THE RAPID increase in use of electromedical apparatus in clinical medicine and medical research has, for the most part, resulted in significant benefits for the patient and, in general, improved medical care. However, the introduction of these instruments into the hospital environment has created new patient hazards which must be recognized by both the clinical user and the electronic designer-manufacturer.
There are two distinct types of electrical hazards in the hospital environment: "macroshock" and "microshock." Macroshock is the familiar hazard of superficial contact shocks that we face every day. Microshock, however, is a new hazard, peculiar to the hospital environment. This type of shock cannot be felt by the operator and may occur without warning. Your patient is increasingly surrounded by and connected to many instruments carrying electric currents. If these instruments are not well grounded, small currents, called leakage currents, can result in undesirable side effects. They will be