米勒麻醉学第七版7

7 – Patient SimulationMarcus Rall,David M. Gaba,Peter Dieckmann,Christoph EichKey Points1.Simulators and the use of simulation have become an integral part of medical education, training,and research. The pace of developments and applications is very fast, and the results arepromising.2.Different types of simulators can be distinguished: computer-based or screen-basedmicrosimulators versus mannequin-based simulators. The latter can be divided into script-basedand model-based simulators.3.The development of mobile and less expensive simulator models allows for substantial expansionof simulator training to areas where this training could not be applied or afforded previously. Thebiggest obstacles to providing simulation training are not the simulator hardware but are (1)obtaining access to the learner population for the requisite time and (2) providing appropriatelytrained and skilled instructors to prepare, conduct, and evaluate the simulation sessions.4.Realistic simulations are a useful method to show mechanisms of error development (humanfactors) and to provide their countermeasures. The anesthesia crisis resource management(ACRM) course model with its ACRM key points (see Chapter 6 on Crisis Resource Management)is the de facto world standard for human factor–based simulator training. Curricula should usescenarios that are tailored to the stated teaching goals, rather than focusing solely on achievingmaximum “realism.”5.Simulator training is being adapted by many other fields outside anesthesia (e.g., emergencymedicine, neonatal care, intensive care, medical and nursing school).6.Simulators have proved to be very valuable in research to study human behavior and failuremodes under conditions of critical incidents and in the development of new treatment concepts(telemedicine) and in support of the biomedical industry (e.g., device beta-testing).7.Simulators can be used as effective research tools for studying methods of performanceassessment.8.Assessment of nontechnical skills (or behavioral markers) has evolved considerably and can beaccomplished with a reliability that likely matches that of many other subjective judgments inpatient care. Systems for rating nontechnical skills have been introduced and tested in anesthesia;one in particular (Anaesthetists' Non-Technical Skills [ANTS]) has been studied extensively andhas been modified for other fields.9.The most important part of simulator training that goes beyond specific technical skills is the self-reflective (often video-assisted) debriefing session after the scenario. The debriefing is influencedmost strongly by the quality of the instructor, not the fidelity of the simulator.10.Simulators are just the tools for an effective learning experience. The education and training,commitment, and overall ability of the instructors are of utmost importance.How can clinicians experience the difficulties of patient care without putting patients at undue risk? How can we assess the abilities of clinicians as individuals and teams when each patient is unique? These are questions that have challenged medicine for years. In recent years, these and related questions have begun to be answered in health care by the application of approaches new to medicine, but borrowed from years of successful service in other industries facing similar problems. These approaches focus on simulation, a technique well known in the military, aviation, space flight, and nuclear power industries. Simulation refers to the artificial replication of sufficient elements of a real-world domain to achieve a stated goal. The goals can include understanding the domain better, training personnel to deal with the domain, or testing the capacity of personnel to work in the domain. The fidelity of a simulation refers to how closely it replicates the domain and is determined by the number of elements that are replicated and the discrepancy between each element and the real world. The fidelity required depends on the stated goals. Some goalscan be achieved with minimal fidelity, whereas others require very high fidelity.Simulation has probably been a part of human activity since prehistoric times. Rehearsal for hunting activities and warfare was most likely an occasion for simulating the behavior of prey or enemy warriors. Technologic simulation probably dates back to the dawn of technology itself. Good and Gravenstein[1] pointed to the medieval quintain as a technologic device that crudely simulated the behavior of an opponent during sword fighting. If the swordsman did not duck at the appropriate time after striking a blow, he would be hit by a component of the quintain. In modern times, preparation for warfare has been an equally powerful spur to the development of simulation technologies, especially for aviation, shipping, and the operation of armored vehicles. These technologies have been adopted by their civilian counterparts, but they have attained their most extensive use in commercial aviation.Simulation in AviationAlthough some aircraft simulators were built between 1910 and 1927, none of them could provide the proper feel of the aircraft because they could not dynamically reproduce its behavior. In 1930, Link