Thursday, 17 January 2013

How real does simulation need to be?

The question of how realistic a simulation needs to be is a perennial one. For a long time time I tended to ignore the question altogether because, as a mentor once told me, "It's all about the debrief!" The view from this camp is that the equipment is secondary to the primary educational intervention of the debrief.

Then I was swayed by Roger Kneebone's argument that the simulation just needs to be "real enough". So in his mobile inflatable simulator the anaesthetic machine is replaced by a couple of posters, with the sounds of the machine playing in the background. (This, I must add, is for simulations aimed at surgeons, not anaesthetists.)

Recently I have been thinking about our IV access arm. We use it in some of our medical undergraduate scenarios if the mannequin does not have IV access at the start of the scenario (e.g. they have just arrived at the emergency department.) Our rationale for this is, I think, two-fold; the students get to appreciate how long IV access can take to achieve (which lets us explore team dynamics, delegation, situational awareness, shared mental model, etc.) and they are provided with the opportunity to carry out a technical skill.

In our more advanced courses the IV arm is no longer used. Either the mannequin already has IV access ("someone" has placed a cannula) or when the participant tells the confederate in the room that they would now obtain IV access, the IV cannula appears on the mannequin. Why is there a change in practice in the more advanced courses? Partly because we no longer want people to "waste" valuable time trying to obtain access, partly because we think that at this stage of their career the participants will be well-trained in IV access and partly because having to go to a separate IV arm some distance from the body may impinge on the realism of the scenario. (I appreciate that we could stick the IV access arm onto the mannequin or use the expensive IV access available on the mannequin but I will try and explain why this is not really the solution below.)

Our final use of the IV access arm is in one-hour workshops we run for medical undergraduates to explore IV fluids and IV access. And it is here where my concerns about the IV arm are greatest. In order to improve our skills at something, we need to have deliberate, coached practice. I am happy to agree with anyone who tells me that the IV arm is useful for teaching students how to prepare for IV access (wash hands, gloves, prepare skin, etc.) but I would have trouble agreeing with anyone who tells me that the actual insertion of the IV cannula into the arm is useful. My reasoning here is that the feel of the needle as it pierces the plastic, the amount of force required and the angle of approach is very different from what is required in a patient. I would worry, in fact, that if someone became very good at obtaining IV access in the IV arm they would be not very good at obtaining IV access in a real person. (Although I have no research to back this up.) As a corollary, if someone is very good at IV access on people then the IV arm can present them with difficulties (which is why we don't get people to obtain access on the more advanced courses.)

This brings me on to my thoughts about the realism in the simulator. Because of time constraints or mannequin fidelity we have to (or think we have to) sacrifice aspects of realism. A septic patient may, in reality, have a few hours between starting to show signs of sepsis and becoming comatose with septic shock. In a simulated scenario we compress the intervening time period down to 15 minutes or so (often the mannequin starts off relatively "well" to allow the candidates to make a diagnosis/initiate treatment and then the mannequin quickly becomes unwell and requires further interventions.) My concern is that, when candidates then go on to see sepsis (for example) outside the simulator, the cues and timings are so different from the simulation that it does not trigger the behaviours and actions we want. Perhaps we are failing in our role as educators for certain conditions because the simulation is insufficiently realistic around the most crucial aspects (whatever they may be)? Answers on a postcard please...