WO2008086786A1

WO2008086786A1 - Cardiovascular measuring device

Info

Publication number: WO2008086786A1
Application number: PCT/DE2008/000076
Authority: WO
Inventors: Harald Ley; Gerhard Schumacher
Original assignee: Isymed Gmbh
Priority date: 2007-01-19
Filing date: 2008-01-18
Publication date: 2008-07-24
Also published as: DE102007002951A1

Abstract

The invention relates to an oscillometer for determining physiological parameters that allow the diagnosis of cardiovascular diseases. The oscillometer according to the invention comprises more cuffs (11) than pulse wave detecting units (10) and a possibility for switching the direction of flow between the cuffs (11) and the pulse wave detecting unit (10), thereby reducing the complexity of the device while making it more convenient and simple to use.

Description

description

Cardiovascular device

The invention relates to a cardiovascular measuring device according to the preamble of claim 1. Such cardiovascular measuring devices are used for the determination of physiological parameters which enable the diagnosis of cardiovascular disease, in particular by means of oscillometric measurement of the ankle-brachial index and the pulse wave velocity.

It is recognized in the medical community that the relationship between systolic ankle and upper arm blood pressure, the so-called ankle-brachial index has a very high clinical relevance for the diagnosis of Peripheral Arterial Disease (PAD).

As the artery walls harden, the pulse wave velocity also increases, which can therefore also serve as an indicator in assessing atherosclerotic changes. The additional determination of the pulse wave velocity is particularly advantageous in the presence of a medial sclerosis, since in this case may be erroneously measured too high ankle systoles, whereby the diagnosis can be unreliable if the ankle-brachial index is the only parameter used to assess arteriosklerotic severity becomes.

The ankle-brachial index can be determined using conventional oscillometric sphygmomanometers, provided that their suitability for ankle measurements was proved. It is also possible to determine the pulse wave velocities between the limbs to which the blood pressure cuffs are applied when two or more of these sphygmomanometers are synchronized with each other in time. For carrying out the measurements described above, prior art devices are based on one of the following methods for obtaining the desired cardiovascular information:

a) a device with an oscillometric pulse wave detection unit, with the resulting need for the user to measure blood pressure manually create a cuff on each limb to be measured manually and then calculate the ankle-brachial index or have it calculated by the device. A device based on this principle is described, for example, in US Pat. 5,961,467 referenced. The measurement of pulse wave speeds is not possible with this arrangement.

b) a device with four oscillometric pulse wave detection units and four cuffs for measuring blood pressure values or pulse wave velocities on all limbs almost simultaneously, as described, for example, in US Pat. 6,758,820 is published.

A device according to method a) is inexpensive to produce, but involves both the disadvantage of a cumbersome application and an unfavorable extension of the entire measurement period, which may significantly reduce the acceptance in daily medical practice under certain circumstances. At first glance, one could favor devices according to method b), above all because of the simplicity of the application as well as with regard to the measurement accuracy, since no manual cuff changes are required between the individual measurements and the required measurements on all limbs approximately at the same time respectively. On closer examination, however, it can be seen that the influence of simultaneity on the measurement deviation in daily practice is negligible, since the patient should have already been in a horizontal rest position for at least five minutes if the measurement method is used correctly, thus resulting in changes the relevant blood pressure parameters are largely excluded. Furthermore, users typically take more than one measurement to determine oscillometric parameters to detect phenomena such as: B. hide the so-called "white coat effect" as much as possible. Misinterpretations due to temporal variation of the blood pressure or the pulse wave velocity become even more unlikely. The equipment required for devices of method b) is relatively high, especially when modular pulse wave detection units are used.

All of the above-mentioned examination methods have in common that pulse waves must be detected on several limbs.

The invention is based on the problem of providing an oscillometric, cardiovascular measuring device for determining the ankle-brachial index and / or one or more pulse wave velocities, which both cost-effectively manufacture compared to devices that correspond to the previously described prior art as well as pleasant and practical in handling is.

According to the invention this object is achieved by a device or a system having the features of the main claim 1. The device or system according to the invention has the advantage that, regardless of the specific design, it comprises fewer pulse wave detection units than are possibilities for connecting cuffs which are simultaneously applied to the body. This contributes significantly to the manufacturing cost reduction, since the pulse wave detection units have or may have a high proportion of the total cost of such a device or system. Controlled switching of the flow direction, controlled in accordance with the measurement to be carried out, simultaneously avoids the need for a gender-related cuff change between the limbs which would otherwise be associated with the reduction of the number of pulse wave detection units.

Specific embodiments of the present invention will become apparent from the subsequent claims to the main claim.

An advantageous arrangement according to the present invention provides that two pulse wave detection units are used to measure the physiological parameters used as a basis for diagnosis. By means of a preferably, but not necessarily, automatically operated device for switching the flow direction, three or more sleeves, all of which can be simultaneously applied, are then connected successively to the pulse wave detection unit. The control of the connection takes place in the way that at least in one of two consecutive measurements on two limbs simultaneously.

