IAccid Emerg Med 1999;16:395-399

REVIEW

Use of human patient simulation to teachemergency medicine trainees advanced airwayskills

Craig Ellis, Geoff Hughes

Advanced airway management skills are essen-tial for emergency physicians and are arequired competency for trainees sitting for theFellowship of the Australasian College forEmergency Medicine. The technical psycho-motor skills are best taught under supervisionin the operating theatre or the emergencydepartment, but the decision making andorganisational skills needed to apply themsafely and manage their complications areharder to teach.The use ofhuman patient simulators, which

model human physiology and the effects ofaging, illness and drugs, is now a commonmethod of teaching crisis management toanaesthetic trainees. It is our view that this is anideal environment to teach the integration ofthe basic technical skills of airway manage-ment, with the goal of trying to manage airwayproblems in the emergency department.

This paper describes a one day advancedairway course we developed and ran, primarilyfor emergency medicine trainees. It includedlectures and skill stations centred on a humanpatient simulator.

Wellington Hospital,Wellington, NewZealandC EllisG Hughes

Correspondence to:Dr G Hughes, Director ofEmergency Medicine,Emergency Department,Wellington Hospital, PrivateBag 7902, Riddiford Street,Wellington, New Zealand.

Accepted 29 May 1999

Patient simulatonPatient simulators have evolved over the last 20years from simple manikins for teachingcardiopulmonary resuscitation to more com-

plex advanced cardiac life support (ACLS)manikins, which can be defibrillated and intu-bated. A recent evolutionary step from theseACLS simulators has been the development ofphysiological modelling simulators. These are

human shaped computerised manikins thatcan be used for complex advanced life supportskills training. Importantly, they simulatenormal human physiology. They breath withchest wall movement, have a pulse, breath andheart sounds, produce urine, and can be moni-tored for variables such as electrocardiography,end tidal carbon dioxide, oxygen saturation,heart rate, and blood pressure. The physiologi-cal model can be adjusted to reflect diseasestates, respond appropriately to administereddrugs, and alter physical findings, as well as

monitored parameters.The principle of realistic simulation of emer-

gency situations has evolved from the trainingof airline pilots. For the last 25 years flight

simulation has been a required standard forteaching commercial pilots, and all active pilotsare required to attend refresher simulatorassessments. By repeatedly being exposed toaccurate simulation of real situations andemergencies, it enables the pilot to respondappropriately when the real situation arises.The same is true ofhuman simulation. Duringsimulation steps are taken to ensure that thingsare as realistic as possible-ambulance hando-ver, similar physical environment and noise,hysterical relatives, equipment failures orlosses, losing staff to other emergencies, etc.Anecdotally it seems the greater the fidelity ofthe simulator, the more the participants are"lost" within the simulation.Thus they allow trainees to experience and

manage crises (some extremely rare) in anenvironment where no patient is at risk andmistakes can be reviewed. The simulation canalso be video recorded and later used in adebriefing session. Video review of a perform-ance can be a personally uncomfortableexperience, but it is rated as a positiveexperience by participants in crisis manage-ment and airway courses.'2

Patient simulators have been embraced bythe anaesthetic community."4 A group fromStanford University did much of the originalwork on the development of anaesthetic simu-lators and their application to anaesthetic edu-cation. They developed the original anaestheticcrisis resource management course,2 whichevolved from the cockpit resource manage-ment course developed by the airline industry.It uses simulated anaesthetic crises, combinedwith instruction in crisis management and acomprehensive debriefing of the video tapedsimulations, to teach crisis management skillsto anaesthetists.

In the Australasian centres that have simula-tors (Wellington, Sydney, Melbourne, Perth),they are used extensively for teaching crisismanagement to anaesthetic trainees and forcontinuing medical education for consultants.There is little published about their use outsideof anaesthesia, although their use in teachingemergency medicine is increasing.The Wellington simulator, a METI-HPS

(figs 1 and 2), is one oftwo commercially avail-able models of human patient simulators, the

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Ellis, Hughes

Figure 1 Wellington simulator: viewfrom above. Traineeswith an instructor.

other being produced by Eagle Technology. Itutilises a modified Windows platform, pro-grammed in Turbo-C. It runs on a script con-

trolled, model driven basis.Script controlled simulation has previously

been used in most computer simulations, a

process where the computer gives a certainresponse, in reaction to a certain event. To havemaximal realism the script needs to becomplex, and to allow for other variables. Forexample it is insufficient to plan for the cardio-vascular responses to a certain dose of an

induction agent. The program must allow forpossible interactions with other systems or

other drugs. This complexity limits the use ofscripting; it is simply not possible to script forevery permutation of variables.To overcome these limitations, the METI-

