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Print version ISSN 0034-7094
Rev. Bras. Anestesiol. vol.55 no.2 Campinas Mar./Apr. 2005
Importance of critical events training for anesthesiology residents. Experience with computer simulator*
Importancia del entrenamiento de los practicantes (médicos en ejercicio) en eventos adversos durante la anestesia. Experiencia con el uso del simulador computadorizado
Domingos Dias Cicarelli, TSA, M.D.I; Ricardo Boari Coelho, M.D.II; Fábio Ely Martins Benseñor, M.D.III; Joaquim Edson Vieira, TSA, M.D.IV
ICo-Responsável do CET da Disciplina
de Anestesiologia do HCFMUSP
IIME2 do CET da Disciplina de Anestesiologia do HCFMUSP
IIISupervisor da Unidade de Apoio Cirúrgico do HCFMUSP/Anestesiologista do HCFMUSP/Doutor em Anestesiologia pela FMUSP
IVAnestesiologista do HCFMUSP/Doutor em Medicina pela FMUSP/Professor Colaborador da Disciplina de Clínica Geral da FMUSP
BACKGROUND AND OBJECTIVES: Because of
monitoring and drugs evolution, there has been a decrease in the incidence of
critical events during anesthetic procedures. Despite this low frequency, critical
event training for Anesthesiology residents remains important. This study aimed
at evaluating Anesthesiology residents' critical care skills during computer-simulated
METHODS: Seventeen anesthesiology residents (first and second year) and 5 anesthesiology instructors were evaluated. Using the Anesthesia Simulator Consultant (2.0 - 1995/Anesoft) simulations of ventricular fibrillation (VF) and anaphylactic reaction (AR) were performed. After simulation, results of each participant were printed and approaches to solve predetermined critical events were evaluated and scored. Participants have evaluated the simulator by filling out a questionnaire.
RESULTS: There were no significant differences in means obtained by groups, but there has been a trend toward better performance of second year residents and Anesthesiology instructors during VF simulation. There has been a trend toward better performance of Anesthesiology instructors during AR simulation.
CONCLUSIONS: Critical events management training should be the focus during residents and anesthesiologists training. Computer simulation could be a way to carry out such training.
Key words: COMPLICATIONS: allergy, cardiac arrest; TRAINING, Simulators
JUSTIFICATIVA Y OBJETIVOS: Con la decurrencia
de la grande evolución de la monitorización y del arsenal terapéutico disponible
en los últimos años, hubo una reducción en la incidencia de eventos adversos
durante los procedimientos anestésicos. Sin embargo, continua importante el
entrenamiento de los médicos practicantes para este tipo de ocurrencia. El objetivo
de este estudio fue evaluar el desempeño práctico de los médicos practicantes
de Anestesiología en eventos adversos durante una anestesia simulada.
MÉTODO: Fueron evaluados 17 médicos en especialización de primero y segundo años de Anestesiología (ME1 y ME2) y 5 instructores del Centro de Enseñanza y Entrenamiento (CEE) del HCFMUSP (Título Superior en Anestesiología - TSA). Fue utilizado el simulador computadorizado Anesthesia Simulator Consultant (ASC) versión 2.0 - 1995/Anesoft para realización de las simulaciones de los eventos. Los incidentes críticos escogidos fueron fibrilación ventricular (FV) y choque anafiláctico. Después de la realización de la simulación, fueron impresos los resultados de cada participante, evaluados y puntuados las conductas adoptadas para resolver los incidentes críticos pre-determinados. Los participantes evaluaron el simulador a través de un cuestionario para ser respondido.
RESULTADOS: No hubo diferencia estadística entre las medias obtenidas por los grupos, sin embargo, se notó una tendencia de un desempeño mejor de los grupos TSA y ME2 en la simulación de FV. En relación al choque anafiláctico, hubo una tendencia de desempeño mejor del grupo TSA.
CONCLUSIONES: El entrenamiento para el diagnóstico y conductas en eventos adversos debe ser un foco de atención durante el entrenamiento de médicos practicantes y en la actualización de anestesiologistas. El uso del simulador puede ser una de las formas de realizar el entrenamiento en estas situaciones.
Scientific knowledge is estimated to double every 6 years and this has led to marked changes in anesthetic practice in the last 10 years 1.
