster in the cadaver than novices who had not (24 vs 86 seconds; P b 0.001). Furthermore, there was no difference in time to intubation in the cadaver between trained novices and experienced attending anesthesiologists (24 vs 23 seconds; P N 0.05). Conclusion: Use of a VR airway simulator enables anesthesia residents to acquire basic FOI skills comparable to those of experienced anesthesiologists in a human cadaver. D 2006 Elsevier Inc. All rights reserved.
1. Introduction Airway management is an integral part of anesthesia practice. Knowledge and skills of airway management must be acquired during training. Despite the use of alternative
* Corresponding author. Tel.: +49 6421 2862516; fax: +49 6421 2866996. E-mail address: [email protected] (K. Goldmann). 0952-8180/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.jclinane.2005.08.021
methods of training and various efforts to structure training, it remains a challenge to ensure that every anesthesia resident gains sufficient experience with core techniques of airway management that are considered essential to be able to deal with the anticipated or unanticipated difficult airway [1-3]. As less time is spent in the operating room during training [4], it becomes less likely that each trainee is exposed to an adequate number of challenging airway cases that enable him or her to practice advanced techniques of airway management under supervision.
174 One of those skills considered to be essential is fiberoptic intubation (FOI) [5,6]. Providing sufficient training in FOI, particularly hands-on experience in anesthetized patients, has always been difficult [7-9] mainly because of technical and ethical problems [10,11]. On the one hand, patients with a known difficult airway requiring awake FOI present relatively infrequently to the operating room, whereas use of elective patients with a normal airway for the teaching of FOI remains controversial. The patient has a right to be protected from the total novice [11,12]. As a consequence, it is mandatory to prepare trainees as well as possible with alternative training methods before they are allowed to attempt FOI in patients. Simple models and manikins have traditionally been used to teach residents how to manipulate the fiberoptic bronchoscope and to improve FOI skills outside the operating room before attempting FOI in patients [13-15]. In the last decade, simulation using partial-task trainers or full-scale simulators has been recognized as a tool that can be used effectively to teach complex cognitive, psychomotor, and judgment skills in medical training [16]. Fiberoptic intubation is one of those complex skills requiring intensive training for acquisition and continuous training for maintenance of the skill. Recently, a virtual reality (VR) bronchoscopy simulator that can be used to practice FOI has become available. This observational study was designed to test the hypothesis that this new simulator can be used to teach basic FOI skills to a degree comparable to those of experienced attending anesthesiologists in a human cadaver.
2. Materials and methods 2.1. Device description The AccuTouch Bronchsocopy Simulator (Immersion Medical, Gaithersburg, MD) is a VR partial-task trainer consisting of a proxy flexible bronchoscope, a robotic interface, a computer, a monitor, and comprehensive simulation software capable of delivering different realistic bronchoscopy scenarios. The simulator bronchoscope feels like a real bronchoscope and can be steered in the same way, but actual placement of an endotracheal tube cannot be simulated. The interface device is capable of tracking the motions of the bronchoscope tip control lever and mimicking the forces and resistances felt during clinical bronchoscopy. The monitor displays computer-generated realistic anatomical images that correlate precisely with the motions of the bronchoscope and the expected anatomical position in the respiratory tract. In addition, the bvirtual patient Q is capable of displaying realistic physiologic responses to the bronchoscope. For instance, hitting the mucous membranes can cause bleeding, or if local anesthetics have been omitted, this causes bthe patient Q to cough, simulating motions of the respiratory tract that one observes in a live patient. All these features produce a training environment
K. Goldmann, T. Steinfeldt that resembles a clinical setting very realistically. The computer records various data related to the performance of the bronchoscopy, such as number of contacts with the mucous membranes, number of attempts needed to pass through the glottis, dose of local anesthetic administered, and total time of the procedure. In addition, a detailed description of the tracheal bronchial tree inspection can be obtained showing all the segments visited and time spent during a complete bronchoscopy. At the end of the case these data can be printed out and used for analysis of performance and for teaching purposes.
