The shelf life of stored whole blood may be doubled by adding a buffer which maintains a desired pH level. However, this buffer causes the generation of CO2 which, if not removed at a controlled rate, causes the pH value of the blood to decrease, which shortens the useful life of the blood. A blood storage bag is described which permits the CO2 to be diffused out at a controlled rate into the atmosphere, thereby maintaining the desired pH value and providing a bag strong enough to permit handling

Bank, H.

Cleland, E. L.

English

NASA Technical Reports Server

United States Patent [191 
Bank et al. 
[111 4,132,594 
[451 Jan. 2, 1979 
[54] GAS DIFFUSION LIQUID STORAGE BAG 
AND METHOD OF USE FOR STORING 
BLOOD 
[75] Inventors: Herman Bank, Altadena; Edward L. 
[73] Assignee: The United States of America as 
Cleland, Duarte, both of Calif. 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
[21] Appl. No.: 700,467 
[22] Filed: Jun. 28,1976 
[51] Int. C l . 2  .......................... A61M 1/03; A61J 1/00; 
B65D 81/24; B65D 81/00 
[52] U.S. Cl. ....................................... 195/1.8; 422/41; 
422/48; 55/158; 128/214 D; 128/272; 150/1; 
206/439; 21ODIG. 23 
[58] Field of Search .................. 23/258.5 R, 258.5 M; 
55/158; 210/DIG. 23; 206/69,439; 128/214 D, 
272, DIG. 24; 150/1, 52 E 19W1.8; 21/2, 58 
1561 References Cited 
U.S. PATENT DOCUMENTS 
3,010,536 11/1961 Plurien et al. ......................... 55/158 
3,060,934 10/1962 Claff et al. ..................... 23/258.5 M 
3,424,218 1/1969 Vanderby et al. ............... 128/272 X 
3,442,002 5/1969 Geary et al. ....................... 55/158 X 
3,445,321 VI969 Groves .............................. 55/158 X 
3,489,647 VI970 Kolobow ................... 23/258.5 M X 
3,874,384 4/1975 Deindoerfer et al. ............... 128/272 
3,953,329 4/1976 Updike .............................. 195A.8 X 
Primaly Examiner-Barry S. Riclhman 
Attorney, Agent, or Firm-Monte F. Mott; Wilfred 
Grifia; Robert Kinberg 
[571 ABSTRACT 
It has been found that the shelf life of stored whole 
blood may be doubled by adding a buffer which main- 
tains a desired pH level. However, this buffer causes the 
generation of C02 which, if not removed at a controlled 
rate, causes the pH value of the blood to decrease, 
which shortens the useful life of the blood. This inven- 
tion provides a blood storage bag which permits the 
C02 to be diffused out at a controlled rate into the 
atmosphere, thereby maintaining the desired pH value 
while providing a bag strong enough to permit handling 
thereof. 
17 Claims, 5 Drawing Figures 
https://ntrs.nasa.gov/search.jsp?R=19790006578 2020-03-20T18:16:18+00:00Z
FIG. 2 
0 55 0 DAYS 7 I4 IN  SBO 21 28 35 42 FIG, 5 
2 
26 
22 
FIG. 3 
24 
FIG. 4 
4,132,594 n 
GAS DIFFUSION LIQUID STORAGE BAG AND 
METHOD OF USE FOR STOWING BLOOD 
ORIGIN OF THE INVENTION 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National 
Aeronautics and Space Act of 1958, Public Law 85-568 
(72 Stat. 435; 42 USC 2457). 
BACKGROUND OF THE INVENTION 
This invention relates to an improved apparatus for 
storing whole blood. 
It has been found that the addition of NaHC03, as a 
buffer, to store whole blood maintains a desired pH 
level which is quite beneficial. It was shown, that with 
such a buffer, the blood can be adequately preserved 
with good viability for 42 days, and that the oxygen 
transport capability (as measured by 2,3-DPG determi- 
nation) is also maintained at levels substantially above 
those achieved by presently available media. 
