WO1994029830A1

WO1994029830A1 - Blood pressure demonstration apparatus

Info

Publication number: WO1994029830A1
Application number: PCT/AU1994/000316
Authority: WO
Inventors: Robert William Futcher; Graham Frederick Orr
Original assignee: Ticca Pty. Ltd.
Priority date: 1993-06-11
Filing date: 1994-06-10
Publication date: 1994-12-22

Abstract

A medical demonstration apparatus (1) adapted for indicating cardiac exertion. The apparatus (1) comprises an elastically and recoverably deformable hollow bulb (3) in the shape of a heart. The bulb (3) is connected via a connector (4) and the tube (5) to a manometer (2) which is used to indicate blood pressure. The bulb (3) is able to be squeezed by hand to indicate the cardiac exertion required to reach a predetermined pressure as indicated on the manometer (2).

Description

BLOOD PRESSURE DEMONSTRATION APPARATUS

The present invention relates to medical demonstration apparatus and particularly discloses apparatus that provides an indication of cardiac exertion. BACKGROUND ART

There exist a number of difficulties for the medical practitioner involved in treating patients suffering from high blood pressure. One major problem is an absence of noticeable symptoms. Thus convincing the patient of the existence of the illness and educating the patient in altering his life style and/or taking a course of medication in order to lessen, or substantially eliminate the condition can often be difficult. This applies especially where there are language and/or educative barriers.

As persons suffering from high blood pressure do not generally feel any symptoms, not only may they not feel the need to change their lifestyle or start a course of medication prescribed by the medical practitioner, but they also may not feel the need to continue. In addition, once a course of medication has been started, the patient does not necessarily feel any improvement and therefore this normal incentive to continue with the medication may be absent.

It has been known to use a partially inflated cuff of a sphyg omanometer to demonstrate the increased force required to emulate patient's blood pressure. However this is a static demonstration using a device which is in fact purpose-built to measure blood pressure; it is in practice rarely used for aforementioned demonstration purposes.

It is also known to provide a medical demonstration apparatus as described in NO 93/02439 by the applicant of the present application. The apparatus as described in that specification includes a recoverably deformable bulb which is connected via.tubing to a manometer. The disclosure of that specification is included herein by cross-reference.

OBJECT OF THE INVENTION It is an object of the present invention to provide a different version of the medical demonstration device as described in the above mentioned specification. DISCLOSURE OF THE INVENTION

In accordance with the present invention there is disclosed a medical demonstration apparatus adapted to indicate cardiac exertion to a patient, said apparatus comprising an elasticaUy and recoverably defor able hollow bulb, a connector tube inter-connecting the interior of said bulb with a manometer to indicate air pressure applied to said manometer via said tube, and a two way flow restrictor inter-connected between said manometer and said bulb to restrict the flow in either direction through said tube wherein cyclic deformation of said bulb forces air from said bulb towards said manometer at a rate faster than said restrictor permits flow from said manometer to said bulb to thereby progressively increase the pressure applied to said manometer, and upon cessation of said deformation to slowly reduce the pressure applied to said manometer.

Preferably, the two way restrictor includes a tube with an internal diameter of approximately 1mm, which ensures that the passage of air is restricted and the manometer level can be maintained for demonstration purposes. In another preferred embodiment, the two way restrictor includes a variable resistance. In a further preferred embodiment a one-way inlet is provided in the bulb to allow air to enter the bulb from the atmosphere.

In a further preferred embodiment, a bleed line to atmosphere from the bulb prevents buildup of pressure within the bulb.

As will be described, the preferred embodiment of the present invention is specifically designed as a visual and tactile interactive simulation device whose purpose is primarily to impart the concepts of blood pressure, cardiac exertion and peripheral resistance. Thus: it is visually reinforcing (it can be a model of a human heart); it demonstrates the effect of drug and other therapy on peripheral resistance; it demonstrates the influence of heart rate; it demonstrates the way in which elevated blood pressure increases the demand for coronary blood flow it demonstrates how external cardiac massage works; it demonstrates why the heart muscle may enlarge as a result of long standing hypertension; it is best used as a dynamic model, requiring repeated application of pressure to maintain the desired effect.

