The present invention relates to pressure applicator devices for applying a predetermined static pressure to a body part of a patient. The invention is particularly useful as a probe for application to a digit (i.e., a finger or toe) of a patient for the non-invasive detection of certain medical conditions in accordance with the method described in our PCT Application PCT/IL97/00249; and the invention is therefore described below especially with respect to such applications.
Our Application PCT/IL97/00249 (WO98/04182, published Feb. 5, 1998) discloses methods and apparatus for the non-invasive detection of a change in a physiological condition of a patient by monitoring changes in the peripheral arterial tone as manifested by changes in the arterial blood volume in a terminal extremity of a body part, preferably a digit (finger or toe) of the patient. The method and apparatus are described in that application particularly for detecting mycardial ischemia and sleep apnea, and also for the continuous monitoring of blood pressure. The described apparatus includes a probe for application to the patient's body part (e.g., finger) which probe includes a housing for receiving the distal end of the patient's body part, and pressurizing means for applying a static pressure field substantially uniformly around the distal end of the patient's body part when received in the compartment, including its terminal-most extremity. The static pressure field is of a predetermined magnitude sufficient to substantially prevent distention of the venous vasculature, uncontrolled venous backflow, and retrograde shockwave propagation into the distal end of the body part, and to partially unload the wall tension of, but not to occlude, the arteries in the distal end of the body part when at heart level or below. The probe further includes a sensor within the housing for sensing changes in the distal end of the patient's body part related to changes in volume therein due to changes in instantaneous blood volume related to arterial tone.
That application described a number of probe constructions in which the static pressure field was applied via a remotely located pressure source connected by tubing to a fluid chamber within the probe. However, utilizing such remotely-located pressure sources complicates the construction of the apparatus and also restricts the mobility of the patient.