Fabricating a phase change blood cooling system
A new blood unit cooling system was designed to cool blood rapidly to about 22° C. and maintain it at about that temperature, even in ambient temperature extremes, for several hours. The system incorporating a preferred eutectic solution including 98% 1-dodecanol 1.5% myristyl alcohol and 0.5% 1-decanol (having a melting point of about 23° C.) contained in a sealed flexible polymer layer, was used to cool whole blood-filled bags. The preferred design uses inner and outer containers, each made of transparent polyethylene sheets, where the inner compartments are filled with the solution and sealed, and then placed into each compartment in an outer container, wherein two compartments in the outer container are separated by a flattened and sealed portion of the polyethylene.
1. A process for forming a flexible polymer pouch containing two containers which contain a phase change material consisting essentially of 98% 1-dodecanol, 1.5% myristyl alcohol and 0.5% 1-decanol and preparing the pouch for rapid cooling of blood bags filled with freshly drawn blood, wherein the pouch will be folded over to cover a major portion of each of the two largest surfaces of the blood bags for about 2 hours for the temperature of the blood in the blood bags to drop to 22° C.±2° C., the process comprising the steps of: forming said two inner containers for the phase change material using two first overlaying polymer sheets wherein a seal at the edges of said two first overlaying polymer sheets is completed after the phase change material is inserted between them; inserting the phase change material consisting essentially of 98% 1-dodecanol, 1.5% myristyl alcohol and 0.5% 1-decanol; forming one outer container for containing both of the inner containers using at least two second overlaying polymer sheets which are sealed along at least one axis to form two compartments; sealing at the edges of both said compartments of the outer container is completed after one of the inner containers is inserted into each compartment such that the second polymer sheets of the outer container overlay the outer surface of the first polymer sheets, to form the flexible polymer pouch; and preconditioning the flexible polymer pouch at about 22° C.
2. The process of claim 1 wherein the polymer sheets are made of polyethylene.
3. The process of claim 1 wherein the polymer sheets are transparent.
4. The process of claim 1 a portion of the edges of the polymer sheets forming the inner containers are sealed before the phase change material is inserted.
5. The process of claim 1 a portion of the edges of the polymer sheets forming the outer compartments are sealed before the inner containers are inserted.
6. The process of claim 1 wherein additional inner containers are formed and used to contain the inner containers containing the phase change material.
7. The process of claim 1 further including preconditioning the flexible polymer pouch at about 22° C. for about 12 hours.
8. The process of claim 1 wherein the blood bags contain 450 ml of blood.
9. The process of claim 8 further including extracting platelets from the contained blood.