filed a patent for a pneumatically driven aircraft simulator. The Link Trainer was a standard for flight training before World War II, but the war accelerated its use and the further development of flight simulators. In the 1950s, electronic controls replaced pneumatic ones through analog, digital, and hybrid computers. The aircraft simulator achieved its modern form in the late 1960s, but it has been continuously refined. Aviation simulators are so realistic now that pilots with experience flying one aircraft are routinely certified to fly totally new or different aircraft, even if they have never flown the actual aircraft without passengers on board. Similar stories of the development of simulators can be told for numerous other industries.Uses of SimulatorsAlthough simulators originally were used to provide basic instruction on the operation of aircraft controls, the variety of uses of simulators in general has expanded greatly. Table 7-1 lists possible uses of simulators in all types of complex work situations. Simulation is a powerful generic tool for dealing with human performance issues (e.g., training, testing, and research) (see Chapter 6 ), for investigating human-machine interactions, and for the design and validation of equipment. As described later in this chapter, each of these uses is potentially relevant to anesthesiology. A few books are devoted solely to the topic of simulation and their use in and outside of anesthesia. [2] [3] [4]Table 7-1 -- Use of Simulators in Complex Work EnvironmentsTeam training, as human factor or CRM trainingTraining in dynamic plant controlTraining in diagnostic skillsDynamic mockup for design evaluationTest bed for checking operating instructionsEnvironment in which task analysis can be conducted (e.g., on diagnostic strategies)Test bed for new applications (e.g., telemedicine tools such as the “Guardian-Angel-System”)Source of data on human errors relevant to risk and reliability assessmentVehicle for (compulsory) testing/assessment and recertification of operatorsAdapted from Singleton WT: The Mind at Work. Cambridge, Cambridge University Press, 1989.CRM, Crisis resource management.Twelve Dimensions of SimulationCurrent and future applications of simulation can be categorized by 12 dimensions, each of which represents a different attribute of simulation ( Fig. 7-1 ).[5] Some dimensions have a clear gradient and direction, whereas others have only categorical differences. The total number of unique combinations across all the dimensions is very large (on the order of 412 to 512—4 million to 48 million). Some combinations overlap strongly with others, and some are inappropriate or irrelevant, so the actual number of meaningful combinations is much lower. Nonetheless, although the demonstrated applications of simulation in health care have been quite diverse, the space of possible applications (a large number,although quite a bit smaller than millions) has by no means been fully examined.Figure 7-1 The 12 dimensions of simulation applications (10 to 12 shown on next page). Any particular application can be represented as a point or range on each spectrum (shown by diamonds). This figure illustrates a specific application—multidisciplinary CRM-oriented decision making and teamwork training for adult intensive care unit personnel. CRM, crises resource management; ED, emergency department; ICU, intensive care unit; OR, operating room. *These terms are used according to Miller's pyramid of learning.Dimension 1: Purpose and Aims of the Simulation ActivityThe most obvious application of simulation is to improve the education and training of clinicians, but other purposes also are important. As used in this chapter, education emphasizes conceptual knowledge, basic skills, and an introduction to work practices. Training emphasizes the actual tasks and work to be performed. Simulation can be used to assess performance and competency of individual clinicians and teams, for low-stakes or formative testing and (to a lesser degree as yet) for high-stakes certification testing. [6] [7] Simulation rehearsals are now being explored as adjuncts to actual clinical practice; for example, surgeons or an entire operative team can rehearse an unusually complex operation in advance using a simulation of the specific patient. [8] [9] [10] Simulators can be powerful tools for research and evaluation, concerning organizational practices (patient care protocols) and for the investigation of human factors (e.g., of performance-shaping factors, such as fatigue,[11] or of the user interface and operation of medical equipment in high hazard clinical settings[12]). Simulation-based empirical tests of the usability of clinical equipment already have been used in designing equipment that is currently for sale; ultimately, such practices may be required by regulatory agencies before approval of new devices.Simulation can be a “bottom up” tool for changing the culture of health care concerning patient safety. First, it allows hands-on training of junior and senior clinicians about practices that enact the desired “culture of safety.”