HPS uses a combination of scripting andmathematical physiological modelling. Thecomputer runs complex models of the mainphysiological systems-for example, cardiovas-cular, respiratory, renal. It integrates the differ-ent system models and uses the knowledge ofhow pathological states and administereddrugs alter normal physiology to produce aresponse. Overall scenario control can be scriptdriven or modified by an operator. This allowsfor a more dynamic response, allowing forhundreds of variables to be included in theoverall simulator response.5

Airways managementIn the early management of the criticallyinjured and ill patient the primary concern isairway security. The gold standard is endotra-cheal intubation, using rapid sequence induc-tion (RSI): the use of sedative agents andneuromuscular blocking agents to facilitate

intubation. Traditionally this has been done byanaesthetists. However with the evolution ofemergency medicine specialists and extendedconsultant cover in the emergency department,it is now an obligatory skill for emergency phy-sicians. In the United States the majority ofemergency department intubations are per-formed by emergency physicians.9 Recentstudies demonstrated that emergency depart-ment intubation by emergency medicine physi-cians, is safe with low complication rates. Thefinal report of the National Emergency AirwayRegistry pilot project found 93% of adult (and57% paediatric, 79% if including paediatricemergency physicians) intubations were per-formed by emergency physicians, with aserious complication rate of 3%. It alsodemonstrated that RSI was superior to seda-tion alone, intubation without any sedation, ornasopharyngeal intubation.8 A study by Uni-versity of California Davis Medical Center of610 emergency department intubations wassimilar, with 97% of intubations performed byemergency physicians. They had a success rateof 98.9% and a complication rate of 9.3%,most of which were minor (such as transientdesaturation or hypotension and dental inju-ries). The surgical airway rate was 1.1 %.9These figures compare favourably with anaes-thetists performing intubations in critically illpatients. 1 Another study of 98 emergency resi-dency programmes, found only 7% mandatedanaesthetic involvement during intubations,with 41% not involving anaesthetists in emer-gency department intubations.6The technical skills of intubation can be

learnt by experience in the operating room, butthe protocol of emergency department RSIand the management of complications aremore difficult to learn. There is often areluctance to allow junior trainees to performthe procedure and when things go wrong themost experienced person is obliged to takeover.We believe that realistic patient simulation

provides an opportunity to develop the neces-sary crisis management and organisationalskills to undertake safe emergency departmentRSI intubations. We designed a one day coursefor emergency trainees. We believe this is thefirst of its type in Australasia or the UK.

Advanced airways courseThe course aim was to teach the theoreticaland organisational skills of RSI and themanagement options for critical problems. Italso reviewed the basic technical skills of intu-bation and the use of airway adjuncts.There were 12 participants, working in

groups of six. The participants comprisedseven emergency medicine trainees, one surgi-cal trainee, and two junior anaesthetic seniorhouse officers. There were also two experi-enced paramedics, included to extend the per-spective to pre-hospital airway managementissues and to assess the value of the patientsimulator in teaching pre-hospital emergencymedicine. The faculty consisted of emergencymedicine and anaesthetic consultants, includ-

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Patient simulation to teach advanced airway skills

Figure 2 Wellington simulator: side view to show equipment under manikin.

ing an Australian emergency physician certi-fied as an anaesthetic crisis resource manage-ment instructor.The 10.5 hour programme covered the

theory of RSI and its pharmacology, assess-ment of a difficult airway, management of a

failed intubation (including surgical airways),and the paediatric airway. There was an initialintroductory session to the use of the simula-tor, which was followed by scenario sessions.All participants were sent detailed pre-course

reading.We developed four scenarios. They were

designed to represent common emergencydepartment presentations needing advancedairway skills. The physiological responses foreach scenario were programmed into the simu-lator directly or adapted from existing anaes-

thetic modules. The candidates were given an

"ambulance officer handover" on each patient,and had to gain further information by assess-ing the simulated patient and starting appro-

priate monitoring. All the standard emergency

department physiological variables (electrocar-diography, oxygen saturation, non-invasiveblood pressure, end tidal carbon dioxide) couldbe monitored.