BRIEF DESCRIPTION OF THE INVENTION Preferred embodiments of the present invention will now be described with reference to the drawings in which: Fig. 1 is a schematic diagram of the medical demonstration apparatus of a first embodiment;

Fig. 2 is a schematic^* di gram of the medical demonstration apparatus of Fig. 1 when pressure is applied; Fig. 3 is a schematic diagram of the medical demonstration apparatus of Fig. 1 when pressure is released;

Fig. 4 is a longitudinal cross-sectional view of the medical demonstration apparatus illustrating the heart shaped bulb and its base; Fig. 5 is a cross-sectional view along the lines V-V of Fig. 4; Fig. 6 is a schematic diagram of the medical demonstration apparatus of a second embodiment;

Fig. 7 is a schematic diagram of the medical demonstration apparatus of Fig. 6 when pressure is applied;

Fig. 8 is a schematic diagram of the medical demonstration apparatus of Fig. 6 when pressure is released;

Fig. 9 is a schematic diagram of the medical demonstration apparatus of Fig. 6 following the release of pressure;

Fig. 10 is a schematic diagram of the medical demonstration apparatus of a third embodiment; Fig. 11 is a schematic diagram of the medical demonstration apparatus of Fig. 10 when pressure is applied;

Fig. 12 is a schematic diagram of the medical demonstration apparatus of Fig. 10 when pressure is released;

Fig. 13 is a schematic diagram of the medical demonstration apparatus of Fig. 10 following the release of pressure;

Fig. 14 is a schematic diagram of the medical demonstration apparatus of a fourth embodiment;

Fig. 15 is a schematic diagram of the medical demonstration apparatus of Fig. 14 when pressure is applied; Fig. 16 is a schematic diagram of the medical demonstration apparatus of Fig. 14 when pressure is released; and

Fig. 17 is a schematic diagram of the medical demonstration apparatus of Fig. 14 following the release of pressure. BEST MODE OF CARRYING OUT THE INVENTION Referring to Figs. 1-3, the medical demonstration apparatus 1 of a first embodiment comprises an interconnected manometer 2 and bulb 3. As illustrated in Fig. 4, the interconnection is via a connector 4 and tube 5. The connector 4 is illustrated in schematic form in Figs. 1-3 and the manometer 2 is connected to the connector 4 by a tube 5 as illustrated in Figs. 1-3.

Referring to Fig. 4, the bulb 3 is made from a moulded plastics material and is preferably coloured and shaped to resemble a human heart. The bulb 3 has a single opening 6 which sealing fits over a ringed flange 7 of an inlet 8 of the connector 4. When the bulb 3 is squeezed and then released, air is forced out of and into the bulb 3 accordingly.

The connector 4 (as illustrated in Figs. 4 & 5) includes a base 10 through which an internal tube 11 passes to an outlet 12. The inlet 8 and outlet 12 are thus able to communicate through the connector 4 for the passing of air therethrough.

The connector 4 includes a cylindrical compartment 13 which communicates with a pipe 14 which is received in one end of the internal tube 11. The connector 4 also includes an aperture 17 which joins the interior of the bulb 3 and the compartment 13.

The operation of the apparatus is as follows. The patient commences manually squeezing the bulb 3 to create pressure on the manometer 2. The air passes through the aperture 17 into the compartment 13 and hence into the internal tube via the pipe 14. The air flows into the tube 5 and through to the manometer 2. When the pressure is relaxed the air travels in the opposite direction.

A pumping action on the heart shaped bulb 3 causes a normal cyclical "blood" pressure reading indicated on the manometer 2. For example, the manometer 2 can read in cyclic fashion between 70 and 130mm Hg. From this, the patient gauges the normal requirements of cardiac exertion through the effort required to squeeze the bulb 3 as well as the pressure indicated on the manometer 2. The internal diameter of the tube 5 is approximately 1mm and this ensures the flow of air is restricted thus regulating the movement of the mercury within the manometer 2. The restriction of the flow of air is represented schematically in Figs. 1-3 as a restrictor 15.

The patient can vary the frequency of squeezing and the pressure applied to the bulb to experience the substantially greater exertion required to simulate higher blood pressure readings.

Referring to Figs. 6-9, in practice it is necessary for the apparatus to be adapted to operate with manometers of varying dynamic characteristics. One way to achieve this is to use a second restrictor 21 in the tube 5 which connects the bulb 3 to the manometer 2. In practice this restrictor 21 can be variable or fixed or selected from a family of restrictors. The Figs. 6-9 illustrate the operation of the apparatus 1 where the second restrictor 21 is variable so that the air circuit of the apparatus 1 can be tuned to suit various manometers 2. Referring to Figs. 10-13, in this third embodiment an inlet 22 into the bulb 2 is added to the apparatus as illustrated in Figs. 6-9. The inlet

22 includes a one-way valve 23 which enables the bulb 2 to reinflate via the inlet 22 before the mercury in the manometer 2 falls to zero. When the bulb 3 is fully reinflated at the end of the cycle (Fig. 13) the mercury reading is above zero. That means that the mercury level at this stage of the cycle simulates diastolic blood pressure.

