Title:
FILTERING CARDIOTOMY RESERVOIR
United States Patent 3768653
Abstract:
A surgical blood sucker and peristaltic pump combination discharge a three-phase mixed stream of blood, air and surgical tissue debris into a cardiotomy reservoir through a slot shape blood inlet nozzle tangentially disposed on the wall of the blood reservoir volume. The tissue debris is collected internally in the reservoir on the reservoir base filter face and the face of the conical air filter. The air, under slight pressure in the reservoir, exits from the reservoir through the air filter and a relief valve. The defoamed blood flows from the reservoir through multiple base filter plate exit apertures, into a blood oxygenator.
Application Number:
05/222124
Publication Date:
10/30/1973
Filing Date:
03/21/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
210/436, 422/45, 210/304, 210/316
International Classes:
A61M1/36; A61M1/32; B01D35/14; B01D31/00
Field of Search:
23/258.5 210/130,136,188,436,321,304,316,472
Primary Examiner:
Spear Jr., Frank A.
Claims:
I claim
1. A cardiotomy reservoir for recovering patient blood in a surgical procedure, comprising in combination:
2. The combination of claim 1 wherein the blood inlet conduit comprises:
3. The combination of claim 1 wherein the base plate comprises:
4. The combination of claim 1 wherein said reservoir base filter comprises:
5. The combination of claim 1 wherein said reservoir base filter comprises:
6. The combination of claim 1 wherein said reservoir air outlet conduit has a pressure relief valve secured thereon, said valve relieving at a pressure not exceeding 100 mm Hg above atmospheric.
7. The combination of Claim 1 wherein said air filter comprises:
8. The combination of claim 7 wherein said truncated cone shape porous filter comprises:
9. The combination of claim 7 wherein said truncated cone shape porous filter comprises:
10. In a cardiotomy reservoir whose internal reservoir volume is enclosed by a reservoir case having a case top and case base, the combination comprising:
11. The combination of claim 10 wherein the nozzle of the blood inlet conduit has a slot aperture providing a flat oriented blood inlet flow tangentially on the inner wall of said case.
12. The combination of claim 10 wherein the blood inlet conduit comprises:
13. The combination of claim 10 wherein the case base comprises:
14. The combination of claim 10 wherein said reservoir base filter comprises:
15. The combination of claim 10 wherein said reservoir base filter comprises:
16. The combination of claim 10 wherein said reservoir air outlet conduit has a pressure relief valve secured thereon, said valve relieving at a pressure not exceeding 100 mm Hg above atmospheric.
17. The combination of claim 10 wherein said air filter comprises:
18. The combination of claim 17 wherein said truncated cone shape porous filter comprises:
19. The combination of claim 17 wherein said truncated cone shape porous filter comprises:
1. A cardiotomy reservoir for recovering patient blood in a surgical procedure, comprising in combination:
2. The combination of claim 1 wherein the blood inlet conduit comprises:
3. The combination of claim 1 wherein the base plate comprises:
4. The combination of claim 1 wherein said reservoir base filter comprises:
5. The combination of claim 1 wherein said reservoir base filter comprises:
6. The combination of claim 1 wherein said reservoir air outlet conduit has a pressure relief valve secured thereon, said valve relieving at a pressure not exceeding 100 mm Hg above atmospheric.
7. The combination of Claim 1 wherein said air filter comprises:
8. The combination of claim 7 wherein said truncated cone shape porous filter comprises:
9. The combination of claim 7 wherein said truncated cone shape porous filter comprises:
10. In a cardiotomy reservoir whose internal reservoir volume is enclosed by a reservoir case having a case top and case base, the combination comprising:
11. The combination of claim 10 wherein the nozzle of the blood inlet conduit has a slot aperture providing a flat oriented blood inlet flow tangentially on the inner wall of said case.
12. The combination of claim 10 wherein the blood inlet conduit comprises:
13. The combination of claim 10 wherein the case base comprises:
14. The combination of claim 10 wherein said reservoir base filter comprises:
15. The combination of claim 10 wherein said reservoir base filter comprises:
16. The combination of claim 10 wherein said reservoir air outlet conduit has a pressure relief valve secured thereon, said valve relieving at a pressure not exceeding 100 mm Hg above atmospheric.
