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Simulation technology in training students, residents and faculty.

PURPOSE OF REVIEW: We provide an overview of the developments in medical education and assessment using high-fidelity simulation. Both descriptive and research papers recently published in the English language are included in this review. RECENT FINDINGS: The majority of articles reviewed are descriptive in nature, outlining the use of simulation for various educational purposes in undergraduate, postgraduate and continuing medical education. Some articles focus on the use of simulation for the acquisition of technical skills in different surgical disciplines using part-task simulation. Other disciplines such as emergency medicine, critical care, paediatrics and nursing have also contributed to the literature in this area. Very little research in the area of simulation is evident in the literature addressing the actual value or the reliability and validity of high-fidelity simulation as an evaluation tool during this time period. A strong interest in decreasing human error and the improvement in patient safety may indicate the future direction of high-fidelity simulation. SUMMARY: Simulation is receiving increasing support as an educational tool and in its use for evaluation purposes. Research into this area is still somewhat limited. As the research impetus increases in the future, we may see simulation as a major focus in all disciplines with respect to its use in the improvement of patient safety. Team training, including both personality and attitudinal issues similar to those performed in other high hazard industries, may become increasingly evident in the literature in the coming decade.

Journal Article↗

Virtual reality ureteroscopy simulator as a valid tool for assessing endourological skills.

AIM: Virtual reality (VR) simulators are now commercially available for various surgical skills training. The Uro Mentor VR Ureteroscopy Simulator by Symbionix is one system that may revolutionize the way we assess and teach surgical residents. Surgical educators may no longer have to depend on the operating room as the sole venue for teaching residents technical skills. We validated performance on this new system with previously developed assessment tools and compared it to performance on a high fidelity ureteroscopy bench model. METHODS: Urology residents (n = 16) were assessed on their ability to perform cystoscopy, guidewire insertion, semirigid ureteroscopy and basket extraction of a distal ureteric stone on the VR simulator. A blinded examiner assessed subject performance using a checklist, global rating scale and a pass/fail rating. In addition, computer-generated parameters including time to complete task, scope and instrument trauma and the number of attempts to insert a guidewire were analysed. Performance on the VR simulator was compared to performance on a high fidelity ureteroscopy bench model. RESULTS: Senior residents (n = 8) scored significantly higher on their global rating scale (29.4 +/- 2.5 vs 20.8 +/- 0.9, P = 0.005), checklist (19.1 +/- 1.1 vs 15.2 +/- 0.9, P = 0.02), pass/fail rating (chi(2) = 7.3, P = 0.007) and required less time to complete the task (352.9 +/- 55.7 s vs 576.8 +/- 67.4 s., P = 0.02) than the junior residents (n = 8) on the VR simulator. Junior residents also had a significantly higher incidence of scope trauma (4 vs 0.6, P = 0.02). No significant differences were noted in instrument trauma and the number of attempts to insert the guidewire. Global rating scale performance on the VR simulator correlated well to performance on the high fidelity ureteroscopy bench model (r = 0.7, P = 0.002) as did time to complete task (r = 0.7, P = 0.004). CONCLUSIONS: The Uro Mentor VR Ureteroscopy Simulator is a useful tool in assessing resident endourological skills. Performance on the VR simulator is comparable to a validated high fidelity ureteroscopy bench model. Future studies will assess the utility of VR simulators in surgical skills training.

Adult↗

The use of simulation for training teamwork skills in health care: how low can you go?

High fidelity simulation has become a popular technique for training teamwork skills in high risk industries such as aviation, health care, and nuclear power production. Simulation is a powerful training tool because it allows the trainer to systematically control the schedule of practice, presentation of feedback, and introduction (or suppression) of environmental distractions within a safe, controlled learning environment. Unfortunately, many within the training community have begun to use the terms simulation and high fidelity simulation almost synonymously. This is unfortunate because doing so overemphasises the instructional technology to the detriment of more substantive issues, such as the training's goals, content, and design. It also perpetuates several myths: simulation fidelity is unidimensional, or higher levels of simulation fidelity lead to increased training effectiveness. The authors propose a typology of simulation fidelity and provide examples of how the different classes of simulation have been successfully used to train teamwork skills in high risk industries. Guidelines are also provided to maximise the usefulness of simulation for training teamwork skills in health care.

Inservice Training↗

A single ventilator for multiple simulated patients to meet disaster surge.

