SE515605C2 - Method and apparatus for dosing an additive in the suction of liquid - Google Patents

Abstract

The invention relates to a method and an apparatus for collecting and transporting liquids, for instance blood, while at the same time dosing an additive, for instance an anticoagulent agent, in an accurate proportion to the amount of the collected liquid. The liquid or a liquid/air/gas mixture is sucked up by means of a suction nozzle (4) and transported through a suction hose (5). A dosage device (6) comprising an exchangeable, flexible container (23) with said dosing additive, for instance a CPD bag, is connected to the suction hose whereby the pressure levels in the apparatus, provided by connecting the apparatus to a vacuum pump (1), are adjusted in such a way relative to each other that no additive at all is introduced when only air/gas is sucked up in the suction nozzle, whereas dosing additive is introduced into the suction hose (5) as soon as liquid is sucked through the suction nozzle (4) so that the amount of dosage additive is in proportion to the amount of sucked liquid. The invention is characterized by connecting the positive pressure side (30) of the suction source (1) to a pressure bag (31) in order to apply the necessary pressure on the CPD-bag (23), for dosing as soon as liquid has been sucked up by the suction nozzle (4).

Description

30 35 .. | m 515 605 ¿_g¿¿jj¿'¿; _ 2 _ then pass in a closed system suitable defoaming and separation filters and recipient for diverting air bubbles trapped in the blood and filtering. The blood is then collected in containers / blood bags completely without admixture of air or other gas by means of a negative pressure in the system. Appropriate negative pressure in the system is created by connecting to a suction source in the form of a vacuum pump.

The anticoagulant is metered in before the blood reaches the filtration and deaerating agents. The dosing device is designed so that it gives an accurate proportional dosing in relation to the amount of blood absorbed. This is achieved by applying the dosing device and the suction nozzle for sucking up liquid under negative pressure of different pressure levels, and wherein the pressure gradient between these different pressure levels is determined so that no additive is added at all when no liquid (blood) is present in the suction nozzle, and that the amount dosed additives become almost completely proportional to the amount of liquid absorbed when liquid is sucked into the suction nozzle. According to SE 467 725, the dosing device is mounted at a higher level (N) than the suction nozzle and the filter. This level must be adjusted to a set pressure gradient so that a balance is obtained between the pressure gradient and the flow resistance of the hose or connecting pipe that connects the dosing device to the suction nozzle on the one hand and the gravitational force that causes the liquid column in the connecting hose to drain into the suction nozzle hose. side. This requires some form of height-adjustable mechanics, which has been a disadvantage of previous devices.

EP 0 742 737 describes a couple of similar examples of how the dosing device can be designed. Even in these cases, some form of height-adjustable mechanism is required for setting the correct dosage. The dosing device preferably comprises a flexible container or bag for anticoagulant, so-called CPD bag, which is enclosed in a rigid housing as shown in Figure 1 of the EP patent. An- 10 15 20 25 30 35 ,, ,,,, .Q _; .f 1, ._,. , ..,. _ »- \ -; lv. . u; l u '; § v .. i _ v »~ 1n f HI. 1 - 1 1 || i 1 »1 n u. f; . The order is designed so that a suction force will act on the dosing means corresponding to a pressure gradient P2-P3. In the alternative embodiment shown in Figure 5, "dosing unit E - outer system", the bag 20 'is under atmospheric pressure or under a pressure produced by a load 58. To set the correct dosage, the bag is arranged at a height. and submersible plate. Even in this case, a mechanical adjustment is required during use.

Since the correct and accurate dosing of additives is very important, especially in a blood collection system, it is a disadvantage to rely on mechanical adjusting devices of the previous type. Since the blood collection devices can be mobile, there is also a risk that a per se correct setting is disturbed when the device is moved. The object of this invention is to solve the problems described above and to provide an automatic and accurate dosing of additives to a absorbed liquid (blood), independent of mechanical adjusting devices and without utilizing the gravitational force, as has been the case in previous elevations. and submersible platforms or containers for additive bags.

