Medical students and residents are expected to manage several critical events following training, but they are often ill-equipped to do so because of limited clinical experiences in the diagnosis and management of many such conditions. Simulation-based training can be utilized across multiple medical specialties and is essential to every didactic curriculum to model critical events. One of the tenets of healthcare education is to develop teaching and evaluation techniques that allow instructors to gauge a trainee’s performance in settings that reflect clinical practice. Standardized patients (SPs) have often been utilized to assess the history and physical examination skills for medical students and graduate physicians.[1] Unfortunately, critical care events are not easily reproducible, employing SPs. Simulation exercises are an ideal method to recreate complex crisis situations both in the operating room and the critical care environment. Simulation provides a realistic setting in which to conduct high-fidelity scenarios that are realistic, reproducible over time and eliminate threats to patient safety. Due to the recognition of its effectiveness, and healthcare’s continued emphasis on patient safety, simulation has become more prevalent over the last two decades. The Institute of Medicine’s report “To Err is Human” underscored preventable deaths related to medical errors, leading to an increased focus on training modalities that emphasize patient safety and minimize patient harm.[2] Regrettably, the mandatory implementation of clinical duty hour reduction to minimize the fatigue-mediated risk of medical errors has resulted in fewer procedural opportunities.[3] Due to the circumstances mentioned above, simulation provides an excellent opportunity to fill gaps in residency training while minimizing patient risk. 

Simulators were first introduced in the aviation industry in the 1920s so pilots could receive standardized flight training without putting travelers’ lives at risk.[4] The first documented use of healthcare simulation occurred in 1960 when anesthesiologist Peter Safar in the United States and Bjorn Lind in Norway collaborated with Norwegian toy manufacturer Asmund Laerdal to develop Resusci Anne, a full-size mannequin simulator of a pulseless dying victim.[4] Shortly thereafter, Sim One, a computer-controlled mannequin simulator, was developed and utilized primarily to teach endotracheal intubation to anesthesia residents.[5] A decade later, Harvey, another computer-controlled mannequin simulator, with the namesake of a cardiologist renowned for teaching auscultation skills, was born, to aid in the detection of heart murmurs and jugular venous pulsations.[6] The evolutionary next step in healthcare simulation was by Gaba and colleagues, who invented a high-fidelity simulator to study anesthesiologist response time to simulated critical care events in the operating room and to train anesthesia providers in crisis resource management (CRM).[7] These advancements are the foundation for much of today’s healthcare simulation resources.

Adverse clinical events in healthcare commonly occur due to interpersonal communication breakdown, systems errors, and lack of coordination between patient care teams. These realizations have largely lead to the emergence of the CRM field.[8] CRM seeks to manage perilous situations by emphasizing the importance of human factors such as hierarchy, culture, fatigue, and the anticipation of errors in stressful situations. Trainees are taught nontechnical skills, including leadership, communication, task management, and mutual respect for colleagues in a simulated environment.[9] an interprofessional training of interpersonal skills has become imperative in high-risk emergencies, including trauma resuscitation, cardiac arrest, and obstetrical emergencies. Systematic reviews reveal improved overall team effectiveness, coordination, and communication skills following team training.[10] A study of critically ill trauma patients demonstrated that team training improved the efficiency of patient care, defined by reduced times from patient hospital arrival to intubation, radiologic imaging, and operating room entry time.[11]Team training also showed improved outcomes in post-op pediatric surgical cardiac arrest, with a sustained increase in teamwork concepts up to three months following formal training.[12] Another significant result of team training has been the prompt engagement of emergency protocols such as rapid response teams due to the empowerment of clinical staff. Non-intensive care unit nurses were shown to have less anxiety and self-doubt following team training in the activation and utilization of the rapid response team.[13]

Debriefing is essential for the trainee to have a comprehensive and successful encounter in a simulation scenario. Debriefing refers to facilitated reflection in the process of experiential learning. Below are some facilitator guided debriefing tools that educators have described. “Debriefing with good judgment” refers to a three-phase conversational structure consisting of reaction, analysis, and summary. The learner is afforded an initial “reaction” to explore his/her emotional response to the simulation encounter. The analysis phase focuses on what happened during the simulation and why the learner performed the way they did. The summary phase focuses on participants describing what they learned and how this knowledge can be applied to future patient care scenarios.[14] Yet another technique is known as the "GAS" debriefing tool, referring to gather, analyze, and summarize. Gathering allows learners to establish a shared mental model through the reiteration of simulation events. Analysis utilizes self-reflection to dissect the exercise while summary enables participants to assimilate activities and knowledge.[14]

Promoting Excellence and Reflective Learning in Simulation, also known as PEARLS,[15] expands on the three phase method to include an additional description phase to identify major clinical difficulties or key events in the creation of a shared mental model. The Plus-Delta model allows learners to identify positive aspects of simulation under the plus sign and ideas for improvements or changes under the delta. The focus of this activity is not only on patient outcomes but also on the identification of systemic processes that may have contributed to these outcomes. A hybrid debriefing model, TeamGAINS, utilizes elements of team guided self-correction, advocacy-inquiry, and constructivist approaches to the debriefing process.[15] Rather than focus on individual behavior, this model centers on team dynamics and individuals within their respective system.

