WO2005075007A1

WO2005075007A1 - Device and apparatus for the elimination of the carbon dioxide from the blood

Info

Publication number: WO2005075007A1
Application number: PCT/IT2005/000047
Authority: WO
Inventors: Angela Caramuta
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-02-05
Filing date: 2005-02-01
Publication date: 2005-08-18
Anticipated expiration: 2006-08-05
Also published as: ITFI20040025A1

Abstract

A device for the elimination of carbon dioxide from the blood, provided with an inlet (98) for pressurized oxygen, an inlet (90) for the blood to be treated, an outlet (50) for the treated blood and an outlet (94) for the carbon dioxide to be eliminated, said device (59) comprising a decapneisator or oxygenating device (9) and a haemo-concentrator (5) having an outlet section (51) for the ultrafiltrate, said outlet section (51) being connected upstream of the decapneisator (9), so as to pre-dilute the blood entering said inlet (90).

Description

TITLE: "Device and apparatus for the elimination of the carbon dioxide from the blood." SPECIFICATION

The present invention relates to a device for the elimination of the carbon dioxide from the blood and apparatus equipped with the same device.

The device is 'usable, even if not exclusively, combined with an apparatus for therapeutic treatments of the type known with the acronym CRR ^' (Continuous Renal Replacement Therapy) or in an extra-corporeal simple circuit not featuring renal depuration.

In other words, besides the use in a CRRT treatment, the present device can be advantageously employed in a treatment which utilizes an extra-corporal circuit without the renal depuration, i.e. for patients suffering of a bronchopathy of obstructive type, with a non invasive ventilation (NIV) , or in other cases where it is suitable such treatment. Relating the CRRT, it is known, for^' various reasons, it may prove necessary to supplement or replace the renal function of patients to remove waste liquids and soluble substances, such as substances contained in the blood as a result of pathology, surgery, etc.

Various procedures are employed for this purpose, including haemodialysis, haemofiltration and ultrafiltration, all of which provide fro removing waste products from the patient. That is, the patient's blood is fed through filters or membranes to eliminate the waste substances in it, and is then fed back to the patient. For patients in grave condition, procedures include Continuous Arterio-Venous Haemofiltration (CAVH) , Continuous Veno-Venous Haemofiltration (CVVH) , or, in general, CRRT as defined above. In this type of procedure, the patient is connected permanently to the haemofiltration machine for a prolonged period of time. Examples of known CRRT machines are described in US-5,211,849 and US-β,349,170. That is, a CRRT machine comprises a central unit connected at the input and output to the patient, e.g. by means of one or more catheters inserted inside corresponding blood vessels, to continuously withdraw the blood for treatment and feed back the treated blood. The central unit of a CRRT machine normally comprises a blood pump, blood heating and processing means, such as, heparin adding means, means for feeding refill liquid into the blood, ad a haemofilter. The blood withdrawn continuously from the patient is thus pumped by the blood pump along the machine circuit, heparin and appropriately heated refill liquid id added, and the blood is then filtered before being back to the patient. A drawback of the conventional systems is that they are very complex and of difficult management. Another drawback of the known systems for CRRT relates to the need of utilizing the infusion pockets, i.e. containers for the blood dilution. The main aim of the present invention is to eliminate the said drawbacks. This result has been achieved, according to the invention, by adopting the principles of the independent claims. Further ^■ characteristics being set forth in the dependent claims. The advantages of the present invention substantially lie in a greatly improving "decapneisation", i.e. in greatly reducing the C0₂ values of the blood, with a pre-dilution of the blood obtained by a simple mechanism of re-infusion in line that allows, moreover, the elimination of the infusion pockets necessary in the known technique. Besides, using a haemo-concentrator external to the decapneisator device, it is obtained a simplification of the internal circuit followed by the blood within the device, with a reduction of the resistances and with an improvement of the clinical management of the device according to the present invention. Another advantage lies in the principle of the present invention being applicable to existing machines, which can be altered to achieve more complete, more effective performance; in practice, the present device has a great flexibility of use which allows its utilization in any CRRT system with open circuit (i.e. with filter not being integral to the lines). With the present invention, moreover, the treatment techniques of the patients result considerably simplified in respect to those of known CRRT type, with lower costs and better characteristic of installation and management.

Other advantages are the possibility of application in clinical cases up today treatable only with very invasive techniques and that the characteristics of an apparatus and of a device in accordance with the invention remain unchanged requiring only a very little maintenance.

These and other advantages and characteristics of the invention will be best understood by anyone skilled in the art from a reading of the following description in conjunction with the attached drawings given as a practical exemplification of the invention, but not to be considered in a limitative sense, wherein: Fig.l shows a possible embodiment of an apparatus which utilizes a device according to the present invention; the particulars are not to scale and represented only schematically; Fig.2 shows a possible embodiment of a device according to the invention, represented in a schematic longitudinal section. Reference numeral 1 in the drawings indicates as a whole an apparatus in accordance with the present invention.

