Anesthesia and Electrical Safety D. John DoyleInsulator does not allow the flow of electrons (or current) // conductors allow flowDirect current electrons flow in one direction / alternating current electron current switches direction at regular intervals(120x per second for 60 Hz wall current)V= IR // P = QRPower (W) = V x I Electrical energy watt-sec (Joule)Capacitance stores charge two parallel conductors separted by insulator // in contrast to DC circuits, capacitor in an AC circuit permits current flow // C= Q/VStray capacitance / Capacitative coupling -- inherent in all electrical equipment, generally undesirable;; not designed into the system

Electrical shock --- hjgh freq current has low tissue penetration and does not excite contractile cells (but can still cause burns) // DC is less dangerous; AC (at 60Hz) is more dangerousMacroshock large current flows that can cause harm /Microshock small amts of current flow dangerous only to susceptible pts (ex pacing wires, central line in situ)100microA Vfib 10microA recommended maximum 60Hz leakage current (in OR) MACROSHOCK --