17. The combination of claim 10 wherein said air filter comprises:
18. The combination of claim 17 wherein said truncated cone shape porous filter comprises:
19. The combination of claim 17 wherein said truncated cone shape porous filter comprises:
Description:
CROSS-REFERENCES TO RELATED APPLICATION
This application is related to the following applications filed earlier by the same sole inventor:
U.S. Pat. application, Ser. No. 175,182 for BLOOD OXYGENATOR AND THERMOREGULATOR APPARATUS by Robert C. Brumfield, filed Aug. 26, 1971;
U.S. Pat. application, Ser. No. 196,458, for BLOOD OXYGENATOR GLOW GUIDE, by Robert C. Brumfield, filed Nov. 11, 1971;
U.S. Pat. application Ser. No. 202779 FOR BLOOD OXYGENATOR, by Robert C. Brumfield, filed Nov. 29, 1971; and
U.S. Pat application Ser. No. 216,649 for LOW PRESSURE HEAT EXCHANGER FOR OXYGENATED BLOOD, by Robert C. Brumfield, filed Jan. 10, 1972.
BACKGROUND OF THE INVENTION
Blood oxygenators useful for oxygenating patient's blood during extra-corporeal circulation are classified in Class 23 Subclass 258.3. The cardiotomy reservoir of this invention is taught to be useful in combination with a blood oxygenator, and the invention is so classified.
Often there is a substantial loss of patient blood during surgical treatment, and surgical blood suckers are useful for processing and returning blood to the patient's extra-corporeal circulation. Since the recovered blood can contain surgical tissue debris, the blood can respond to the debris by initiating the clotting mechanism. It is desirable to remove the debris from the recovered blood as quickly as possible prior to returning this blood to the patient. The cardiotomy reservoir of this invention quickly and cleanly processes patient blood, filtering the surgical debris and simultaneously defoaming the blood for rapid return to the patient's circulation.
SUMMARY OF THE INVENTION
A cardiotomy reservoir for recovering patient's blood in a surgical procedure has a uniform tubular case having a base plate and a top plate, together providing an enclosed reservoir volume. A blood inlet conduit is secured in the reservoir providing a slot aperture discharge nozzle directing a flat blood inlet stream flow tangentially onto the inside tubular wall of the reservoir. The small centrifugal force of the blood stream flow tends to deposit the surgical tissue debris on the tubular wall. A reservoir base filter is coextensive with the base plate and has a porosity suitable for filtering whole blood, yet retaining surgical tissue debris on the base filter inside the receptacle. A retaining ring means coplanarly secures the reservoir base filter to the reservoir base plate. An air filter is concentrically coextensive with the tubular case, from the top plate of the reservoir to the base filter, the air filter having a porosity suitable for filtering air, yet blocking blood flow through it. An air exit conduit is normally centrally disposed from the reservoir top plate, discharging filtered air from the reservoir. A plurality of blood exit apertures conductively disposed through the base plate provide for flow of filtered blood from the cardiotomy reservoir. The reservoir base filter and the air filter are both treated with a very thin film of a defoaming composition which is physiologically compatible with patient blood, thereby facilitating the defoaming of the blood, air and surgical tissue debris as it is pumped into the cardiotomy reservoir. A slight internal reservoir positive pressure ranging up to 100 mm Hg maintains a positive flow of blood out of the cardiotomy reservoir through the base plate blood exit apertures. The positive pressure is maintained inside the cardiotomy reservoir by a low pressure release valve secured to the air exit conduit. The air filter can be truncated cone shaped porous filter having a cone apex centrally disposed adjacent the reservoir base filter and a cone base disposed adjacent the top plate of the reservoir. The reservoir base filter and the air filter can be porous reticulated polyurethane foam or a porous silicone foam of selected porosity. The air filter is typically a foam having 10. pores per lineal inch. The reservoir base filter typically passes particle sized to 100 microns.
Other objects and advantages of this invention are taught in the following description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
A description of this invention is to be read in conjunction with the following drawings:
FIG. 1 is an elevational perspective partial sectional view of the cardiotomy reservoir of this invention, disposed in a blood oxygenator.
FIG. 2 is a sectional view through 2--2 of FIG. 1.
FIG. 3 is a sectional view disclosing a further modification of this invention similar to the view of FIG. 2.