According to the invention, this is achieved by using a separate suction source, for example a vacuum pump, for both suction of liquid and addition of dosing agent. The negative pressure created by the suction source, the suction side of the suction source, is connected to the blood collection system itself (blood collection bags) (suction nozzle, while the suction source overpressure, the pressure side of the suction source, is connected to the dosing device for applying the required (over) - show a CPD bag, for the dosage when liquid is sucked up by the suction nozzle.

According to a preferred embodiment, the dosing device comprises 515 605 _ 4 _ n. N:. ; =. .- arrangement a pressure bag, "bellows bag", which is applied an adjustable pressure from the pressure side of the suction source.

In the following, an example of the invention will be described in more detail in connection with the accompanying drawings, in which Figure 1 schematically shows a flow chart for a blood collection device in a surgical operation, Figure 2 shows in principle, but in more detail, the initial position when applying a pressure on the dosing container in the form of a CPD bag by means of a pressure bag, figure 3 shows the position after pressure application and when the CPD bag is almost emptied of its contents, figure 4 shows a side view of the dosing box with lid, and figure 5 shows schematically a pressure vessel for applying a pressure directly to a dosing vessel placed in the pressure vessel in the form of a CPD bag.

The blood collection device according to Figure 1 consists of a number of main parts which work with a certain preset pressure gradient to produce a negative pressure (suction) in the device. The device comprises a vacuum pump 1 to create a suitable negative pressure. The pump can have a suction capacity for about 2000 ml of blood per minute, and is suitably adjustable for different pressure levels by means of control device 2. The pump has a suction side (suction) and a pressure side (pressure) in a known manner, the suction side being primarily connected. to the device for creating the required negative pressure in the apparatus in a manner similar to that shown in EP 0 742 737. The pump is connected to the various parts of the device by means of a pipe or hose system with valves, manometer and pressure sensor 3 which are known per se. kind and therefore will not be described in more detail here. 10 15 20 25 30 35 515 605 _ 5 _,. . . The device comprises the following main parts: a suction nozzle 4 for collecting blood under atmospheric pressure, a suction hose 5 connected to a dosing device 6 for additives in the form of anticoagulants, a mixing and defoaming unit (mixer) 7 for mixing and removal of foam of the aspirated blood, a recipient 8 in the form of a canister bag 9 placed in a container 10, and double transfer bags 11, 12 for automatic filling of the aspirated blood.

This invention relates in particular to the dosing device 6, for which reason the other parts of the device will not be described in detail here. Reference is also made in these parts in general to the above-mentioned patent publications SE 467 725 and EP 0 742 737.

The dosing device 6 is thus connected to the suction hose 5 at the inlet of the mixer 7. The connection hose is provided with a control and non-return valve device with drip chamber 13 for supply of anticoagulant in a suitable proportion, for example 5-15%. The base level is infinitely adjustable and the proportion is determined with the selected cannula in the system or with the control valve.

The blood is sucked up with the nozzle 4, which is provided with finger holes 14, and is then sucked via the said suction hose 5 to the mixer which can be made in the manner shown in EP 0 742 737. The mixer has a coarser hose 15 which rotates in a known manner for mixing the aspirated blood with the added anticoagulant and separating air bubbles from the blood.

The blood so centrifuged is sucked via a filter arrangement 16 with in this case a coarse filter 17 with a mesh size of c = a 150 - 250 y and a fine filter 18 with the mesh size cza 30 - 40 y into the canister bag 9 which holds 2000 ml. A photo-optical sensor S1 reacts when the absorbed blood volume amounts to approximately 700 ml. This opens a 10 15 20 25 30 35 515 605 _ 5 _ -. -. . , - f | . . . . . Oh. . ; a. solenoid valve 19 which allows about 500 ml of blood to transfer to transfer bag ll. When that bag is full, a sensor S2 gives a signal to the device control panel for opening the solenoid valve 20 and closing the solenoid valve 19. Furthermore, the hose valve 42 is closed and instead the hose valve 43 is opened for filling the transfer bag 12. When that bag is also full, this is indicated on the same way of a sensor S3 with light and sound signals. The suction system can be used without interruption during the exchange of the transfer bags because the canister bag 9 has a reserve capacity of min. 1300 ml. The transfer bags can of course be exchanged repeatedly, which is why the capacity of the device is in principle limitless.

