FR2653003A1 - Automatic and ambulatory tensiometer for measuring blood pressure - Google Patents

Abstract

The tensiometer comprises an inflatable cuff (3) intended to be placed around the arm (2) of the patient, means (G) for inflating the cuff in order to temporarily obstruct an artery, means (D) for detecting the blood flow sounds in the artery, means (M) for measuring the pressure of inflation, and means (E) for recording the systolic pressure and the diastolic pressure. The inflating means (G) comprise at least one container (4) of pressurised gas for inflating the cuff (3) and two solenoid valves (7, 11), one of which (7) makes it possible to establish a connection between the gas container (4) and the cuff (3), and the other of which (11) makes it possible to connect the cuff (3) to the atmosphere for the purpose of deflation, electronic means (12) for controlling the solenoid valves additionally being provided in order to effect the inflation cycles at a defined pressure and deflation cycles at predetermined intervals.

Description

 The invention relates to an automatic and ambulatory sphygmomanometer for measuring the arterial pressure of a patient according to the auscultatory method, of the kind comprising an inflatable cuff intended to be placed around the arm of the patient whose blood pressure is measuring means, means for inflating the cuff to temporarily occlude an artery, means for detecting blood flow noises in the artery when the inflation pressure is gradually released, means for measuring the inflation pressure, and means for recording at least systolic blood pressure and diastolic blood pressure for a period of time.

 It is known that arterial hypertension substantially reduces life expectancy, but hypertensive disease is nevertheless difficult to characterize and therefore to diagnose. A good knowledge of the variations of the arterial pressure is necessary to the doctor who wants to prevent any complication whose hypertension is the symptom, like cardiac abnormalities or malfonctionnements of the kidney.

 A simple measurement of blood pressure, such as that done during a consultation, is rarely sufficient. Indeed, the arterial pressure varies greatly according to the moment of the measurement, the activity or the emotivity of the patient. Thus, it is estimated that on average the difference between the systolic blood pressure (SBP) measured by the patient at home and by the doctor in his office reaches 27 mm Hg.

 There are currently many devices for measuring blood pressure. There is a whole range of digital sphygmomanometers based on the principle of oscillometric methods allowing anyone to measure their voltage. The oscillometric method is easy to implement and inexpensive, but is not precise enough to qualify for medical use.

 The tensiometer targeted by the invention is intended to operate according to the auscultatory method, the oldest because it derives from the detection technique usually used by the doctor and his stethoscope.

As illustrated by the diagram of Figure 1 of the accompanying drawings, the cuff, clamped around the arm, is inflated above the systolic blood pressure (PAS). At this point, the artery is completely obstructed by the cuff and blood does not flow into this artery anymore. No flow signal is therefore captured, which makes it possible to verify that it is well above the PAS. The cuff is then deflated slowly. From a certain pressure, equal to the PAS, the blood begins to flow by puffs and noises appear, called noises of
Korotkoff and represented by peaks K. The first of these noises corresponds to the PAS.

After this first sound, the blood begins to flow turbulently until the last sound of
Korotkoff which corresponds to the diastolic blood pressure (DBP). After this last sound, the flow regime of the blood in the artery becomes laminar
The main advantage of this auscultatory method is its precision. Its disadvantage is its sensitivity to external noises, source of artifacts that hinder the accurate detection of Korotkoff sounds.

 An average failure rate of about 3% has been reported for ambulatory devices implementing this method.

 The object of the invention is, above all, to provide an automatic and ambulatory blood pressure monitor of the kind defined above which makes it possible to ensure a measurement of the blood pressure with both great accuracy and good reliability, in particular by a great immunity to noise. , which makes this measurement compatible with medical requirements.

 According to the invention, an automatic and ambulatory tensiometer of the kind defined above is characterized in that the inflation means comprise at least one gas container under a pressure greater than the maximum inflation pressure of the cuff, and at least two solenoid valves of which one makes it possible to establish a connection between the gas container and the cuff for the inflation of the latter, and the other of which makes it possible to connect the cuff to the atmosphere for deflation, electronic means for controlling the solenoid valves being further provided to cause inflation cycles at a defined pressure and deflate at predetermined times.

