|Title of Invention||
A BLOOD OXYGENATOR
|Abstract||This inyention relates to a blood o>:ygenator comprising a hoLlsing ,it a first chamber being an oxygenating chamber and a second c:hamber being a heat e>:change chamber, said first and second cl,ambers separated by a par't;ition I...all, a blood inlet and oLltlet located at the lolaJer end of said hoLlsing and sLlch that the blood is allolaJed to flol... Llpl...ardly from said inlet I...ithin the hoLlsing and then do\£JnI...ardly and discharged from saicl oLltlet|
|Full Text||FIELD OF THE IWVENTtON:
jhis invention relates to Improvements in or relating to hollow fiber membrane based blood oxygenator. More particularly, this Invention relates to an oxygenator having an integral heat exchanger,
BACKGROUND OF THE INVEWTIQW:
Blood oxygenators are disposable devices more often used In open-heart surgeries to function as an artificial lung. The input to the device is the venous blood from the patient and supplied oxygen "as. The output of the device Is the oxygenated blood. The exhaust gas Is vented to the atmosphere. During surgical procedure, there is a requirement to alter the body temperature and a heat exchanger is also provided for this,
US patent No, 5225161 and 5120501 to Mathewson et al discloses a device including an integrally formed membrane oxygenator and heat exchange device positioned in a single housing. The device includes a thermally conductive body formed with a plurality of blood pathways on its surface, and a gas permeable membrane, positioned in the housing in contact with the heat exchange body to cover or He within a portion of each of the pathways. The membrane defines a gas pathway separate fl-om the blood pathway through which a gas Is directed. The blood is directed through the individual blood pathways. The device also includes various ports and passageways for delivering the blood to the individual channels, and for collecting and removing the blood from the device. However, the need exists to provide means within the oxygenators, which can act as a trap for bubbles, which may get into the blood circuit. Further, the heat transfer efficiency also needs to be enhanced.
OBJECTS OF THE INVENTION:
An object of this invention is to propose an improved construction of a blood oxygenator.
Another object of this invention Is to propose a blood oxygenator having a heat transfer module.
Still another object of this invention is to propose a blood oxygenator which imparts insignificant damage to the blood.
Yet another object of this Invention is to propose a blood oxygenator which prevents air bubbles from entering a patient"s body.
BRIEF DESCRIPTION OF THE INVENTION:
According to this invention, there is provided a blood oxygenator comprising a housing with a first chamber being an oxygenating chamber and a second chamber being a heat exchange chamber, said first and second chambers separated by a partition wall, a blood inlet and outlet located at the lower end of said housing and
sucn that the biood is allowed to now upwardly from said Inlet within the housing and then downwardly and discharged from said outlet,
DESCRtPTIOli WITH REFERENCE TO ACCOMPAMYiWG DRAWINGS:
The invention will now Pe explained in greater details with the help of the accompanying drawings where,
Fig. 1 shows a perspective view of the biood oxygenator of the present invention; Fig 2 shows a front sectional view; Fig. 3 shows a back sectional view.
The hollow fiber membrane biood oxygenator with integral heat exchanger descroned here has a housing consisting of a shell (4) with ribs (16) having a top cover (6) and a bottom over (5), all made of rigid plastics like polycarbonate, polystyrene, etc. There are two chambers inside the shell viz. Oxygenating chamber (20) and heat exchanger chamber (21) both separated t^om each other by a partition (18). Shell has the blood inlet (1A) and outlet (IB) ports, cardioplegia port (12), sampling port (13), thermowell port (14) and air release port (15). Water inlet (3A) and outlet (3B) ports and gas Inlet port (2A) are located on the bottom cover. Top cover has the gas outlet port (2B). A neck Is provided on the top cup (19) for coupling to the "venous reservoir"-another device to be used alongwith this device,
The device comprises an oxygenating chamber (20) to consist of bundle of microporous hollow fibers (7) made of materials like polypropylene. The hollow f\bef& sf& Pjst f^sds Into a ff.Bt fo.^TJ s.nd the.n wound Into an oval s.hsos. Such s bundle is then inserted into oxygenating chamber (20) and ends are potted (6). Blood flow is extraluminar and the oxygen gas flows inside hollow fibers (7).