All participants completed scenario 1, as

team leader, which let each control anuneventful RSI. In the remaining scenariosroles were rotated, enabling the participants toeach undertake the role of team leader in oneof the scenarios, and to be involved in theremainder as team members. In scenarios 2-3,the simulation controller had some freedom tomodify the situation as scenarios evolved.These included a fall in blood pressure atinduction, failed intubation, bronchial intuba-tion, an undetected pneumothorax, and a car-diac arrest. The person in the team leader rolewas responsible for the decision and timing ofintubation, the choice of drugs, airway vigi-lance, and coordination of the intubation.* Scenario 1: 25 year old male involved in a

motorcycle accident; isolated head injury;Glasgow coma score 9/15; uncooperativeand aggressive.

* Scenario 2: 68 year old female involved in a

high speed motor vehicle accident; multiple

injuries; haemodynamically unstable; com-promised airway.

* Scenario 3: 18 year old female after a tricyclicoverdose who arrives in rapid pulse produc-ing ventricular tachycardia; deteriorates topulseless ventricular tachycardia.

* Scenario 4: 35 year old male in severe respi-ratory distress; uncertain cause; found to beupper airway foreign body.

Analysis ofthe courseThe response to this course was very positive-the commonest request was for more simulatortime. The main lesson we learned was that thedecision pathways for the complicated sce-narios need to be planned in advance, so thecontroller can respond in a more defined way.During a simulation events can unfold ex-tremely rapidly as decisions are made and cer-tain actions taken. We found that our scriptingof the scenarios was slightly too superficial toallow the controller to be consistent across allcandidates in any given situation. This problemwas minimised due to the underlying model-ling and responses generated by the simulatorthat were consistent across all participants.On this initial pilot course there was no for-

mal assessment of the candidates performanceor comparison between them, although a criti-cal event and error summary, adapted fromone of the anaesthetic simulation modules, wasused. Its role was to identify discussion pointsfor the scenario debriefing rather than as a spe-cific rating tool. The difficulty of assessing per-formance on a simulator is addressed in thediscussion.The commonest clinical errors identified by

observation during the scenarios were:* Prolonged periods of poor oxygenation

before intubation or airway control.* Failure to prepare drugs before the induc-

tion.* Forgetting ACLS algorithms and advanced

trauma life support principles.* Failure to maintain cricoid pressure during

induction.These errors were made by all of the partici-

pants to greater or lesser degrees. There didnot appear to be a difference between special-ties or between scenarios.

Less common errors included:* Failure to consider drug reactions/

anaphylaxis as a cause for rapid deteriora-tion after intubation.

* Administration of neuromuscular blockingagents before team members were ready toproceed.

* Release of in-line immobilisation duringinduction.

* Role confusion with the identified teamleader/"intubator" for each intubation; oth-ers tried to lead. This led to conflict aboutdrugs and timing of their administration.

* Poor airway vigilance after intubation. At-tention was easily distracted from ensuringthe tube and circuit remained secured.Overall the frequency of errors was fairly

constant over all four scenarios. The final sce-nario involving the upper airway foreign bodywas probably the least well performed, with

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398 Ellis, Hughes

Table 1 Bloom's cognitive educational objectives" (with examples relating to RSI)

1. Knowing: Knows basic facts and definitionsFor example, correct dose of suxamethonium

2. Comprehending: Understands significance of basic facts and can interpret written and graphical data, andsummarise/paraphrase that informationFor example, indications and contraindications to use of suxamethonium

3. Applying: Applies information to new situations, can manipulate the information, and predict consequencesFor example, able to use suxamethonium in a real or simulated situation

4. Analysing: Breaks down information into its constituent parts, recognises relationships, and checks for consistency of dataagainst a hypothesisFor example, establishes a cause for hypotension after administration of suxamethonium

5. Synthesising: Draws information together from multiple sources and integrates them, and produces a plan or a hypothesisFor example, responds appropriately to hypotension after suxamethonium

6. Evaluating: Ability to make judgments about the value of ideas, based on internal consistency, external reference, or logicalaccuracyFor example, reflects upon and makes a logical evaluation of the treatment reponse

consistently the longest length oftime to estab-lishment of a definitive airway.From these observations we identified four

lessons.* The importance of application of the of

advanced life support principles to all emer-gency situations (even simulated ones).

* The importance of team work with a clearlyidentified team leader.

* The importance of familiarity with the phar-macokinetics and dynamics of drugs.

* The importance of technique in RSI andairway vigilance.These are all basic and well established con-

cepts. It was a sobering experience for severalparticipants to realise how easily mistakesoccur.The choice of induction and neuromuscular

blocking agents were generally appropriate forthe scenarios presented. Some constantly dis-played the reflex thinking of "thiopentone [thio-pental] and suxamethonium", regardless of theclinical situation, and despite the pharmacologylecture and pre-course reading material. Mostparticipants identified the organisational andprocedural points required for a safe RSI.