However, the buffer releases C02 during storage 
which, if not removed at a controlled rate, causes the 
pH value of the blood to change to a value which rap- 
idly damages the blood. 
Storage of the blood in the conventional blood bags, 
used for such storage, even though the buffer is added 
to the blood does not increase the storage life of the 
blood significantly because of the C02 released by the 
buffer. Materials to make a bag, other than the medi- 
cally approved material presently used, which can pass 
COS at a controlled rate and yet which is strong enough 
to withstand handling are either too expensive or not 
suitable for storing blood, as far as is known. 
OBJECTS AND SUMMARY OF THE 
INVENTION 
An object of this invention is the provision of a novel 
blood storage bag whereby buffered blood shelf life is 
increased. 
Another object of this invention is the provision of a 
novel and useful blood bag which permits the escape of 
C02 from the blood stored in it and yet is sufficiently 
durable to enable handling and to withstand the pres- 
sure on its walls by the stored blood. 
The foregoing and other objects of the invention are 
achieved with a blood bag which has a structure which 
is thin enough to pass C02 effectively, yet strong 
enough to withstand handling without being ruptured. 
The blood bag is made out of a medical grade plastic 
material, such as polyvinyl chloride (PVC). The bag is 
made with regions thin enough to permit a desired rate 
of diffusion therethrough of C02. It also has thick or 
otherwise sufficiently reinforced regions which provide 
handling strength for the bag. 
BRIEF DESCRIPTION OF THE DRAWINGS 
FIG. 1 is a view in elevation of a preferred embodi- 
FIG. 2 is a cross-sectional view of FIG. 1 along the 
FIG. 3 is a cross-sectional view of another embodi- 
FIG. 4 is a cross-sectional view of still another em- 
FIG. 5 is a graph comparing performance of the prior 
ment of the invention. 
lines 2-2. 
ment of the invention. 
bodiment of the invention. 
art with the present invention. 
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DESCRIPTION OF THE EMBODIMENT OF THE 
INVENTION 
In FIG. 1, there may be seen a view in elevation of a 
container for blood. FIG. 2 is a cross-section along the 
lines 2-2. The container 10, is filled with blood 
through entrance pipes IIA, 11B, 1lC, 11D. These 
entrance pipes are then sealed. These blood bags are 
usually made of a medical grade plastic material such as 
polyvinyl chloride (PVC), having essentially a uniform 
thickness on the order of 0.08 to 0.015 inch. It has been 
found that when sodium bicarbonate (NaHC03) is 
added to the blood, it maintains the desired pH level 
which has been proved beneficial in laboratory tests 
whereby the blood can be adequately preserved with 
great viability for 42 days, and oxygen transport capa- 
bility (as measured by 2, 3-DPG determination) is main- 
tained at levels substantially above those achieved by 
presently available media. However, the problem pres- 
ented is that the blood bag containers do not permit the 
C02 which is generated as a result of the addition of the 
buffer to escape at an acceptable rate. This effectively 
reduces the benefits obtained by using the buffer. 
The C02 removal must be at a rate such that the 
buffer can maintain the pH. If it escapes too slowly, as 
occurs in the present 15 mil thick PVC bags, the pH 
goes below pH 6. If C02 removall is too fast (as occurs 
with silicone bags), the pH goes to 9. It has been found 
that if the present medical grade PVC plastic bag, used 
for storing whole blood (or red blood cells), has its 
thickness sufficiently reduced then it becomes more 
permeable to the C02 generated within the bag, 
whereby it is released out into the atmosphere at a con- 
trolled higher rate, thereby the desired pH value of the 
whole blood may be maintained, while still shielding the 
whole blood from the atmosphere. However, when the 
bag is reduced to the thinness required for rendering it 
more permeable to C02, it effectively becomes so frag- 
ile that any handling of the bag, unless utmost care is 
taken, can cause a rupture of the bag. The bag must be 
handled since, for example, even in storage it is turned 
over periodically to produce a kind of stirring of the 
stored blood. 