 Under these conditions, the inflation and deflation operations are performed in a particularly silent manner and do not introduce any significant parasites in the detection of Korotkoff sounds.

 Advantageously, to improve the reliability, the tensiometer comprises electrodes intended to be placed on the patient whose voltage is to be measured, these electrodes being suitable for providing a signal at each heartbeat, electronic means being provided for correlating the noises. of Korotkoff with these signals due to the heartbeat so as to validate a sound captured only if the electrodes have shown a signal corresponding to a wave R of an electrocardiogram.

 It is recalled that the electrocardiogram signals consist of a succession in time of areas of high variation called QRS, the R wave constituting a peak in the central portion of this QRS area.

 The pressure vessel is advantageously constituted by at least one can containing a liquefied gas at ordinary temperature, at a pressure of about 5 bars.

 The electronic means for controlling the solenoid valves advantageously comprise a microprocessor programmed to ensure not only the management of the solenoid valves but also that of the various measurements to be made, displays and storage in memory, in digital form, of the collected data.

 The means for detecting blood flow sounds includes a microphone clamped by the cuff against the patient's arm, while a pressure sensor is provided to provide an electrical signal representative of that pressure, amplifiers, filters and a converter. analog / digital being combined with this microphone and with this pressure sensor to provide the information, in digital form, to the microprocessor.

 Advantageously, the tensiometer comprises a control means allowing the patient to intervene in the measurement cycle, in particular to delay a measurement, to make a measurement at a time not planned, or to mark an arterial pressure measurement when it is accomplished during an effort. This control means is generally constituted by a push button.

 The blood pressure monitor is advantageously arranged to enable a doctor to program, easily, for example by a simple answer whether or not "questions displayed on a screen, the conditions under which the measurements will be made, including the periodicity of the measurements. for the daytime cycle and for the nocturnal cycle, and the instants of passage from the diurnal cycle to the nocturnal cycle and vice versa.

 The entire pressure vessel, solenoid valves and electronic means is arranged in a box, of substantially rectangular parallelepiped shape, intended to be worn by the patient, this box comprising on one end face a connection for a flexible pipe connected to the cuff and a connection socket to the microphone cable, and any electrodes.

The face of the casing provided with the connectors preferably comprises a display screen. An adjustment knob and an indicator light are combined with the electrodes for giving the heart rhythm, the adjustment to be made by the doctor during the installation of the blood pressure meter in such a way that the indicator light comes on blatantly at the rate of Heart beats ; two pushbuttons corresponding respectively to a roui n response and a "no to a asked question on the screen" answer are provided, as well as a pushbutton
VAL (validation) and a push-button DEF (scrolling).

 Preferably, the blood pressure monitor comprises warning means capable of emitting a sound indicator a few seconds before a blood pressure test so as to allow the patient to intervene to postpone the measurement if he wishes. A switch is provided on this side of the box for the possible removal of the audible indicator or its start.

 The rear face of the casing includes a plug connection to a personal computer or a printer for transferring the data stored in the memory of the tensiometer, when measuring this rear face also includes a connection socket on a telematic terminal, for example on a device of the n minitel type, the microprocessor of the tensiometer being programmed to perform a processing of the stored data, before being displayed on the telematic terminal.

 The ambulatory blood pressure monitor can be combined with an ambulatory electrocardiogram machine.

 The invention consists, apart from the arrangements set out above, in a certain number of other arrangements which will be more explicitly discussed below with respect to a particular embodiment described with reference to the attached drawings, but which is in no way limiting.

 FIG. 1, of these drawings, is a diagram illustrating the ausculatory method, in which the time is plotted on the abscissa while the ordinate is plotted respectively the inflation pressure in mm Hg of the cuff, and the level of the noises. of blood flow in the artery in decibels.

FIG. 2 is a simple diagram of the sphygmomanometer
Figure 3 is a block diagram of the tensiometer.

 Figure 4 is a diagram of the analog portion of the tensiometer.

 Figure 5 is a block diagram of the microprocessor environment.

 Figure 6 is a simplified perspective view of the end face of the casing comprising the screen.