[13] Simulation also can be a rallying point about culture change and patient safety that can bring together experienced clinicians from various disciplines and domains (who may be “captured” because the simulations are clinically challenging) along with health care administrators, risk managers, and experts on human factors, organizational behavior, or institutional change.Dimension 2: Unit of Participation in the SimulationMany simulation applications are targeted at individuals. These may be especially useful for teaching knowledge and basic skills or for practice on specific psychomotor tasks. As in other high hazard industries, individual skill is a fundamental building block, but a considerable emphasis is applied at higherorganizational levels, in various forms of teamwork and interpersonal relations (often summarized under the rubric of crisis resource management (CRM) adapted from aviation cockpit resource management) (more on human factors and CRM concepts, see Chapter 6 ). [14] [18] CRM is based on empirical findings that individual performance is not sufficient to achieve optimal safety.[15] Team training may be addressed first to crews (also known as single discipline teams), consisting of multiple individuals from a single discipline, and then to teams (or multidisciplinary teams).[16] There are advantages and disadvantages to addressing teamwork in the single discipline approach that “trains crews to work in teams” versus the “combined team training” of multiple disciplines together.[21] For maximal benefit, these approaches are used in a complementary fashion.Teams exist in actual “work units” in an organization (e.g., a specific intensive care unit [ICU]), each of which is its own target for training. There also is growing interest and experience in applying simulation to nonclinical personnel and work units in health care organizations (e.g., to managers or executives)[22] and to organizations as a whole (e.g., entire hospitals or networks).Dimension 3: Experience Level of Simulation ParticipantsSimulation can be applied along the entire continuum of education of clinical personnel and the public at large. It can be used with early learners, such as schoolchildren, or lay adults to facilitate bioscience instruction, to interest individuals in biomedical careers, or to explain health care issues and practices. The major role of simulation has been, and will continue to be, to educate, train, and provide rehearsal for individuals actually involved in the delivery of health care. Simulation is relevant from the earliest level of vocational or professional education (students) and during apprenticeship training (interns and residents), and increasingly for experienced personnel undergoing periodic refresher training. Simulation can be applied regularly to practicing clinicians (as individuals, teams, or organizations) regardless of their seniority, [17] [18] providing an integrated accumulation of experiences that should have a long-term synergism.Dimension 4: Health Care Domain in Which the Simulation Is AppliedSimulation techniques can be applied across nearly all health care domains. Although much of the attention on simulation has focused on technical and procedural skills applicable in surgery, [11] [20] [21] [22] obstetrics, [23] [24] invasive cardiology, [25] [26] and other related fields, another bastion of simulation has been recreating whole patients for dynamic domains involving high hazard and invasive intervention, such as anesthesia, [27] [28] critical care, [29] [30] and emergency medicine. [31] [32] [33] [34] Immersive techniques can be used in imaging-intensive domains, such as radiology and pathology, and interactive simulations are relevant in the interventional sides of such arenas.[35] In many domains, simulation techniques have been useful for addressing nontechnical skills and professionalism issues, such as communicating with patients and coworkers, or addressing issues such as ethics or end-of-life care.Dimension 5: Health Care Disciplines of Personnel Participating in the SimulationSimulation is applicable to all disciplines of health care, not only to physicians. In anesthesiology, simulation has been applied to anesthesiologists, Certified Registered Nurse Anesthetists, and anesthesia technicians. Simulation is not limited to clinical personnel. It also may be directed at managers, executives, hospital trustees, regulators, and legislators. For these groups, simulation can convey the complexities of clinical work, and it can be used to exercise and probe the organizational practices of clinical institutions at multiple levels.Dimension 6: Type of Knowledge, Skill, Attitudes, or Behavior Addressed in SimulationSimulations can be used to help learners acquire new knowledge and to understand conceptual relations and dynamics better. Today physiologic simulations allow students to watch cardiovascular and respiratory functions unfold over time and respond to interventions—in essence making textbooks, diagrams, and graphs “come alive.” The next step on the spectrum is acquisition of skills to accompany knowledge. Some skills follow immediately from conceptual knowledge (e.g., cardiac auscultation), whereas others involve intricate and complex psychomotor activities (e.g., catheter placement or