OBJECTIVES: To determine if a ventilator available in an emergency department could quickly be modified to provide ventilation for four adults simultaneously. METHODS: Using lung simulators, readily available plastic tubing, and ventilators (840 Series Ventilator; Puritan-Bennett), human lung simulators were added in parallel until the ventilator was ventilating the equivalent of four adults. Data collected included peak pressure, positive end-expiratory pressure, total tidal volume, and total minute ventilation. Any obvious asymmetry in the delivery of gas to the lung simulators was also documented. The ventilator was run for almost 12 consecutive hours (5.5 hours of pressure control and more than six hours of volume control). RESULTS: Using readily available plastic tubing set up to minimize dead space volume, the four lung simulators were easily ventilated for 12 hours using one ventilator. In pressure control (set at 25 mm H2O), the mean tidal volume was 1,884 mL (approximately 471 mL/lung simulator) with an average minute ventilation of 30.2 L/min (or 7.5 L/min/lung simulator). In volume control (set at 2 L), the mean peak pressure was 28 cm H2O and the minute ventilation was 32.5 L/min total (8.1 L/min/lung simulator). CONCLUSIONS: A single ventilator may be quickly modified to ventilate four simulated adults for a limited time. The volumes delivered in this simulation should be able to sustain four 70-kg individuals. While further study is necessary, this pilot study suggests significant potential for the expanded use of a single ventilator during cases of disaster surge involving multiple casualties with respiratory failure.

Adult↗

Comparisons of pilot performance in simulated and actual flight.

Five highly experienced professional pilots performed instrument landing system approaches under simulated instrument flight conditions in a Cessna 172 airplane and in a Link-Singer GAT-1 simulator while under the influence of orally administered secobarbital (0, 100, and 200 mg). Tracking performance in two axes and airspeed control were evaluated continuously during each approach. The data from the airplane and simulator were compared. Error and RMS variability were about half as large in the simulator as in the airplane. The observed data were more strongly associated with the drug level in the simulator than in the airplane. Further, the drug-related effects were more consistent in the simulator. Improvement in performance suggestive of learning effects were seen in the simulator, but not in actual flight. It is concluded that the GAT-1 simulator is a useful and sensitive device for studies of the effects of mild stress on pilot performance, but extrapolation of simulator data to the flight environment must be approached with considerable caution.

Achievement↗

Simulator induced syndrome: evidence for long-term aftereffects.

Pilots have experienced various adverse symptoms hours and even days following flight simulator training. This study surveyed pilots undergoing simulator training in an attempt to provide an initial gauge of the extent, severity, and possible risk factors of long-term (greater than 1 day) simulator aftereffects. A three-part voluntary and anonymous questionnaire was used to gather data. We studied pilots of varying experience undergoing advanced flight training which included the use of flight simulators. Some 238 pilots participated in the study, and 196 completed the follow-up survey concerning long-term effects. Nine (4.6%) pilots experienced adverse symptoms 24 h or more after completion of their last simulator training, which they attributed to their recent simulator experience. Symptoms reported included: recurrent visual flashbacks, continued balance disturbance, and hand-eye discoordination. Three pilots (1.5%) reported difficulties flying aircraft. Pilot flight experience level, total simulator time, length of simulator session, and sex were not predictive of risk. This study suggests that long-term (greater than 1 day) adverse aftereffects may occur following simulator training.

Aircraft↗

A simulator for objectively evaluating prospective drivers of the Scott van.

A simple simulator for evaluating the physical capabilities of severely handicapped prospective drivers was developed and evaluated. The simulator presents a two-dimensional tracking task to be carried out using the driving controls of the Scott van, which is a uni-lever servo-controlled vehicle designed for the severely impaired. Twenty-five able-bodied subjects were tested on the simulator and 13 of them were then given driving tests in a Scott van. Simulator RMS tracking error and the number of traffic cones knocked down were the respective performance measures for these tests. Nine severely disabled subjects were then tested in the simulator and in driving tests in the van. In order to compare the simulator performances of the handicapped subjects with their driving performances, their performance scores were all converted to T-scores. The T-score transformed the performance of these subjects into scores having as a common reference the performances of the able-bodied subjects. Simulator T-scores for the handicapped subjects reflected large variations in their tracking abilities due to differences in their functional capabilities. Most importantly, in the authors' opinion, was the fact that the simulator T-scores of the handicapped subjects correlated very well with their driving performance T-scores. This type of simulator therefore appears to be a valuable tool for providing objective and quantitative data for evaluating severely handicapped prospective drivers.

