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Posted

Hello everyone,

I'm currently in my bachelorassignment and have a certain problem that I need to solve. For this I would like your idea's on the subject, because all of you can look at the assignment with a fresher view than I can :D
So if ur up for a challenge, this is your chance! Thanks in advance for all replies.

 

off-pump coronary artery bypass graft simulator

Assignment context:
Bypass surgery on the heart can be performed in two ways, on and off pump. The off pump method is called: off-pump coronary artery bypass graft (opcab). This relates to the fact that no heart-lung machine is connected to the heart during the operation and the heart is still beating. Opcab gives certain advantages over the on pump method but is used far less. This is because opcab is considered a newer method of creating a bypass on the heart and as such most surgeons are unfamilliar with the techniques. The learning curve for opcab is quite high because the surgeon now needs to create accurate stiches on a moving object and the bloodpressure of the patient is now directly influenced by the surgeons actions. The bloodpressure of the patient is a crucial parameter to see if the surgery can continue or not. If the bloodpressure becomes too low, the surgery must stop and the patient must first be stabilized. This pushes surgeons to use the on pump method with which they are familiar and experienced even though it might not have been the optimal method for that particular patient. This situation is undesirable as you may expect.

So to train these surgeons a realistic simulator is required!

Surgery context:

During the surgery the surgeon creates a bypass from the top surface of the heart to the bottom surface of the heart (approximatly, differs per patient). To reach the bottom surface of the heart, the heart needs to be lifted. To do this the apex (the point/top) of the heart is lifted to the right side of the body (seen from the anatomical position). Doing this creates a bloodpressure drop which unexperienced surgeons do not know how to deal with. The drop itself is acceptable as long as it doesnt take too long (5mins max approximatly). But seeing such a low blood pressure may cause surgeons to get stressed.

 

Assignment problem:

Create a system in/on or around a heart which simulates the following phenomena:

- When lifting the apex of the heart a bloodpressure drop must occur (unnatural position for the heart -> difficulty pumping -> bloodpressure drop)

- When squeezing the heart a bloodpressure drop must occur (lower influx of blood into the heart -> bloodpressure drop)

- When lifting the apex of the heart too far to the right a further bloodpressure drop must occur. (Right ventricle of the heart is compressed against the pericardium -> lower influx of blood into the ventricle -> bloodpressure drop)

- The heart is attached to the major bloodvessels (aorta and superior/inferior vena cava, pulmonary artery/veins are optional for this assignment). These will function as the hinge for the heart. A twist of these bloodvessels must lead to a bloodpressure drop.

- Lifting the heart out of the body must lead to a bloodpressure drop. (Lower influx into heart because of gravity -> bloodpressure drop).

 

The bloodpressure can be created in two major ways (i believe), a virtual and a real bloodpressure.

Real bloodpressure: There is a medium (air, water, etc.) that is manipulated during the operation. Sensors meet the changes on the medium and this is converted to a bloodpressure reading. Example: a balloon with air is present in the heart -> the surgeon squeezes the heart -> pressure in the balloon rises -> pressure sensor transforms this into a bloodpressure value)

Virtual bloodpressure: A sensor senses a certain movement of the heart, the moving of the heart or the position it is in is connected to a certain bloodpressure value which is displayed. Example: a gyroscope on the heart measures the x,y,z values of the heart. A certain position of the heart is then transformed into a bloodpressure reading.

A mix of virtual and real is possible too of course.

 

Optional:

Ive added a pdf file of a study relating this subject. This study uses a porcine heart however and doesnt have the functionality mentioned above. But it is another solution for this problem and can serve as example. The study uses difficult terms and may be hard to understand for some.

 

What kind of system would you use to achieve these phenomena, or at least some of them. Let me know in the comments!

 

Cheers,

 

Gizmo

 

P.s. im new to this forum so im not sure if this is the right place to post this, if it is not, i will move it.

910.full.pdf

Posted (edited)

I recomend the use of Rift Glasses in order to be more realistic. About the system you should take a look for unity3d or unreal4. In order to make the heart and the tools, i recomend you create them manually you can put a kind of emitter on each tool and you would know the position of it. There is also a kind of glove that give the touch feelling maybe you should take a look at it, you may not need to create the tools manually. However it will make the program more complex for you.

Edited by Yvtq8k3n

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