FIG. 4 is another sectional view through 4--4 of FIG. 1.
FIG. 5 is a detailed perspective fragmentary view illustrating the base plate 13 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A surgical blood sucker and a peristaltic pump combination are used to suck up blood lost in a surgical procedure or the like. The sucker and pump combination discharge a three-phase mixture of blood, air and surgical tissue debris into the cardiotomy reservoir.
Referring to FIG. 1 in detail, the cardiotomy reservoir 10 of this invention is shown disposed in the top portion of the blood oxygenator 11. The cardiotomy reservoir 10 has a uniform receptacle tubular case 12 closed by a base plate 13 and a top plate 14, providing an enclosed reservoir volume 15. A blood inlet conduit 16 is normally secured through the top plate 14, and has a blood inlet conduit discharge nozzle 34, whose slot discharge aperture 17 is permanently positioned, directing a flat blood inlet stream flow tangential to the inner wall 18 of the case 12. A reservoir base filter 19 is coextensive with the base plate 13, the filter 19 providing a porosity suitable for filtering whole blood. Typically the filter 19 has pore openings sized to pass 100 micron size particles, and retain surgical tissue debris inside the reservoir volume 15 on the base filter 19. A retaining ring 20 secures the filter 19 on the base plate 13. The ring 20 is sealed to the tubular case ring 30, which is in turn sealed to the base plate 13. The tubular case 12 is sealed to the ring 30 and the top plate 14, providing an integral structure.
An air filter 21 is shown concentrically conextensively disposed in the reservoir 10, coextending from the top plate 14 to the base filter 19. The truncated cone 21 has a truncated apex 22 and a cone base 23. The air filter 21 is a plastic sponge having a porosity suitable for filtering air yet blocking blood flow. An air exit conduit 24 is normally centrally disposed through the top plate 14 providing an exit conduit discharging filtered air from the reservoir volume 15. Typically, the conduit 24 is sealed to the top plate 14. A pressure relief valve 25 is shown conductively disposed on the conduit 24, the relief valve being set to relieve at a pressure approximately 100 mm Hg above atmospheric pressure. A plurality of blood exit apertures 26 are conductively disposed through the base plate 13, providing for the flow of filtered blood from the cardiotomy reservoir 10. The filter components, the air filter 21 and the reservoir base filter 19 are both coated by well known procedures with physiological compatible compositions which accelerate blood defoaming on contact with the film coating. Typically, a silicone composition is well known and used for this purpose. Plural base filter leaf supports 27 are shown coplanarly integrally secured to the base plate 13, providing blood exit flow relieving passage means for the blood filtered through the filter 19.
The reservoir 10 is shown disposed in the top of an oxygenator 11, of the previously cited inventions of this inventor. The blood inlet conduit 16 and the air outlet conduit 24 are sealed through the oxygenator top 35 by the conventional O-ring seal combinations 36 and 37. The oxygen gas exit conduit 38 releases the gas stream 33 from the oxygenator 11.
FIG. 2 illustrates in detail through the cross sectional view through 2--2 of FIG. 1, that the nozzle 34 having a slot discharge aperture 17 of the blood inlet conduit 16 is tangentially disposed to the internal wall 18 of the reservoir volume 15 formed by the wall 12. Thus, blood mixture 31 pumped into the cardiotomy reservoir 10 through the narrow slot aperture 17 is spread in a flat blood inlet stream flow tangentially over the wall 18 tending to distribute the surgical tissue debris pumped into the cardiotomy reservoir over a large wall area. The debris is retained on the reservoir base filter 19 and on the air filter 21, as the foamed blood 28 is defoamed on contact with the two filters 19 and 21. The curved nozzle 34' represents another wall curvature conforming tangential nozzle.
In surgical procedures the cardiotomy reservoir 10 operates at pressures above atmospheric, resulting from the pump pressurized discharge of blood, air and surgical tissue debris into the reservoir 10. The relief valve 25 allows escape of the air stream 32 at the set relief pressure of the valve 25, which can typically be 100 mm Hg.