An additional photo-optical sensor S4 in the recipient 8 indicates a certain permissible minimum level in the canister bag 9. The canister bag 9 and the transfer to the transfer bags 11 and 12 are described in more detail in our parallel patent application no. . . . . . . . . . . . . . . ..

The bloodstream around the device - such as suction nozzle, suction hose, mixer hose, filter arrangement and transfer system - is otherwise coated with a blood-compatible layer of a kind known per se.

The dosing device 6 consists of a holder or box 27 with a rigid housing 21 and an internal space 22 with space for the CPD bag 23 or other flexible container from which the anticoagulant is to be supplied to the suction hose 5, see Figures 2 and 3. This is done via a connecting hose 24 which is connected to the filled CPD bag 23 and the suction hose 5.

The holder or box 27 can be placed on the outside 26 of the device so that it is easily accessible when changing the CPD bag. It has a swivel lid 25 with snap lock 28 to open and close the box when changing the CPD bag, see figure 4.

The dosing device is connected to the vacuum pump 1 via a hose system 29, 30.

As mentioned in the introduction, it is important that the anticoagulant be dosed continuously and in accurate proportion to the amount of blood drawn. When the device sucks only air / gas mixture, the pressure in the suction hose 5 is greater than in the dosing device 6, which prevents the dosing means from flowing from the bag into the mixer hose. As soon as liquid is sucked up through the suction hose, the dosing agent must no longer be prevented from being supplied. In this situation, a greater pressure drop is obtained in the suction hose due to the suction liquid restricting the free inflow of air and the pressure difference becomes so small that the dosing agent can flow down through the connecting hose by suitable means 24. This has previously been achieved with the aid of of the force of gravity.

According to the invention, the vacuum pump 1 is used instead for this purpose. By connecting the dosing container to the pressure side of the vacuum pump, a sufficient hydrostatic pressure is obtained to allow the supply of the dosing agent.

According to a suitable embodiment, the pressure is applied through a pressure bag 31 which is also placed in the dosing holder or box and is connected to the vacuum pump through the hose system 29, 30. The hose 29 is connected to the suction side of the vacuum pump and the hose 30 to the pressure side of the pump. Preferably, the pressure bag is placed next to the filled bag 23, as shown in Figure 2. The two bags are vertically placed, side by side, with the pressure bag at the far end as shown in Figures 2 and 3, suitably fixed by means of straps or other fixing means. 32 with one side against the inner wall of the box, so that it is always in the device (the box), but free to expand towards the CPD bag when it is put under pressure. The pressure bag then works according to the "bellows principle".

When connected to the suction side of the vacuum pump (hose 29), the bag 31 is compressed due to the negative pressure, against the box wall as shown in figure 2. This is the starting position, when a filled CPD bag 23 is placed in the box next to the empty pressure bag and presses it against the inner wall of the box. In this position the pressure side of the vacuum pump is switched on instead, and the bag 31 is put under pressure 10 15 20 25 30 35 515 605 _ 3 _ which in this case can amount to about 20 mbar. The bag is filled and presses on the filled CPD bag, as shown in Figure 3. This pressure is then sufficient that when liquid (blood) begins to be sucked up into the suction nozzle to allow a flow of dosing agent to the suction hose 5, which flow is related. to the current, non-balancing pressure gradient between suction hose and dosing container. However, the pressure is low enough to prevent the flow of dosing agent as the nozzle only sucks air / gas. The pressure is otherwise adjustable by means of a control device 33 in the pressure hose 30. Furthermore, sound-absorbing means 44 are arranged on the pressure side in order to reduce any sound effects due to pressure changes in the system. The suction system of the suction connection comprises a needle valve 45 and a safety valve 46.

