US2896620A - Blood arterializing method and apparatus therefor - Google Patents

Description

y 28, 1959. JEAN-LOUIS TREMBLAY- 2,895,520

BLOOD ARTERIALIZING METHOD AND APPARATUS THEREFOR Filed Nov. 28, 1955 v 5 Sheets-Sheet 1 .IIIIIIIIII INVENT OR Joan Lou/5 TAEHBLHY ATTORNEYS- July 28, 1959 JEAN-LOUIS TREMBLAY BLOOD ARTERIALIZING METHOD AND APPARATUS THEREFOR Fil ed Nov. 2a, 1955 5 sheets-sheet 2 DVVENTOR TREMEUIY Jean tou /b ATTORNEYS JEAN-LOUIS TREMBLAY 7 2,896,620

BLOOD ARTERIALIZING METHODAND APPARATUS THEREFOR July 28, 1959 a Sheets-Sheet 5 Fil e d Nov. 28, 1955 INVENTOR I Jean Lou/is l'fli/IBLAY ATTORNEYS United States Patent BLOOD ARTERIA'IJIZING METHOD AND APPARATUS THEREFOR The present invention relates to a method for trans- 2,896,620 Patented July 28, 1959 "ice exceed a maximum predetermined pressure so as to enforming venous blood into arterial blood and to an apparatus therefor of the type normally known as artificial lung and such as to be used in conjunction with an artificial heart or blood pump.

Artificial lungs are used to add oxygen to and remove carbon dioxide from the blood stream of a human or animal during surgery at a sufficiently rapid rate and such that the arterializd blood may be pumped back into the person or animal without occluded air or oxygen bubbles and in an uncoagulated condition. When the blood stream of a human or animal completely bypasses the lungs the arterialization must be effected on large quantities of blood up to about 5 litres per minute.

One conventional type of artificial lung machine treats the venous blood stream by exposing it as a very thin film, no more than about half a millimeter thick, to an oxygen atmosphere. Therefore, the task of such artificial lungs is to spread out fromone to five litres of blood per minute in :a film covering two to ten square meters, to expose this film to an oxygen atmosphere under sterile conditions and to collect the oxygenated blood without occluded gas.- Various devices have been used to eifect the above task: rotating cylinders; rotating discs or rings partly immersed. ina bath of blood; the spreading of blood in a film on the inside of cups or over screens, membranes or in rotatingspiral tubes.

. Another type of lung machine now available drops blood on-a cushion of blood-oxygen foam, where the blood rivulets film out between the gas bubbles.

The first mentioned type of apparatus is necessarily large in volume on account of the large quantity of blood a involved, while the secondtype of apparatus, namely the dropping of blood on a cushion of blood-oxygen foam, produces a great quantity of foam from which it is diflicult to collect a continuous stream of blood without occluded gas bubbles.

- Accordingly, the general object of the present invention is the provision of a method for arterializing blood and of an apparatus therefor which will obviate the above mentioned defects, the apparatus occupies a relatively small volume compared-to its arterializing capacity and 1 is so designed that the arterialized blood will be associated with a minimum of foam which will be relatively easy to separate in its constituents, namely, liquid blood and a gaseous stream containing oxygen and carbon dioxide. Another important object of'the present invention is the provision of a method and apparatus of the character described which will not affect or deteriorate or otherwise damage the blood corpuscles in the blood stream. Still another important object of the present invention is the provision of a blood arterializing method and apparatus provided with means for treating the spent gas stream to remove the carbon dioxidetherefrom so that said stream maybe recycled.

Yetanother portant object of the present invention is the provision of means for entirely preventing the tirely prevent occlusion of gas in the blood stream emerging from the apparatus, 4

The toregoing and 'other important objects of the present invention will become more apparent during the following disclosure and by referring to the drawings in which:

Figure 1 is a diagrammatic elevation of the blood arterializing apparatus according to the present invention; Figure 2 is a longitudinal section of the gas stream circulating means; Figure 3 is a longitudinal section of the blood arterializing part of the apparatus;

