Device for Automatically Establishing the Venous Inflow to a Blood Reservoir of an Extracorporeal Blood Circulation System

Abstract

A device for establishing venous inflow to a blood reservoir of an extracorporeal blood circulation system includes a restricting unit for restricting a venous inflow line and a vacuum unit for supplying vacuum to the blood reservoir. The device includes a control unit that, upon setting the desired venous flow rate, automatically supplies a first actuating signal to the restricting unit for restricting venous inflow to the blood reservoir and supplies a second actuating signal to the vacuum unit for establishing a degree of vacuum within the blood reservoir, so as to achieve the set venous flow rate. The device includes a venous flow sensor.

Claims

1. A device for establishing venous inflow to a blood reservoir of an extracorporeal blood circulation system including a venous inflow line from a patient to the blood reservoir and an arterial outflow line extending from the blood reservoir to the patient, the device comprising: a restricting unit configured for clamping the venous inflow line in order to act on the venous inflow amount to the blood reservoir in the range below a basic value, the basic value comprising a value established by gravitational conveyance while the inflow line is not restricted by the restricting unit; a vacuum unit configured for applying a vacuum to the blood reservoir in order to act on the venous inflow amount to the blood reservoir in the range above the basic value; a control device that includes a single operating element having a plurality of operating positions and configured to be manipulated in a single manipulation by a user to establish both a degree of closure of the venous inflow line and an amount of vacuum in the blood reservoir for venous inflow to the blood reservoir at, above or below the basic value; and a venous flow sensor disposed on the venous inflow line and configured to measure a venous flow rate of the circulating blood in the venous inflow line and to send a venous flow rate signal representing the venous flow rate to the control device; wherein, at each operating position of the plurality of operating positions, the control device is configured to supply a different combination of a restricting unit setting that corresponds to an extent of a restriction of the venous inflow amount to the blood reservoir below the basic value, based on the manipulation of the single operating element in the single manipulation and a vacuum unit setting that corresponds to the operating position to the vacuum unit for establishing the amount of vacuum in the blood reservoir to define an extent of the increase in the venous inflow amount to the blood reservoir above the basic value based on the manipulation of the single operating element in the single manipulation, without the use of a blood level sensor and blood level signals; wherein the control device is configured to automatically determine a first flow rate adjustment value based on the venous flow rate measured by the venous flow sensor and the selected operating position; wherein the control device is configured to automatically send a first flow rate adjustment signal to the restricting unit and a second flow rate adjustment signal to the vacuum unit such that the restricting unit adjusts the degree of closure at the venous inflow line and the vacuum unit adjusts the amount of vacuum in the blood reservoir to collectively adjust the flow rate of the circulating blood in the venous inflow line by the two flow rate adjustment values.

2. The device according to claim 1, wherein the control device further comprises a display device for visual display of a display value corresponding to the venous inflow amount.

3. The device according to claim 1, wherein the vacuum unit is connected to a vacuum source via a line.

4. The device according to claim 1, wherein the vacuum unit comprises an integrated vacuum source.

5. The device according to claim 1, further comprising a vacuum sensor for detecting a vacuum in the blood reservoir, the vacuum sensor connected to the control-device for providing a first measuring signal.

6. The device according to claim 1, wherein the vacuum unit further comprises a safety device configured such that, upon actuation by the control device or upon failure of the control device, an application of a vacuum to the blood reservoir is interrupted which establishes atmospheric pressure in the blood reservoir.

