In Helsinki University medical school education of basic skills such as intravenous cannulation and airway management are incorporated in the anaesthesia curriculum. After 18 h theoretical teaching and one 3 h intubation training session students have 1 week of practical training in the operating theatre during which they apply their skills to patient care under supervision. Entering an operating theatre to receive training for anaesthesia induction after a very modest skill station practice may easily create stress in the student . Moreover, patient safety aspects limit the type of procedures that can be practised [2–4]. As a result, the level of experience of the students often remains lower than expected by the faculty members .
Full-scale simulation combines a life-size manikin with computer programs allowing the manikin to produce realistic physiological responses to pharmacologic and other interventions . Both part-task training and correct sequence of induction of general anaesthesia can be practised in a safe and realistic environment [7–11]. The exercises can be repeated according to individual needs, and the level and speed of training can be adjusted depending on the development of the speed of skills acquisition . At several institutions, full-scale simulation is used for the assessment of the performance of anaesthesiologists [11,13].
In our country, medical students are allowed to work under supervision as locum tenens in anaesthesia after the fourth study year. The construction of a structured and cost-effective programme for the introduction of students to the work of clinical anaesthesiologists is an educational challenge. Therefore, we designed a study to compare the effectiveness of teaching of general anaesthesia induction using either full-scale simulation or traditional supervised teaching with patients in the operating room. The secondary outcome was to evaluate whether a group of five or six students acquire similar clinical knowledge in a simulator as an individual student does when being allowed to train under supervision by a teacher in the operating theatre during the same time period.
After approval by the Ethics Committee of the Helsinki University hospital, 46 fourth year medical students were enrolled in this study. Informed written consent was obtained from each participant, including consent to video record the test situations. The course began with 1 week of lectures attended by all of the students. After that the students were divided into groups of 6–8 and received 3 h of hands-on instruction on bag–valve mask ventilation and endotracheal intubation with an advanced life support manikin. Before their practical week in the operating theatre, each student was randomly assigned to one of two study groups: simulation group (SIM) (n = 23) and traditional training group (TT) (n = 23). All instructors standardized their teaching sessions according to predetermined learning goals.
Students in the SIM group received a 3 h teaching session in groups of five or six in the Arcada Medical Simulation Center. The same anaesthesiologist taught all groups of students. After the skills training, each student administered two simulated general anaesthesia inductions in ASA I patients. Each student also observed other students' training through a one-way window from an adjacent room. A short debriefing session was held after each case. A SimMan (Laerdal AS, Norway) manikin and Avance (GE, USA) anaesthesia machine were used. The training session started with the skill training including bag–valve mask ventilation, endotracheal intubation and general anaesthesia induction and continued to a full-scale simulation.
In the TT group, each student trained in the operating theatre for 3 h according to our instructor–student routine. During this time the student practised bag–valve mask ventilation, endotracheal intubation and general anaesthesia induction on ASA I surgical patients. The choice of intravenous drugs and inhalation anaesthetics for general anaesthesia as well as dosages were discussed. The training took place in Helsinki University Hospital under the supervision of two consultant anaesthesiologists, both of whom hold an anaesthesiology faculty appointment in the University of Helsinki.
Within 1–2 weeks from the training session, each student's ability to carry out the induction of general anaesthesia was tested in the patient simulator in the Arcada Medical Simulation Center and the testing was recorded using DVD (Digital Video Device). The same test scenario was used on all occasions. Details of the ASA I patient scheduled for an elective cholecystectomy are given below. There was a trained anaesthesia nurse to assist the student similarly to a real case in the operating theatre. During the test the nurse assisted the student being tested only when asked or instructed, and was not allowed to make any comments or perform any procedures on her own.
The test scenario was assessed using a 40-item scoring list constructed by the authors. The scoring list items are as follows:
- asks for glycopyrrolate
- asks for fentanyl
- asks for fentanyl in a 10 ml syringe
- asks for propofol
- asks for succinylcholine
- asks for rocuronium
- asks for sevoflurane/desflurane as maintenance gas
- greets the patient
- asks for SpO2 monitoring
- asks for ECG/rhythm monitoring
- asks for NIBP (noninvasive blood pressure) monitoring
- places an i.v. line
- uses gloves
- fixes the i.v. line with care
- checks that the i.v. line is functioning
- checks the suction unit
- sets the suction catheter ready to use
- checks the patient's head positioning
- connects the nerve stimulator for neuromuscular block monitoring
- explains the anaesthesia procedure to the patient
- preoxygenation more than 2 min
- gives the right amount of opioid
- gives the right amount of propofol
- gives the right amount of succinylcholine/rocuronium
- checks the muscle relaxation prior to intubation
- intubates the patient
- intubation attempt less than 30 s
- fills/asks for filling of the cuff
- starts ventilation
- checks EtCO2
- auscultates breath sounds
- correct fixing of the intubation tube
- sets FiO2 30–40%
- respiratory rate (anaesthesia machine) 10–14/min
- minute volume 6–7 l
- sets the anaesthesia gas MAC more than one
- instructions to the nurse: SpO2 more than 95%
- instructions to the nurse: MAP more than 60 mmHg
- instructions to the nurse: heart rate more than 50/min
- instructions to the nurse: EtCO2 4–5 kPa.
Reliability of this list was acceptable (Cronbach's alpha 0.766). All instructors standardized their learning sessions according to it, that is, all the issues on the list were shown, practised or discussed in connection with the teaching cases. The core clinical tasks were divided into five parts: preparations for anaesthesia, induction of anaesthesia, start of ventilation and endotracheal intubation, actions after intubation and instructions to the anaesthesia nurse. The first part was included to evaluate knowledge concerning anaesthesia induction and the last to allow the students to make predictive conclusions of the patient's vital functions after the induction. Prior to the study, all authors participated in setting the cut-off point using the Angoff method [14,15]. The cut-off point became 0.687 × 40 items = 27.48. Time used for attempted intubation was recorded.
