MEDICAL FLUSHING PUMP WITH TWO SUCTION LINES

Description

[0001] The present invention relates to a device for flushing a body cavity with a fluid, wherein the fluid is pumped out of the body cavity via two lines. The respective pumping power is regulated via controllable pinch valves, the two pinch valves being coupled in antiparallel. Field of application of the invention

[0002] It is common practice to perform fluid lavage during endoscopic examinations and particularly during therapeutic interventions. This involves flushing the body cavity (e.g. a joint cavity, a bladder or a uterus) with a fluid (e.g. saline solution). For this purpose, a lavage fluid can be pumped from a reservoir into the body cavity via a pump, e.g. a roller pump. In the simplest case, the lavage fluid can flow out of the cavity through an opening. However, suction pumps are usually used to pump the lavage fluid out again. The typical procedure for such minimally invasive interventions involves the use of additional medical devices for cutting, ablating or cauterizing, each of which has its own suction line. If all of these suction lines are unlocked, no pressure can be built up to expand the body cavity.Typically, as few incisions as possible should be made in the walls of the body cavity and this results in one supply line being combined with several suction lines.

[0003] During therapeutic interventions in body cavities (e.g. knee or shoulder joints, bladder, uterus or other artificial body cavities) two medical instruments are often used: a shaver and a radiofrequency (RF) ablation device. Furthermore, it has proven advantageous if both medical instruments are connected to a suction line. Controlling the suction power has proven to be a challenge. On the one hand, the volume of fluid suctioned out must correspond to the inflowing volume, otherwise either the necessary expansion of the body cavity can no longer be guaranteed or the pressure in the body cavity increases so much that tissue injury can occur. On the other hand, it is advisable for the pumped out volume to be discharged via the discharge line of the respective instrument.

[0004] Furthermore, it is state of the art to pinch and close the suction lines using pinch valves with a solenoid or linear magnet (solenoid) through a plunger. This fulfills the boundary condition that the medium used for distension does not come into contact with the device, allowing the medium to reach the body cavity via a sterile tube. However, the force with which the solenoid acts on the tube is directly proportional to the speed, meaning that high switching speeds place a high load on the tube's abutment and the tube material.

[0005] EP 0173816 A2 describes a rinsing device for the endoscopic examination of ureters with two parallel piston pumps whose piston rods are connected by toothed racks.

[0006] US 2012 / 0090620 A1 describes a device for flushing body cavities with two pumps that are controlled by a manual control unit, so that the second pump pumps fluid from the device into the body cavity, while the first pump sucks fluid from the body cavity into the device.

[0007] EP 1 374 925 B1 describes a device for flushing a body cavity with a flushing pump and a suction pump, wherein the flushing pump is controlled as a function of the desired flow rate in the body cavity and the suction pump is controlled as a function of the desired pressure in the body cavity and wherein the speed of the suction pump serves as a sensor signal for controlling the flushing pump.

[0008] The medical device described below ensures that the above-mentioned tasks are met in a simple manner: Exactly as much volume is pumped out of the body cavity as is supplied. Furthermore, pumping occurs primarily via the discharge line of the instrument being operated. Furthermore, an improved pinch valve control system has been developed.

[0009] The device according to the invention is in the Figures 1 and 2 described, to which reference is hereby made.

[0010] Within the scope of the device according to the invention, a storage container for the rinsing fluid is first set up. The supply line from this storage container leads into the body cavity via a controlled roller gear pump. The supply line is expediently coupled to the roller gear using a corresponding cassette, as is known in the art. A controlled vacuum pump is used to suction the fluid from the body cavity. The two medical instruments (e.g., shaver and high-frequency ablation device) each have a suction line. Both lines are each provided with a pinch valve, which is described in more detail below. The discharge lines lead, in the direction of flow, downstream of the pinch valves into a storage container. This storage container is connected to the controlled vacuum pump. The storage container is designed so that the suctioned fluid collects in it and does not reach the vacuum pump.

[0011] Typically, an additional line is installed between the body cavity and the reservoir. This additional line contains a restrictor, ensuring that only a very small amount of irrigation fluid is withdrawn (less than 10% of the total flow rate). The flow rate can also be restricted by a correspondingly reduced tube diameter. The additional line serves only to maintain a constant flow rate to drain any small hemorrhages and tissue debris that may occur, thus enabling a clear view of the fluid-filled body cavity.

[0012] An important element of the medical device described are the pinch valves. These are coupled in such a way that one line is fully open when the other line is fully closed. This is achieved by a stepper motor that drives two racks via a gear. The two racks are positioned opposite each other on the gear so that one rack extends from the device when the other retracts (antiparallel operation). The two hoses are each positioned in a clamping device, which also serves as a support for the racks that serve as the pinch device. By controlling the stepper motor, it is possible to select which line the irrigation fluid is suctioned through. In the respective end positions, suction occurs either completely through one line or completely through the other line (volume flow ratio 100:0 or 0:100).However, intermediate positions can also be set so that, for example, the liquid flow is divided in a ratio of 80:20 or 60:40.

[0013] The squeezing elements, which are firmly connected to the toothed racks, act on the tube sections to be clamped and, analogous to the state of the art, exert a pressure which leads to a deformation or even closure of the tube lumen.

[0014] An optional feature of the invention is a position sensor located on the gear, which enables absolute position determination of the gear at any time. The advantage of this is that the position can be determined even when stationary, eliminating the need for movement of the position sensor, which would result in partial or temporary opening of the clamped tube lumen. This property is utilized for a further feature of the invention: a drive control for the gear that is variable during the closure phase. This control system ensures that the gear racks are moved at maximum speed during the switching phase, and that during the clamping phase, or part of the clamping phase up to the final closure, the movement is performed with a drive power that corresponds to a defined and predetermined pressure on the tube to be clamped.In order to achieve this, also according to the invention, the drive device is designed in such a way that a motor-gearbox combination that can be used there is designed in such a way that the maximum possible speed can be achieved in the switching phases with the minimum force required for disconnection.