7. A device for establishing venous inflow to a blood reservoir of an extracorporeal blood circulation system including a venous inflow line from a patient to the blood reservoir and an arterial outflow line extending from the blood reservoir to the patient, the device comprising: a restricting unit configured for clamping the venous inflow line in order to act on the venous inflow amount to the blood reservoir in the range below a basic value, the basic value comprising a value established by gravitational conveyance while the inflow line is not restricted by the restricting unit; a vacuum unit configured for applying a vacuum to the blood reservoir in order to act on the venous inflow amount to the blood reservoir in the range above the basic value; a vacuum sensor configured for detecting a vacuum in the blood reservoir, the vacuum sensor connected to the control-device for providing a first measuring signal; a control device that includes a single operating element having a plurality of operating positions and configured to be manipulated in a single manipulation by a user to establish both a degree of closure of the venous inflow line and an amount of vacuum in the blood reservoir for venous inflow to the blood reservoir at, above or below the basic value; a venous flow sensor disposed on the venous inflow line and configured to measure a venous flow rate of the circulating blood in the venous inflow line and to send a venous flow rate signal representing the venous flow rate to the control device; and wherein, at each operating position of the plurality of operating positions, the control device is configured to supply a different combination of a restricting unit setting corresponding to an extent of a restriction of the venous inflow amount to the blood reservoir below the basic value based on the manipulation of the single operating element in the single manipulation and/or a vacuum unit setting corresponding to the operating position to the vacuum unit for establishing the amount of vacuum in the blood reservoir to define an extent of the increase in the venous inflow amount to the blood reservoir above the basic value based on the manipulation of the single operating element in the single manipulation; wherein the control device is configured to automatically determine a first flow rate adjustment value based on the venous flow rate measured by the venous flow sensor and the selected operating position; wherein the control device is configured to automatically send a first flow rate adjustment signal to the restricting unit and a second flow rate adjustment signal to the vacuum unit such that the restricting unit adjusts the degree of closure at the venous inflow line and/or the vacuum unit adjusts the amount of vacuum in the blood reservoir to collectively adjust the flow rate of the circulating blood in the venous inflow line by the two flow rate adjustment values.

8. The device according to claim 7, wherein the control device further comprises a display device for visual display of a display value corresponding to the venous inflow amount.

9. The device according to claim 7, wherein the vacuum unit is connected to a vacuum source via a line.

10. The device according to claim 7, wherein the vacuum unit comprises an integrated vacuum source.

11. The device according to claim 7, wherein the vacuum unit further comprises a safety device configured such that, upon actuation by the control device or upon failure of the control device, an application of a vacuum to the blood reservoir is interrupted which establishes atmospheric pressure in the blood reservoir.

12. A device for establishing venous inflow to a blood reservoir of an extracorporeal blood circulation system including a venous inflow line from a patient to the blood reservoir and an arterial outflow line extending from the blood reservoir to the patient, the device comprising: a restricting unit disposed on the venous inflow line and configured to adjustably restrict the venous inflow line in order to adjust the flow rate of the blood circulating in the venous inflow line in the range below a basic value, the basic value comprising a value established by gravitational conveyance while the inflow line is not restricted by the restricting unit; a vacuum unit configured for adjustably applying a vacuum to the blood reservoir to adjust a reservoir vacuum in order to adjust the flow rate of the blood circulating in the venous inflow line in the range above the basic value; a control device that includes a single operating element configured to be manipulated by a user to select a target venous flow rate of the circulating blood in the venous inflow line; and a venous flow sensor disposed on the venous inflow line and configured to measure a venous flow rate of the circulating blood in the venous inflow line and to send a venous flow rate signal representing the venous flow rate to the control device; wherein the control device is configured to at least one of automatically send a first flow rate adjustment signal to the restricting unit and automatically send a second flow rate adjustment signal to the vacuum unit such that at least one of the restricting unit adjusts the degree of restriction at the venous inflow line and the vacuum unit adjusts the reservoir vacuum in the blood reservoir to adjust the flow rate of the circulating blood in the venous inflow line until the target venous flow rate is achieved.

13. The device according to claim 12, wherein, the control device is configured to automatically determine a flow rate adjustment value based on the venous flow rate measured by the venous flow sensor and the target venous flow rate selected via the single operating element, and upon determining a target venous flow rate higher than the venous flow rate measured by the venous flow sensor, the control device is configured to at least one of automatically send a first flow rate adjustment signal to the restricting unit and automatically send a second flow rate adjustment signal such that at least one of the restricting unit decreases the degree of restriction at the venous inflow line and the vacuum unit increases the reservoir vacuum in the blood reservoir to increase the flow rate of the circulating blood in the venous inflow line by the magnitude of the flow rate adjustment value.

