SPHYGMOMANOMETER

• US 20130261475A1
• Filed: 05/29/2013
• Published: 10/03/2013
• Est. Priority Date: 09/10/2004
• Status: Active Grant

• Current Assignee: Terumo Kabushiki Kaisha
• Original Assignee: Terumo Kabushiki Kaisha
• Inventors: MOCHIZUKI, Hiroshi
• Granted Patent: US 8,734,354 B2
• Time in Patent Office: Days
• US Class Current: 600/493
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/02225 using the oscillometric method
• CPC Class Codes: A61B 5/02233 Occluders specially adapted therefor tourniquets A61B17/132

Abstract

A sphygmomanometer measures blood pressure in accordance with an oscillation in an artery wall, resulting from an arterial pulse correspondent with a change in cuff pressure. It comprises a cuff that is connected to the sphygmomanometer main body by a tube, a display unit for displaying the results of blood pressure measurements, and an air supply unit for supplying air to, and thus pressurizing, the cuff, which is detachable from the sphygmomanometer main body. The air supply unit is screwed into the sphygmomanometer main body with a screw assembly, and the screwed-in state is preserved by a caulking ring. The air supply unit also comprises a filter for keeping dust from entering the sphygmomanometer main body.

Claims

1. A sphygmomanometer, that measures blood pressure in accordance with an oscillation in an artery wall, resulting from an arterial pulse correspondent with a change in cuff pressure, comprising:

a cuff that is connected to a sphygmomanometer main body by a tube;

an air supply unit for supplying air to and pressurizing the cuff, the air supply unit being detachable from the sphygmomanometer main body, and forming a single unit when attached to the sphygmomanometer main body;

a mode switch for selecting a measurement mode from among a Normal mode that measures blood pressure automatically, a Slow mode that measures blood pressure automatically, and a Stethoscope mode for measuring blood pressure manually via a stethoscope;

a control unit for controlling opening and closing of an electromagnetic valve of the sphygmomanometer to adjust a speed at which air is exhausted from the cuff according to the measurement mode selected via the mode switch so that the control unit controls the electromagnetic valve to;

i) keep the exhaust speed at a first preset exhaust speed during blood pressure measurement when the Normal mode is selected by the mode switch;

ii) keep the exhaust speed at a second preset exhaust speed during blood pressure measurement when the Slow mode is selected by the mode switch, the second preset exhaust speed being approximately half of the first preset exhaust speed; and

iii) keep the exhaust speed at a third preset exhaust speed during blood pressure measurement when the Stethoscope mode is selected by the mode switch, the third preset exhaust speed being approximately the same as the second preset exhaust speed;

a display unit which displays a blood pressure measurement result and the selected measurement mode;

a memory storing pressure values measured by the pressure sensor during depressurization of the cuff;

wherein

the control unit determines a systolic blood pressure based on the stored pressure values;

the control unit obtains a pressure value as a first candidate from the stored pressure values at a point where a difference between a squared value of a measured amplitude of the pressure and a squared value of an estimated amplitude of the pressure is within a first prescribed percent range of a maximum amplitude of the pressure for a first time, the estimated amplitude being estimated from temporally previous pressure values;

the control unit obtains a pressure value as a second candidate from the stored pressure values at a point where a difference between the squared values is within a second prescribed percent range of the maximum amplitude for a first time as seen from a timing of the maximum amplitude, and the control unit determines a blood pressure corresponding to the first candidate as the systolic blood pressure when the difference between the first candidate and the second candidate is within a prescribed value.

2. A sphygmomanometer, that measures blood pressure in accordance with an oscillation in an artery wall, resulting from an arterial pulse correspondent with a change in cuff pressure, comprising:

a cuff connected to a sphygmomanometer main body by a tube;

an air supply unit for supplying air to and pressurizing the cuff, the air supply unit being detachable from the sphygmomanometer main body, and forming a single unit when attached to the sphygmomanometer main body;

a mode switch configured to be operated to permit selection, one at a time, of three different measurement modes including a Normal mode during which blood pressure is measured automatically, a Slow mode during which blood pressure is measured automatically, and a Stethoscope mode during which blood pressure is measured manually via a stethoscope;

a control unit configured to control, according to the measurement mode selected by operation of the mode switch, opening and closing of an electromagnetic valve of the sphygmomanometer to adjust a speed at which air is exhausted from the cuff so that;

i) whenever the Normal mode is selected through operation of the mode switch the control unit controls the electromagnetic valve to keep the exhaust speed at a first preset exhaust speed during blood pressure measurement;

ii) whenever the Slow mode is selected through operation of the mode switch the control unit keeps the exhaust speed at a second preset exhaust speed during blood pressure measurement, wherein the second preset exhaust speed is approximately half of the first preset exhaust speed; and

iii) whenever the Stethoscope mode is selected through operation of the mode switch the control unit keeps the exhaust speed at a third preset exhaust speed during blood pressure measurement, wherein the third preset exhaust speed is approximately the same as the second preset exhaust speed;

a display unit which displays a blood pressure measurement result and the selected measurement mode;

a memory containing stored pressure values measured by the pressure sensor during depressurization of the cuff;

wherein

the control unit determines a systolic blood pressure based on the stored pressure values;

the control unit obtains a pressure value as a first candidate from the stored pressure values at a point where a difference between a squared value of a measured amplitude of the pressure and a squared value of an estimated amplitude of the pressure is within a first prescribed percent range of a maximum amplitude of the pressure for a first time, with the estimated amplitude being estimated from temporally previous pressure values;

the control unit obtains a pressure value as a second candidate from the stored pressure values at a point where a difference between the squared values is within a second prescribed percent range of the maximum amplitude for a first time as seen from the time of the maximum amplitude; and

the control unit determines a blood pressure corresponding to the first candidate as the systolic blood pressure when the difference between the first candidate and the second candidate is within a prescribed value.