Data on anesthetic and surgical related mortality show decreased mortality in the last 50 years 2, while at the same time more complex surgical procedures are performed in older patients 3. The concept that provider's skills directly influence quality of service is critical for all aspects of society 3.
Accordingly, one may assume that with more highly skilled anesthesiologists better performances will be observed and lower perioperative complication rates will be recorded 3. Some authors 3, however, believe that the incidence of adverse events is directly related to morbidity factors intrinsic to patients. Other authors 4-6 recommend anesthesiologists updating courses every 6 months to maintain adequate skills and help adaptation to management protocols. Societies adopt written and oral tests to evaluate the theoretical knowledge of anesthesiologists 1,7,8. Practical skills, however, are slightly harder to evaluate 1,9. Some authors believe in the role of simulators for this evaluation, which could complement oral evaluations 10-14.
Simulators had their origin in different activities, such as aircraft and nuclear industries, where operators have to be alert and trained to face critical events. Reproducing such events without any catastrophic consequence is only possible with the aid of a simulator 10,14-18. In this sense, anesthesiology is a medical specialty very similar to the mentioned activities.
Anesthesia simulators may promote skills development and maintenance and provide prompt responses to uncommon, however severe, anesthetic incidents 4,10,11,15,19-21. Due to such characteristics, they may become essential to training and evaluation of individual and teams performance during critical situations 11,13,22-25. One limitation to their wide use is the high cost of high fidelity simulators 5,10,18,24,26-29 and the lack or realism of low fidelity simulators10,18,29,30-32. However, even low fidelity computer simulators such as Anesthesia Simulator Consultant (ASC) 10,33 have been used for training and teaching with positive results 10,31,32.
This study aimed at evaluating the performance of resident anesthesiologists and instructors exposed to simulated critical events 34,35.
After the institution's Ethics Committee approval, participated of this study 22 physicians being 11 first year residents, 6 second year residents and 5 anesthesiology instructors of the Teaching and Training Center and belonging to the clinical team of Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo. Participants answered a questionnaire about in-depth or updating courses they had attended in the last 2 years.
Anesthesia Simulator Consultant (ASC) version 2.0 - 1995 / Anesoft was used for simulations. This simulator has 4 different patients to be anesthetized with 11 possibilities of critical events and physiological and pharmacological models to be used to determine the effects of different interventions.
After selecting the case, the screen displays patient's clinical history and summarized physical evaluation, which are no longer accessed after beginning of simulation. The simulator allows the anesthesiologist to examine the patient, administer drugs, control airways, ventilate and administer fluids by clicking the mouse. It also provides real time display of ECG trace, pulse oximetry, noninvasive and invasive blood pressure, capnogram, blood gases and temperature.
An anesthesia machine with flowmeters, vaporizers and patient's image with the type of airway control (facial mask, tracheal tube) is displayed on the screen (Figure 1).
The menu, on top of the screen, displays options such as Patient (respiratory sounds, neurological status, pulse); Vent (respiratory circuit checking, spontaneous, controlled ventilation); Monitor (TOF, noninvasive and invasive blood pressure); Fluids (crystalloids, colloids); Airway (facial mask adaptation, laryngoscopy); Drugs (opioids, neuromuscular blockers, cardiovascular drugs); Surgeon (preparation, incision, starting cardiac resuscitation).
A simulated anesthesia without intercurrences and lasting approximately 15 minutes was performed to familiarize participants with the simulator. Next, participant performed two anesthesias in which two highly severe, and potentially lethal if not treated, critical events were simulated 36: anaphylactic reaction (AR) and ventricular fibrillation (VF).
To prevent that potential inability in handling mouse and computer could interfere with anesthesiologist's performance, a physician not participating in the study handled the mouse according to participants' verbal orders.
Anaphylactic reaction simulation started with histamine release few minutes after the administration of the first anesthetic gas, causing tachycardia, vasodilation and hypotension. Maximal blood pressure decrease was seen in 3 minutes and was followed by skin erythema. Pulmonary auscultation revealed wheezing 5 minutes after with increased tracheal pressure and capnographic changes. If blood pressure were not corrected, patient would evolve to cardiac arrest. Treatment of hypotension would prevent cardiac arrest, but final treatment would include aggressive fluid administration and 2 to 3 µg.kg-1 epinephrine's.