basic surgical skills). Isolated skills must be assembled into a new layer of clinical practices. An understanding of the concepts of general surgery cannot be combined only with basic techniques of dissecting and suturing or manipulation of instruments to create a capable laparoscopic surgeon. Basic skills must be integrated into actual clinical techniques, a process for which simulation may have considerable power, especially because it can readily provide experience with even uncommon anatomic or clinical presentations. In the current health care system, for most invasive procedures, novices at a task typically first perform the task on a real patient,albeit under some degree of supervision. They climb the learning curve, working on patients with varying levels of guidance. Simulation offers the possibility of having novices practice extensively before they begin to work on real patients as supervised “apprentices.”In this way and others, simulation is applicable to clinicians throughout their careers to support lifelong learning. It can be used to refresh skills for procedures that are not performed often. Knowledge, skills, and practices honed as individuals must be linked into effective teamwork in diverse clinical teams, which must operate safely in work units and larger organizations. [36] [37] [38] Perpetual rehearsal of responses to challenging events is needed because the team or organization must be practiced in handling them as a coherent unit.Dimension 7: Age of the Patient Being SimulatedSimulation is applicable to nearly every type and age of patient literally from “cradle to grave.” Simulation may be particularly useful for pediatric patients and clinical activities because neonates and infants have smaller physiologic reserves than most adults. [40] [41] Fully interactive neonatal and pediatric patient simulators are now available. Simulation also addresses issues of the elderly and end-of-life issues for every age.Dimension 8: Technology Applicable or Required for SimulationsTo accomplish these goals, various technologies (including no technology) are relevant for simulation. Verbal simulations (“what if” discussions), paper and pencil exercises, and experiences with standardized patient actors [41] [42] [43] require no technology, but can effectively evoke or recreate challenging clinical situations. Similarly, very low technology—even pieces of fruit or simple dolls—can be used for training in some manual tasks. Certain aspects of complex tasks and experiences can be recreated successfully with little technology. Some education and training on teamwork can be accomplished with role playing, analysis of videos, or drills with simple mannequins.[44]Ultimately, learning and practicing complex manual skills (e.g., surgery, cardiac catheterization) or practicing the dynamic management of life-threatening clinical situations that include risky or noxious interventions (e.g., intubation or defibrillation) can only be fully accomplished using either animals—which for reasons of cost and issues of animal rights is becoming very difficult—or a technologic means to recreate the patient and the clinical environment. The different types of simulation technologies relevant to anesthesiology are discussed later in this chapter.Dimension 9: Site of Simulation ParticipationSome types of simulation—those that use videos, computer programs, or the Web—can be conducted in the privacy of the learner's home or office using his or her own equipment. More advanced screen-based simulators might need more powerful computer facilities available in a medical library or learning center. Part-task trainers and virtual reality simulators are usually fielded in a dedicated skills laboratory. Mannequin-based simulation also can be used in a skills laboratory, although the more complex recreations of actual clinical tasks require either a dedicated patient simulation center with fully equipped replicas of clinical spaces or the ability to bring the simulator into an actual work setting (in-situ simulation). There are advantages and disadvantages to doing clinical simulations in situ versus in a dedicated center. Using the actual site allows training of the entire unit with all its personnel, procedures, and equipment. There would at best be limited availability of actual clinical sites, and the simulation activity may distract from real patient care work. The dedicated simulation center is a more controlled and available environment, allowing more comprehensive recording of sessions, and imposing no distraction on real activities. For large-scale simulations (e.g., disaster drills), the entire organization becomes the site of training.Video conferencing and advanced networking may allow even advanced types of simulation to be conducted remotely (see dimension 10 ). The collaborative use of virtual reality surgical simulators in real time already has been shown, even with locations that are separated by thousands of miles (see later for more on Site of Simulator).Dimension 10: Extent of Direct Participation in SimulationMost simulations—even screen-based simulators or part-task trainers—were initially envisioned as highly interactive activities with significant direct “on-site” hands-on participation. Not all learning requires direct participation, however. Some learning can occur merely by viewing a simulation involving others, as one can readily imagine being in the shoes of the participants. A further step is to involve the remote viewers either in the simulation itself or in debriefings about what transpired. Several centers have been usingvideoconferencing to conduct simulation-based exercises, including morbidity and mortality conferences.