Secondary Logo

Journal Logo

Original Articles – General

Teaching anaesthesia induction to medical students: comparison between full-scale simulation and supervised teaching in the operating theatre

Hallikainen, Juhanaa,b; Väisänen, Ollia,b; Randell, Tarjaa; Tarkkila, Pekkaa; Rosenberg, Per Ha; Niemi-Murola, Leilaa

Author Information
European Journal of Anaesthesiology: February 2009 - Volume 26 - Issue 2 - p 101-104
doi: 10.1097/EJA.0b013e32831a6a76

Abstract

Introduction

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 [1]. 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 [5].

Full-scale simulation combines a life-size manikin with computer programs allowing the manikin to produce realistic physiological responses to pharmacologic and other interventions [6]. 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 [12]. 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.

Methods

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.

Assessment

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:

  1. asks for glycopyrrolate
  2. asks for fentanyl
  3. asks for fentanyl in a 10 ml syringe
  4. asks for propofol
  5. asks for succinylcholine
  6. asks for rocuronium
  7. asks for sevoflurane/desflurane as maintenance gas
  8. greets the patient
  9. asks for SpO2 monitoring
  10. asks for ECG/rhythm monitoring
  11. asks for NIBP (noninvasive blood pressure) monitoring
  12. places an i.v. line
  13. uses gloves
  14. fixes the i.v. line with care
  15. checks that the i.v. line is functioning
  16. checks the suction unit
  17. sets the suction catheter ready to use
  18. checks the patient's head positioning
  19. connects the nerve stimulator for neuromuscular block monitoring
  20. explains the anaesthesia procedure to the patient
  21. preoxygenation more than 2 min
  22. gives the right amount of opioid
  23. gives the right amount of propofol
  24. gives the right amount of succinylcholine/rocuronium
  25. checks the muscle relaxation prior to intubation
  26. intubates the patient
  27. intubation attempt less than 30 s
  28. fills/asks for filling of the cuff
  29. starts ventilation
  30. checks EtCO2
  31. auscultates breath sounds
  32. correct fixing of the intubation tube
  33. sets FiO2 30–40%
  34. respiratory rate (anaesthesia machine) 10–14/min
  35. minute volume 6–7 l
  36. sets the anaesthesia gas MAC more than one
  37. instructions to the nurse: SpO2 more than 95%
  38. instructions to the nurse: MAP more than 60 mmHg
  39. instructions to the nurse: heart rate more than 50/min
  40. 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.

Statistical analyses

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.

Results

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.

Table 1
Table 1:
Items with statistical difference from the scoring list

Discussion

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 [16], who evaluated the performance of endotracheal intubation by first year medical students.

McIvor [17] 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.[18] 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 [19]. In anaesthesia, the simulation environment and associated scenarios are generally perceived as highly realistic [20–22]. Manser et al.[22] 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 [23].

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 [10]. 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 [24].

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 [25] 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.

References

1 Cleave-Hogg D, Morgan PJ. Experiential learning in an anaesthesia simulation centre: analysis of students' comments. Med Teach 2002; 24:23–26.
2 Morgan PJ, Cleave-Hogg D. Evaluation of medical students' performance using the anaesthesia simulator. Med Educ 2000; 34:42–45.
3 Rall M, Dieckmann P. Safety culture and crisis resource management in airway management: general principles to enhance patient safety in critical airway situations. Best Pract Res Clin Anaesthesiol 2005; 19:539–557.
4 Rall M, Dieckmann P. Simulation and patient safety. The use of simulation to enhance patient safety on a system level. Curr Anaesth Crit Care 2005; 16:273–281.
5 Ringstedt C, Schroeder TV, Henriksen J, et al. Medical students' experience in practical skills is far from stakeholders' expectations. Med Teach 2001; 23:412–416.
6 Fitch M. Using high-fidelity emergency simulation with large groups of preclinical medical students in a basic science course. Med Teach 2007; 29:261–263.
7 Farnsworth S, Egan T, Johnson S, Westenskow D. Teaching sedation and analgesia with simulation. J Clin Monit Comput 2000; 16:273–285.
8 Goodwin MW, French GW. Simulation as a training and assessment tool in the management of failed intubation in obstetrics. Int J Obstet Anesth 2001; 10:273–277.
9 Morgan PJ, Cleave-Hogg D, DeSousa S, Tarshis J. Identification of gaps in the achievement of undergraduate anesthesia educational objectives using high-fidelity patient simulation. Anesth Analg 2003; 97:1690–1694.
10 Dalley P, Robinson B, Weller J, Caldwell C. The use of high-fidelity human patient simulation and the introduction of new anesthesia delivery systems. Anesth Analg 2004; 99:1737–1741, table of contents.
11 Murray D, Boulet J, Kras J, et al. A simulation-based acute skills performance assessment for anesthesia training. Anesth Analg 2005; 101:1127–1134, table of contents.
12 Issenberg SB, McGaghie WC, Petrusa ER, et al. Features and uses of high-fidelity simulations that lead to effective learning: a BEME systematic review. Med Teach 2005; 27:10–28.
13 Berkenstadt H, Kantor G, Yusim Y, et al. The feasibility of sharing simulation-based evaluation scenarios in anesthesiology. Anesth Analg 2005; 101:1068–1074.
14 Snee S, Blackmore D. Setting standards for an objective structured clinical examination: the borderline group method gains grounds on Angoff. Med Educ 2001; 35:1009–1010.
15 Boulet J, De Champlain A, McKinley D. Setting defensible performance standards on OSCEs and standardized patient examinations. Med Teach 2003; 25:245–249.
16 Owen H, Plummer J. Improving learning of a clinical skill: the first year's experience of teaching endotracheal intubation in a clinical simulation facility. Med Educ 2002; 36:635–642.
17 McIvor W. Experience with medical students simulation education. Crit Care Med 2004; 32(Suppl):66–69.
18 Forrest FC, Taylor MA, Postlethwaite K, Aspinall R. Use of a high-fidelity simulator to develop testing of the technical performance of novice anaesthetists. Br J Anaesth 2002; 88:338–344.
19 Mayo PH, Hackney JE, Mueck JT, et al. Achieving house staff competence in emergency airway management: results of a teaching program using a computerized patient simulator. Crit Care Med 2004; 32:2422–2427.
20 Gaba DM, Howard SK, Fish K, et al. Simualtion-based training in anesthesia crisis resource management. Simulation Gaming 2001; 32:175–193.
21 DeVitt JH, Kurrek MM, Cohen MM, Cleave-Hogg D. The validity of performance assessments using simulation. Anesthesiology 2001; 95:36–42.
22 Manser T, Dieckmann P, Wehner T, Rall M. Comparison of anaesthetits' activity patterns in the operating room and during simulation. Ergonomics 2007; 50:246–260.
23 Wright SW, Lindsell CJ, Hinckley WR, et al. High fidelity medical simulation in the difficult environment of a helicopter: feasibility, self-efficacy and cost. BMC Med Educ 2006; 6:49.
24 Kane MT. The assessment of professional competence. Eval Health Prof 1992; 15:163–182.
25 Rogers P. Simulation in medical students critical thinking. Crit Care Med 2004; 32(Suppl):70–71.
26 Kneebone RL, Scott W, Darzi A, Horocks M. Simulation and clinical practice: strengthening the relationship. Med Educ 2004; 38:1095–1102.
27 Bligh J, Bleakey A. Distributing menus to hungry learners: can learning by simulation become simulation of learning? Med Teach 2006; 28:606–613.
Keywords:

anaesthesia general; education medical undergraduate; safety management; simulation

© 2009 European Society of Anaesthesiology