Accordingly, as can be seen in FIGS. 1 and 2, an 
arrangement is provided for making the bag thin 
enough over a sufficient area to attain the desired rate of 
passage therethrough of C02, while thick enough or 
strong enough, to enable the handling required, such as 
the indicated “turnovers”, by giving the bag a waffle- 
type construction. That is, the conventional-sized bag, 
by way of example, has thin regions 14, having a thick- 
ness on the order of 1 to 6 mils, and thick regions 16, 
having a thickness on the order of 50 to 150 mils. The 
material of which the bag is constructed, in the end 
regions 12, is nominally also between 50 to 150 mils 
thick. The conventional sized storage blood bag is typi- 
cally 7 inches long by 5 inches wide and stores 500 to 
6W ml of fluid. Substantially 50%’ of the area of the bag 
constitutes the thin regions 14. The thick regions of the 
waffle grid, which incidentally extends on both sides of 
the bag, provide the necessary strength, abrasion resis- 
tance, etc. required to enable the bag to be handled 
without any problems. The thin regions provide the 
diffusion areas for the C02. 
While the structure shown in FIGS. 1 and 2 can be 
made from a single sheet of plastic material, such as the 
medically approved PVC, other medically approved 
plastic materials may be used as well, in thicknesses that 
4,132,594 
3 4 
give a satisfactory C02 permeability rate. Also, the 
structure need not be made from a sinele. thick sheet of 
2. A system for the storage of a liquid within a closed 
bag wherein a predetermined gas is formed, and for 
material. The bag may be made of twopa& as shown in 
FIG. 3. An inner bag 20 which is made of medical grade 
plastic material, is placed within an outer bag 22. The 
bag 22 has surfaces which are perforated to enable the 
C02 passing through the inner bag to vent to the atmo- 
sphere. The outer bag may be of elastic material such as 
rubber or plastic or any other suitable material and is 
sued so that when the inner bag is tilled, it will be in 
pressing contact against the outer bag. The outer bag 
supplies the necessary reinforcement to the inner bag so 
that it may be handled as required. 
FIG. 4 shows still another embodiment of the inven- 
tion in cross section. Here the bag 24 is reinforced by 
embedding in the surface thereof a reinforcing mesh 
material 26, such as metallic foil (stainless steel) or plas- 
tic (nylon). The bag is made sufficiently thin over a 
large enough area to vent the C02 contained therein to 
the atmosphere at the rate required to maintain the pH 
of the stored fluid within the desired pH value. 
FIG. 5 is a graph illustrating the results obtained by 
testing the health of the blood, as measured in DPG 
units, which is kept in a conventional bag as compared 
with the health of the blood kept in a bag made in accor- 
dance with this invention. The ordinate of the graph is 
DPG units and the abscissa comprises days of storage. 
The curve 30 shows the data obtained by testing blood 
kept in a thin wall bag in accordance with this inven- 
tion, as compared to the curve 32 indicating the health 
of the blood kept in the conventional bag. Blood at less 
than 8 DPG cannot be used. The chart shows that blood 
stored in a conventional bag may deteriorate to below 8 
DPG in about 21 days, whereas blood stored under 
identical conditions, but in a bag in accordance with this 
invention, does not deteriorate to this value until ap- 
proximately 40 days. 
This high permeability blood bag concept can also be 
utilized to facilitate the diffusion of various gases or 
liquids into or out of the blood bag as desired (i.e., oxy- 
gen diffusion into the blood bag containing blood plate- 
lets). Furthermore, it is believed that the high permea- 
bility bag’s design will result in a reduction of phthalate 
contamination of the blood compared to the contamina- 
tion occurring in standard PVC blood bags. 
Accordingly, there has been shown and described 
above a novel and useful bag for storing blood or other 
fluids where it is necessary to protect the fluid content 
of the bag, permit handling, while permitting the con- 
trolled diffusion of C02 from inside the bag to the atmo- 
sphere. 