A further advantageous arrangement according to the present invention provides that only one pulse wave detection unit is used. By means of the aforementioned device for switching the flow direction, two or more sleeves, all of which can be simultaneously applied, are then individually connected in succession to the pulse wave detection unit. In this case, the parameters required to determine the cardiovascular condition on the various limbs are determined solely by successive individual measurements. The determination of a pulse wave velocity is not possible with this arrangement.

The required measurements need not necessarily be made on the upper arm and ankle in the context of the arrangements described above. Alternatively, measurements on other limbs, e.g. Wrists, fingers, thighs or toes are performed. Furthermore, the application of the described invention is not limited to the human body, also devices for the diagnosis of cardiovascular diseases in animals are covered by the claims of this patent.

Further details of the invention will be described with reference to the accompanying drawings and there schematically illustrated embodiments. It shows:

1 shows a prior art device comprising a cuff and a pulse wave detection unit for measuring the ankle-brachial index. 2 shows a prior art arrangement in which four pulse wave detection units and four cuffs are used to measure the ankle-brachial index and pulse velocity.

3 shows by way of example a possible, advantageous embodiment of the invention described here with four sleeves and two pulse wave detection units for measuring the ankle-arm index and the pulse wave velocity,

4 shows a further embodiment of the measuring device according to the invention.

FIG. 1 represents an arrangement with only one oscillometric pulse wave detection unit 10.

With this arrangement, the user must apply the single existing cuff 11 on all four limbs one after the other. In the oscillometric pulse wave detection unit 10, the cardiac output pulse waves from which the cuff is worn at the time of each measurement are converted into electrical signals to derive blood pressure parameters one by one sequentially for all limbs to be measured within a complete measurement cycle , The ankle-arm index can then be calculated by the user or in the instrument after all successive individual measurements have been completely completed.

In a more convenient approach, as shown in FIG. 2, four pulse wave detection units 10 and four sleeves 11 are used to detect the pulse waves on all four limbs almost simultaneously, without the placement of the sleeves during a measurement cycle must be changed. Almost simultaneously means that z. B. due to physiological circumstances on individual limbs automatic repetition measurements may be required to complete a measurement cycle completely. On the basis of these approximately simultaneously obtained pulse waves, the required blood pressure parameters and the ankle-arm index can then be calculated manually or automatically after completion of a complete measurement cycle. With this arrangement, in addition, the pulse wave velocity or the pulse wave transit time between different limbs can be determined when the corresponding pulse wave detection units 10 are synchronized with each other, that is, when a temporal reference is made between the pulse waves detected in the respective limbs.

A pulse wave detection unit 10 comprises at least one or more pressure sensors 12, one or more pressure relief devices 13 for controlling the cuff pressure, one or more pressure sources 14 for inflating the cuff 11, wherein a plurality of pulse wave detection units 10 may share a pressure source 14, and one or more filters 15, 16 for separating the static cuff pressure and the pulse waves superimposed on the static cuff pressure. Both signal components originate from the electrical cuff pressure signal converted by the pressure sensor 12, the filter or filters may be implemented both as hardware and as software.

Usually, but not necessarily, the measurement process is controlled by a microcontroller with memory 17, wherein the user is granted the higher-level control by means of a user interface 18. In each of the above-described pulse wave detection units 10, a separate microcontroller 17 or a separate user interface 18 may be implemented, but it may also be several pulse wave detection units 10 connected to a respective microcontroller 17 or to a user interface 18.

The pulse wave detection units 10 may be coupled with a capability for blood pressure parameter determination, pulse wave velocity or pulse wave transit time determination, or other means of determining parameters for diagnosing peripheral vascular occlusions. This option for determining parameters may be part of the microcontroller 17 or the user interface 18, but may also be part of a pulse wave detection unit 10 or otherwise implemented.

In more detail, the exact functional relationships between the individual components of the pulse wave detection unit 10 are not discussed here, since this is assumed to be familiar to those familiar with these techniques, and this is not a prerequisite for understanding the present invention.

Fig. 3 shows a possible, advantageous arrangement of the present invention. The main disadvantages of the prior art devices of FIGS. 1 and 2 are avoided by the combination of two oscillometric pulse wave detection units 10 with four sleeves 11. The measurements are carried out in such a way that, in a first step of the measurement procedure, measurements are taken simultaneously on two arbitrary limbs, and the remaining two limbs are then measured, again at both simultaneously. To achieve this, two sleeves 11 are each coupled to a pulse wave detection unit 10 by means of an electrically, pneumatically or otherwise controlled switching device 20. Among other things, various valve arrangements are conceivable for implementing this functionality.

Fig. 3 exemplifies, as one of various possible embodiments, an arrangement with two 4/2-way solenoid valves 21. Port l (P) 22 of each valve 21 serves as an inflow port and is connected to the pressure source 14 each Pulse wave detection unit 10 is connected, wherein for the purposes of this invention, two or more pulse wave detection units 10 may be connected to a common pressure source 14.

A sleeve 11 is connected to port 2 (B) 23 of the valve, a second sleeve with port 4 (A) 24. Port 3 (R) 25 is not occupied on both valves to at any time a pressure release for each of the connected sleeves 11 for To allow atmosphere.