2.2. Training study Before we conducted the study we sought advice from the local university ethics committee. Because a formal arrangement to train trainees with noninvasive methods of airway management such as laryngeal mask insertion or FOI in cadavers had already been approved and because the study did not involve care of a patient, approval of the ethics committee was not deemed necessary.
2.3. Curriculum design and study groups All participating residents had received formal teaching in FOI during a half-day (6-hour) airway management course that consisted of formal lectures and use of the flexible bronchoscope in manikins. The course was held at our department one month before the study took place. After a formal one-hour instruction session in which the participants were allowed to familiarize themselves with the VR airway simulator device and an initial pretraining assessment of performance using the same adult FOI scenario, all participants were allowed to have as many training sessions with the VR airway simulator under the supervision of an experienced attending anesthesiologist as they wished throughout a one-week training period (Fig. 1). These training sessions happened in the afternoons and evenings on 4 consecutive working days after the regular duty hours. The same adult FOI scenario that was used for pretraining assessment was used for the final posttraining
Fig. 1
Resident using the VR airway simulator.
Training basic fiberoptic intubation skills assessment of performance on the fifth day. In addition, everybody who had used the simulator for training purposes was asked to give a subjective assessment of the quality of the VR, the handling, the usefulness of the device for training in FOI, and the improvement of their own FOI skills by filling out a short questionnaire. For definite assessment of FOI performance, all participants were asked to perform a FOI in a cadaver two weeks later. The same cadaver was used for all participants (Fig. 2). Before we conducted the study, we identified 20 residents in our department who did not have any clinical experience in FOI before the start of this study. As a consequence of clinical commitments or annual leave, 9 residents were unable to attend either the formal instruction and initial assessment at the beginning of the one-week training period or the definite assessment two weeks after the training experience, leaving 11 residents for the b novice training Q group. Four experienced attending anesthesiologists served as the bexpertsQ group for FOI performance with the adult VR FOI scenario and FOI in the cadaver. bExpert Q in our study was defined as having a minimum of 50 FOI. Four residents who were unable to use the VR airway simulator throughout the one-week training period served as the bnovice nontraining Q control group for FOI in the cadaver.
2.4. Measurements Primary end point for assessment of FOI performance was time to reach the carina in both the VR simulator and the cadaver. The number of training sessions and the total time of training were recorded for each participant. At the end of the study, all participants were asked to answer the following 4 questions using a numeric analogue scale (NAS) ranging from 0, indicating the worst, to 10, indicating the best: Do you think the opportunity to use a VR airway simulator for training FOI is in general bnot useful Q (0) or bvery usefulQ (10)? Do you think your FOI skills have bnot improved at allQ (0) or bimproved a lotQ (10)?
175 Table 1 Comparison of time to intubation in the adult VR scenario separated by groups Initial assessment; duration of FOI (s) Final assessment; duration of FOI (s)
Experts
Novices training
79 F 18.2 (50-108)* 72 F 18.0 (43-101)*
114 F 32.3 (93-136)** 75 F 18.8 (62-87)**
* P N 0.05, experts’ initial vs final assessment. ** P b 0.001, novices’ initial vs final assessment.
Do you think the VR simulation has a bvery low degreeQ (0) or a bvery high degreeQ of reality (10)? Do you think the handling of the VR airway simulator is bvery badQ (0) or bvery goodQ (10)?
2.5. Statistics Results were analyzed using the SPSS (SPSS Inc, Chicago, IL) computer program. Unless otherwise stated, data are expressed as mean F SD (95% confidence intervals) or median values (ranges). The paired t test was used for comparison between pre- and posttraining performance using the adult FOI scenario of the virtual VR simulator. Student t test was used for comparison between the novice training group, the expert group, and the novice nontraining control group. Results were considered statistically significant for a P value of less than 0.05.