DiscussionBloom's cognitive theory of learning identifiessix levels of educational objectives (table 1). lThese levels of learning apply well to clinicalmedical education and the application of thiscognitive model can be applied to help define arole for simulation in the teaching of aspects ofemergency medicine.

In our opinion human patient simulation hastwo discrete roles in teaching emergency medi-cine trainees within this cognitive model. Atlower levels, it can instruct trainees in specificskills, and demonstrate physiological responsesto drugs and illness more dynamically than atextbook description. At higher levels, itprovides the opportunity to learn individualskill integration in dealing with complex prob-lems, within a team environment.

It also has a role in the continuing medicaleducation for emergency medicine specialistsin crisis management.

In addition to its teaching role, the simulatorhelps in the formal assessment of skills andknowledge. Multiple choice questions andessay questions assess only factual knowledge,without the integration of these facts. Methodssuch as the objectively structured clinicalexaminations go some way towards assessing

more complete integration. These are still lim-ited by a lack of reality. A patient simulator canaddress this. In addition to knowledge, itsassessment of the integration, application, andevaluation of that knowledge (Bloom's levels3-6), goes beyond any other current assess-ment procedure. It allows candidates todemonstrate how they integrate knowledge incomplex problems and how they evaluate andincorporate into their everyday practice.There is currently debate in the anaesthetic

literature over what is the best way to assesscrisis management skills using simulators.Assessment of simple technical skills isstraightforward. The assessment of perform-ance in a crisis management simulation re-mains subjective. There are different ways toachieve the same end. The combination of anassessment, which assesses both crisis behav-iours and technical skills, may provide the mostreliable objective measure. The main problemhas been variability between examiners. Devittet al have proposed a system which appears tobe consistent across assessors and to provideexperience level discrimination.'21'

ConclusionIt is our opinion that the use of patient simula-tion is the ideal way to integrate individualskills into the context of managing an emer-gency situation in the emergency department.It provides a dynamic and interesting learningenvironment, which at the same time is safe forpatients and trainees. In the case of RSI it letsthe trainee integrate the practical skills of intu-bation in the environment of an emergencydepartment airway problem.The technology of patient simulators contin-

ues to evolve rapidly and as their degree of fidel-ity increases so does their value as a teachingtool. Work that has already been done in usingsimulation to teach crisis management in anaes-thesia can act as a starting point for developingits further use in emergency medicine.We plan to continue running this course, as

well as developing additional courses for crisismanagement in emergency medicine.

We would like to thank Dr Brian Robinson, Director of theNational Patient Simulator, Wellington Hospital, Wellington,New Zealand and Dr Stephen Priestly, Emergency MedicineProgramme Director, Southern Health Care Network Simula-tion Centre, Melbourne, Australia.

Conflict of interest: none.

Funding: we would like to acknowledge the generous support ofHoechst Marion Roussel, who provided sponsorship for theworkshop.

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TOXBASE 399

1 Kardash K, Tessler MJ. Videotape feedback in teachinglaryngoscopy. Can JAnaesth 1997;44:54-8.

2 Howard S.K, Gaba DM, Fish KJ. Anaesthetic crisis resourcemanagement: teaching anaesthesiologists to handle criticalincidents. Aviat Space Environ Med 1992;63:763.

3 Riley RH, Wilkes DH, Freeman JA. Anaesthetist's attitudesto an anaesthesia simulator. A comparative survey: USAand Australia. Anaesth Intensive Care 1997;25:514-19.

4 Kurrek MM, Fish KJ. Anaesthesia crisis resourse manage-ment training: an intimidating concept, a rewarding experi-ence. Can JAnaesth 1996;43:430-4.

5 Van Meurs WL, Good ML, Lampotang S. Functional anat-omy of full-scale patient simulators. J Clin Monit 1997;13:317-24.

6 Ma O, Bentley B, Debehnke D. Airway managementpractices in emergency medicine residencies. Am J EmergMed 1995;13:501-4.

7 Gallagher EJ, Coffey J, Lombardardi G, et al. Emergencyprocedures important to the training of emergencymedicine residents: who performs them in the emergencydepartment? Acad Emerg Med 1995;2:630-3.

8 Walls R, Vissers R, Sagarin M, et al. Emergency departmentintubations: final report of the national emergency airwaysregistry pilot project. Jf Accid Emerg Med 1998;15:392(abstract).