Automobile Driving↗

Simulation in surgical training: educational issues and practical implications.

BACKGROUND: Surgical skills are required by a wide range of health care professionals. Tasks range from simple wound closure to highly complex diagnostic and therapeutic procedures. Technical expertise, although essential, is only one component of a complex picture. By emphasising the importance of knowledge and attitudes, this article aims to locate the acquisition of surgical skills within a wider educational framework. SIMULATORS: Simulators can provide safe, realistic learning environments for repeated practice, underpinned by feedback and objective metrics of performance. Using a simple classification of simulators into model-based, computer-based or hybrid, this paper summarises the current state of the art and describes recent technological developments. Advances in computing have led to the establishment of precision placement and simple manipulation simulators within health care education, while complex manipulation and integrated procedure simulators are still in the development phase. EVALUATION: Tension often exists between the design and evaluation of surgical simulations. A lack of high quality published data is compounded by the difficulties of conducting longitudinal studies in such a fast-moving field. The implications of this tension are discussed. THE WIDER CONTEXT: The emphasis is now shifting from the technology of simulation towards partnership with education and clinical practice. This highlights the need for an integrated learning framework, where knowledge can be acquired alongside technical skills and not in isolation from them. Recent work on situated learning underlines the potential for simulation to feed into and enrich everyday clinical practice.

Clinical Competence↗

Anatomy of the clinical simulation.

Computer-based clinical simulations have been used in medical education for the past 25 years. During this period, the technology has evolved from mainframe computers to microcomputers to multimedia. All designers of simulations must decide which elements of reality to include explicitly in a simulated case, which to leave to the user's imagination, and when to intervene for educational purposes. Once these decisions are made, developers of simulations have many options for structuring the simulation itself. They can develop simulations with single or multiple patient encounters, with menu or natural-language requests for data, with varying levels of volunteered information about the simulated patient, with interpreted or uninterpreted clinical findings, with deterministic or probablistic evolution of the case, with various ways to give users feedback about their progress through the case, and with manual or automated creation of specific cases. Simulations derive their specific character from how these options are implemented.

Computer Simulation↗

Simulation in undergraduate medical education: bridging the gap between theory and practice.

OBJECTIVE: To evaluate the use of simulation-based teaching in the medical undergraduate curriculum in the context of management of medical emergencies, using a medium fidelity simulator. DESIGN: Small groups of medical students attended a simulation workshop on management of medical emergencies. The workshop was evaluated in a post-course questionnaire. SUBJECTS: All Year 4 medical students allocated to the resuscitation rotation during the first half of 2002. MAIN OUTCOME MEASURES: Student perceptions of learning outcomes, the value of the simulation in the undergraduate curriculum and their self-assessed improved mastery of workshop material. RESULTS: A total of 33 students attended the workshop and all completed questionnaires. Students rated the workshop highly and found it a valuable learning experience. In all, 21 (64%) students identified teamwork skills as key learning points; 11 (33%) felt they had learnt how to approach a problem better, particularly in terms of using a systematic approach, and 12 (36%) felt they had learnt how to apply their theoretical knowledge in a clinical setting better. All 33 students were positive about the use of simulation in their training; 14 students wrote that simulation should be used more or should be mandatory in training; 5 students commented positively on the realism of the learning experience and a further 5 said they valued the opportunity to learn new skills in a safe environment. CONCLUSION: This study demonstrates that medical students value simulation-based learning highly. In particular, they value the opportunity to apply their theoretical knowledge in a safe and realistic setting, to develop teamwork skills and to develop a systematic approach to a problem. A medium fidelity simulator is a valuable educational tool in medical undergraduate education.

Attitude of Health Personnel↗

Flexible endoscopy simulators.

Training in flexible endoscopy is becoming increasingly complex. In an effort to improve the efficiency of endoscopic education, physicians are turning to simulation technology to provide a platform for training away from the endoscopy suite. The concept of medical simulation is not new, but the recent addition of powerful computer-generated virtual reality simulation has revolutionized the field. These compact computers are now able to generate a simulated environment that not only mimics the movement of the endoscope, but also recreates the sounds of the endoscopy suite, the feel of the movement of the scope, the reaction of intestinal tissue, and the response of a patient experiencing discomfort. Within this life-like simulated environment, a wide variety of diagnostic and therapeutic endoscopic procedures can be performed. This article reviews the history of flexible endoscopy simulators and details the most advanced models currently available. The literature supporting the use of these simulators is also presented, and issues involving the incorporation of simulation technology into endoscopic education and credentialing are discussed.