First, both 4/2-way valves 21 are energized. In this initial state, the pressure system is vented through the venting devices 13 of the pulse wave detection units 10 which, for patient safety reasons, are typically designed to open to the atmosphere in the de-energized state.

When the user now starts a measurement cycle, the valves 21 remain initially de-energized, the flow between the cuffs 11 and the pulse wave detection units 10 by the connection between port l (P) 22 and port 2 (B) 23 to the right arm and the right Guided ankle. In this operating state, the required oscillometric measurements are now carried out in the usual way Way on both right limbs. In a next step of the measurement cycle, after the measurement on both right limbs has been completely finished, both 4/2 -way valves 21 are now energized. This directs the direction of flow to the left arm and left ankle, since Port 1 (P) 22 is now connected to Port 4 (A) 24. Now, the oscillometric measurements take place in a conventional manner, but on the two left-sided limbs of the patient. After these measurements have also been completely completed, the entire measuring cycle is completed and both 4/2 -way valves 21 fall back into the de-energized state.

During the entire measuring cycle, which in this example consists of a left and a right measuring period, the cuffs 11, which are currently not in use, are vented through port 3 (R) 25 of each 4/2-way valve 21. The pressure release required to control the actual oscillometric measurement continues to be performed by the bleed devices 13 of the pulse wave detection units 10 and is unaffected by the 4/2-way valves 21, provided that by the 4/2-way valves 21 additionally introduced flow resistance is sufficiently low.

Instead, a measurement period may also consist of measurements made simultaneously on upper or simultaneously lower extremities, the left-side cuffs are then port 2 (B) 23 and port 4 (B) 24 of the one 4/2-way valve 21 and the right side cuffs connected to port 2 (B) 23 and port 4 (A) 24 of the other 4/2-way valve 21. Other pairwise combinations of approximately simultaneous limb measurements, such as left arm with right ankle, are also possible within the meaning of this invention. In patients whose condition measurements on specific limbs impossible or forbids, as z. For example, after amputations or vascular accesses are applied, any limb may be excluded from the measurement, for example, by disabling the measurement function for that limb at the user interface 18. In these cases, if only one limb of was excluded during one of the two measurement periods an approximately simultaneous pair measurement, during the other measurement period only a single measurement.

For reasons of patient safety, it is advantageous to design the changeover device 20 so that the secure application of the device is ensured even under various possibilities of error, for example in the event of the failure of the auxiliary energy that excites the changeover device. In the present embodiment, in case of failure of the auxiliary power, the cuff 11 currently connected to the pulse wave detection unit 10 is vented by the discharge device 13 of the corresponding pulse wave detection unit, while the other cuff is vented through port 3 (R) 25 of the 4/2 way -Ventils 21 is vented.

The present invention may also be implemented with any other arrangement for a switching device 20 than that described above, which provides the corresponding functionality. For example, the combination of several 3/2-way valves or the parallel connection of more than one valve to reduce the flow resistance equally a solution to the described problem. Likewise, the switching device 20 by any other energy, so for example instead of electrically and pneumatically , hydraulically or manually operated. FIG. 4 shows a further embodiment of the cardiovascular measuring device, which differs from that of FIG. 3 only in that a single changeover device 20 is connected to four cuffs. The switching device 20 connects a single pulse wave detection unit 10 sequentially to the sleeves 11. This allows sequential oscillometric measurements to be performed on various limbs without requiring manual sleeve changes between these sequential measurements.

Claims

claims

A cardiovascular instrument having a plurality of sleeve ports to which cuff leading lines are connectable, comprising oscillometric pulse wave detection units having at least one pressure sensor and a pressure relief device in the pulse wave detection units, characterized by more cuff connections as pulse wave detection units (10) Pulse wave detection units (10) each having at least one pressure sensor (12) and a pressure relief valve (21), a switching device (20) for connecting the sleeve connections with the pulse wave detection units (10) for performing consecutive oscillometric measurements on different limbs , and means for determining parameters for determining the ankle-brachial index or pulse wave velocity.

A cardiovascular measuring device according to claim 1, characterized in that two oscillometric pulse wave detection units (10) are provided, and in that the switching device (20) connects three or more sleeve terminals to these two oscillometric pulse wave detection units (10) for successive oscillometric measurements on different limbs, being measured on at least two limbs almost simultaneously, without manual cuff changes are required between the successive measurements.

3. Cardiovascular measuring device according to claim 1, characterized in that only one oscillometric pulse wave detection unit (10) is used, that a switching device (20) successively connects two or more sleeves (11) with this oscillometric pulse wave detection unit (10) perform consecutive oscillometric measurements on different limbs without requiring manual cuff changes between these successive measurements.

4. Cardiovascular measuring device according to at least one of the preceding claims, characterized in that the means for determining parameters have an electronic memory (17) and / or a microcontroller (17).

5. Cardiovascular measuring device according to at least one of the preceding claims, characterized in that the switching device (20) for a pair of sleeve connections has a 4/2-way valve (21).

6. Cardiovascular measuring device according to at least one of the preceding claims, characterized in that one or more 4/2-way valves (21) of the switching device (20) with the microcontroller

(17) the means for determining parameters are connected.