The switching from suction function to pressure function can take place mechanically by means of a suitable switching device in the hose 29, for example a hose clamp 34 which restricts the suction function so that the pressure through the line 30 can instead act on the pressure bag. This has been indicated by an indentation of the hose in figure 1. In figures 2 and 3 the hose clamp is shown open resp. closed. Conveniently, the lid 25 of the box can instead be designed so that it pinches and restricts the hose 29 into the box when the lid is closed, after a new CPD bag has been put in place. A standard CPD bag is normally enough for 2.5 liters of blood.

A sensor S5 detects when the amount of anticoagulant in the bag is below a certain minimum level, ie when the bag is almost empty, eg when 5% of the liquid is left in the bag (30-40 ml). The sensor can also detect and sound an alarm if a bag is missing in the container. Sensor and contact means can be designed in different ways, preferably in the form of a spring-loaded connector which is actuated by the pressure bag, when it is extended to a predetermined position, as indicated by figure 3. For this reason, the pressure bag can be provided with a band, platta e dyl. which when tightened or moved to its end position 35 may affect a contact or switch. 10 15 20 25 30 35 515 605 _ 9 _ - »| . . . ,. -. v.

In this way, a more distinct contact function is obtained.

According to an alternative embodiment, the holder or box 27 can be designed as a tight container or can 36, pressure chamber, with lid and with space for a filled CPD bag, see figure 5. In this case the pressure is applied directly into the container so that the overpressure formed in the container presses on the filled CPD bag and allows a flow of dosing agent to the suction hose 5 in the same way as in the previous embodiment.

Suitably the lid 37 is designed as a unit with a peripheral sealing ring 38 against the wall of the pressure vessel and a central bushing 39 with hose system whose one end in the form of a so-called nail 40 is connected to the CPD bag and the other end 41 is connected to the connecting hose 24.

The invention is not limited to the example shown in the figures but can be varied within the scope of the appended claims.

Claims (20)