 Figure 7 is a partial view of the rear face of the casing.

 Figure 8, finally, is a simplified flow chart of the procedure for measuring blood pressure.

 Referring to the drawings, particularly in Figure 2, we can see an automatic and ambulatory blood pressure monitor 1 for measuring the blood pressure of a patient whose arm 2 has been schematically represented.

 The sphygmomanometer comprises an inflatable cuff 3 intended to be placed around the arm 2, inflation means G of the cuff 3 to temporarily block an artery, means D for detecting the blood flow noises in the artery 1 of the measuring means M inflation pressure, and means E to record at least systolic blood pressure and diastolic blood pressure for a certain period of time.

 The inflation means G comprise, for example, two gas containers 4 connected in parallel to a flexible pipe 5. Each container 4 contains gas under a pressure greater than the maximum inflation pressure of the cuff. Preferably, each container contains a liquefied gas at room temperature under its vapor pressure. For example, the containers contain a freon gas of the type used for aerosol cans at a pressure of about 5 bars. The mass of each container 4 when put into service is advantageously of the order of 110 grams.

 The maximum inflation pressure cuff is of the order of 22 ~ mm Hg, or about 0.29 bar.

 The flexible pipe 5 is connected, via a pressure reducer 6, to a first solenoid valve 7. The output of this solenoid valve is connected, in particular via a chamber 8 to a connection 9 allowing the connection of a flexible tube 10 connected to the cuff 3 to ensure inflation.

 A second solenoid valve 11 allows, when it is open, to connect the tube 10, through the chamber 8, to the atmosphere, to deflate the cuff 3. The other solenoid valve 7 is then closed to isolate the gas containers 4 of the atmosphere.

Electronic means 12 for controlling the solenoid valves 7, 11 are provided to cause the inflation cycles of the cuff 3 at a defined pressure, and deflation, at predetermined times. These electronic means 12 comprise a microprocessor P, for example a 280 A version C
MOS with its environment. This microprocessor P is programmed to ensure not only the management of solenoid valves 7, li, but also that of the various measurements to be made, displays and storage in memory, in digital form, of the data collected.

The means D for detecting the blood flow noises comprise a microphone 13 clamped by the cuff 3 against the patient's arm 2
A pressure sensor 14 is provided to provide an electrical signal, representative of the inflation pressure of the cuff 3. Advantageously, this sensor 14 is connected to the chamber 8 which is at the same pressure as the cuff 3.

 The information from the microphone 13 and the sensor 14 are sent to the electronic means 12.

The tensiometer also preferably comprises electrodes 15, 16, 17 (FIG. 3J intended to be placed on the patient The electrode 16 is a reference electrode, while the two electrodes 15 and 17 are capable of providing signals ss each heartbeat.The electronic means 12 are provided to correlate the sounds of
Korotkoff, provided by the microphone 13, with the signals dts heartbeats, so as to validate a noise picked up by the microphone 13 that If the electrodes were apparattre a signal corresponding to a wave R of an electrocardiogram.

 The three electrodes 15, 16, 17 are connected, by means of targets such as floating potential shielding 18, to a high-performance voltage amplifier 19 (see FIG. 4). The output signal of this amplifier then goes through a low-pass filter 2 <5 whose cut-off frequency can be at 40 Hz, then by a rejection filter 21 of 5 ~ Hz.

 The microphone 13 (see FIG. 4) is advantageously of the piezoelectric type, of a flat model with a large surface area. The electrical signals supplied by this microphone 13 are then amplified by an amplifier 22 and filtered by a low-pass filter 23 whose cutoff frequency is also 4 × Hz.

 The pressure sensor 14 delivers, for its part, an electrical signal proportional to the pressure difference between the cuff bag 3 and the external environment. This signal is supplied to a calibratable amplifier 24 (FIG. 4) whose cutoff frequency is advantageously of the order of 1 <5 Hz.

 The three electrical signals collected at the output of the filters 21, 23 and 25 are analog signals. These signals are multiplexed by an analog switch 26 followed by an impedance adapter. At the output of the switch 26, the analog signals thus multiplexed, are sent on an 8-bit analog / digital converter 27.

