Virtual reality in anesthesia "simulation".

Simulation in anesthesia is a field that has revolutionized the teaching outlook. The uncommon grave situations are no more unseen. The ability of these devices to test and give a taste of nerves to an anesthetist is actually preparing him for a safe future management when the need be. The role of simulation in testing a new device for its likely success in clinical world can be foreseen. Mastering a difficult skill no longer subjects a patient to danger. These advanced methods not only see how anesthetist responds to environment, but also how the OT environment reacts to him. The review highlights how technology will help us become technically sound clinicians for tomorrow.

INTRODUCTION

The idea of simulation is not a recent one but it has changed forms to become a great asset in medicine today. The origin of simulation dates back to the medieval times when soldiers learnt the art of swordsmanship on dummy soldiers.[1] Today the simulator technology has gone past leaps and bounds from a dead dummy nonresponding soldier to a patient who responds in a naturally expected way to drugs and maneuvers. In other words “soldiers who never witnessed war can become top swordsmen, thanks to simulation.” Societies such as Society for Simulation in Healthcare and Society in Europe for Simulation Applied to Medicine have been constantly striving to promote knowledge and use of simulation in healthcare. The recognition by the scientific world for the need of simulation in anaesthesia is highlighted by the fact that it has now been added as a mandatory training course for-continuing professional practice requirements for board-certified anesthesiologists by the American board of anesthesiologists for maintenance of certification in anesthesiology.[2] Simulators have become an integral part of the residency training program of our institute and hence has helped in writing this review.

DEFINITION AND ASPECTS OF SIMULATION

Simulation can be defined as “a person, device, or set of conditions which attempts to present evaluation problems authentically. The student or trainee is required to respond to the problems as he or she would under natural circumstances. Frequently the trainee receives performance feedback as if he or she were in the real situation.”[3] The equipment used for the above condition is known as a simulator. They can range from simple paper drawings to an operative room environment. The nonelectronic devices have also been referred to as training devices in the literature.[45] Since the targets set for a simulator vary from a simple procedure to an actual scenario, it becomes difficult to classify them into system incorporation all possible available simulators. The basis of classification can vary on the basis used as a divide Hardware based

Device or skill based – a simple board-based simulation used to teach how laryngeal and pharyngeal axis needs to be aligned for intubation during laryngoscopy.

Patient based – a virtual patient who responds to laryngoscopy and drugs given to obtund the laryngoscopic responses.

Environment based – a virtual operating room with fire in breathing circuit.

User interaction-, physiology-, and use Based

Cumin et al.[5] described a framework based upon three simulator attributes: How the user interacts with the simulator; its simulated physiology; and its use.

User interaction

Screen-based: This simulator runs on a computer and has no additional hardware.

Hardware based: People interact with it as though interacting with a real patient through keyboard or mouse.

Virtual reality based: They simulate the physical environment via specialized equipment like headsets and haptic devices which provide physical feedback to the user.

Physiology

It looks into the normal physiology, pathological process and response to the intervention. Attributes of such simulation can have

no physiology;

script-controlled: Commands (a script) specifying physiological responses;

Model-controlled: Depend upon mathematical models to determine the physiological responses to various interventions.

Usefulness for teaching

Simulator can impart knowledge or cognitive skills or psychomotor skills.

For example Sim One (hardware; script; psychomotor and cognitive).

Simulator response based

Open loop – they include simple simulator, most often nonelectronic that are used to teach a particular skill or a procedure, where simulator dose not respond back to provide the effectiveness of the trainees action. Like a mannequin used for teaching of emergency cricothyrotomy.

Closed loop – they are advanced simulators that can gauge the effectiveness of the trainees’ action in terms of their responsiveness to solution of the problem. In other words, they provide feedback to the learner that how appropriate was the action by responding in a naturally expected manner.