The embodiments of the invention in which an exclu- 
sive property or privilege is claimed are defined as 
follows: 
1. A method of storing blood which has been treated 
with a selected compound to extend the useful life of the 
blood, said treatment resulting in the subsequent pro- 
duction of C02, the method comprising the steps of: 
providing a closeable plastic bag adapted to contain a 
preselected quantity of treated blood, the bag hav- 
ing first wall portions of a thickness chosen to 
enable C02 to diffuse through said portions at a 
selected predetermined rate so as to maintain the 
pH of said treated blood within a selected range, 
said bag having second wall portions for providing 
strength for said bag to withstand pressure applied 
thereto at least by the stored blood; and 
storing the treated blood in said bag. 
controlling a selected characteristic of said liquid, 
which is related to the content of said gas in said bag, 
a bag having semi-permeable wall means including 
thin wall means of preselected thickness for en- 
abling said gas to diffuse through said thin wall 
means at a selected rate, to thereby control the 
selected characteristic of said liquid, said wall 
means including reinforcing means for enabling 
said bag to withstand pressure, wherein said rein- 
forcing means comprises a spaced ribbing of the 
same material as the material of said thin wall 
means and which is integral therewith and of a 
thickness sufficient to reinforce said bag and the 
ratio of the surface area of said thin wall means to 
the total surface area of said bag is preselected to 
control the characteristic of said liquid by control- 
ling the rate of diffusion of said gas through said 
5 said system comprising: 
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thin wall means. 
3. A system as recited in claim 2 wherein said rein- 
forcing means are in excess of 50 mils thick. 
4. A system as recited in claim 3 wherein the surface 
area that said thin wall means occupies is on the order of 
50% of the total surface area of said wall means. 
5. A system for storing whole blood or red blood cells 
which has been treated to extend its usable life, which 
treatment results in the production of C02 and requires 
the removal of C02 at a predetermined rate, so as to 
maintain the pH of the blood or the red blood cells 
within a selected range, said system comprising: 
a bag having semi-permeable wall means including 
thin wall means of preselected thickness for en- 
abling C02 to diffuse through said wall means at a 
selected rate, said wall means including reinforcing 
means juxtaposed with said thin wall means for 
enabling said bag to withstand pressure, the ratio of 
the surface area of said thin wall means, which do 
not include said reinforcing means, to the total 
surface area of said wall means being selected to 
control the rate of diffusion of the C02 through 
said thin wall means so that the pH of the blood or 
the red blood cells in said bag is maintained within 
said selected range. 
6. A system as recited in claim 5 wherein said thin 
wall means of said bag form a first closed bag and said 
reinforcing means of said bag constitute a second open 
mesh bag into which said first bag is inserted, said sec- 
ond open mesh bag being made of elastic material and 
being sized to apply pressure to said first bag when it is 
filled with said blood or red blood cells. 
7. A system as described in claim 5 wherehi the sur- 
face area that said thin wall means Occupies is on the 
order of 50% of the total surface area of said wall 
means. 
8. A system as recited in claim 5 wherein said rein- 
forcing means comprises a mesh of material embedded 
in the surface of said thin wall means. 
9. A system as recited in claim 8 wherein said mesh of 
material is nylon. 
10. A system as recited in claim 8 wherein said mesh 
of material is a metallic foil. 
11. A system as described in claim 5 wherein at least 
said thin wall means are made of medical grade mate- 
rial. 
12. A system as described in claim 11 wherein said 
thin wall means and said reinforcing means are of the 
4,132,594 
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same material with the thicbess of said thin wall means 
being on the order of 1 to 6 mils and the thickness of 
said reinforcing means being not less than 50 mils. 
13. A system as described in claim 12 wherein the 
surface area that said thin wall means occupies is on the reinforcing are in of mils thick. 
means. 
thickness of said thin wall means is on the order of 1 to 10 means. 
6 mils. 
15. A system as described in claim 14 wherein the 
surface area that said thin wall means Occupies iS On the 
order of 50% of the total surface area of said wall 
means. 
16. A system as described in claim 14 wherein said 5 
order Of 50% Of the total Surface arm Of Said Wall 17, A system as described in 16 wherein the 
surface area that said thin wall means occupies is on the 
order of 50% of the total surface of said wall 14. A system as described in claim 11 wherein the 
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Gas diffusion liquid storage bag and method of use for storing blood

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