It is thus possible to have 256 numerical values, using these bits, which gives a precision, over a range of 3Z mm Hg to 285 mm Hg, of 1 mm Hg. The measurement accuracy is therefore decreased by this value.

The power supply of the device is supplied by batteries and delivers the voltages - 5
V, ~ and + 5 V. The batteries must have sufficient autonomy to power the device for 24 hours. In addition, the device has a permanent memory for data backup, this memory consisting of a random access memory RAM 28 (see FIG. 5), for example with a capacity of 8
Koctets, and type C MOS, this memory being combined with an electric battery 29 of the watch battery type
In FIG. 3, there is a block F corresponding to all the means described with reference to FIG. 4.

 The apparatus comprises a display or alpha-digital screen 3 ~, with liquid crystals, disposed on an end face 32 (see Figure 6) of a box 31 substantially shaped parallelepiped rectangle whose large dimension, placed horizontally in FIG. 6t is intended to be vertical when the casing 31 is worn by the patient; the end face 32 is then turned upwards and located in a substantially horizontal plane.

 The face 32 is provided with buttons 33, 34 for programming the tensiometer. When a question appears on the display 3 ~, for programming, question to which it should answer with "yes" or "no", the doctor presses the button 33 to answer us or or on the button 34 for an answer n no "to the displayed question.

 A VAL button is provided to allow, when pressed, to validate a displayed data. Another DEF button allows you to scroll through the data until you have the desired one (for example scrolling hours and minutes for setting the time).

 The face 32 also has a button 35 on which the patient can press, for example to mark a recorded data while the patient is making a effort, which does not correspond to the usual circumstances of taking voltage.

 On the same face 32 there is the connection 9, mentioned with reference to Figure 2, for the connection of the flexible tube 1 <5 cuff inflation.

A plug 36 is provided for connecting the cable from the microphone 13 and cables connected to the electrodes 15, 16 and 17.

 A two-position switch 37 is provided on this face 32 to allow the patient, according to the position given to this switch 37, either to suppress or to leave a warning light intended to warn the patient of a voltage test a few seconds before that this taking takes place.

 An adjustment potentiometer knob 38 is also accessible on this face 32 to enable the level of the signals coming from the electrodes 15, 16, 17 to be adjusted. This button 38 is combined with a light indicator 39, in particular formed by a light-emitting diode. The physician performing the blood pressure monitor should adjust the knob 38 so that the tell-tale 38 lights up positively at the rhythm of the beats of the patient's heart.

 A general switch 40 is finally provided for the commissioning or stopping of the blood pressure monitor. On its rear face 41, opposite to the face 32, the apparatus comprises a socket 42 (see FIG. 7) for connection to a telematic terminal, for example of the "minitel" type, and another socket 43 for connection to a computer of the type PC, or to a printer.

 Referring to FIG. 5, it can be seen that the microprocessor P is combined with several peripherals controlled by this microprocessor.

 There is the analog / digital converter 27, and the display or liquid crystal display (LCD) 3 <5. The peripherals further include a real-time clock 44, combined with timing circuits 45 (timers); an input / output unit 46, a module 47 for transferring data to a computer of the PC type, this module 47 constituting an interface between the microprocessor P and a computer provided with an RS-232 interface.

 The microprocessor P is also connected to two memories namely the RAM 28 already mentioned above to store the data acquired during the measurements and a read-only memory 48 (ROM), 8 K bytes. The program enabling the microprocessor to manage the peripherals and all the measurements to be made during a 24-hour cycle in general, is stored in this read-only memory 48.

 That said, the use and operation of the tensiometer according to the invention are as follows.

 When placing the device on the patient, the doctor must first put batteries in the device for the power supply, for example, four 1.5 V stick batteries or four batteries of the same size. The contrast setting of the display 30 is set.

 The doctor must then ensure that the containers 4 of compressed gas are full. If not, they must be refilled or replaced with full containers.

 After having cleaned with alcohol the application points of the electrodes 15, 16, 17, generally of the self-adhesive type, and richly coated with conductive gel, the doctor sets up the electrodes 15, 16 on the sternum and on the side of the patient, half-way between the arm and the hip. The reference electrode 16 is placed on the hip of the other side.