[45] Because the simulator can be paused, restarted, or otherwise controlled, the remote audience can readily obtain more information from the on-site participants, debate the proper course of action, and discuss with those in the simulator how best to proceed.Dimension 11: Feedback Method Accompanying SimulationSimilar to real life, one can learn a great deal just from simulation experiences themselves, without any additional feedback. For many simulations, specific feedback is provided to maximize learning. On screen-based simulators or virtual reality systems, the simulator itself can provide feedback about the participant's actions or decisions,[46] particularly for manual tasks where clear metrics of performance are readily delineated. [47] [48] More commonly, human instructors provide feedback. This can be as simple as having the instructor review records of previous sessions that the learner has completed alone. For many target populations and applications, an instructor provides real-time guidance and feedback to participants while the simulation is going on. The ability to start, pause, and restart the simulation can be valuable. For the most complex uses of simulation, especially when training experienced personnel, the typical form of feedback is a detailed postsimulation debriefing session, often using audio-video recordings of the scenario. Waiting until after the scenario is finished allows experienced personnel to apply their collective skills without interruption, and then allows them to see and discuss the advantages and disadvantages of their behaviors, decisions, and actions.Dimension 12: Organizational, Professional, and Societal Embedding of SimulationAnother important dimension is the degree to which the simulation application is embedded into an organization or industry.[19] Being highly embedded may mean that the simulation is a formal requirement of the institution or is mandated by the governmental regulator. Another aspect of embedding would be that—for early learners—the initial (steep) part of the learning curve would be required to occur in a simulation setting before the learners are allowed to work on real patients under supervision. Also, complete embedding of simulation into the workplace would mean that simulation training is a normal part of the work schedule, rather than being an “add-on” activity attended in the “spare time” of clinicians. Conceptual Issues about Patient Simulation“The key is the programme, not the hardware,” was a truth about simulation learned early in aviation. Using simulators in a goal-oriented way is equally or more about the conceptual aspects of the technique than it is about the technology of the simulation devices. An understanding of the conceptual and theoretical aspects of the use of simulation techniques can be helpful for determining the right applications of the technique and the important matchups that must be made in the design and conduct of simulation exercises to get the best results. When used most effectively, simulation can be—to borrow a line from the band U2—“even better than the real thing.”[20] The concepts discussed in this section concern the nature of “realism” and “reality” as they apply to simulation, and the way that these issues relate to the goals of simulation endeavors to generate a complex social undertaking. The ideas and concepts presented here are largely contributed by Peter Dieckmann and his adaptation of broader psychological concepts to simulation in medicine.Reality and Realism of SimulationUnless we are dreaming about it or we are an unrepentant solipsist, a simulation exercise is always “real” (it is actually happening), but it may or may not be a “realistic” replication of the reality that is the target of the exercise. Realism addresses the question of how closely a replication of a situation resembles the target. A key distinction is between a simulator (a device) and a simulation (the exercise in which the device is used).A simulator could be indistinguishable from a real human being (e.g., a standardized patient actor) and yet be used in an implausible and useless fashion. Conversely, certain kinds of realism (see later) can be evoked by simulation exercises that use very simple simulators or even no simulator at all (as in role-playing when the participants in a sense “become the simulator”). Merely creating a realistic simulation does not guarantee that it would have any meaning or utility (e.g., learning). [21] [22] A closely related aspect concerns the question of relevance and the social character of simulation.Three Distinct Dimensions for Simulation RealismA lot has been written about simulator and simulation realism using a