TARGETS OF SIMULATION

The goals set to achieve by simulation all target to make learners into more confident and learned clinicians. The first simulator in anesthesia “SIM ONE” in 1960s started off with a simple goal to teach about intubation responses and response to succinylcholine in form of fasciculations.[6] Various areas in the field of anesthesia where simulators have been widely used are summarized in Table 1. Over these years, technology has seen advancement and refined the human interaction with the now day simulators which can achieve.

Table 1

Various uses of simulator-based training in anesthesia and intensive care

Teaching skills

Starting off with one of the simplest procedure of intravenous cannulation for an intern[78] to a challenging surgery[910] nowadays can be learnt without experimenting on a patient. The literature is replete with studies proving that how learning on simulators prepares the intern to become better resident.[11] A very useful aspect of simulator-based teaching in anaesthesia is teaching of decision making to our residents. A new resident conventionally works in a fully supervised environment but in the simulator-based training he is the one who decides what to do next! This fact was highlighted by a study by Park et al. where novice residents after 6 weeks of such simulator-based training on comparison with conventional learning-based residency showed much better skills in management of critical events.[12] Other unique aspect of simulator-based training is preparing the residents for the unforeseen rare events. Difficult airway can be a catastrophe and even the most experienced may fail to respond appropriately to situation. Kuduvalli et al. in their study found that the ability to deal with cannot intubate-cannot ventilate situation significantly improved in residents primed with simulator technology and they recommended 6 monthly review of the simulation training exercise.[13] Teaching residents an emergency skill is important but teaching when and how to use it is even more important. The conventional teaching may arm the resident with hundreds of safety protocols but when the real catastrophe occurs even the most experienced ones may give up to their nerves. Again the virtual reality-based simulation comes to forefront in this arena and the very fact was highlighted by the study by Rosenstock et al., where they showed that how learned skills to handle difficult airway on paper turns out to be a completely different aspect when it comes to an actual situation.[14] One must not go all out in favor of the virtual reality as not only the literature supports positive outcomes of simulator-based training there are examples cited that show no advantage to conventional teaching practices. Study by Borges et al. demonstrated no beneficial outcome in teaching skilled anesthetists the ASA algorithm for difficult airway using simulation sessions over the conventionally learned groups. They noted major deviations in following ASA algorithm, time for cricothyrotomy and time to achieve ventilation in CVCI situation remained same.[15]

Clinical assessment

A skill learnt has to be tested on realistic grounds. Medicine is a field where ethical concerns govern our learning limitations. A novice student cannot be expected to be tested on a patient as his inadequately learnt skill can cost a life. Yet again a logical answer will be to use simulation to test the skill. In fact over the last years many countries such as Israel and Denmark have made it mandatory to pass a simulation test for anaesthesia certification.[16] By creating virtual situations the applicability of the current guidelines can be put to test and can be figured out how well the clinician follows what was supposed to be done. The Japanese society of anesthesiologist's holds regular meetings to impart and test knowledge on ASA algorithm for difficult airway using simulation as the basis of assessment.[17] The advantage of simulation-based tests is that they can be charted out according to the level of trainee. A situation may suit more for a third year resident than a first year, keeping this in mind the person planning the simulation can increase the level of expertise needed to bail out of situation. A lot of studies have looked upon this aspect of segregation testing according to different levels of trainees and have determined their readiness for the next training level.[181920] In our scenario, we can test our residents at the end of each year for the adequacy of learnt skill before the responsibilities of next year of residency are put on them. The conventional method of our examination inform of question papers was discredited by Zausig et al. when they compared the ability to answer the questionnaire on rapid sequence intubation versus the simulation of actual process. They found many flaws in the skill performance that were simply missed out by the conventional questionnaire.[21] One must remember that the actual aim of residency training in not only to provide appropriate and adequate knowledge, but also to equip the resident with clinical skill that can only be tested by performing the procedure only.

