Abstract:

In view of the decreasing exposure that cardiothoracic surgery trainees have to perform coronary artery bypass grafting (CABG), it is increasingly important that clinical proficiency is achieved and maintained by alternate means. While performing procedures on a virtual-reality simulator may go some way in correcting this, much of the stereotactic response of human tissue cannot be accurately replicated by the simulator. In view of this, we have used a porcine model in a simulated operating theatre environment with real-time haemodynamic monitoring and coronary blood flow, in arrested and beating heart states.

Porcine hearts were obtained from animals killed for consumption and prepared by dissecting the mediastinal lymph nodes, liver segments, trachea and proximal hilar structures in order to expose the great vessels. The prepared heart was then connected to a computer-controlled pumping mechanism. The pump used was a linear actuator that is configured to compress a pneumatic bladder. A perfusion line was introduced into the aortic arch and hidden by a drape. The movement of the ‘lungs’ in the simulation was adjusted by increasing or decreasing the amount of air in the pulmonary circuit (i.e. simulated ‘tidal volume’ is variable), thereby increasing or decreasing the movement of the lateral walls of the simulated pericardial well.

Simulated parameters were displayed on a monitor beside the operating table and include the cardiac monitor, systemic arterial, central venous, and pulmonary arterial pressure tracings, and core body temperature.

Five surgical residents, all of whom have prior experience of assisting in CABG procedures were invited to participate. Each resident performed the procedure on one porcine heart and was asked to rate the educational value of the training. All five rated it as superior to prior simulation that they had undertaken using virtual reality simulators and much more lifelike. Furthermore, our improvised setup is far cheaper than commercially available virtual reality simulators and may therefore be a useful adjunct to training in low-resource settings.

Keywords:

Cardiac surgery, simulation, high-fidelity, low-resource.