After the first simulation, a second anesthesia was started, in which participants anesthetized a patient who evolved to cardiac arrest in ventricular fibrillation. Correct diagnosis and resuscitation based on Advanced Cardiac Life Support (ACLS) protocol would assure the success of the treatment. Sinus rhythm returned when 360J defibrillation was performed after an epinephrine dose.
Results of each participant were printed after the simulation to evaluate the approaches adopted to solve critical events. An approach score was developed for each situation: no response to situation (0 points), compensatory intervention defined as physiological correction (5 points), correct treatment defined as final therapy (10 points) 37 (Chart I). ACLS recommendations for cardiac complications were used to evaluate participants' responses. Groups were compared based on their scores.
At the completion of simulation, subjects filled out a questionnaire with their impressions about the simulator.
ANOVA test was used for between group comparisons 40-42.
Table I shows means for all groups in terms of performance during both adverse events.
There were no statistically significant differences among means of the three groups.
Questionnaire evaluation has shown some participants' characteristics. All instructors had 5 to 10 years of clinical practice and had attended the ACLS course within the last 2 years. All second-year residents have attended the ACLS course in the last 6 months. Only two first year residents had attended the course so far and had the best performance during VF simulation.
From the 17 residents participating in the study, 16 had never seen the simulator and considered that its use might be useful for training. Among simulator's positive aspects, all residents stated that training might improve diagnostic skills and approaches for adverse events. Among negative aspects, 59% of participants considered that some situations cannot be simulated and 41% of participants stated that lack of realism is the most negative aspect.
When asked to list complications seen during their residence period, all residents had already experienced at least one cardiac arrest and one bronchospasm during their training. Among 17 residents, only one reported having seen a case of anaphylactic reaction.
Although no statistical difference among scores was observed, there was a clear trend toward better performance with VF in the groups whose participants had already attended the ACLS course (second-year residents and instructors). Among first-year residents, two participants who had attended ACLS had the best performance with VF. This trend agrees with other authors 6 who reported that individuals submitted to specific training perform better as compared to those not trained. Schwid et al. 6 have even stated that knowledge retention after a specific training is higher for a 6-months period, and that trained and untrained individuals have the same performance 2 years after training.
In our institution, the ACLS course is mandatory for second- year residents, aiming at complementing adverse events training 43.
Anaphylactic reaction simulation results have shown a different picture. Since no resident had been submitted to a specific training for this situation, first and second-year resident means were very similar, with a trend to be lower as compared to instructors'. This observation may be explained by the lack of specific training for this situation and by the fact that anaphylactic reaction is a complication increasingly less frequent. Longer practical experience may be the only factor differentiating groups 44. So, practical experience can make the difference for prompt diagnosis and adequate management 6.
In analyzing results, it has to be considered that this simulator has no alarms as compared to anesthesia machines and monitors, which prevents the physician to have his attention shifted to some alteration passively presented by the patient. The simulator imposes to participants an active search for alterations in patients' status. Most participants diagnosed bronchospasm and treated the patient without actively looking for other clinical signs, such as skin erythema. Very often during anesthesia, the anesthesiologist has his attention shifted to some passive clinical sign, such as the mere observation of an erythema, making the diagnosis without logic reasoning or active search to confirm such diagnosis.
In our study, 83% of participants have agreed with the potential usefulness of the simulator for the training of uncommon critical events during anesthesia, and that it is of significant importance for residents training. However, it is necessary to highlight the importance of adequate training supervision to obtain the best possible result 45.
Major criticism to ASC was the difficulty in simulating some situations, as well as the lack of realism. This may be minimized with high fidelity simulators, however their high cost prevents their dissemination and decreases the importance of the positive impact of more realism. In spite of its low fidelity, the simulator used in our study may play an important role in resident physicians training 11, and its cost makes it affordable to any anesthesiologist or Training Center 45.
Training for adverse event diagnosis and management should be a constant focus of attention during resident physicians training and anesthesiologists' updates.
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Submitted for publication August 3, 2004
Accepted for publication December 1, 2004
* Received from CET da Disciplina de Anestesiologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC FMUSP), São Paulo, SP