Animals↗

Diversity matters: dynamic simulation of distributed bacterial states in suspended growth biological wastewater treatment systems.

A MATLAB-based program was developed to simulate the distributions of states and behaviors of microbial storage product-accumulating bacteria in suspended growth systems. Currently available computer simulators of these systems predict dynamic behaviors by numerically solving differential biokinetic equations using average, or "lumped" system states (e.g., average microbial storage products concentrations). However, individual bacterial states are expected to diverge from average values, in part because individuals can have different hydrodynamic histories in terms of their residence times in upstream completely mixed flow reactors. The distributed state simulation program presented in this paper (DisSimulator 1.0) tracks individual bacteria as they move through a completely mixed reactor system. The program was evaluated for competition between polyphosphate-accumulating organisms (PAOs) and non-polyphosphate-accumulating heterotrophs in an enhanced biological phosphorus removal (EBPR) system for treatment of domestic wastewater. For identical systems and process conditions, simulations accounting for distributed states predicted larger anaerobic and aerobic solids residence time requirements for successful EBPR than did simulations using the lumped approach. One reason for this was that distributed simulations predicted large numbers of the PAOs were essentially inactive due to depleted or maximized storage product contents, while the lumped simulations predicted homogenous, 100% active PAO populations. Characteristic state profile shapes developed rapidly and were stable as total population numbers changed. Lumped state assumptions were demonstrated to produce large errors in predictions of EBPR system performance, and so consideration of distributed states may improve the accuracy of microbial storage products-based process simulations in systems with completely mixed hydrodynamics.

Bacterial Physiological Phenomena↗

Comparison of various implicit solvent models in molecular dynamics simulations of immunoglobulin G light chain dimer.

The present study tests performance of different solvation models applied to molecular dynamics simulation of a large, dimeric protein molecule. Analytical Continuum Electrostatics (ACE) with two different parameter sets, older V98 and new V01, and Effective Energy Function (EEF) are employed in molecular dynamics simulation of immunoglobulin G (IgG) light chain dimer and variable domain of IgG light chain. Results are compared with explicit solvent and distance dependent dielectric constant (DDE) calculations. The overall analysis shows that the EEF method yields results comparable to explicit solvent simulations; however, the stability of simulations is lower. On the other hand, the ACE_V98 model does not seem to achieve the accuracy or stability expected in nanosecond timescale MD simulation for the studied systems. The ACE_V01 model greatly improves stability of the calculation; nonetheless, changes in radius of gyration and solvent accessible surface of the studied systems may indicate that the parameter set still needs to be improved if the method is supposed to be used for simulations of large, polymeric proteins. Additionally, electrostatic contribution to the solvation free energy calculated in the ACE model is compared with a numerical treatment of the dielectric continuum model. Wall clock time of all simulations is compared. It shows that EEF calculation is six times faster than corresponding ACE and 50 times faster than explicit solvent simulations.

Computer Simulation↗

Assembly of a tetrameric alpha-helical bundle: computer simulations on an intermediate-resolution protein model.

Discontinuous molecular dynamics (DMD) simulation on an intermediate-resolution protein model is used to study the folding of an isolated, small model peptide to an amphipathic alpha-helix and the assembly of four of these model peptides into a four-helix bundle. A total of 129 simulations were performed on the isolated peptide, and 50 simulations were performed on the four-peptide system. Simulations efficiently sample conformational space allowing complete folding trajectories from random initial configurations to be observed within 15 min for the one-peptide system and within 15 h for the four-peptide system on a 500-MHz workstation. The native structures of both the alpha-helix and the four-helix bundle are consistent with experimental characterization studies and with results from previous simulations on these model peptides. In both the one- and four-peptide systems, the native state is achieved during simulations within an optimal temperature range, a phenomenon also observed experimentally. The ease with which our simulations yield reasonable estimates of folded structures demonstrates the power of the intermediate-resolution model developed for this work and the DMD algorithm and suggests that simulations of very long times and of multiprotein systems may be possible with this model.

Amino Acids↗

Comparing atomistic simulation data with the NMR experiment: how much can NOEs actually tell us?

