Abstract: An adapter suitable for ready insertion into a fluid line extending between a source of electrically-conductive fluid and a part of a living body, to enable convenient electrical contact to the fluid. The adapter is T-shaped and has a through-bored portion on the opposite ends of which quick-disconnect luer-lock connectors are formed to receive the ends of the adjacent tubing sections. An electrical connector pin extends through the stem of the T, at right angles to the through bore, to contact the fluid in the through bore; the external end of the pin is provided with a quick-disconnect connector terminal so that it can easily be connected to and disconnected from associated electrical equipment, such as an ECG monitor. The body of the adapter may be of molded plastic, and the entire unit so inexpensive that it can economically be discarded after use. In addition to ECG monitoring the adapter is specially suitable for use in regional block anesthesia.