Surgical diathermy and electrical hazards: causes and prevention

The hospital environment is both unique and unusual in that electrical equipment is directly applied to the human body. From this contact either capacitive or resistive coupling may lead to current flow and harm. Surgical diathermy, patient monitoring and imaging, although universal, are often misunderstood, and many clinicians are ignorant of their principles and hazards. Electrical equipment in hospital therefore has the potential to lead to serious injury or death. This article outlines the basic physics of electricity, in particular the principles behind diathermy, the hazards posed by it and by other devices and the various measures available to reduce the risk of these.