Figure 4 is a longitudinal section of the defoaming part of the apparatus; and

Figure 5 is a longitudinal section of the decarboxylating part of the apparatus, that is, the carbon dioxide removing portion of the apparatus. Referring now. more particularly to the drawings in which like reference characters indicate like elements throughout, the blood arterializing apparatus comprises essentially means to feed and circulate a stream of gas containing oxygen, means to mix the stream of blood with said stream of gas, means to prolong the time of contact between the gas and the blood stream, means to separate the gas from the arterialized blood and means for washing the spent gas by removing the carbon dioxide therein so that the remaining oxygen may be recycled.;, The means for feeding and circulating the gas containing oxygen stream comprises a container 1, half filled with water, a centrifugal pump 2 having its inlet connected to the bottom of the container 1 by a tubing 3, and having its outlet connected to a riser tube 4 which is bent at its upper end to form a horizontal portion 5 which is itself bent to form the downward extension 6 which is er. minated by a nozzle 7 inside an ovoidal chamber 8. The nozzle 7 opens opposite a restricted opening 9 of a nipple 10 which extends downwardly within the container 1 and terminates above the water level .11, as shown at'12 in Figure 2. The spent gas containing oxygen stream which has been washed to remove the carbon dioxide therefrom, is sucked into the chamber 8 through a tube 13 which opens therein laterally of the nozzle 7 and restricted opening 9 and intermediatethe same. The elements 7, 8', 9 and 13 form a water aspirator acting under the principle of the Venturi' tube whereby the water discharged under pressure through the nozzle 7 creates a partial vacuum within the chamber 8 to thereby suck and carry the .gas emerging from the tubing 13 and discharge the same under a suitable constant pressure into the container.;

The container 1, centrifugal pump 2, tubing 4, 5. and 6 and aspirator 8 form a closed water circuit through which the same water is constantly recycled. The pressure under which the gas collects in the upper part of the corn tainer '1 may be accurately regulated by controlling the speed of the centrifugal pump 2. Thegas containing oxygen stream is thus discharged under pressure to the means for mixing the gas with the blood through the tubing 14 which is connected at its upper end to the top part of the container .1 as shown at 15. n At the start of the blood arterializing process, or during said process, oxygen is supplied to the horizontal tubportion 5 which is provided with a three way valve 16, i

the tubing branch 17 of which is connected to a suitable supply of oxygen under pressure, such as a cylinder of compressed oxygen (not shown) which is provided with a suitable pressure regulating valve. Thus, oxygen under the tubing 20 which consists in a downward part20' followed by a horizontal part 20 which inturricommunicates with a riser tube 21 in communication at its upper end with the bottom of the mixing chamber 18. 7 A long spiral tube '22 is connected at its lower end 23 tolthe'side of the chamber .18 diametrically opposite the discharge end 19 of the gas supply tube 14. The circumvolutions of the spiral tube 22 are slightly inclined upwardly and said tube discharges at its upper 24 into a first separator cham ber generally indicated at 25. The internal diameters of the tubes 14, 21 and 22 and of their communication with the mixing chamber 18 are substantially equal to one another. l

The blood stream entering the mixing chamber 18 partially fills the latter against the'pressure exerted by the gas stream entering chamber 1 8 through tube 14. The gas stream fills the upper part of the mixing chamber -18 and slowly builds its volume until the meniscus 2-6 of the blood within the mixing chamber 18 drops below the level of the lower end 23 of the spiral tube 22 to thereby admit a gas bubble in said tube 22. Thus the respective rates at which the gas and blood streams are fed to chamber 18 are such that the blood level in said chamber will rise above the level of the tube end 23 and then fall below said level, so that in the tube 22 gas bubbles 27 will alternate with discrete quantities of blood 28. Due to the upward slope of the spiraltube 22, the gas bubbles 27 within said tube, because of their lower specific gravity, will cause the upward flow of the blood toward the discharge end 24 of the tube 22. The speed at which the bubbles 27 and blood quantities 28-travel in the spiral tube 22 may be accurately regulated by controlling the pressure and rate of flow of the gas fed through pipe 14 in a manner previously described. The duration of contact between the oxygenating gas stream and the venous blood in the spiral tube is controlled so as to completely arterialize the blood. The gas bubbles 27 occupy the entire cross-sectional area of the tube 22 so as to prevent the blood from collecting in continuous lengths and so as to prevent intermixing of the gas with the blood. Therefore, each discrete quantity of blood 28 has such a length that it may be completely arterialized by the two adjacent gas bubbles 27. The system considerably decreases the amount of foaming which usually occurs when mixing blood with oxygen. The length of the spiral tube 22 will be determined according to the species of patient being treated and may, for instance, be as long as 20 feet for a human patient. Despite the foregoing arrangement for the arterialization of the blood, and despite the fact that the blood is subjected to a of turbulence, a certain amount which consists in oxygenated blood plus a mixture of carbon dioxide and oxygen, rises in the upper part of the separator chamber 25, as shown at'29, while the liquid blood 30 falls in the lower part of the chamber 25 and is returned to the patient through tubings 31, 32 and 33. The arterialized blood will preferably pass through a mechanical heart before being fed to the patient.