A further modification of the blood inlet nozzle is shown in FIG. 3, in a cross sectional view similar to 2--2 of FIG. 1. The cardiotomy reservoir 10" is disposed in a blood oxygenator 11. In the reservoir modification 10", the blood inlet conduit 16" has a nozzle 34" integrally tangentially disposed on the exterior wall of the tubular case 12", providing a slot aperture 17" disposed in the case 12". The base 23 of the air filter 21 is shown disposed, as in FIG. 2.
Referring to FIG. 4 in detail, the base plate 13 is shown in two modifications separated by a diametrical line 41. The plurality of blood exit apertures 26 are shown conductively disposed through the base plate 13 providing for the flow of filtered blood from the cardiotomy reservoir under slight pressure. The plural base filter leaf supports 27 are shown coplanarly integrally secured on the plate 13, providing recesses between the leaf supports 27 for the channel flow of filtered blood from the superimposed reservoir base filter 19. On the other half of the filter plate 13' separated by the diametrical line 41 is shown a plurality of blood exit apertures 26' which also are conductively disposed through the base plate 13'. A circular recess channel 42 formed in the base plate 13' has a plurality of blood exit recess channels 40 leading from the circular recess channel 42 to the blood exit apertures 26'. Thus in principle, the base plate 13 and the modified base plate 13' can have the blood flow relieving passage means 27, or the means comprising 42 plus 40 disposed in the filter plate 13'. Each blood flow relieving passage means 27, or the like, provides for the flow of blood from the cardiotomy reservoir typically into the defoaming chamber, or the like, of a blood oxygenator.
Typically, the cardiotomy reservoir 10 disposed in the blood oxygenator 11, as shown in FIG. 1, is mounted on the top of a tubular array 43 in the recessed aperture 44 providing for the support of the reservoir 10. The tubular array 43, including its various modifications, are disclosed in the above cross-referenced patent applications of this inventor.
This invention provides a cardiotomy reservoir which quickly processes a three-phase mixture of blood, air and surgical tissue debris providing rapid removal of tissue debris from the blood, together with prompt defoaming of the blood, thus allowing the treated blood to be returned to a patient's extra-corporeal circulation. By the prompt treatment and return of the blood to circulation, the potential for initiating blood clotting is reduced, hence the post operative prognosis is enhanced.
Many modifications and variations in the improvement in a cardiotomy reservoir can be made in the light of my teaching. It is therefore understood that within the scope of the appended claims, this invention may be practiced otherwise than as specifically described.
This application is related to the following applications filed earlier by the same sole inventor:
U.S. Pat. application, Ser. No. 175,182 for BLOOD OXYGENATOR AND THERMOREGULATOR APPARATUS by Robert C. Brumfield, filed Aug. 26, 1971;
U.S. Pat. application, Ser. No. 196,458, for BLOOD OXYGENATOR GLOW GUIDE, by Robert C. Brumfield, filed Nov. 11, 1971;
U.S. Pat. application Ser. No. 202779 FOR BLOOD OXYGENATOR, by Robert C. Brumfield, filed Nov. 29, 1971; and
U.S. Pat application Ser. No. 216,649 for LOW PRESSURE HEAT EXCHANGER FOR OXYGENATED BLOOD, by Robert C. Brumfield, filed Jan. 10, 1972.
BACKGROUND OF THE INVENTION
Blood oxygenators useful for oxygenating patient's blood during extra-corporeal circulation are classified in Class 23 Subclass 258.3. The cardiotomy reservoir of this invention is taught to be useful in combination with a blood oxygenator, and the invention is so classified.
Often there is a substantial loss of patient blood during surgical treatment, and surgical blood suckers are useful for processing and returning blood to the patient's extra-corporeal circulation. Since the recovered blood can contain surgical tissue debris, the blood can respond to the debris by initiating the clotting mechanism. It is desirable to remove the debris from the recovered blood as quickly as possible prior to returning this blood to the patient. The cardiotomy reservoir of this invention quickly and cleanly processes patient blood, filtering the surgical debris and simultaneously defoaming the blood for rapid return to the patient's circulation.