14. The device according to claim 13, wherein, upon determining a negative flow rate adjustment value, the control device is configured to at least one of automatically send a first flow rate adjustment signal to the restricting unit and automatically send a second flow rate adjustment signal such that at least one of the restricting unit increases the degree of restriction at the venous inflow line and the vacuum unit decreases the reservoir vacuum in the blood reservoir to reduce the flow rate of the circulating blood in the venous inflow line by the magnitude of the flow rate adjustment value.

15. The device according to claim 14, wherein the control device is configured to automatically determine whether to send the first flow rate adjustment signal, the second flow rate adjustment signal, or both the first and the second flow rate adjustment signals, based on one or more of target flow rate, flow rate adjustment magnitude, target response time, target sensitivity, and target accuracy.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention will be described in more detail in the following with reference to the drawing, in which:

[0017] FIG. 1 shows a view of the basic structure of an extracorporeal blood circulation system having a device according to a first embodiment of the invention.

DETAILED DESCRIPTION

[0018] As is shown in FIG. 1 by means of a first embodiment of a device according to the invention, an extracorporeal blood circulation system basically includes, in addition to a reservoir 1, a venous inflow line 2 from a patient P to the reservoir 1 and an arterial outflow line 3 from the reservoir 1 to the patient P. In order to supply blood from the reservoir 1 to the patient P, a pump 9, such as a roller pump or a centrifugal pump, is provided on or in the arterial outflow line 3. As is apparent from FIG. 1, the reservoir 1 is located at a lower level than the patient so that a venous inflow to the reservoir is already possible owing to gravity alone, the extent of which also depends, however, on the cross-section and the length of the tube used in the venous inflow, besides the height difference between patient and reservoir.

[0019] In order to restrict the venous inflow to the reservoir 1 below the basic value, the first embodiment of the invention as described herein includes a restricting unit 4, by which the venous inflow line 2 can be restricted (e.g., by being gradually closed), for example by clamping or squeezing. For this purpose, the restricting unit 4 includes an electromagnetically, pneumatically or hydraulically-operated clamp which is not shown in detail in FIG. 1. The restricting unit 4 is arranged on the venous inflow line 2 and in some embodiments acts externally on the tube without coming into contact with the blood. If the venous line is unrestricted by the restricting unit 4 and no vacuum is applied to the reservoir, the venous inflow is at its basic value.

[0020] In order to increase the venous inflow to the reservoir 1 above the basic value, the first embodiment of a device according to the invention includes a vacuum unit 5 for applying a vacuum to the reservoir 1. For this purpose, the vacuum unit 5 is connected via a vacuum line 10 to the reservoir 1 which is accordingly designed so as to become pressure-tight, when vacuum is applied. If the vacuum unit 5 is itself not configured for generating the vacuum, for example by integration of a suitable pump, the vacuum unit 5, as is the case in the first embodiment shown in FIG. 1, is connected to a vacuum source via a vacuum source line 11. Suitable vacuum sources are generally available in the form of stationary installations in hospitals where the device according to the invention is primarily used.

[0021] According to the invention, the setting of the venous inflow by the user occurs in a simple and comfortable yet also safe manner via a control means 6 (e.g., a control device) which is shown in FIG. 1. The control means 6 supplies to the restricting unit 4, via a first actuation line 4a, a first actuating signal for establishing the degree of closure of the venous supply line 2 in order to carry out restriction of the venous inflow amount to the reservoir below the basic value. The control means 6 furthermore supplies to the vacuum unit 5, via a second actuation line 5 a, a second actuating signal for establishing the amount of vacuum in the reservoir 1 in order to carry out an increase in the venous inflow amount to the reservoir above the basic value. In embodiments, one or more of the actuation lines 4a and 5a can be implemented as analogue or digital signals, as carriers or analogue or digital signals, as a digital bus system, and/or the like.