The, foam slowly rises through the upper part ofthe separator chamber 25, enters the loop tube 34 and reaches the lower part of the chamber to mix with blood 30. The remaining foam flows down along the loop tube 34 to be discharged at the bottom end thereof into the tube 36 which discharges the foam into the upper part of a first defoaming chamber 37 wherein most of the blood separates from the gas stream and collects at the bottom of the chamber, as shown at 39, and is returned to the patient through the three way valve 40, tubing 41, 42 and 33. The valve 40 is provided with a drain branch 43. A second defoaming chamber 38 is connected to the upper end of the first defoaming chamber 37 by tubing 44 which terminates at its lower end into the enlarged part 45 of said second defoaming chamber 38. The remaining blood in the gas stream is separated therefromand collects at the bottom of the chamber 38 wherefrom it is discharged into the tubing 42 through the three way valve 46 and tubing 47. The three way valve 46 is provided with a drain branch 48 for drainingthe chamber 38.

The gas stream emerging from the second chamber 38 passes through tubing 49 into a chamber 50 which serves to collect the remaining blood and which also acts-as means to prevent any blood from entering the decarboxylating section of the apparatus and conversely to 'pre vent any decarboxylating agent from mixing with the blood intended to go back to the patient. The blood col lected at the bottom of the chamber 50 is drained at inter vals through the one way valve 51 and drain 52.

The gas stream containing carbon dioxide* and oxygen leaves the chamber 50 through the riser pipe 53 and then travels downwardly through tube 54 to enter a spherical chamber 55. A spiral tube 56 communicates at its lower end with the side of the spherical chamber 55 and at its upper end with the enlarged part 57 of a cylindrical upright decarboxylating chamber 58. The bottom end of of foaming occurs during arterialization The foam,

the uppermost part 35 of loop tube 34 and at the same time it gradually loses sorne'of theblood which falls into the chamber 58 is in communication with the spherical chamber 55 through tubes 59 and 60, and with a container 63 of an aqueous solution of potassium or sodium bydroxide, which is the decarboxylating agent, through the three way valve 61 and tube '62. The three way valve 61 is provided with a drain tube 64.1

The gas stream is washed in the hydroxide solution while travelling either through the spiral tube 56 or through tubes 60 and 59 and chamber 58. The gas which emerges at the top of the chamber 58 is completely free of the carbon dioxide which has been absorbed by the hydroxide solution. The spent decarboxylating solution is discharged through drain tube 64 andafresh amount of solution is admitted from the container 63. n The decarboxylated gas, which is"substantially pure oxygen, leaves the decarboxylating chamber'58 through the upper end thereof by the tube '65 which enters and terminates at the enlarged part 66 of a separating'chamber 67, wherein any'liquid decarboxylating agent carried over by the gas is separated therefrom and collected at the bottom of said chamber 67 as shown at 68', whereit is drained at intervals through the valve'69 and drain tube 70. The oxygen stream, which is now completely free of liquid, leaves the top end of the separating chamber 67 through tube 13 which is in communication with the water aspirator 8 of the means for feeding the recycled oxygen to the blood mixing chamber 18 as previously described. The present invention also includes the provision of safety means to offset the variations of pressure in the blood coming from the patient. Said variations of, pressure could cause gas occlusions in the blood discharged from the apparatus. Therefore, an additional upright cylindrical chamber 72 is provided to'form a reserve of coming from the patient through the tube 20, the arterialized blood will automatically be recycled through the opening 70 and riser tube 21 to thereby maintain the balance of gas and blood pressures in the mixing chamber 18.

