[Fundamentals and requirements of peripheral electric nerve stimulation. A contribution to the improvement of safety standards in regional anesthesia].

The use of a nerve stimulator allows an injection cannula to be located without the cooperation of the patient. Regional anesthesia thus becomes safer because the basic condition "no paresthesia, no anesthesia" becomes irrelevant. In accordance with the basic electrophysiological conditions, a stimulator should have the following properties: (1) adjustable constant current at resistances of 0.5-10 kOhm; (2) monophasic square-wave initial impulse; (3) impulse duration selectable (0.1 ms + 1 ms, and exactly adjustable; (4) impulse amplitude (0-5 mA) exactly adjusted, unequivocal scale graduation or current indicator, in particular in the range of 0.05-1.0 mA; (5) impulse frequency 1-2 (-3) Hz; (6) alarm at high impedance and check on electrical circuit; (7) battery test (indication of battery voltage); (8) unequivocal assignment of load end; (9) high-quality connecting cable and plug; and availability of (10) instructions for use with relevant parameters (tolerated variations, steady-state characteristic curves, etc.).