The heat exchanger chamlber €21;» has a plurality of Metallic tubings iWJ) onade of onaterials, like stainless steel, (^^odised aluminitum, propylerme, polyester, etc. arranged in aMultiple stag¬gered layers with tooth ends potted (11) and located inside the heat exchanger chanftier. Blood f IOMIS outside the tubings and Mater at appropriate temperature is circiudated inside tuA)ings (8). Each layer consists of tiubiirvgs iHttich are spaced between them. Porous spacer made of material like polyethylene is placed between the heat exchanger tube layers to enhance the heat tratnsfer efficieiTDcy by increasing the (mixing of blood.
Blood enters the dev"ice at the blood inlet port (1A]» at the bottom end of the heat exchanger chamber and rises up as shown by arncRM line €X]i- Heat exchange takes place during this path. Once it reaches the top, blood flon^> down over the hollow fibers (7) and the gas is exchanged. TUrtrauigh the outlet port (IB) located at the bottom of the oxygenating column, the blood is discharged frofin the device?. Iktie to this up—down flow, any air nthich may get into the device will get trapped at the top edge of the device and slowly diffuse out through the hollow fibers. This unique flow pattern thus prevents the budsble from entering into the patient.
Water at adequate temperature enters the device through water inlet (2A) port flows alosmtg the luumen of the tube and is discharged through the water outlet port €2B>. The heat exchanger tubes are filled with flow agitators V^"% made of materials like polypropylene, polyethylene, etc tMhich enhances the heat traunsfer efficierwcy by providing tuirbulent flow of water. A water fltaw) partition «!(&), integral part of the bottcm cover is
provided to give two pass water flow path enhance the heat transfer further.
Oxygen gas enters through the gas inlet port (3A) and flows along the lumen of the hollow fibers and is vented to the atmosphere through the gas outlet port (3B).
The blood flow path in the device first rises and then dips, by means of which the device acts as trap for bubbles, If any, which get into the blood circuit. Further, the presence of flow agitators Inside the heat exchanger and porous spacers In between the heat exchanger tube layers enhance heat transfer efTiciency by increasing the mixing of blood.
1. A blood oxygenator comprising a housing (4) with a first chamber being an oxygenating chamber (20) and a second chamber being (21) a heat exchange chamber, said first (20) and second (21) chambers separated by a partition wail (18), a blood inlet (1A) and outlet (IB) located at the lower end of said housing (4) and such that the blood is allowed to flow upwardly from said inlet within the housing and then downwardly and discharged from said outlet.
2. A blood oxygenator as claimed in claim 1 comprising a bundle of microporous hollow fibers (7) disposed within said oxygenating chamber (20), the gas flow being within said hollow fibers (7) and being connected to a gas Inlet (2A) and outlet (2B).
3. A blood oxygenator as claimed in claim 1 wherein the heat exchanger chamber (21) has a plurality of parallel tubes (8) arranged In multiple layers.
4. A blood oxygenator as claimed In claim 1 wherein the heat exchanger tubes (8) are filled with flow agitators (9) which enhances the heat transfer efficiency by providing turbulent flow for water.
5. A blood oxygenator as claimed In claim 1 wherein porous spacers (10) are placed between the heat exchanger tube layers to enhance the heat transfer efficiency by Increasing the mixing of blood.
6. A blood oxygenator substantially as herein described and illustrated, by way of accompanying drawing.
|Indian Patent Application Number||1153/MAS/1999|
|PG Journal Number||26/2007|
|Date of Filing||29-Nov-1999|
|Name of Patentee||M/S. SREE CHITRA TIRUNAL INSTITUTE FOR MEDICAL SCIENCES & TECHNOLOGY|
|Applicant Address||BIOMEDICAL TECHNOLOGY WING, SATELMOND PALACE, TRIVANDRUM 695 012.|
|PCT International Classification Number||A 61M 1/14|
|PCT International Application Number||N/A|
|PCT International Filing date|