3. Results Nineteen anesthesiologists, 15 residents, and 4 attending physicians, participated in the study. They used the simulator in 4 training sessions (range, 1-14) for 50 minutes (range, 15-115 minutes). Time to intubation using the adult FOI VR scenario and the cadaver are presented in Tables 1 and 2, respectively. Both novices from the training group and attending physicians from the experts control group were able to improve time to intubation in the adult FOI VR scenario, but the values were only significant for novices ( P = 0.001). There was a difference between novices and experts before, but not after, training. In the cadaver, novices of the training group were able to perform FOI as fast as attending physicians of the experts group, but novices from the nontraining group required significantly longer ( P b 0.001). The users (n = 19) found the simulator very Table 2 Comparison of time to intubation in the cadaver separated by groups
Duration of FOI (s) Fig. 2
Residents performing FOI in a fresh cadaver.
Experts
Novices training
Novices nontraining
23 F 4.6 (16-30)*
24 F 5.3 (20-27)*,**
86 F 38 (25-147)**
* P N 0.05, novices training vs experts. ** P b 0.001, novices training vs novices nontraining.
176 useful (NAS = 10; range, 7-10) for training FOI and felt that their FOI skills had improved a lot (NAS = 8; range, 2-10). They assessed the degree of reality as very high (NAS = 9; range, 7-10) and handling of the VR airway simulator as very good (NAS = 9; range, 2-10).
4. Discussion Fiberoptic intubation plays a central role in difficult airway management [17-19]. It is believed that awake FOI offers the highest degree of safety in a patient with an anticipated difficult airway [19]. As a consequence, it is considered one of the core techniques of airway management [5,6]. If something is considered a core skill, then all residents must receive sufficient training during residency in this particular technique. Apparently, this is not the case. Various recent surveys from different countries revealed that the prevalence of sufficient FOI skills is still low [20-24]. Although the value of bench models, manikins, and simple simulators for training FOI has been shown in several studies [13-15], they do not imitate a realistic clinical scenario. In our own experience, simple bench models and manikins carry the limitation that the trainees often know the tasks to be performed after a short period and then stop using these training tools because they do not feel they could gain any more than they have already learned. The fact that patients with a known difficult airway requiring awake FOI present relatively infrequently to the operating theater is the reason [7] why trainees and attending anesthesiologists still lack sufficient experience in FOI, despite efforts to structure training and to use alternative methods of training outside the operating room [1-3]. A VR airway simulator could help to overcome the existing lack of appropriate clinical and nonclinical training opportunities for FOI. One advantage of modern VR simulators is that the computer software can provide a large number of ever changing tasks, can give immediate feedback, and mimic breal patients.Q All these features help to produce very realistic clinical scenarios and thereby make VR simulators very attractive to trainees as is shown by the very positive assessment of the VR airway simulator by the participants of this study. However, the question that remains is how effective VR simulators are in terms of the transfer of skills learned and practiced outside the operating room into clinical practice. The results of this study indicate that this VR airway simulator can be used very effectively to teach basic FOI skills to novices. Residents with no clinical FOI experience were able to acquire a degree of dexterity with the flexible bronchoscope that enabled them to perform a FOI in a cadaver as fast as experienced attending physicians would, whereas residents who did not use the airway simulator for training needed significantly longer. This confirms the results of the study by Rowe and colleagues, who showed that residents who practiced FOI with this airway simulator were able to improve their FOI skills significantly in
K. Goldmann, T. Steinfeldt comparison to trainees who did not use the airway simulator [25]. In contrast to the study by Rowe, we chose to use a cadaver instead of live pediatric patients for definite assessment of FOI performance for several reasons. First, use of cadavers for the training of airway management techniques has been recommended and practiced for a long time [26-28]. In our own practice we have found use of cadavers not only valuable for training purposes, but also for assessing whether a trainee can be considered bready Q for performing FOI under supervision in the operating room. Second, assessment of performance in live patients would have carried the limitation that each participant would have been assessed in a different patient with anatomical differences of the airway. Third, because of the limited number of patients requiring FOI, definite assessment of performance could not have been achieved on the same day for all participants if we had chosen to use live patients. Some residents