Apparatus and Methods for Measuring Blood Pressure and Other Vital Signs Via a Finger

An apparatus for measuring blood pressure (BP) of a person via a pad of the underside of a finger comprising:

• a) a base having a top and a bottom;
• b) a substantially inflexible arcuate cradle affixed to the top of the base so as to facilitate receipt of the finger;
• c) a flexible inflatable blood pressure measurement bladder (“measurement bladder”) having an underside secured to the cradle such that the measurement bladder substantially conforms to the shape of at least a portion of the arc of the cradle, an upper side of the bladder defining a finger pad contact surface and being adapted to apply pressure to the finger pad when inflated;
• d) adjustable force application structure (“force structure”), separate from the measurement bladder, adapted to adjustably apply a force to an upper side of the finger press the finger pad against the finger pad contact surface sufficient to limit lateral movement of the finger pad relative to the finger pad contact surface to a range of about 0.4 mm to about 4 mm;
• e) a measurement bladder pump and a measurement bladder relief valve for inflating and deflating the measurement bladder, respectively, a pressure sensor for providing data indicative of air pressure and air pressure oscillations in the measurement bladder, each of the measurement bladder pump, measurement bladder relief valve and pressure sensor disposed in the base;
• f) there being no light emitter or detector systems employed to provide an indication of BP;
• g) a control system disposed in the base and coupled to the measurement bladder pump, the measurement bladder relief valve and the pressure sensor, the control system including a microprocessor and a memory having program instructions for execution by the microprocessor stored therein for controlling the operation of the measurement bladder pump and the measurement bladder relief valve and for processing data received from the pressure sensor and to:
• i. inflate the measurement bladder such that the finger pad contact surface is urged against the finger pad and the upper side of the finger is urged against the force structure;
• ii. stop measurement bladder inflation when a predetermined inflation pressure, that has been determined to substantially stop the flow of blood in arteries of the finger pad (inflation pressure), has been reached and thereafter controllably deflating the measurement bladder;
• iii. detecting resumption of blood flow in the arteries by monitoring the pressure data and detecting pressure oscillations therein;
• iv. detecting when normal flow has resumed via the pressure oscillations, and the pressure at which normal blood flow resumes (deflation pressure);
• and,
• v. calculating an indication of blood pressure based on the inflation and deflation pressures by generating a heart rate power spectrum from the waveform, then next convolving the power spectrum, and
• then next applying a fixed ratio method to provide an indication of systolic and diastolic BP wherein none of steps g(i)-g(v) employ data from a light emitter or a light detector.

A method of using an apparatus that comprises:

• a. a substantially inflexible arcuate cradle;
• b. a flexible, arcuate, inflatable blood pressure measurement bladder (“measurement bladder”) having an underside secured to the cradle such that the measurement bladder substantially conforms to the shape of at least a portion of the arc of the cradle, an upper side of the bladder defining a finger pad contact surface and being adapted to apply pressure to a human finger pad when inflated;
• c. a measurement bladder pump in pneumatic communication with the measurement bladder for inflating the bladder;
• d. a relief valve in pneumatic communication with the measurement bladder for deflating the measurement bladder;
• e. a pressure sensor for providing data indicative of air pressure in the measurement bladder;
• f. a control system for receiving the data from the pressure sensor and for controlling the operation of the measurement bladder pump and relief valve, and comprising a microprocessor and program instructions stored in the memory for:
• i. inflating the measurement bladder such that the finger pad contact surface is urged against the finger pad and the upper side of the finger is urged against the force structure;
• ii. stopping measurement bladder inflation when a predetermined inflation pressure, that has been determined to substantially stop the flow of blood in arteries of the finger pad (inflation pressure), has been reached and thereafter controllably deflating the measurement bladder;
• iii. detecting resumption of blood flow in the arteries by monitoring the pressure data and detecting oscillations therein;
• iv. detecting when normal flow has resumed via the pressure oscillations, and the pressure at which normal blood flow resumes (deflation pressure);
• and,
• v. calculating an indication of blood pressure based on the inflation and deflation pressures;
• the method comprising:
• g. inserting a finger into the cradle such that the finger pad contacts the finger pad contact surface;
• h. applying a force to a portion of the finger opposite the finger pad in an amount no more than is required to prevent the finger from moving no more than about 0.4 mm and less than about 4 mm laterally with respect to finger pad contact surface;
• and
• i. causing the control system to initiate an operation that carries out steps (f)(i)-f(v).