SUMMARY OF THE INVENTION
A cardiotomy reservoir for recovering patient's blood in a surgical procedure has a uniform tubular case having a base plate and a top plate, together providing an enclosed reservoir volume. A blood inlet conduit is secured in the reservoir providing a slot aperture discharge nozzle directing a flat blood inlet stream flow tangentially onto the inside tubular wall of the reservoir. The small centrifugal force of the blood stream flow tends to deposit the surgical tissue debris on the tubular wall. A reservoir base filter is coextensive with the base plate and has a porosity suitable for filtering whole blood, yet retaining surgical tissue debris on the base filter inside the receptacle. A retaining ring means coplanarly secures the reservoir base filter to the reservoir base plate. An air filter is concentrically coextensive with the tubular case, from the top plate of the reservoir to the base filter, the air filter having a porosity suitable for filtering air, yet blocking blood flow through it. An air exit conduit is normally centrally disposed from the reservoir top plate, discharging filtered air from the reservoir. A plurality of blood exit apertures conductively disposed through the base plate provide for flow of filtered blood from the cardiotomy reservoir. The reservoir base filter and the air filter are both treated with a very thin film of a defoaming composition which is physiologically compatible with patient blood, thereby facilitating the defoaming of the blood, air and surgical tissue debris as it is pumped into the cardiotomy reservoir. A slight internal reservoir positive pressure ranging up to 100 mm Hg maintains a positive flow of blood out of the cardiotomy reservoir through the base plate blood exit apertures. The positive pressure is maintained inside the cardiotomy reservoir by a low pressure release valve secured to the air exit conduit. The air filter can be truncated cone shaped porous filter having a cone apex centrally disposed adjacent the reservoir base filter and a cone base disposed adjacent the top plate of the reservoir. The reservoir base filter and the air filter can be porous reticulated polyurethane foam or a porous silicone foam of selected porosity. The air filter is typically a foam having 10. pores per lineal inch. The reservoir base filter typically passes particle sized to 100 microns.
Other objects and advantages of this invention are taught in the following description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
A description of this invention is to be read in conjunction with the following drawings:
FIG. 1 is an elevational perspective partial sectional view of the cardiotomy reservoir of this invention, disposed in a blood oxygenator.
FIG. 2 is a sectional view through 2--2 of FIG. 1.
FIG. 3 is a sectional view disclosing a further modification of this invention similar to the view of FIG. 2.
FIG. 4 is another sectional view through 4--4 of FIG. 1.
FIG. 5 is a detailed perspective fragmentary view illustrating the base plate 13 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A surgical blood sucker and a peristaltic pump combination are used to suck up blood lost in a surgical procedure or the like. The sucker and pump combination discharge a three-phase mixture of blood, air and surgical tissue debris into the cardiotomy reservoir.
Referring to FIG. 1 in detail, the cardiotomy reservoir 10 of this invention is shown disposed in the top portion of the blood oxygenator 11. The cardiotomy reservoir 10 has a uniform receptacle tubular case 12 closed by a base plate 13 and a top plate 14, providing an enclosed reservoir volume 15. A blood inlet conduit 16 is normally secured through the top plate 14, and has a blood inlet conduit discharge nozzle 34, whose slot discharge aperture 17 is permanently positioned, directing a flat blood inlet stream flow tangential to the inner wall 18 of the case 12. A reservoir base filter 19 is coextensive with the base plate 13, the filter 19 providing a porosity suitable for filtering whole blood. Typically the filter 19 has pore openings sized to pass 100 micron size particles, and retain surgical tissue debris inside the reservoir volume 15 on the base filter 19. A retaining ring 20 secures the filter 19 on the base plate 13. The ring 20 is sealed to the tubular case ring 30, which is in turn sealed to the base plate 13. The tubular case 12 is sealed to the ring 30 and the top plate 14, providing an integral structure.
An air filter 21 is shown concentrically conextensively disposed in the reservoir 10, coextending from the top plate 14 to the base filter 19. The truncated cone 21 has a truncated apex 22 and a cone base 23. The air filter 21 is a plastic sponge having a porosity suitable for filtering air yet blocking blood flow. An air exit conduit 24 is normally centrally disposed through the top plate 14 providing an exit conduit discharging filtered air from the reservoir volume 15. Typically, the conduit 24 is sealed to the top plate 14. A pressure relief valve 25 is shown conductively disposed on the conduit 24, the relief valve being set to relieve at a pressure approximately 100 mm Hg above atmospheric pressure. A plurality of blood exit apertures 26 are conductively disposed through the base plate 13, providing for the flow of filtered blood from the cardiotomy reservoir 10. The filter components, the air filter 21 and the reservoir base filter 19 are both coated by well known procedures with physiological compatible compositions which accelerate blood defoaming on contact with the film coating. Typically, a silicone composition is well known and used for this purpose. Plural base filter leaf supports 27 are shown coplanarly integrally secured to the base plate 13, providing blood exit flow relieving passage means for the blood filtered through the filter 19.