would have been assessed shortly after their training experience, whereas others would have been assessed a considerable time after their training experience. Both aspects would have made it difficult to compare the performance of all participants. Another difference between the study by Rowe et al. and our study is that we included a group of consultants who were experienced in FOI. The main reason to include an bexpert groupQ was to compare the performance of trainees who were newly trained outside the operating room using this VR airway simulator with clinicians who had been trained by traditional methods and were now, as a consequence of their clinical experience, considered competent in performing FOI. The results indicate that residents can be taught basic FOI skills to a degree that compares to physicians who have been trained using traditional methods. The fact that residents with training using the VR airway simulator improved their skills in contrast to residents who did not have this training proves that this improvement can be attributed to the training with this VR airway simulator. In contrast, time to intubation in the after-training assessment did not differ much from the initial assessment in the group of attending anesthesiologists. This shows that experts with advanced FOI skills are unlikely to improve their performance significantly using this VR airway simulator. This is not surprising because these physicians have gained advanced FOI skills over a long period and are experienced in performing FOI in clinical cases whose level of difficulty can be far more complex than what a VR scenario can display. It is reasonable to assume that these attending anesthesiologists had already reached a level of basic FOI skills that could hardly be improved. Furthermore, in this study, novices with training performed as well as attending anesthesiologists both in their final simulator assessment and in the cadaver. This indicates that simulator assessment could be used to compare novices’ performance with experts’ performance in the same way that cadaver assessment is used. This seems
Training basic fiberoptic intubation skills particularly helpful when one wants to determine whether trainees have reached a level of skill that is sufficient to allow them to perform a FOI in a live patient. Until now there has been no method of assessment outside the operating theater that comes close to the clinical situation that trainees will experience in the operating theater when they perform their first FOI. In most institutions, current practice is to allow trainees to perform their first FOI under supervision in anesthetized patients after they have had basic FOI training in models or manikins in the absence of any reliable standardized assessment. This can result in a very unpleasant training experience when it turns out that the trainee has not acquired sufficient FOI skills to succeed in a complex clinical situation. Training and evaluation using this VR airway simulator could make clinical teaching safer for the patient and the learning experience more comfortable for the trainee by providing an effective training tool and a reliable method to determine the level of acquired FOI skills. However, the validity of any such evaluation using a VR airway simulator would have to be determined in a separate study because the main objective of our study was to investigate the value of this device for training. Nevertheless, our results indicate that VR airway simulator assessment can be used for assessment of FOI performance. The improvement of performance in the VR scenario in the trainees to a level that was similar to the experts’ level explains why the level of performance in the cadaver was also similar in both groups. The main limitation of our study is that we did not assess the participants’ performance during an awake FOI in a live patient; placing the fiberscope is only half of a FOI, the other half is placing the endotracheal tube into the trachea. Therefore, our study does not give any data on how the trainees would have performed in a clinical case. However, our aim was to investigate into basic and not advanced FOI skill training and to have comparable conditions at the same time for all participants. We choose the cadaver over live patients for final assessment of FOI skills. No doubt, a VR airway simulator assessment would still have to be considered a substitute for a clinical FOI assessment. However, under medicolegal aspects, we feel that using a patient for such an initial assessment is debatable and, to date, VR assessment is the closest one can get to a clinical assessment. In conclusion, this VR airway simulator offers an effective tool for training basic FOI skills in an environment that comes closer to reality than any other FOI training modality outside the operating room. Another value of this tool is that it can be used for assessment of performance before allowing trainees to attempt FOI in a live patient.
Acknowledgments The AccuTouch Bronchoscopy Simulator was provided free of charge for the study by Immersion Medical
177 (Gaithersburg, MD). The authors thank Dr John Henderson for reviewing the manuscript critically.
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