High fidelity medical simulation should be a close approximation to clinical practice and is most successful when feedback is provided directly during and after the learning experience.[16] With regard to medical education, simulation-based practice has a direct relationship to achieving desired outcomes; more practice yields superior results for trainees. It acts as an excellent complement to patient care grounded in clinical care settings. Simulation should be a part of a comprehensive didactic curriculum, including clinical experience, high yield lectures and question review, problem based learning discussions, journal clubs, and other learning modalities. Trainees should practice with increasing levels of difficulty and the simulator should be adaptable to multiple learning strategies. While the simulator should be able to capture a wide degree of clinical variation, it should be entrenched in a controlled environment. Trainees should be able to experience individualized acquisition of knowledge, and outcomes should be clearly defined and measured by the instructor.

Previously, in the critical care environment, training methods for skills teaching commonly utilized an apprenticeship technique. With this approach, an experienced teacher modeled the correct technique for performing a specific skill and then evaluated the trainee, also known as "see one, do one, teach one." This model is now obsolete. The constructivist learning theory suggests learners gain knowledge based on their personalized experiences. Trainees’ clinical knowledge becomes solidified, and instructors can highlight key learning points during the simulation.  Participants should be made to feel supported and respected, with the instructor encouraging nonjudgmental and open discussion. In addition to constructing and effectively executing simulation scenarios, debriefing is crucial to help learners identify gaps in knowledge, pre-conceived attitudes, and emotional reactivity that can contribute to performance deficiencies. Scaffolding refers to an effective debriefing session that guides learners to think through their actions and reactions, allowing the integration of simulation sessions with previous experiences.[17] Educators must set realistic objectives for each session based on the learners’ level of training. Active participation of trainees and comprehensive feedback is integral to solidify concepts and techniques learned during the simulation.[18] There are some limitations to the implementation of a simulation-based curriculum for trainees. It can be costly and resource-intensive in terms of the availability of staff and equipment.

The Kirkpatrick model for evaluating the effectiveness of training programs can be utilized to ascertain the utility of simulation for learner assessment and ongoing quality improvement (QI) of intensive care practice. Kirkpatrick’s hierarchy serves as a classification tool to communicate the level of learning outcome for each trainee.[19] In its original framework, there are four levels of classification of learning outcomes from educational interventions. Level one is known as reaction and refers to participants’ perception of an educational intervention. Level two is known as learning, and measures participants’ acquisition of skills, knowledge, and change of attitudes in a non-clinical setting. Evaluation during such training should demonstrate knowledge. Level three is behavior, which measures a learner’s behavioral changes, attitudes, skills, and knowledge from the training setting to a professional practice setting. Level four, referred to as results, measures the effect of learners’ skill acquisition through training on patient outcomes.[20]

Meaningful assessment of learners is provided by the Accreditation Council for Graduate Medical Education (ACGME) through entrustable professional activities (EPAs) and milestones.[21] Essential for all medical subspecialties, EPAs are tasks that trainees are expected to perform successfully and independently following graduation. Milestones refer to competency-based developmental outcomes that can be progressively demonstrated from the beginning of residency to graduation.[22] In 2014, milestones for critical care medicine fellowship training were published, utilizing simulation to evaluate the competence of fellows.[22] Nationally, six training programs implemented a high fidelity simulation program to assess trainee’s resuscitation of critically ill patients.[23] Through this program, fellows’ ability to work effectively and successfully with other members of the inter-professional care team was assessed and shown to be superior to fellows trained traditionally. Numerous studies have substantiated successful skill acquisition with simulation. A prospective randomized trial found that residents’ endotracheal intubation performance showed improvement with the use of simulator training as compared to traditional teaching.[24] Also, pulmonary fellows trained with virtual reality bronchoscopy performed with more agility on their first patient bronchoscopy and demonstrated a more rapid progression in clinical bronchoscopy performance compared to traditionally trained fellows.[25]

Psychologist K Anders Ericsson originated deliberate practice (DP), which refers to simulation oriented interventions that create and refine a trainee’s knowledge, skills, and attitudes.[26] The foundation of DP lies within information processing and behavioral theories of skill acquisition and preservation. Successful DP requires highly motivated learners with good concentration, engagement with a well-defined learning objective at an appropriate level of difficulty, and repetitive practice that yields informative feedback from educational sources. Trainees should monitor their learning experiences and subsequently engage in more DP until reaching a mastery standard with advancement to another more complex task. National medical foundations are increasingly turning to simulation for credentialing and continuing education purposes. The American Board of Surgery requires the ‘Fundamentals of Laparoscopic Surgery’ course to be utilized as a summative simulation-based assessment.[15] Also, the American Board of Anesthesiology allows certified healthcare simulation courses to meet its QI maintenance of certification requirements.[27] Thus far, simulation-based assessment is not a part of critical care certification.