As part of our ongoing work with Imperial College school of Medicine, we were asked to create a simulated anaesthetic machine for use in our simulated operating theatre. During am operation where the patient is under a general anaesthetic, the anaesthetic machine plays a crucial role in keeping the patient alive, but also telling the clinical team about the patient’s status. In particular the machine regulates breathing, and monitors the heart rate and blood pressure. The clinical team will respond to the readings of an aneasthetic machine to ensure the safety and well-being of the patient. We wanted to make a low cost simulated machine that would offer genuine interactions that contribute to the realism of the simulation.

There are two key innovations in our resulting design:

1. Use of iPads and an iPod
We used two iPads with purpose made apps on the anaesthetic machine, one represents the ECG that displays the heart beat and Blood pressure waves, complete with the ‘beep’ of the heart beat. The other iPad represents the control panel with the all the buttons and switches. The two iPads are connected via bluetooth to an iPod touch (or iPhone). The iPod acts as a remote allowing a technician on the outside of the simulation to ‘be the patient’. With the remote app the technician can change the vital signs of the simulated patient, such as vary the heart rate and blood pressure, and even set off alarms when the vital signs reach danger levels. This allows the technician to influence and respond to the simulation as it happens as greatly enhances the fealing of reality. Crucially this system is very easy to set up and use.

2. Manual breathing pump using a balloon inside a balloon
Anaesthetic machines include a manual breathing circuit allowing the anaesthetist to manually breath for the patient by squeezing a balloon that in tern fills the patient’s lungs with air. A skilled anaesthetist can tell from the feeling of the balloon valuable information about the state of the patient. As there is no real pair of lungs to squeeze air into within the simulation, we replaces them with a pre-inflated party balloon inside the anaesthetic machine. In order to make if feel realistic, we need the balloon to inflate and deflate in its most elastic state (think how hard it is to start blowing up a ballon compared to filling it up once you have got going). To achieve this we inflated one balloon inside another so that the outer balloon could not deflate too far. The best part about this innovation, is that although the balloons only last a few weeks, they cost pennies and can be bought in any supermarket.