The tube 75 is provided with a drain 8t} normally closed by a valve (not shown) and used for draining the entire apparatus.

The blood arterializing section of the apparatus, that is the tubes 20, 21, 22, 3 1, 32, 74, 75, mixing chamber 18, part of tube 14 and part of the chambers 25 and 72 are immersed in a liquid, such as water, as shown at 81, and which is contained in a container '82. The liquid 81 is kept substantially at the temperature of the patient. Thus the arterialized blood leaves the apparatus at 33 substantially at the body temperature.

To prevent blood coagulation within the apparatus, the tubes and chambers thereof, which are preferably made of glass, are coated with an inner layer of suitable wax.

Before service, the entire apparatus is disinfected or sterilized by running therethrough for several hours a solution of an antibiotic such as penicillin.

While a preferred embodiment according to the present invention has been illustrated and described it is understood that various modifications may be resorted to without departing from the spirit and scope of the appended claims.

I claim:

1. A blood arterializing apparatus comprising in combination a spherical mixing chamber, a first tube opening at the bottom of said chamber for supplying liquid venous blood thereto, a second tube in communication with said spherical mixing chamber at the side of the latter for supplying oxygen under a predetermined constant pressure to said mixing chamber, a third tube in communication with said mixing chamber at substantially the same level as said second tube, means to regulate the oxygen pressure in said second tube such that the blood in said mixing chamber will be maintained at a level substantially opposite the communication of said mixing chamber with said third tube so as to cause flowing of said blood into said third tube'as discrete quantities of blood alternating with oxygen bubbles, said oxygen bubbles occupying the entire cross-sectional area of said third tube to separate adjacent discrete quantities of blood, said third tube being only slightly upwardly inclined and having a sufficient length to maintain said oxygen bubbles and said discrete quantities of blood in mutual contact for a period of time sufficient to effect arterialization of the blood, the crosssectional areas of said first, second and third tubes and of their communications with said mixing chamber being substantially equal to one another.

2. A blood arterializing apparatus as claimed in claim 1, further including an upright separating chamber communicating at its middle portion with the upper end of said upwardly inclined third tube, said oxygen bubbles and said arterialized blood discharging into said chamber as liquid blood falling into the bottom of said separating chamber and as :foam consisting of an intimate mixture of gas and blood which rises in said separating chamber, discharge tubing means in communication with the bottom end of said separating chamber for discharging liquid arterialized blood to the exterior of the apparatus, and means to separate the foam into liquid blood and gas containing carbon dioxide and oxygen free from b ood.

3. An apparatus as claimed in claim 2, wherein said last mentioned means comprises a plurality of additional separating chambers connected in series, the upper end of said first named separating chamber communicating with the upper end of the first of said series of additional separating chambers and the preceding chamber in said series communicating with the upper end of the next chamber in said series, the bottom ends of said additional separating chambers communicating with said discharge tubing means.

4. An apparatus as claimed in claim 3, further including means for decarbox-ylating the gas stream emerging from the last of said additional separating chambers.

5. A blood arterializing apparatus as claimed in claim 4, further including a reserve chamber for containing a reserve of arterialized blood, in communication at its upper and lower ends with the upper and lower ends of said first named separating chamber respectively.

6. An apparatus as claimed in claim 5, further including a tube having a restricted orifice making communication between said first tube and said discharge tubing means.

7. An apparatus as claimed in claim. 1, wherein said means to regulate the oxygen pressure of the oxygen supplied to said mixing chamber comprises a closed water circuit, a pump for circulating said water through said closed circuit, and an aspirator in said circuit for sucking oxygen into said circuit and discharging the same under pressure into said second tube.

References Cited in the file of this patent FOREIGN PATENTS Italy Nov. 17, 1931 Great Britain Sept. 15, 1954 89, No. 6, December 1949, pages 684-588. (Available in Scientific Library.)

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