variety of terms and concepts that are subtly different and often overlapping. These include physical fidelity (the device replicates physical aspects of the human body), environmental fidelity (the simulation room looks like an operating room), equipment fidelity (the clinical equipment works like or is the real thing), and psychological fidelity[23] (the simulationevokes behaviors similar to the real situation), and a variety of forms of validity, such as face validity (“looks and feels” real to participants), content validity (the exercise covers content relevant to the target situation), construct validity (the simulation can replicate performance or behavior according to predefined constructs about work in real situations), and predictive validity (performance during a simulation exercise predicts performance in an analogous real situation). [24] [25]The results of studies trying to investigate roots and effects of simulation “realism” are not conclusive partly because they may each concentrate on a different aspect of this complex whole. It is simply not true that maximum “realism” is either needed or desired for every type of simulation endeavor. For some applications with some target populations, it can be highly advantageous to reduce the realism to heighten the learning experience.[26]In 2007, we published an article attempting to clarify some issues about realism, reality, relevance, and the purposes of conducting simulations.[21] We applied the model of thinking about reality by the German psychologist Laucken to the realism of simulation.[21] Laucken described three modes of thinking—physical, semantical, and phenomenal, which have been renamed physical, conceptual, and emotional and experiential modes by colleagues in Boston.[27]Physical ModeThe physical mode concerns aspects of the simulation that can be measured in fundamental physical and chemical terms and dimensions (e.g., centimeters, grams, and seconds). The weight of the mannequin, the force generated during chest compressions, and the duration of a scenario all are physical aspects of the simulation reality. Existing simulator mannequins have many “unrealistic” physical elements despite their roughly human shape: they are made of plastic, not flesh and bone; they may have unusual mechanical noises detectable during auscultation of the chest; the “skin” does not change color. Some physical properties are not readily detectable and can be manipulated. Some clinical equipment used in mannequin-based simulation is fully functional and physically identical to the “real thing,” although in some cases functional physical limitations may have been introduced for convenience or for safety.[24] Labeled syringes may contain only water instead of opioids, or a real defibrillator may have been modified so that it does not actually deliver a shock (one manufacturer sells a “Hollywood defibrillator”). That certain physical properties and functions have been altered is not usually apparent to participants, at least without special briefings or labels.Semantical ModeThe semantical mode of thinking concerns concepts and their relationships. Within the semantical mode, a simulation of hemorrhage might be described in conceptual terms as “bleeding” of flow rate X beginning at time Y occurring at site Z and associated with a blood pressure of B that is a decrease from the prior value of A. In this mode of thinking, it is irrelevant how the information is transmitted or represented. The same pieces of information could be represented using a vital signs monitor, a verbal description, or the tactile perception of decreasingly palpable pulses. The semantical recoding of physical objects is the cornerstone of simulation. It allows the simulation exercise to represent a real situation, and it allows water-filled syringes to be treated as if they contain a drug.Phenomenal ModeThe phenomenal mode deals with the “experience,” including emotions and beliefs triggered by the situation. For many purposes, providing high phenomenal realism is the key goal, and the physical realism and semantic realism are merely means to this end.Relevance versus RealityA naive view of simulation would suggest that greater realism in all modes would lead to better achievement of the goals of simulation; this view has been criticized repeatedly. [23] [28] [29] Simulation is a complex social endeavor, conducted with different target populations for different purposes. The relevance of a simulation exercise concerns the match between the characteristics of the exercise and the reasons for which the exercise is conducted. Different elements of realism are emphasized or sacrificed to maximize the relevance of a simulation exercise. When training on invasive procedures, it is typical to forgo phenomenal realism and emphasize physical and semantic realism so that psychomotor skills can be the focus. Semantic realism may be sacrificed, especially to help early learners. Situations that might become lethal (e.g., trigger a cardiac arrest) very quickly may be slowed down so that inexperienced clinicians can try to think their way out of the problem. If such a situation were allowed to evolve at its normal speed, it would。