Here, there is no such a thing familiar as pursuing the designer of a device or product because of it's malfunction.This is the same for the things you buy from market and somehow appliable to the Industrial/Electrical equipments (which also includes medical equipments).Since seller(Not producer) sold you the product he will no longer feel any responsibilty to you regarding the product.You should look for a product which it's Warranty has been provided by a third party company.There is nothing such as 'returning because of unsatisfaction' recognised around here.
Normally nobody will be put into jail because of manufacturing unreliable products ! This is normal , what is unusual is if your product doesn't fail !
Three month's ago i was offered to recopy a heart beat mointor product. I refused to do that althought there was a big money awaiting for me.You know Medical equipments are pretty expensive.When in such a situations i just start to think about those Gurus in NASA who build a 1000 Million dollar robot and send it to Mars.They fail sometimes.What the hell i am being compared to them ? There are reasons for such equipments to be so expensive and those are what Kai mentioned.
I have herad these equipment take a long long test before getting approvals.
Here you see signs that tell you not to use your Cell Phone at Gas stations and Hospitals. Noboy even pays attention to them ! sometime they search people in order not to let them take their phones in prohibited areas.Just imagine what could happen to a poorly designed MCU board operating along GSM signals...

Dear Mehdi , This is no offense to you , these are just my concerns of this new revolution here.There are many equipments being reproduced here without the knowledge.

Farshid