The microphone 13 is positioned on the arm 2, at the place where the stethoscope is usually placed, by means of a plaster or band
The microphone 13 must always be compressed by the cuff 3.

 The cuff 3 is then placed properly on the arm and the flexible inflatable conduit 1 <5 is connected to the connector 9 of the device.

 The casing 31 is fixed to the belt of the patient, for example using a bag containing the casing 31, the face 32 facing upwards.

To start the device, the doctor only uses the following buttons
- the four pushbuttons 33 ("yes1 '), 34 (" no "), VAL, DEF
the potentiometer 38 to adjust the signal of the heart
- 40 step switch
This switch is placed in the on position. If the power supply is insufficient, a message appears on the screen 30.

 Then, a series of messages, managed by the microprocessor P, will be displayed successively on the screen 30 to allow to define the various parameters of the measurement cycle which will generally extend over 24 hours.

The VAL button is used to indicate to the device that the doctor agrees with what is displayed and move on
If the doctor wants to change what is displayed, such as the time or the month, he must press the DEF key, which causes a scrolling values, for example the time or the month in the example. When the display of the screen corresponds to what is desired, it must be confirmed by pressing the VAL key.

 The display 30 will then scroll through a series of messages or questions to which it will suffice to answer generally by n yes "or by n no n to determine the various parameters of the measurement cycle such as the measurement intervals during the diurnal cycle ( for example, a quarter of an hour between two measurements), the nocturnal cycle (for example, a half-hour interval between two measurements), the transition time between the daytime cycles and the nocturnal cycles, and the time of night transition to daytime Beforehand, a clock reset operation has been performed.

 The doctor also adjusts the signals of the electrodes with the potentiometer 38 as already explained above.

 The doctor can finally perform, if desired, a measurement test with or without registration of this test.

 From this moment, the blood pressure monitor is ready for the measuring cycle and only the buttons 35 and 37 are to be used by the patient who can leave and have his usual occupations.

 The button 37, as explained above, allows the patient to choose whether he will be notified of the measurement a few seconds before or if instead he does not want to be solicited by the audible indicator, especially during his sleep period.

 The button 35 has several uses and allows, in addition to the already mentioned function of marking a measurement to indicate a force, to postpone a measurement, to trigger a measurement, or to interrupt the inflation of the cuff 3 in case of problems .

 The report function of the measurement can be performed when the switch 37 is in the audible indicator position. A few seconds before the measurement begins, a message appears on the screen 3 ~ asking the patient if he wants to postpone the measurement. If so, the patient just has to press button 35.

 The measurement function is performed when the device is waiting for a measurement, which can be seen from the message on the display 3 <5. The patient can then trigger a measurement by pressing the 35 button. can be interesting, especially when waking up, or in special circumstances.

The effort function is provided at the end of the measurement. A message appears on the screen 3 ~ asking the patient if he wants to indicate a stress. If the patient presses the button 35 at this time, the device marks the data for example of a cross. This option makes it possible to mark certain measurements made under particular conditions, in order to distinguish them from the others
Finally; the interrupt function is provided in the following manner. If for some reason the inflation of the cuff 3 goes wrong, causing a danger for the patient, it suffices for the patient to press the button 35 to cancel the inflation. The next measurement will take place after a diurnal or nocturnal cycle period. There is therefore a triple safety on the inflation: the regulator, the function interruption and a regulation by the software of the speed of inflation if the flow of gas (freon) is too important

 The measurements will take place automatically, at specified intervals, and the results will be stored in the RAM 28.

 At each measurement, the tensiometer stores in the memory 28 five data, namely: the time of measurement; the step ; PAD; heart rate a possible indication of effort.

 A measurement procedure, controlled by the microprocessor P, takes place according to the flowchart illustrated in FIG. 8.

 At 49, inflation of the cuff 3 is controlled by opening the solenoid valve 7 and simultaneous closing of the solenoid valve 11. This inflation is effected in successive steps of incrementing. At each step, the microprocessor P checks at 58 if there are still Korotkoff noises provided by the microphone 13.