Apparatus 1 is connected, a the inlet, to a patient P by a first conduit 161, which may be constituted, for example, by a Horizon Medical Product DLC600 KC 11.5 Fr or DLC 800 KC femoral catheter, or by other suitable elements, since other means may, of course, be used to connect the apparatus to the patient, and data relative to other component parts described herein is also provided purely by way of non-limiting examples .

The catheter 161 is connected to a conduit 16. A blood pump 3 is fitted and acting on the conduit 16 downstream to the catheter; on the conduit 16 is also provided a gauge 2 to measure intake arterial pressure of the patient. The pump 3 pumps the blood downstream (the direction of the blood flow is indicated by the arrows VS) in the conduit 16 which, downstream of the pump 3, receives a conduit 18 (also said refill conduit in this description) which is connected to a haemo-concentrator 5, described later on. Prosecuting downstream, on the conduit 16 is provided a device 4 for introducing an anticoagulant substance and, subsequently, the conduit 16 is connected to an inlet 90 of a decapneisator or oxygenating device 9, which is schematically shown in Fig.l and better visible in Fig.2.

Downstream of the oxygenating device 9 (or device for eliminating the carbon dioxide) it is provided the hae o- concentrator 5, from which the treated blood, through the conduit 160 return back to the patient P, passing through a respective catheter 162. Along the conduit 160, upstream of said catheter 162, are provided a gauge 12 for the venous pressure, a device 13 for detecting possible air bubbles and a clamp 14 for closing the conduit.

In other words, an apparatus 1 according to the present invention is provided with a device 59 for eliminating carbon dioxide which comprises a decapneisator 9 and a haemo- concentrator 5. The decapneisator or oxygenating device is connected, by a conduit 7, to an oxygen tank 78 and it is provided with an outlet 94 through which the C0₂ is eliminated, i.e. conveyed toward relevant measuring means not shown (the outlet flow of C0₂ is indicated by the relevant arrows) . Referring in particular to Fig.2, the device 9 for eliminating the carbon dioxide comprises an external container o shell 97, which can be made of rigid polyurethane. The external shell 97 has an inlet aperture 98 for the oxygen disposed upwardly, to which said conduit 7 is connected.

In the inner of the shell 97, the blood coming in from the inlet 90 arrives into a substantially frusto-conical chamber 77, disposed above said inlet 90 and provided with a plurality of holes 72 disposed circumferentially and apt to allow the passage of the blood outwardly in a radial direction. Outwardly to the holes 72 it is provided a plurality of hollow polypropylene fibres 71 defining a kind of barrier; said fibres can be wound to form a skein or hank or disposed parallel each other. The fibres have a surface substantially comprised between 0,6 and 0,8 m² and are jointed by a polycarbonate potting.

The oxygen entering the aperture 98 is insufflated, passing through an upper chamber 74 and through the fibres 71 with a preferable flow of about 3 litres/minute. In such a way, the blood flows outwardly the fibres with a flow rate of 250-400 ml/ in and the haemogloblin contained in the erythrocytes exchanges carbon dioxide with oxygen.

Around the fibres 71 is provided an annular chamber 76 connected, by a conduit 55, to the haemo-concentrator 5. The released carbon dioxide is discharged from the device 7 through the aperture 94 since upwardly to the fibres 71 the passage of the carbon dioxide is not allowed, the chamber 74 being closed upwardly. In the shown example, the device for eliminating carbon dioxide 59 comprises a haemo-concentrator 5 which is disposed externally and upwardly to the oxygenating device 9. In other embodiments, not shown, the haemo-concentrator 5 can be disposed laterally to the oxygenating device 9 or also internally to the same. In particular, the haemo-concentrator device 5 is constituted of a substantially cylindrical polyurethane hollow body containing hollow polysulfone fibres 53 featuring high permeability. The hollow fibres 53 are disposed parallel each other and are joined by a polycarbonate potting. The passage of the blood flow through the fibres 53 determines the removal of the water in excess so that the blood returns to the patient in the correct concentration. The haemo-concentrator device 5 is provided with an outlet section 52 connected, by the outlet 50, to the conduit 160 for the treated blood and with an outlet 51 to which is connected said refill conduit 18 through which passes the ultrafiltrate (flow indicated with the arrow Vϋ) . Along the refill conduit 18 is provided a device 10 of the type called bubble-trap, destined to intercept possible bubbles of air in the flow. Downstream of the device 10 are disposed, in succession, a . pump 11 for the ultrafiltrate, a device 8 detecting blood in the ultrafiltrate (of the type called BLD or blood detector) and a clamp 15. As said before, the refill conduit 18 lets in the conduit 16 upstream of the decapneisator 9. In such a way it is realized a pre-dilution of the blood obtained by a simple mechanism of in-line re-infusion, thus eliminating the use of the infusion pockets. In practice, the ultrafiltrate pump 11 conveys the same ultrafiltrate upstream of the decapneisator for determinating a dilution share which allows to have a blood more fluid in the system, reducing the coagulation danger and maintaining a positive pressure within the oxygenating-decapneizating fibres to avoid the risk of passage of air bubbles in the - blood. In particular, the apparatus is advantageous in all the cases in which it is necessary to product an integration of the blood saturation in oxygen concentration, but especially, a removal of C0₂ in the patients for whom it is difficult to adopt a correct respiratory substitutive therapy. • In use, the beginning of the treatment or priming it is executed with saline solution. Regarding the dimensions, the shell 97 of the device is substantially cylindrical shaped, with a height (L) comprised between 5 and 20 cm and a diameter (D) comprised between 3,5 and 15 cm. In particular, the height (L) is about 10 cm and the diameter (D) of about 7 cm. These dimensions, in respect to the conventional devices, are extremely reduced and allow to hang the device without the need of a supporting base element . It is important also that the blood flow follows a path from the bottom upwards, thus determinating a more correct elimination of the carbon dioxide, with an optimal blood treatment. Practically, all the construction details may vary in any equivalent way as far as the shape, dimensions, elements disposition, nature of the used materials are concerned, without nevertheless departing from the scope of the adopted solution idea and, thereby, remaining within the limits of the protection granted to the present patent for invention.