In the arrangement of the fourth embodiment illustrated in Figs. 14-17, the apparatus further includes a bleed line 24 with a restrictor 25. The bleed line 24 with the restrictor 25 is used to prevent a gradual buildup to the mercury reading in the manometer 2 by allowing excess air pressure to be bled from the bulb 3. The bleed line 24 also allows the reading of the manometer 2 to slowly drop to zero after use. The apparatus of the various embodiments is operated by a cyclic sequence of squeezing the bulb 3 to force the air in the bulb into the tube 5 and hence to the manometer 2. In the first embodiment (Figs. 1-5) the response of the mercury column in the manometer 2 is damped by the restrictor 15. This damping prevents the mercury column from "bouncing" and appearing too sensitive. The resistor 15 also provides an extra load and this has the effect of providing to the patient greater contrast between the effort required to replicate normal blood pressure and the effort required to replicate high blood pressure in the manometer 2.

The greater squeezing effort applied to the bulb 3 provides a higher reading on the manometer. The apparatus is so tuned by the use of the restrictor 15 that the greater effort required is easily perceived by the patient.

In the second embodiment (Figs. 6-9), the apparatus is adapted to be used with manometers 2 having varying dynamic characteristics. The variable restrictor 21 allows the apparatus to be used in a similar fashion to the first embodiment where the air within the apparatus is contained therein during its operation. In the third embodiment (Figs. 10-13), the inlet 22 ensures that during the operation of the apparatus the mercury column of the manometer 2 does not drop to a zero reading between the cyclic squeezing operation of the bulb 3. When the bulb 3 is reinflated after squeezing, the mercury level returns to a reading which replicates diastolic pressure. That means that the mercury level does not go to zero.

In the fourth embodiment (Figs. 14-17) the bleed line 24 with the restrictor 25 prevents the gradual buildup of the mercury level. This means that the level should remain relatively constant if the effort in squeezing the bulb 3 is maintained.

INDUSTRIAL APPLICABILITY There are numerous other advantages associated with the use of the apparatus. For example, the greater perception of the disease on the part of a patient may lessen any resistance for accepting treatment and life style adjustments. Also, the patient is better able to conceptualize the positive effects of treatment, which is usually by means of a course of medication. Further, the patient learns to associate the lowering of blood pressure with the lessening of grip pressure required to operate the apparatus 1 and is therefore better able to accept possible adverse reactions to the therapy.

The apparatus provides a convenient and inexpensive way of communicating a complex medical issue between the medical practitioner and the patient.

The use of the apparatus also provides for a number of advantages to the general public as it can be used in medical and nursing training as well as in general improving community awareness of the problems of high blood pressure and hypertension. As such, morbidity and mortality rates can be lowered.

The medical practitioner also obtains a number of advantages from the use of the apparatus in that its use provides for a basis for the return of the patient for monitoring of the condition and the opportunity to diagnose other diseases. Also it provides for the opportunity to assess other cardiac risk factors. The use of the apparatus 1 saves time and provides an attractive alternative to other methods of communicating what can be, at times, mundane and non-challenging subject matter. It will also be understood, that the apparatus 1 can be used to overcome language barriers as its demonstration requires lessened explanation. The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention.

Claims

CLAIMS :

1. A medical demonstration apparatus adapted to indicate cardiac exertion to a patient, said apparatus comprising an elasticaUy and recoverably deformable hollow bulb, a connector tube inter-connecting the interior of said bulb with a manometer to indicate air pressure applied to said manometer via said tube, and a two way flow restrictor inter-connected between said manometer and said bulb to restrict the flow in either direction through said tube wherein cyclic deformation of said bulb forces air from said bulb towards said manometer at a rate faster than said restrictor permits flow from said manometer to said bulb to thereby progressively increase the pressure applied to said manometer, and upon cessation of said deformation to slowly reduce the pressure applied to said manometer.

2. The apparatus acording to claim 1, wherein the two way restrictor includes a tube with an internal diameter of approximately lmm, which ensures that the passage of air is restricted and the manometer level can be maintained for demonstration purposes.

3. The apparatus according to claim 1, wherein said two way restrictor includes a variable resistance.

4. The apparatus according to claim 1, wherein a one-way inlet is provided in the bulb to allow air to enter the bulb from the atmosphere.

5. The apparatus according to claim 1, wherein a bleed line to atmosphere from the bulb prevents buildup of pressure within the bulb.

6. The apparatus according to any of the preceding claims, wherein said bulb is sized to be squeezed by one hand of the patent.

7. The apparatus according to any one of claims 1-5, wherein said bulb is sized to be squeezed by one hand of the patent and the exterior of said bulb is shaped to resemble the appearance of the human heart.