Testing a new equipment

The National Patient Safety Agency had issued a Patient Safety Alert with the aim of eliminating Luer connectors from equipment for lumbar puncture and subarachnoid injections by 1 April 2011, and from all neuraxial and regional anaesthesia equipment by 2013. This would prevent normal syringes to be connected to the intrathecal delivery system and avoid wrong agents and wrong doses to be injected. Cook and Payne et al. conducted a simulation-based study where trained anesthetists were to perform neuraxial procedure and rate the new equipment. The result was significantly low scores to the newer nonluer lock equipment due to lack of familiarity to the equipment. Thus, they concluded that prior to widespread replacement of conventional luer lock system a formal training should be carried out.[22] A product before being launched into market can be evaluated on simulation-based patient and clinicians perspectives and thus improves safety and utility of the product.

Practicability of a new guideline: Testing and formulation

It is important not only to test how well we understand a guideline but much more important to test how well the guideline understands us. The years of revision of the cardiopulmonary resuscitation guidelines by American Heart Association have seen its way to find more practical applicability at the time of need. Once a guideline framework is laid down it comes to a stage of testing for its practical flaws. The CPR guidelines we see have undergone many such tests prior to introduction into the clinical world. A review by Seethla et al. describes ways to improve CPR guidelines by use of simulation testing of the guidelines.[23] A need for review of certification guideline for CPR in obstetric population was concluded by simulation-based study by Lipman et al.[24] The use of various airway devices in CPR 2010 guidelines derives evidence form a simulation-based study on management of airway in cardiac arrest by Ocker et al.[2526] The official paper by American Society of Anesthesiology in guidelines for management of difficult airway quotes at least 19 references of simulation-based studies from which it derives its evidence.[27] The contribution of simulation-based studies in shaping our guidelines is bound to go up in the future.

Team work

The literature can write a million words but cannot actually incorporate co-ordination among a clinical team. An anesthesiologist at the time of crisis needs a help hand, which understands what to do next. A published review focusing on how to improve team effectivenessrecognized many lacunae in the conventional literature where it fails to enhance team effort in clinical fields.[28] Simulation-based training has shown to bring down time of performing a clinical task as a group in emergency settings.[2930] A simulated exercise cannot only improve communication skills in urgent situations but also is capable of deciding an appropriate team leader capable of enhancing the co-ordination.

Eliminating latent errors in practice

Once a resident learns a practice, he tends to develop on it. Practice may have minor flaws, which may be routinely missed out. An observed simulation on noncritical cases may bring out latent errors that a resident makes while handling routine cases. This could be a simple failure to maintain sterility while connecting intra venous line to an interaction flaw with anaesthesia machine monitor. Howard-Quijano et al. in their study observed that despite adequate knowledge about the procedures in pediatric resuscitation residents suffered actual performance gaps in terms of drug doses and diagnosing the cause of clinical condition.[31] A simulation study proved inadequacy of knowledge about rescue in pediatric sedation among residents. The authors proved that seemingly trivial sedation procedure is completely unsafe if the resident is unaware what to do if sedation becomes more than need.[32] Mudumbai et al. showed inability of residents to respond adequately in event of oxygen and nitrous oxide pipeline switch using a simulation-based scenario.[33]

Perfection of skills

A recent addition to the armamentarium of managing difficult is the video-laryngoscopes. With few available opportunities to use it in live patients the learning curve and hence their use is delayed. A proper hand eye co-ordination is often missed in their initial uses. Lim et al. in their study concluded that anesthesiologist once versed with video technology actually find it easier to use them over conventional scopes in difficult airway situations.[34] Most of the workshops held all over world on difficult airway use mannequins to enhance the fiber optic skills.