 If so, the microprocessor P controls at 51 the continuation of the inflation. If the answer to the question in 50 is no, it means that the systolic blood pressure has been exceeded.

 The microprocessor then controls at 52 the gradual deflation by step of decrementation, cuff 3. The deflation is fast at the beginning and slower when arriving near the diastolic blood pressure. At 53 the microprocessor checks if there is noise provided by the microphone 13.

If the answer is no, it means that the deflation is insufficient and must be continued.

If the response is nouin, the next step 54 is to check if the noise is correlated with the signals from the electrodes 15, 17, that is, if the noise is correlated with an R wave of the electrocardiogram. This verification is ensured by interrogation at step 54 "is the noise correlated with an R wave of the electrocardiogram"?
If the answer is negative, further deflation is controlled.

 If the answer is no, another question is made in step 55 to find out if the noise has the required form. If the answer is nnonn, the deflation is continued.

 If the answer is "yes", another poll is taken at 56 to find out if this is the first noise.

If the answer is "yes", the cuff pressure is the systolic blood pressure PAS, the value of which is stored in memory.
If the answer to the interrogation 56 is "no", the microprocessor checks at 58 if the pressure of the cuff is less than 5 ~ mm Hg. If the answer is nouin, a message appears at 59 indicating that the microphone 13 is incorrectly positioned. . The program may comprise a branch enabling a second measurement to be taken if the patient so wishes following the message displayed at 59.

 If the answer to the interrogation 58 is n no ", the microprocessor P at the next step 6 ~ checks whether the detected Korotkoff noise is the last, for example by checking if no noise has been detected, after this noise. For a period of time greater than the maximum possible interval between two Korotkoff sounds, if the response is correct, deflation is continued.

 If the answer is "yes", the pressure supplied by the sensor 14 during the last Korotkoff sound and which has been stored constitutes the diastolic blood pressure PAD, which is stored as such. This step is shown schematically by block 61.

Step 62 consists of calculating mean arterial pressure MAP from PAD and PAS, this mean arterial pressure also being stored.

 The measurement procedure is complete; the microprocessor P goes on standby in step 63, until the next measurement which will take place after a given interval, for example a quarter of an hour in the case of the daytime period or half an hour in the case of the night time.

 After the monitor has measured the patient for 24 hours, the patient will return to their doctor.

If the doctor has a personal computer, it will be sufficient to connect the socket 43 of the monitor to the computer via a standard RS 232 interface. A program provided in the computer then reads the stored data. in the memory 28 of the tensiometer and perform the following treatments:
- calculation of average PAM, PAS and PAD and their standard deviation
- comparison with standard curves or with other stored curves
- display of a diagram as a function of time of the arterial pressures
- statistical analysis to detect correlations with external data such as norepinephrine, angiotensin, etc.

 If the doctor does not have a personal computer, but simply a telematic terminal, for example a minitel ", it will be enough to connect the plug 42 of the monitor to its terminal.The microprocessor P of the monitor is programmed to perform a processing of the data collected during the measurements and stored in the memory 28, for a display of the results on the screen of the terminal.

 The tensiometer of the invention is an ideal tool for a physician or for hospitals for the prevention and characterization of hypertensive diseases.

 The device operates with an accuracy of t 2 mm Hg on the voltage taps. The measurement of the blood pressure does not exceed 9 ~ seconds not to annoy the patient.

Claims (12)