DVD recordings were evaluated by two independent consultant anaesthesiologists. They scored the cases separately and were blinded regarding the study group. Each of the actions was graded on a 3-point scale: 1 = yes, 2 = no, 3 = not clear. If there was disagreement between the two anaesthesiologists, the recordings were viewed by the first author.
All statistical calculations were made using the SPSS version 12 (SPSS Inc, Chicago, Illinois, USA). Because the data were not normally distributed, the differences between the checklist items and time needed for intubation were analysed using the Mann–Whitney nonparametric test. Cronbachs alpha was used to test the internal consistency of the checklist. P value less than 0.05 was considered as statistically significant.
Forty-one students, 23 (12 female) in the SIM group, and 18 (10 female) in the TT group completed the study. Five students dropped out of the study due to logistic reasons (i.e. simultaneous mandatory learning sessions during day time).
In the SIM group 20/23 (87%) and in the TT group 6/18 (33%) students passed the test. The difference was statistically significant (P < 0.001), using the predetermined cut-off value (27.48 points).
The greatest differences between groups in favour of the SIM group were in the following categories: for preparation of anaesthesia (request of glycopyrrolate) (P < 0.001), asked for SpO2 monitoring (P < 0.001), used gloves when placing an intravenous cannula (P = 0.012), intubation attempt in 30 s or less (P < 0.04), anaesthesia gas set at MAC greater than one (P < 0.04) and instructions to anaesthesia nurse to keep SpO2 at least 95% (P < 0.05), to keep MAP at least 60 mmHg (P < 0.05), to keep heart rate more than 50 beats per minute (P < 0.002), to keep end-tidal pCO2 4–5.5 kPa (P < 0.002) (Table 1). In the other tasks there were no statistically significant differences between the two groups.
The main finding of this study was that the students trained in the simulator performed better than the students trained by the traditional method. Training given in the simulator seems to give more standardized results in students' clinical skills tests, especially in critical areas such as preparation for anaesthesia, intubation and instructions to the nurse. The differences between these two groups may partly reflect personal routines of the operating theatre instructors and partly the operating theatre routines carried out by the active real-life anaesthesia nurse. In a simulator, the training session can be more structured to emphasize the physiological consequences of anaesthesia induction and there are fewer distracting events. It is also possible that observing the performance of others and a debriefing session gives better results than does instructions in the operating theatre. Our results are in accordance with a previous report by Owen and Plummer , who evaluated the performance of endotracheal intubation by first year medical students.
McIvor  described the use of simulators during the anaesthesia course and how it has changed over the years but there are no previous reports on the teaching of general anaesthesia to medical students in a full-scale simulator; however, there are several studies on teaching airway management in a simulator [3,6,8], or on assessing anaesthesiology residents or medical students' performance in a simulator [2,8–9,11]. Forrest et al. found that novice anaesthesiologists' performance in rapid sequence induction in a high-fidelity simulation setting improved significantly over the 12-week training period.
Simulations are used to reproduce some aspect of the working environment and simulation-based assessments have been used to test clinical skills [8,9,11,13]. There is some evidence to show that skills acquired in a simulator are transferable to clinical practice . In anaesthesia, the simulation environment and associated scenarios are generally perceived as highly realistic [20–22]. Manser et al. found similarly increased action density in both operating theatre and simulation during anaesthesia induction.
With the same time and with same amount of teaching personnel we could train five or six medical students in a full-scale simulator compared with one medical student at a time in the operating theatre. This obviously saves time, but probably also benefits the patients, when hazardous tasks, such as anaesthesia induction, can be practised in a simulated but albeit an authentic environment without risk to the patient. When assessing advantages and disadvantages of the simulation education, the cost of full-scale simulation itself also has to be taken into account. The highest cost is the staff, who must have a good clinical background and simulator trainer education .
Limitations of the study
The better test performance by the SIM group might be at least partly due to the fact that the same simulator was used for training and testing, and all the groups had the same teacher. This kind of bias is not uncommon in simulated education . On the contrary, every student had a brief introduction to the simulation room to become acquainted with it and its contents before the tests. All the students in this study were volunteers for this randomized study and it can be assumed that they were curious about the new teaching method. It can be argued that the TT group might have performed better had they been tested in a familiar clinical environment; however, it is difficult to arrange standardized test situations in the operating theatre and, thus, to obtain standardized information about performance in practice .
In conclusion, the simulation method for teaching anaesthesia induction was well received by the medical students. The students trained in a group of five or six performed better than those students taught one at the time by the traditional expert–novice method in the operating theatre. In the simulator the learning objectives can be more precisely set up and achieved  and the search for suitable patients from the operating schedule is not needed. Necessary operating room training can be given after the simulations and the interaction between effective simulation and work-based learning can increase the power of both [26,27]. More research is needed to find out whether our results can be applied more generally to anaesthesia teaching and training.
Test case information
There was some important information that needed to be provided to the students at the beginning of the test.
Information to the students at the beginning of the test scenario
The patient is a slightly overweight female (165 cm, 70 kg), who has had gall bladder symptoms for about 1 year. She is now admitted to the operating theatre from the surgical ward for a scheduled laparoscopic cholecystectomy. She does not smoke, takes no regular medications, her mouth opens normally and she was rated ASA I in the preanaesthetic clinic. She has had no food or drink since midnight.
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