SIMULATION PROCESS

A simulation session takes place in three stages[35] – briefing, simulation exercise, and de-briefing. During the briefing the leader introduces the clinical exercise and familiarizes the trainees with the manikins and the operation room set up. The actual exercise takes place in this operation room and a few events are programmed and the trainee responds to the clinical situation to the best of his capability. During the de briefing session, the videotaped exercise is shown to the candidate along with the other team members. The trainee's performance is critically analyzed and constructively criticized.[36]

SIMULATORS – EXPENSIVE PLAY TOYS

The cost of simulation is the main concern in their routine implementation. Especially in developing countries this economic barrier is huge. The shocking figures of 2010 of GDP spent on healthcare tell the tale. For example India spent a mere of 0.36% (world's lowest) compared to the USA 17.3%. Can we really afford to deviate from conventional training methods toward modern technology, which may cost our country a fortune? The figures do not end here. A recent review on affordable simulator with patient based simulation estimated the minimum cost to be around 40000$[US].[37] This is a basic pediatric intubation simulation, the same art is taught to our residents at much practically affordable prices. Harlow et al. analyzed that the average cost of a fully functional nursing laboratory turned out to be around 246422$.[38] For a freestanding center cost of setting up a medical simulator was estimated to be 200000 to 1.6 million USD and a maintenance cost turned out to be around 15000 USD per year.[394041] These values are certainly financially out of reach for a small center in a developing country. The west has always come up with technologies and newer medications that have tried to change the way classical medicine is practiced specially in the developing countries. The past two decades have shown us that many such highly recommended technologies and medications are withdrawn in due course of time. Cox 2 inhibitors and the advantages of HRT are the classical examples of these. Lately BIS monitoring is being pushed in as the latest technology marvel in anesthesia monitoring. Simulators too fall into this group of innovations.

SIMULATORS – HOW CLOSE TO REALITY?

The complexity of human body is beyond imitation by technology. No matter how close we get we still cannot predict in unusual ways human body may respond. Building a car or a machine is much different than the goals we setup to build a simulator. It is not necessary that a technique learnt on simulation may work in a real life crisis. This limitation is demonstrated by a study by Sayre et al. They studied emergency medical technicians (EMT) who learned intubation techniques on anesthesia mannequins. After they had successfully intubated the mannequins 10 times, they were allowed to intubate patients in the field, where their proficiency turned out to be only 53%.[42] Another aspect where simulators may fail to surpass the conventional ways is that the trainee at back of mind always knows that he is in simulation and thus the nerve and agitation as in real life would not affect his choices or some may even not take the situation to be as gravely as it would have been in the real life.[43] There are potential dangers in being trained by simulators, one may learn a skill on simulator that may respond unlike a patient and thus the trainee has learnt a wrong skill and is now under false sense of security to manage the clinical scenario involved.[44]

FUTURE OF SIMULATORS IN ANESTHESIA

Over the last 5 year, the anesthesiology residency programs over the world have seen a major revolution in technology. Advantages of simulator-based training as compared to conventional teaching aids have been summarized in Table 2. Almost half the residency programs in USA have incorporated simulator-based training into their curriculum. An area of residency that always suffered was interdepartmental learning, as most simulation centers have single simulation unit capable of carrying out simulations for most of the specialties. It can be made sure at the beginning of residency an anesthesiology resident actually learns basic skills of other specialties that he will use in daily practice but otherwise would have not acquired. For example basic microbiological training may in long run help to prevent operative room infections. Learning ophthalmological fundus examination may become useful in the intensive care setting. Keeping in mind that most of simulation centers around the world are actually run by anesthesiology departments, it becomes even more imperative for us to adopt them into our own residency programs. Most of simulators are built by engineers and used by clinicians, which may have been an initial hurdle in development of highly realistic simulators. But with the promoting of biomedical engineering as a separate branch of medical specialization this obstacle no longer exists. The simulators will now be built by people who are actually doctors and thus will be more equipped medically. The downside of simulators at the moment is the cost, but with increasing number of companies taking up to manufacturing simulators. The competition is liable to cut down the costs in the near future.

Table 2

Advantages of simulator-based training compared to conventional teaching tools