10 15 20 25 30 35 515 605 "'' n.» »S:. |» - - »PATENTKRAV A method of simultaneously dosing an additive in exact proportion to the amount of liquid absorbed during the suction and transport of liquids, for example blood, wherein the liquid or a liquid / air / gas mixture is sucked up by means of a suction nozzle (4) and pass through a suction hose (5) and that a dosing device (6) comprising a replaceable, flexible dosing container (23) with said additive is connected to the suction hose, the pressures in the device, created by connection to a suction source (1), being regulated in so in relation to each other that no additive is supplied as only air / gas is sucked in through the suction nozzle, while on the other hand additives flow into the suction hose as soon as liquid is sucked into the suction nozzle so that the amount of dosed additive is proportional to the amount of liquid absorbed. (1) pressure side (30) the arrangement (6) for applying the required pressure thereon is connected to the dosing duct flexible dosing container (23), for example a so-called CPD bag, for dosing when liquid is absorbed by the suction nozzle (4). Method according to claim 1, characterized in that the pressure side (30) of the suction source (1) is connected to a pressure bag (31) arranged in the dosing device (6), which applies said pressure to the flexible dosing container (23) when dosing the additive. Method according to claim 1, characterized in that the pressure side (30) of the suction source (1) is connected to a tight container, pressure chamber (36) arranged in the dosing device (6), which applies said pressure to a dosing container (23) placed in the pressure chamber. ) for dosing the additive. A method according to claim 2, characterized in that the suction side (29) of the suction source (1) is connected to the pressure on 10 15 20 25 30 35 515 605 _ 11 _ i .. n. ,. - .- late (31) before dosing to allow placement of a filled bag (23) with additives in a holder or box (27) next to the pressure bag (31) compressed by the negative pressure of the device. Method according to Claim 4, characterized in that switching to the pressure side (30) of the suction source (1) is effected by throttling the suction connection (29) by means of a hose clamp (34). A method according to claim 4, characterized in that the pressure side (30) is made by throttling the suction connection (29) by means of the lid (25) of the holder or box when the lid is closed after placing a filled bag (23) by switch to the suction source (27) for dosing medium with dosing agent in the holder or box. A method according to claim 1, characterized in that the ratio between the amount of dosing agent and the amount of liquid absorbed can be regulated by means of a control valve (13) in the connection hose (24) to the suction hose (5). Method according to claim 1, characterized in that the pressure on the pressure side (30) of the suction source (1) is regulated by a control means (33). Device for sucking and transporting liquids, for example blood, at the same time, dosing an additive in exact proportion to the amount of liquid sucked up, comprising a suction nozzle (4) for sucking up the liquid or a liquid / air / gas mixture, a suction hose (5) through which the aspirated liquid is arranged to pass and a dosing device (6) connected to the suction hose (5) comprising a replaceable, flexible dosing container (23) with said additive, the pressures in the device being created by connection to a suction source (1) and so regulated in relation to each other that no additive 10 15 20 25 30 35 515 605 ._12__,. . ~ v. then only air / gas is sucked in through the suction nozzle (4), while on the other hand additives are arranged to flow into the suction hose (5) as soon as liquid is sucked into the suction nozzle (4) so that the amount of dosed additive is proportional to the amount of absorbed liquid characterized in that the pressure side (30) of the suction source (1) is connected to the dosing device (6) in order to apply the required pressure there to the flexible dosing container (23), for example a so-called CPD bag, for the dosage when liquid is sucked up by the suction nozzle (4). Device according to claim 9, characterized in that the pressure side (30) of the suction source (1) is connected to a pressure bag (31) arranged in the dosing device (6) which is arranged to apply said pressure to the flexible dosing container (23) during dosing. of additives. 11. ll. Device according to claim 9, characterized in that the pressure side (30) of the suction source (1) is connected to a tight container, pressure chamber, (36) arranged in the dosing device (6) for applying said pressure to a dosing container (23) placed in the pressure chamber. for dosing the additive. Device according to claim 10, characterized in that the suction side (29) of the suction source (1) is connected to the pressure bag (31) before dosing to allow placement of a filled bag (23) with additives in a holder or box (27) at the side of the pressure bag (31) compressed by the negative pressure of the device. Device according to claim 12, characterized in that the suction connection (29) of the dosing device (6) comprises switching means (34) for switching between suction and pressure connection to the pressure bag (31). 14. Device according to claim 13, characterized in that the switching means are constituted by a hose clamp 10. 15. 20 25 30 35 515 605,. »'« F - - (34). Device according to claim 13, characterized in that the lid (25) of the holder or box (27) for the dosing means is arranged to, when closing the holder or box, after changing the bag (23) for dosing means, squeeze the suction connection pipe (29) so that this is strangled. Device according to claim 9, characterized in that a control valve (13) is arranged in the connecting hose (24) from the dosing device (6) to the suction hose (5) for controlling the ratio between the amount of dosed additive and the amount of liquid absorbed. 17. Device according to claim 9, characterized in that control means (33) are arranged on the pressure side (30) of the suction source (1) for regulating the pressure applied to the dosing device (6). Device according to claim 9, characterized in that the dosing device (6) comprises a sensor 19. (S5) to indicate when the amount of additive in the flexible dosing bag is below a certain minimum level, for example when 5% of the liquid is left. Device according to claim 18, characterized in that the sensor comprises contact means which are arranged to be actuated by a clamping band, plate or the like arranged on the pressure bag (31) when this due to the applied pressure, and corresponding compression of the dosing bag (23), has extended to a predetermined end position (35). Device according to claim 9, characterized in that when the liquid consists of blood, the bloodstream through the apparatus - such as suction nozzle, suction hose, mixer hose, filter arrangement and transfer system - is coated with a blood-compatible layer.