The reservoir 10 is shown disposed in the top of an oxygenator 11, of the previously cited inventions of this inventor. The blood inlet conduit 16 and the air outlet conduit 24 are sealed through the oxygenator top 35 by the conventional O-ring seal combinations 36 and 37. The oxygen gas exit conduit 38 releases the gas stream 33 from the oxygenator 11.
FIG. 2 illustrates in detail through the cross sectional view through 2--2 of FIG. 1, that the nozzle 34 having a slot discharge aperture 17 of the blood inlet conduit 16 is tangentially disposed to the internal wall 18 of the reservoir volume 15 formed by the wall 12. Thus, blood mixture 31 pumped into the cardiotomy reservoir 10 through the narrow slot aperture 17 is spread in a flat blood inlet stream flow tangentially over the wall 18 tending to distribute the surgical tissue debris pumped into the cardiotomy reservoir over a large wall area. The debris is retained on the reservoir base filter 19 and on the air filter 21, as the foamed blood 28 is defoamed on contact with the two filters 19 and 21. The curved nozzle 34' represents another wall curvature conforming tangential nozzle.
In surgical procedures the cardiotomy reservoir 10 operates at pressures above atmospheric, resulting from the pump pressurized discharge of blood, air and surgical tissue debris into the reservoir 10. The relief valve 25 allows escape of the air stream 32 at the set relief pressure of the valve 25, which can typically be 100 mm Hg.
A further modification of the blood inlet nozzle is shown in FIG. 3, in a cross sectional view similar to 2--2 of FIG. 1. The cardiotomy reservoir 10" is disposed in a blood oxygenator 11. In the reservoir modification 10", the blood inlet conduit 16" has a nozzle 34" integrally tangentially disposed on the exterior wall of the tubular case 12", providing a slot aperture 17" disposed in the case 12". The base 23 of the air filter 21 is shown disposed, as in FIG. 2.
Referring to FIG. 4 in detail, the base plate 13 is shown in two modifications separated by a diametrical line 41. The plurality of blood exit apertures 26 are shown conductively disposed through the base plate 13 providing for the flow of filtered blood from the cardiotomy reservoir under slight pressure. The plural base filter leaf supports 27 are shown coplanarly integrally secured on the plate 13, providing recesses between the leaf supports 27 for the channel flow of filtered blood from the superimposed reservoir base filter 19. On the other half of the filter plate 13' separated by the diametrical line 41 is shown a plurality of blood exit apertures 26' which also are conductively disposed through the base plate 13'. A circular recess channel 42 formed in the base plate 13' has a plurality of blood exit recess channels 40 leading from the circular recess channel 42 to the blood exit apertures 26'. Thus in principle, the base plate 13 and the modified base plate 13' can have the blood flow relieving passage means 27, or the means comprising 42 plus 40 disposed in the filter plate 13'. Each blood flow relieving passage means 27, or the like, provides for the flow of blood from the cardiotomy reservoir typically into the defoaming chamber, or the like, of a blood oxygenator.
Typically, the cardiotomy reservoir 10 disposed in the blood oxygenator 11, as shown in FIG. 1, is mounted on the top of a tubular array 43 in the recessed aperture 44 providing for the support of the reservoir 10. The tubular array 43, including its various modifications, are disclosed in the above cross-referenced patent applications of this inventor.
This invention provides a cardiotomy reservoir which quickly processes a three-phase mixture of blood, air and surgical tissue debris providing rapid removal of tissue debris from the blood, together with prompt defoaming of the blood, thus allowing the treated blood to be returned to a patient's extra-corporeal circulation. By the prompt treatment and return of the blood to circulation, the potential for initiating blood clotting is reduced, hence the post operative prognosis is enhanced.
Many modifications and variations in the improvement in a cardiotomy reservoir can be made in the light of my teaching. It is therefore understood that within the scope of the appended claims, this invention may be practiced otherwise than as specifically described.