[0015] According to the invention, a motor-gearbox combination is selected that can achieve a maximum achievable squeezing force. By coupling increasing power transmission and decreasing travel speed in gearboxes, a travel speed achievable at full motor speed is determined by defining the maximum achievable squeezing force. This assumes that the components used are not oversized and are therefore as inexpensive as possible. The selection guideline according to the invention is therefore to first dimension the motor-gearbox combination for moving the racks so that just the required compressive force can be generated to clamp the hoses and thus securely close them. This means that the maximum achievable travel speed of the motor-gearbox combination will be higher than with motor-gearbox combinations that generate a stronger compressive force.The required pressure force can be determined by measuring the pressure on the hose to be clamped until it closes.

[0016] Optionally, the position sensor can also be attached to one of the racks. It is also possible to use multiple position sensors (e.g., on the rack and gear, or on both racks).

[0017] An advantage of the valve control according to the invention is that the hose sections and the abutments can be designed in such a way that less robust and thus cheaper material can be used or material can be saved and at the same time the suction lines can be closed as quickly as possible.

[0018] The valve control according to the invention is such that the current position of the racks determined by the position sensor influences the travel speed. The travel speed is maximum in the phases in which there is no contact between the squeezing elements or racks and the hose to be squeezed. The drive unit is designed for this maximum travel speed. According to a speed profile according to the invention, the speed is reduced to 50% in the last 10 to 20% of the travel, i.e. until the hose is completely squeezed. By reducing the speed at which the hose lumen is squeezed closed, pressure surges in the suction line are avoided and the hose material and abutment are protected, thus extending the service life of the hose and the cassette or hose insertion aid that guides the hose. This is not possible with linear magnets.Other values ​​for the travel speed reduction and the times at which the travel speed is changed, including continuous changes and multiple steps, are also in accordance with the invention.

[0019] A further development of the inventive concept is a travel speed profile in which the travel speed is reduced for a short distance before hose contact, then increased upon hose contact, followed by a continuous reduction to zero in the position where the hose is completely clamped. Other profiles with any combination of increased and reduced travel speed are also within the scope of the invention.

[0020] At the start of treatment, irrigation fluid is pumped into the body cavity via the roller wheel pump until the required pressure or dilation of the body cavity is reached. Once the required pressure is reached, the suction pump is activated, with the output of the roller wheel pump and suction pump being linked. Only as much fluid is pumped out as is supplied. When the medical instruments are activated (e.g. shaver and radiofrequency ablation device), the pinch valves are adjusted so that the pump output is directed primarily via the drainage line of the respective instrument. When the shaver is activated, the drainage line connected to the shaver is opened and the line connected to the radiofrequency ablation device is closed. If the other medical device is used at a later time, the other line is opened and the first line is closed.As described above, opening or closing can also be performed partially. In this case, for example, 80% of the suction power would be directed through the suction line connected to the activated medical instrument, while 20% would be directed through the other instrument. At the end of the procedure, it is possible to stop the roller pump but continue activating the suction pump until as much of the irrigation fluid as possible has been aspirated. List of reference symbols:

[0021] (1) Reservoir for the rinsing fluid, (2) Supply line (3) Controlled roller pump (4) Controlled vacuum pump (5) First medical instrument (6) First suction line (7) Second medical instrument (8) Second suction line (9) Third suction line (optional) (10) Throttle on optional third suction line (11) First pinch valve (12) Second pinch valve (13) Waste container (14) First rack with first pinch element (15) Second rack with second pinch element (16) Gear (17) Abutment for pinch element on first rack with inserted and clamped hose (20) (18) Abutment for pinch element on second rack with inserted, non-clamped hose (21) (19) Position sensor

Claims

1. A device for irrigating a body cavity (K), including (i) a reservoir (1) for the irrigation fluid, (ii) a feed line (2) (iii) a controlled roller pump (3) (iv) a controlled vacuum pump (4) (v) a first medical instrument (5) with a first suction line (6) (vi) a second medical instrument (7) with a second suction line (8) (vii) optionally a third suction line (9) with a restrictor (10) (viii) a first pinch valve (11) at the first suction line (6) (ix) a second pinch valve (12) provided at the second suction line (8) (x) a waste container (13) connected to the first suction line (6), the second suction line (8) and optionally the third suction line (9) as well as to the controlled vacuum pump (4), characterized in that the first pinch valve (11) and the second pinch valve (12) are coupled with each other in an anti-parallel manner.

2. The device according to Claim 1, characterized in that the anti-parallel coupling is carried out such that the two pinch valves (11, 12) are formed through pinch elements which are each attached to gear racks (14, 15) and the two gear racks are coupled with each other via a gear wheel (16) so that they perform an anti-parallel motion.

3. The device according to Claim 2, wherein the gear wheel (16) is driven by a stepper motor.

4. The device according to Claim 2 or 3, wherein the gear wheel (16) includes a position sensor which allows for an absolute position determination of the gear wheel at all times.

5. The device according to any one of Claims 2 to 4, wherein one or both gear rack(s) include(s) one or more position sensors which allow for absolute position determination of the gear wheels at all times.

6. The device according to any one of Claims 1 to 5, wherein the third suction line (9) includes a restrictor so that less than 10% of the total volume flow is suctioned through the third suction line (9).

7. The device according to any one of Claims 1 to 6, wherein the first and third medical instruments (5, 7) are formed by a shaver and a high-frequency ablation device, each of which is respectively connected to a suction line (6, 8).