Since you mention testing the device this means that the context is biomedical research. In general there are guidelines and procedures to follow to protect the people participating in the trial or study from unecessary harm. Sometimes some side-effects of certain procedures are known and the study personnel makes every effort to prevent or relieve these effects. All of this should be made known to the patient who will sign what is called an "informed consent form" that will detail the purpose of the testing, the known risks and many other items.
It all started with the Declaration of Helsinki.