 t. An automatic and ambulatory sphygmomanometer for measuring the blood pressure of a patient according to the auscultatory method, comprising an inflatable cuff (3) intended to be placed around the patient's arm (2), inflation means (G) for the cuff for temporarily blocking an artery, means (D) for detecting blood flow noises in the artery when the inflation pressure is gradually released, means (M) for measuring the inflation pressure, and means (E ) for recording at least arterial pressure the systolic and the arterial pressure the diastolic, for a certain period of time, characterized in that the inflating means (G) comprise at least one container (4) of gas under a higher pressure at the maximum inflation pressure of the cuff (3), and at least two solenoid valves (7, 11), one of which (7) makes it possible to establish a connection between the gas container (4) and the cuff (3) for inflating d e the latter, and the other (11) allows to connect the cuff (3) to the atmosphere for deflation, electronic means (12) for controlling the solenoid valves being further provided to cause the inflation cycles to a defined pressure and deflation, at predetermined times.  2. Blood pressure monitor according to claim 1, characterized in that it comprises electrodes (15, 16, 17) intended to be placed on the patient whose voltage is to be measured, these electrodes being suitable for providing a signal at each beat. of heart, electronic means (12) being provided for correlating the Korotkoff noise (K) with these signals due to the heartbeat so as to validate a sound captured only if the electrodes (15, 16, 17) have appeared a signal corresponding to an R wave of an electrocardiogram.  3. Tensiometer according to one of the preceding claims, characterized in that the pressure vessel is constituted by at least one can (4) containing a liquefied gas at ordinary temperature.  4. Tensiometer according to one of the preceding claims, characterized in that the electronic control means (12) of the electro-valves comprises a microprocessor (P) programmed to ensure not only the management of the solenoid valves (7, 11) but also that of the various measurements to be made, displays and storage in memory, in digital form, of the data collected.  5. Tensiometer according to one of the preceding claims, characterized in that the means (D) for detecting the blood flow noise comprises a microphone (13) clamped by the cuff (3) against the arm (2) of the patient, while a pressure sensor (14) is provided to provide an electrical signal representative of that pressure, amplifiers (22, 24)> filters (23, 25) and an analog-to-digital converter (27) being combined with this microphone (13) and with this pressure sensor (14) to provide the information, in numeric form, to the microprocessor (P).  6. Tensiometer according to one of the preceding claims, characterized in that it comprises a control means (35) allowing the patient to intervene in the measurement cycle, in particular to postpone a measurement, to perform a measurement to a unintended time, or to mark a blood pressure measurement when it is performed during a force, the control means being generally constituted by a push-button (35).  7. Blood pressure monitor according to one of the preceding claims, characterized in that it is arranged to allow a doctor to program, easily, for example by a simple answer "yes" or "no" to questions posted on a screen t3 ~), the conditions in which the measurements will be made, in particular the periodicity of the measurements for the diurnal cycle and for the nocturnal cycle, and the instants of transition from the diurnal cycle to the nocturnal cycle and vice versa.  8. Tensiometer according to one of the preceding claims, characterized in that the entire pressure vessel (4)> solenoid valves (7, 11) and electronic means (12) is disposed in a housing (31), of substantially parallelepipedal shape rectangle, intended to be carried by the patient, this housing comprising on one end face (32) a connection (9) for a flexible pipe (1 ~) connected to the cuff, and a connection socket (36). ) to the microphone cable and any electrodes.  9. A blood pressure monitor according to claim 8, characterized in that the face (32) of the housing provided with connectors comprises a display screen (3 ~), and a control knob (38) and a light (39) combined with the electrodes (15, 16, 17) for giving the heart rate, the adjustment to be made by the physician during the installation of the blood pressure meter so that the indicator light (39) lights up frankly to the rhythm heartbeat.  10. A blood pressure monitor according to claim 8 or 9, characterized in that the end face (32) provided with the connectors comprises two push buttons (33, 34) respectively corresponding to a "yes" answer and a "no" answer to a asked question appearing on the screen, as well as a push button VAL (validation) and a push-button DEF (scrolling).  11. Tensiometer according to one of claims 8 to 1 ~, characterized in that it comprises warning means adapted to emit a sound indicator a few seconds before a power take-off so as to allow the patient to intervene to defer the If desired, a switch (37) is provided on the end face (32) of the casing for the possible suppression of the audible indicator or its start.  12. A blood pressure monitor according to one of the preceding claims, characterized in that the rear face (41) of the housing (31) comprises a connection socket (43) to a personal computer or a printer for transferring data stored in the memory of the tensiometer, during the measurements, this rear face (41) also comprising a plug (42) for connection to a telematic terminal, for example on a device of the "minitel" type, the microprocessor (P) of the tensiometer being programmed for perform a processing of the stored data, before their display on the telematic terminal.