Claims

1) Device for the elimination of carbon dioxide from the blood, characterized in that it is provided with an inlet

(98) for pressurized oxygen, an inlet (90) for the blood to be treated, an outlet (50) for the treated blood and an outlet (94) for the carbon dioxide to be eliminated, said device (59) comprising a decapneisator or oxygenating device (9) and a haemo-concentrator (5) having an outlet section (51) for the ultrafiltrate, said outlet section (51) being connected upstream of the decapneisator (9), so as to pre- dilute the blood entering said inlet (90) .

2) Device according to claim 1, characterized in that said decapneisator (9) comprises a hollow shell (97) provided with an inlet (98) for pressurized oxygen, an inlet (90) for the blood to be treated, an outlet (76) for the treated blood connected to the haemo-concentrator (5), and an outlet (94) for the carbon dioxide to be eliminated, and a plurality of fibres (71) forming a permeable barrier disposed between said inlet (90) and said outlet (76) , said barrier intercepting the oxygen flowing between said inlet (90) and said outlet (76).

3) Device according to claim 2, characterized in that said fibres (71) are hollow polypropylene fibres.

4) Device according to claim 2, characterized in that said fibres (71) form a skein.

5) Device according to claim 2, characterized in that said fibres (71) are disposed parallel each other.

6) Device according to claim 1, characterized in that said haemo-concentrator (5) is disposed externally to said oxygenating device (9).

7) Device according to claim 1, characterized in that said haemo-concentrator (5) is disposed internally to said oxygenating device (9) .

8) Device according to claim 1, characterized in that said haemo-concentrator (5) is constituted of a hollow body containing hollow permeable fibres (53) . 9) Device according to claim 8, characterized in that said hollow fibres (53) are polysulfone fibres. 10) Device according to claim 8, characterized in that said hollow fibres (53) are joined by a polycarbonate potting. 11) Device according to claim 2, characterized in that said shell (97) has a substantially cylindrical shape, with a height (L) comprised between 5 and 20 cm and a diameter (D) comprised between 3,5 and 15 cm. 12) Device according to claim 2, characterized in that said shell (97) is substantially cylindrical shaped, with a height (L) of about 10 cm and a diameter (D) of about 7 cm. 13) Device according to claim 1, characterized in that the blood flows within the device along a path from the device bottom upwards. 14) Apparatus for blood treatment of CRRT type and the like, and/or of. the type without renal depuration, characterized in that it is provided with a device for eliminating carbon dioxide (97) comprising a decapneisator or oxygenating device (9) having an inlet (90) for the blood to be treated and a haemo-concentrator (5) having an outlet section (51) for the ultrafiltrate, said ultrafiltrate outlet section (51) being connected upstream to the decapneisator (9), so as to pre- dilute the blood entering said inlet (90) . 15) Apparatus according to claim 14, characterized in that it comprises a pump (11) for the ultrafiltrate disposed and

- acting on a conduit (18) connecting the oulet (51) of the haemo-concentrator (5) to a conduit (16) which conveys the patient's blood to the oxygenating device (9). 16) Apparatus according to claim 14, characterized in that said haemo-concentrator (5) is disposed externally to said oxygenating device (9) . 17) Apparatus according to claim 14, characterized in that said haemo-concentrator (5) is disposed internally to said oxygenating device (9) .