Method and apparatus for the non-invasive detection of medical conditions by monitoring peripheral arterial tone

A probe for detecting changes in peripheral arterial tone, comprising:

• a pressure applicator including an end cap for receiving, and for applying pressure to, the most distal phalange of a patient's digit, and a cuff for receiving, and for applying pressure to, the phalange of the patient's digit preceding the distal part of the digit;
• said cuff acting as a venous tourniquet to prevent venous blood pooling in said digit, retrograde venous blood flow, and retrograde venous shock wave propagation into the distal part of the digit;
• and
• said cap detecting pulsatile volume changes of the arteries in said most distal phalange, preventing venous pooling in said digit and partially unloading the wall tension of, but not occluding the arteries therein.

A method for measuring the arterial blood pressure of a subject, comprising:

• heating the distal end of a digit of the subject's body to a predetermined temperature to maximally dilate the arterial blood vessels in said digit;
• and
• measuring volume-related changes in said distal end of the digit accompanying blood pressure waves;
• and converting said measured changes to arterial blood pressure.

A probe for measuring changes in peripheral arterial tone of a subject, comprising:

• a rigid casing having an open end and a closed end;
• a compliant membrane disposed inside said casing and hermetically connected to the open end of said casing;
• a circular pressure band provided inside said casing and positioned to press said membrane against interior wall of said casing;
• and
• a substantially U-shaped restraining bar disposed inside the casing and positioned against the membrane so as to prevent axial shifting of the membrane when inflated to avoid expelling of a finger placed therein.

An apparatus for monitoring the arterial pulse waves of a subject, comprising:

• a pressure applicator including a tubular socket for receiving a predetermined length of the distal end of a digit of the subject's body, including the extreme distal tip of the digit;
• a pressure source for applying a static pressure field around the distal end, including the extreme distal tip, of the digit of the subject's body when received in said tubular socket, which static pressure field acts as a venous tourniquet to substantially prevent pooling of venous blood in the distal end of the digit, to prevent retrograde venous blood flow and erratic venous shock wave propagation into the distal part of the digit, which could produce artifacts at the measuring site, and to partially unload the wall tension of, but not to occlude, the arteries therein when the digit is at heart level;
• and,
• a measuring device for measuring changes in said distal end of the digit associated with blood pressure waves.

Apparatus for monitoring a hemodynamic condition of a subject, comprising:

• a tubular socket for receiving the distal end of a digit of the subject's body;
• a heater within said socket for heating the distal end of the digit of the subject's body to a predetermined temperature to maximally dilate the arterial blood vessels in said digit;
• and
• a measuring device for measuring changes in said distal end of the digit associated with blood pressure waves.

Apparatus for detecting cardiopulmonary distress in a subject, comprising:

• a pressure applicator including a tubular socket for receiving a predetermined length of the distal end of a digit of the subject's body, including the extreme distal tip of the digit;
• a pressure source for applying a static pressure field around the distal end of said digit of the subject's body when received in said tubular socket, which static pressure field is sufficient to substantially prevent pooling of venous blood in the distal end of the digit and to partially unload the wall tension of, but not to occlude, the arteries therein when the digit is at heart level;
• a measuring device for measuring changes in said distal end of the digit associated with blood pressure waves;
• and an indicator for providing an indication of the existence of cardiopulmonary distress when said measured changes exceed a predetermined percentage as compared to a normal known condition of the subject when cardiopulmonary distress is not present.

Apparatus for monitoring a sleeping subject, comprising:

• a pressure applicator including a tubular socket for receiving a predetermined length of the distal end of a digit of the subject's body, including the extreme distal tip of the digit;
• a pressure source for applying a static pressure field around the distal end of the digit when received in said tubular socket, which the static pressure field is sufficient to substantially prevent pooling of venous blood in the distal end of the digit and to partially unload the wall tension of, but not to occlude, the arteries therein when the digit is at heart level;
• a measuring device for measuring changes in said distal end of the digit associated with blood pressure waves;
• and an indicator utilizing said measured changes for providing an indication of the sleeping condition of the subject.