A Method to Detect the Microshock Risk During a Surgical Procedure

During a surgical procedure, the patient is exposed to a risk that is inherent in the use of medical electric equipment. The situations involved in this study presume that, in open thorax surgery, 60-Hz currents with milliampere units can pass through the myocardium. A current as small as 50 or 70 muA crossing the heart can cause cardiac arrest. This risk exists due to the electrical supply in the building and medical electric equipment. Even while following established standards and technical recommendations, the equipment use electricity and can cause problems, even with a few milliamperes. This study simulates by software an electrical fault possibility of this type and shows the efficiency of the proposed method for detecting microshock risks. In addition to the simulation, a laboratory experiment is conducted with an electric circuit that is designed to produce leakage currents of known values that are detected by equipment named Protegemed. This equipment, as well as the simulation, also proves the efficiency of the proposed method. The developed method and the applied equipment for this method are covered in the Brazilian Invention Patent (PI number 9701995).