Abstract: A probe for transcutaneous blood gas analysis composed of a housing (10) and a cap (18) which are assembled together by a snap-fit. The housing (10) holds an electrode unit (38, 40, 42) and the cap (18) carries a membrane (30) which spans an opening (20) in the cap (18) through which the electrode unit (38, 40, 42) projects. The membrane (30) contains an electrolyte between the electrode unit (38, 40, 42) and the membrane (30).

Abstract: A contact probe arranged to detect dislodgement of the probe from a body to which it has been attached. Probe dislodgement is detected by sensing an increased radiation level falling on a main sensor (14) located in the contact surface (10a) of the probe. The main sensor cooperates with a reference sensor (16) located in another surface (10b) of the probe which receives radiation reflected from the skin of the body to which the probe is attached. The reference sensor (16) provides a floating reference for the main sensor (14). In addition to providing an indication of probe dislodgement, the two sensors cooperate to develop an indication when they are shielded from the radiation source, thereby rendering the probe inoperative to sense probe dislodgement.

Abstract: A probe having a contact surface adapted to be placed on a body surface to monitor or control a body function. When the probe is dislodged from the body, an increased radiation level impinging on the contact surface is sensed and an indication of probe dislodgement is provided.