Simulated molecular dynamics trajectories of proteins and nucleic acids are often compared with nuclear magnetic resonance (NMR) data for the purposes of assessing the quality of the force field used or, equally important, trying to interpret ambiguous experimental data. In particular, nuclear Overhauser enhancement (NOE) intensities or atom-atom distances derived from them are frequently calculated from the simulated ensembles because the distance restraints derived from NOEs are the key ingredient in NMR-based protein structure determination. In this study, we ask how diverse and nonnative-like an ensemble of structures can be and still match the experimental NOE distance upper bounds well. We present two examples in which simulated ensembles of highly nonnative polypeptide structures (an unfolded state ensemble of the villin headpiece and a high-temperature denatured ensemble of lysozyme) are shown to match fairly well the experimental NOE distance upper bounds from which the corresponding native structures were derived. For example, the unfolded ensemble of villin headpiece, which is on average 0.90 +/- 0.13 nm root-mean-square deviation away from the native NMR structure, deviates from the experimental restraints by only 0.027 nm on average. However, this artificially good agreement is largely a consequence of 1) the highly nonlinear effects of r(-6) (or r(-3)) averaging and 2) focusing only on the experimentally observed set of NOE bounds. Namely, in addition to the experimentally observed NOEs, both simulated ensembles (especially the villin ensemble) also predict a large number of NOEs, which are not seen in the experiment. If these are taken into account, the agreement between simulation and experiment gets markedly worse, as it should, given the nonnative nature of the underlying simulated ensembles. In light of the examples given, we conclude that comparing experimental NOE distance restraints with large simulated ensembles provides just by itself only limited information about the quality of simulation.

Animals↗

Molecular dynamics simulations of the cytochrome c3-rubredoxin complex from Desulfovibrio vulgaris.

Molecular dynamics simulations have been carried out on the complex formed between the tetraheme cytochrome c3 and the iron protein rubredoxin from the sulfate-reducing bacterium Desulfovibrio vulgaris. These simulations were performed both with explicit solvent water molecules included, and without solvent molecules using a distance-dependent dielectric constant to approximate the screening effects of solvent. The results of both simulations are strikingly different, indicating that the representation of environmental effects is important in such simulations. For example, a striking adaptation of the two proteins seen in the nonsolvated simulation is not seen when explicit solvent water is included; in fact, the complex appears to become weaker in the solvated simulation. Nonetheless, the iron-iron distance decreases more significantly in the solvated simulation than in the nonsolvated simulation. It was found that in both cases molecular dynamics optimized the structures further than energy minimization alone.

Computer Simulation↗

Using lazy evaluation to simulate realistic-size repertoires in models of the immune system.

We describe a method of implementing efficient computer simulations of immune systems that have a large number of unique B- and/or T-cell clones. The method uses an implementation technique called lazy evaluation to create the illusion that all clones are being simulated, while only actually simulating a much smaller number of clones that can respond to the antigens in the simulation. The method is effective because only 0.001-0.01% of clones can typically be stimulated by an antigen, and because many simulations involve only a small number of distinct antigens. A lazy simulation of a realistic number of clones and 10 distinct antigens is 1000 times faster and 10,000 times smaller than a conventional simulation--making simulations of immune systems with realistic-size repertoires computationally tractable.

Algorithms↗

Constructing a 3-D mesh model for electrical cardiac activity simulation.

The 3-D ventricle model in this study was reconstructed from a series of MRI torso cross-section data. We used a 3-D voxel array to represent the ventricle. As in cardiac simulations proposed by previous studies, the activation sequence and body surface ECG were simulated in this model. But to reduce the amount of elements in the model, so that the amount of parameters in the model can be handled numerically, we propose another approach to simulate cardiac activity. A mesh model was constructed on the closed surface formed by epicardiac and endocardiac surfaces of the ventricle. We propose a method to simulate the activation sequence on the epicardiac and endocardiac surfaces of the mesh model. As with the uniform double layer theorem, body surface ECG can be estimated in terms of epicardiac and endocardiac surface current source. Consequently, we can also generate ECG waveforms corresponding to this mesh simulation. Both the depolarization sequence and ECG simulated by the mesh model resemble those generated by the 3-D voxel model. However, the mesh model greatly simplified the process of ECG simulation. Both the simulation of depolarization and ECG estimation were expressed in terms of clear and simple mathematical representations. Consequently, we can analytically investigate the effects of the mesh model's parameters on the cardiac activation sequence and ECG. It could be a useful tool to numerically study the relation of ECG waveforms and electrical activity of the heart.

Computer Simulation↗