9 Sakles JC, Laurin EG, Rantapaa AA, et al. Airwaymanagement in the emergency department: a one yearstudy of 610 tracheal intubation. Ann Emerg Med 1998;31:325-32.

10 Swartz DE, Matthay MA, Cohen NH. Death and othercomplications of emergency airway management in criti-cally ill adults. Anaesthesiology 1995;82:367-76.

11 Gronlund NE. Stating behavioural objectives for classroominstruction. MacMillan, 1970.

12 Devitt JH, Kurrek MM, Cohen MM. Testing the raters:inter-rater reliability of standardised anaesthesia perform-ance. Can JAnaesth 1997;44:924-8.

13 Devitt JH, Kurrek MM, Cohen MM. Testing internal con-sistency and construct validity during evaluation ofperformance in anesthetic patient simulation. Anesth Analg1998;86: 1160-4.

TOXBASE on the internet

A M Good, D N Bateman

TOXBASE, the clinical toxicology database ofthe UK National Poisons Information Service(NPIS), went on-line in 1983 using Viewdatatechnology.' Since then it has provided a 24hour service, access being available at the costof a local telephone call to any registered medi-cal professional within the NHS with aViewdata terminal or personal computer(PC).' There are currently more than 570 reg-istered users who make around 50 000 compu-ter accesses each year.TOXBASE consists of approximately

13 000 substance/product monographs onpharmaceuticals, agricultural and industrialchemicals, household products, toiletries,plants, and venomous animals. Each mono-graph contains information on toxic ingredi-ents, toxicity, features after overdose, and clini-cal management. In addition there is generalinformation on gut decontamination, slangterms for drugs, paediatric poisoning, non-toxic plants, poisoning in pregnancy, labora-tory services for selected centres, and availabil-ity of antidotes for selected toxins.The top 10 substance types that were the

subject of TOXBASE inquiries during 1998were (in decreasing order) paracetamol,codeine/dihydrocodeine, salicylates, ibuprofen,diazepam, zopiclone, petroleum distillates, caf-feine (as a component of compound analge-sics), fluoxetine, and dothiepin. The top threehave held their positions since at least 1995.Inquiries about dothiepin are decreasing andzopiclone increasing.'The six centres of the NPIS also deal with

more than 200 000 telephone inquiries on poi-sonings every year, and this workload has beenincreasing. Many of these inquiries arestraightforward, but the call load preventsrapid access for inquiries about more seriouscases. To address this issue the UK Depart-ments of Health decided to promote the use ofTOXBASE to hospitals and general practition-ers for answering poisons inquiries, particularlythose involving less toxic substances. This will

Scottish PoisonsInformation Bureau,Royal Infirmary NHSTrust, EdinburghEH3 9YWA M GoodD N Bateman

Correspondence to:Dr Bateman, Director, NPIS(Edinburgh) and ConsultantPhysician.

leave the more complicated issues involvingserious poisonings and combinations of drugsfor information staff and doctors.TOXBASE is now available on the internet

(http://www.spib.axl.co.uk/). To use the newTOXBASE a PC with Windows 95, 98, or NTand a frames enabled, Java compliant internetbrowser is required. This will typically beMicrosoft Explorer version 4 (or above) orNetscape version 4 (or above). Access to theinternet via either an NHSnet connection or amodem and access to an internet serviceprovider is also needed. Those already regis-tered for the old Viewdata version have beenkept informed of developments and can usetheir current user name and password to accessthe database. Others, within the NHS, can reg-ister on-line. The existing Viewdata service willcease to operate at the end of 1999.The new internet version ofTOXBASE, with

improved search and printing facilities, shouldlead to increased uptake, particularly in Englandand Wales (most in Scotland and NorthernIreland already use it). The ability to print keydetails on the management of a poisoning willassist in patient care, and promote best practice.It will remove the need for a "routine" call to theNPIS. NPIS centres will be involved in the pro-motion ofTOXBASE in their locality. The newinternet system will also have a feedback facility,which it is hoped will assist in data collection onthe toxicology of unusual poisons and of newdrugs. In this way the information provided onTOXBASE will be updated to reflect UKexperience. Work will then start on a newimproved version of the database, in consulta-tion with UK toxicologists and TOXBASE usergroups. Accident and emergency staff willtherefore have a key role in developing theTOXBASE system for the future.

1 Proudfoot AT, Davidson WSM. A viewdata system for poi-sons information. BMJ 1983;286:1125-7.

2 TOXBASE for poisons. Health Bulletin 1994;52:393.3 Scottish Poisons Information Bureau. Annual report.

Edinburgh: Scottish Poisons Information Bureau, 1998.

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