Apparatus for Making Extracorporeal Blood Circulation Available

Abstract

The present invention relates to an apparatus or making extracorporeal blood circulation available, in particular a heart-lung machine, comprising a venous connection and an arterial connection, between which a blood reservoir, a blood pump and a bubble detector for the detection of air bubbles are provided, with, downstream of the bubble detector, an arterial line leading to the arterial connection via an arterial clamp and a bypass leading via a bypass clamp back into the blood reservoir which is connected to a pump extracting air from the blood reservoir. In addition, the present invention relates to a method of operating such an apparatus.

Claims

1. An apparatus for making extracorporeal blood circulation available, in particular a heart-lung machine, comprising a venous connection and an arterial connection, between which a blood reservoir, a blood pump and a bubble detector for the detection of air bubbles are provided, with, downstream of the bubble detector, an arterial line leading to the arterial connection via an arterial clamp and a bypass leading via a bypass clamp back into the blood reservoir which is connected to a pump extracting air from the blood reservoir.

2. An apparatus in accordance with claim 1, wherein at least one of an oxygenator and an arterial filter is provided between the blood pump and the bubble detector.

3. An apparatus in accordance with claim 1, wherein blood conducting components of the apparatus, in particular at least one of an oxygenator and an arterial filter, are connected to the blood reservoir via a venting line, with venting clamps being respectively provided between the blood-conducting components and the blood reservoir for the closing of the venting line.

4. An apparatus in accordance with claim 1, wherein the blood pump is made as a centrifugal pump with a central inlet and a tangential outlet, with the tangential outlet facing downwardly when the apparatus is in an operating position.

5. An apparatus in accordance with claim 1, wherein the pump extracting air from the blood reservoir is a roller pump, preferably with a clamping function.

6. An apparatus in accordance with claim 1, wherein an air container is arranged downstream of the pump extracting air from the blood reservoir.

7. An apparatus in accordance with claim 1, wherein the blood reservoir is split into an inlet region and an outlet region by a membrane impermeable for air bubbles.

8. An apparatus in accordance with claim 1, wherein means are provided for the monitoring of the filling level of the blood reservoir.

9. An apparatus for making extracorporeal blood circulation available, in particular a heart-lung machine, comprising a venous connection and an arterial connection, between which a blood reservoir split into an inlet region and an outlet region by a membrane impermeable for air bubbles and having means for the monitoring of the filling level, a blood pump made as a centrifugal pump, an oxygenator, an arterial filter and a bubble detector for the detection of air bubbles are provided, with, downstream of the bubble detector, an arterial line leading to the arterial connection via an arterial clamp and a bypass leading via a bypass clamp back into the blood reservoir which is connected to a roller pump conveying air from the blood reservoir into an air container.

10. A method of operating an apparatus for making extracorporeal blood circulation available, wherein blood entering through a venous connection is pumped by a blood pump through a blood reservoir to an arterial connection, with a bubble detector for the detection of air bubbles being arranged downstream of the arterial connection and, as soon as the bubble detector detects an air bubble, an arterial clamp disposed between the bubble detector (50) and the arterial connection is closed and a bypass clamp is opened so that the blood is guided from the bubble detector via a bypass back into the blood reservoir which is connected to a further pump which extracts air from the blood reservoir and wherein, as soon as the blood detector no longer detects any air bubbles, the arterial clamp is opened again and the bypass clamp is closed so that the operating state prevailing before the detection of an air bubble is established again.

11. A method in accordance with claim 10, wherein the bypass clamp is opened at regular time intervals to flush the bypass.

12. A method in accordance with claim 10, wherein at least one of an oxygenator and an arterial filter is arranged upstream of the bubble detector.

13. A method in accordance with claim 10, wherein blood conducting components of the apparatus, in particular an oxygenator and/or an arterial filter, are connected to the blood reservoir via a venting line, with venting clamps closing the venting line being opened at regular time intervals.

14. A method in accordance with claim 10, wherein the blood pump is made as a centrifugal pump with a central inlet and a tangential outlet, with the tangential outlet facing downwardly when the apparatus is in an operating position.

15. A method in accordance with claim 10, wherein a roller pump, in particular with a clamping function, is used as the pump for the extraction of air from the blood reservoir.

16. A method in accordance with claim 10, wherein the pump for the extraction of air from the blood reservoir conveys the air from the blood reservoir into an air container.

17. A method in accordance with claim 10, wherein the blood reservoir is split into an inlet region and an outlet region by a membrane impermeable for air bubbles.

18. A method in accordance with claim 10, wherein the blood reservoir is provided with means for the monitoring of the filling level; and in that, when the filling level falls beneath a first threshold value, the second pump is started to extract air from the blood reservoir and, when the filling level falls beneath a second threshold value lying beneath the first threshold value, the blood pump is stopped.

19. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention should be described in more detail in the following with reference to a preferred embodiment and to the enclosed FIGURE.

[0022] The enclosed FIG. 1 shows a schematic representation of the individual components of a heart-lung machine.

DETAILED DESCRIPTION

[0023] The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0024] The patient blood coming from a venous connection V is guided via a line 18 into a blood reservoir 20 and moves from there via an outlet 23 into an inlet 34 of a centrifugal pump 30. The inlet 34 is arranged centrally at a pump head of the centrifugal pump 30. The blood is pumped via a tangential outlet 32 arranged at the bottommost point of the pump head of the centrifugal pump 30 into an oxygenator 40 to which an oxygen supply line is connected. The blood enriched with oxygen is subsequently filtered in an arterial filter 44 and finally flows, in the normal case, through an arterial line 68 via the arterial connection A back into the body of the patient.

[0025] The blood reservoir 20 is split into an inlet region (at the top in FIG. 1) and an outlet region (at the bottom in FIG. 1) by a membrane 28. The membrane 28 is permeable for blood, but prevents air bubbles entering into the outlet region from the inlet region.

[0026] A bubble detector 50 is arranged between the arterial filter 44 and the arterial connection A. As long as it does not detect any air bubbles, an arterial clamp 60 in the arterial line 68 remains open, while a bypass clamp 62 remains closed. A throughflow sensor 66 measures the blood flow in the arterial line 68 so that said blood flow can be constantly monitored.

[0027] If an air bubble is detected in the bubble detector 50, the arterial clamp 60 is closed immediately. The reaction path between the bubble detector 50 and the arterial clamp is so long that the detected air bubble only reaches the clamp when this has already been closed. The clamp 60 is a fast-closing clamp which closes in less than 300 ms. Such a fast-closing clamp is described in U.S. patent application Ser. No. 11/366,914 to which reference is herewith made. It can be precluded by the sufficiently long reaction path and the fast closing of the clamp that the air bubble detected in the bubble detector 50 can reach up to the arterial connection A before the closing of the clamp 60.

[0028] At the same time, the bypass line 62 is opened so that the blood, together with the detected air bubble, flows via a bypass 64 back into the line 18 and into the blood reservoir 20.

[0029] In the blood reservoir 20, bubbles rise upwardly so that the blood is located at the bottom in the reservoir, while air collects at the top. Means 22 for the monitoring of the filling level of the blood reservoir are electronically coupled to a roller pump 70 for the extraction of air from the reservoir, for example via an electronic control unit. As soon as the means 22 for the monitoring of the filling level of the blood reservoir 20 report that the filling level has fallen below a first threshold value, the roller pump 70 is switched on, extracts the air present at the top in the reservoir 20 and pumps it into an air container 80. The roller pump 70 has a clamping function so that it acts as a clamp if it is not actively pumping and prevents a backflow of air into the blood reservoir 20.

[0030] If the filling level of the blood reservoir falls further despite the pumping away of air by the roller pump 70 and if it falls below a second threshold value, for example because the venous connection V is not properly connected, the centrifugal pump 30 is switched off and an alarm signal is output.

[0031] The oxygenator 40 and the arterial filter are each connected to the upper region of the blood reservoir 20 not filled with blood via a venting line 96 provided with venting valves 92, 94. The venting line first serves for the flushing and venting of the heart-lung machine during a priming procedure before its putting into operation. In this connection, a so-called priming liquid is filled in via a priming connection PR and the extracorporeal blood circuit is vented. The priming circuit is shown by broken lines in FIG. 1. The venting clamps 92 and 94 are normally closed during the operation of the heart-lung machine. They are, however, opened briefly at regular time intervals, for example every 10 to 15 minutes, so that air which has collected in the oxygenator or the arterial filter is guided into the reservoir 20 and can be extracted from there.

[0032] The reference numerals 24 and 26 designate pressure sensors which monitor the pressure before and after the oxygenator. The measured values of the pressure sensors are forwarded to a pressure monitoring unit 27 via a connection not shown in FIG. 1 for reasons of clarity. In the event of an unusually increasing pressure drop at the oxygenator 40, this can be clogged by coagulated blood so that there is a need for action.

[0033] In addition, the extraction pressure at which blood is extracted from the patient into the line 18 is monitored with the aid of a pressure sensor 25. In this connection, the line anyway present between the blood reservoir 20 and the roller pump 70 is utilized to measure this pressure. The measured result is likewise passed on to the pressure monitoring unit 27.

[0034] To avoid blood standing in the bypass 64 in FIG. 1 beneath the bypass clamp 62 coagulating while the arterial clamp 60 is open and the bypass clamp 62 is closed, the bypass clamp 62 is opened at regular time intervals for a short period. The bypass 64 is periodically flushed in this manner so that blood coagulation cannot occur in the bypass 64.

[0035] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.