[0022] According to the invention, the control means 6 includes a single operating element 7 for setting of the amount of venous inflow to the reservoir by a user of the device. Solely by actuating this single operating element 7, the user can set the venous inflow amount to the reservoir 1 and thereby undertake both an increase to beyond the amount which is essentially determined by the gravitational drainage, the length and the cross-section of the tube used on the venous side, as well as a reduction to below this value. The control means 6 according to the invention converts the setting carried out by the user by means of the single operating element 7 into a corresponding actuation of the restricting unit 4 or the vacuum unit 5 so as to thereby cause a reduction of the venous inflow below the gravitational amount by closing (clamping) the venous inflow tube line 2, or alternatively, an increase above the gravitational amount in the venous inflow by creating a vacuum in the reservoir 1. In some examples, the single operating element 7 may be a control knob and/or a control interface.

[0023] As is shown by FIG. 1, the first embodiment includes a pressure sensor 12, which is arranged on or in the reservoir 1 so as to detect the vacuum in the reservoir 1 and provide a corresponding first measuring signal. The measuring signal of the vacuum sensor 12 is supplied via a first measuring signal line 12a to the control means 6, which can carry out regulation of the vacuum taking into account this measured value. In embodiments, the vacuum sensor 12 may also be connected directly to the vacuum line 10.

[0024] The control means 6 according to the first embodiment furthermore includes a display 8 which indicates to the user the set venous inflow amount and/or the percentage tube occlusion and/or the reservoir vacuum. In embodiments, the functionality of the control means 6 and the vacuum unit 5 may be included in one single unit or may be distributed across various physical devices which communicate with each other.

[0025] As is shown by FIG. 1, the first embodiment includes a sensor 16 (e.g., a flow sensor), which is arranged or disposed on the venous inflow tube line 2, such as between the restricting unit 4 and the reservoir 1. In certain examples, the sensor 16 may be disposed on the inflow tube line 2 between the restricting unit 4 and the patient P. The sensor 16 is configured to measure a venous flow rate (e.g., volumetric flow rate) of the circulating blood in the venous inflow tube line 2.

[0026] In various examples, the sensor 16 is coupled (e.g., operatively, communicatively, electrically, and/or electronically) to the restricting unit 4, the vacuum unit 5, and/or the control means 6. For example, the sensor 16 may be configured to send a flow rate signal (e.g., representing or corresponding the flow rate of the circulating blood in the venous inflow tube line 2) to the control means 6, such as continuously or intermittently. In certain embodiments, the control means 6 is configured to determine a flow rate adjustment value and to send a flow rate adjustment signal (e.g., representing the flow rate adjustment value) to the restricting unit 4 and/or the vacuum unit 5. In some examples, the flow rate adjustment value corresponds to the difference between the flow rate measured by the sensor and a target flow rate (e.g., set via the single operating element 7). In various embodiments, the restricting unit 4 (e.g., a clamp) is configured to be electronically controlled, modified, manipulated, and/or adjusted, such as to be automatically adjusted (e.g., by the control means 6) in response to the venous flow rate measured by the sensor 16. The sensor 16 outputs a measuring signal (e.g., representing the measured flow rate) that is supplied to the control means 6 via a measuring signal line 16a. That is, for example, if the measured (by the sensor 16) venous flow rate is higher than the set value (target flow rate), then the control means 6 acts on the restricting unit 4 by causing it to restrict the line 2 until the set value and the measured value are equal (or at least approximately equal).

[0027] In certain examples, the restricting unit 4 is configured to reduce restriction (e.g., automatically) if flow rate is to be increased at the venous inflow tube line 2. For example, the restricting unit 4 is configured to reduce restriction (e.g., automatically) upon receiving a flow rate adjustment signal representing a positive flow rate adjustment value (e.g., when measured flow rate is less than the target flow rate). In certain examples, the restricting unit 4 is configured to increase restriction (e.g., automatically) if flow rate is to be decreased at the venous inflow tube line 2. For example, the restricting unit 4 may be configured to increase restriction (e.g., automatically) upon receiving a flow rate adjustment signal representing a negative flow rate adjustment value (e.g., when measured flow rate is greater than the target flow rate). In various examples, the restricting unit 4 is configured to both increase and reduce restriction in response to the flow rate measured by the sensor 16, such as automatically increase and/or reduce. In some examples, the restricting unit 4 (e.g., a restrictor) is configured to be adjustable from 0% open (i.e., 100% closed) to 100% open (i.e., 0% closed), such as continuously or step-wisely adjustable.

[0028] In various embodiments, the vacuum unit 5 is configured to be electronically controlled, modified, manipulated, and/or adjusted, such as to be automatically adjusted (e.g., by the control means 6) in response to the venous flow rate measured by the sensor 16. In certain examples, the vacuum unit 5 is configured to reduce pressure (e.g., automatically) in the reservoir 1 (e.g., increase vacuum level) if flow rate is to be increased at the venous inflow tube line 2. For example, the vacuum unit 5 is configured to reduce pressure (e.g., automatically) in the reservoir 1 (e.g., increase vacuum level) upon receiving a flow rate adjustment signal representing a positive flow rate adjustment value (e.g., when measured flow rate is less than the target flow rate). In certain examples, the vacuum unit 5 is configured to increase pressure (e.g., automatically) in the reservoir 1 (e.g., reduce vacuum level) if flow rate is to be decreased at the venous inflow tube line 2. For example, the vacuum unit 5 may be configured to increase pressure (e.g., automatically) in the reservoir 1 (e.g., reduce vacuum level) upon receiving a flow rate adjustment signal representing a negative flow rate adjustment value (e.g., when measured flow rate is greater than the target flow rate). In various examples, the vacuum unit 5 is configured to both increase and reduce pressure in the reservoir 1 in response to the flow rate measured by the sensor 16, such as automatically increase and/or reduce. That is, if the measured flow value is lower than the set value, the control means 6 causes the restricting unit 4 to unclamp the line 2 until the line gets fully open, and if the set value is still higher than the measured value, the control means 6 causes vacuum to be applied, via the vacuum unit 5, to the reservoir until the set and measured values are equal (or at least approximately equal).

[0029] In some embodiments, the restricting unit 4 and the vacuum unit 5 are configured to dynamically controlled and/or adjusted in response to a flow rate adjustment value. For example, the control means 6 may be configured to send (e.g., automatically) a first flow rate adjustment signal to the restricting unit 4 and to send a second flow rate adjustment signal to the vacuum unit 5 to jointly adjust the flow rate from the measured flow rate (e.g., measured by sensor 16) to the target flow rate (e.g., set via the single operating element 7). In certain examples, the control means 6 is configured to automatically determine whether to send a flow rate adjustment signal to the restricting unit 4 and/or to send a flow rate adjustment signal to the vacuum unit 5. In some examples, the restricting unit 4 is configured to adjust flow rate (e.g., in the venous inflow tube line 2) within a first flow rate range (below gravitational value), with a first response time, at a first sensitivity, and/or at a first accuracy. In some examples, the vacuum unit 5 is configured to adjust flow rate (e.g., in the venous inflow tube line 2) within a second flow rate range (above gravitational value), with a second response time, at a second sensitivity, and/or at a second accuracy. In certain embodiments, the control means 6 is configured to automatically determine where to send its one or more flow rate adjustment signals, based on one or more of target flow rate range, flow rate adjustment magnitude, target response time, target sensitivity, and target accuracy. For example, in case the reservoir is placed at the same level of the patient or higher than the patient, there is little or no gravitational drainage; therefore, the set value is almost always higher than the measured value, which requires that the line be fully open and vacuum be applied to the reservoir so that the set and the measured values become equal or at least approximately equal.

[0030] As is shown in FIG. 1, the vacuum unit 5 can be equipped in all of the embodiments with a safety device 15 which, upon corresponding actuation by the control means 6 or if control should fail, interrupts the application of a vacuum to the reservoir 1 and establishes atmospheric pressure in the reservoir 1.