New insulation technology provides next-generation containers for "iceless" and lightweight transport of RBCs at 1 to 10 degrees C in extreme temperatures for over 78 hours.

BACKGROUND: There is a universal need, in both civilian and military settings, for a lightweight container capable of maintaining RBCs at 1 to 10 degrees C in remote areas, during extended transit times, and under austere environments. The use of ice in insulated containers or small commercial coolers for these purposes often results in loss of RBCs due to failure to maintain temperatures within the requisite range. A lightweight and thermally efficient container capable of carrying 4 to 6 units of RBCs at 1 to 10 degrees C for over 72 hours under extreme conditions would help resolve current problems in RBC transportation. STUDY DESIGN AND METHODS: Six different prototype containers incorporating phase-change materials (PCMs) in their designs were evaluated for their ability to maintain RBCs between 1 and 10 degrees C while exposed to external temperatures of -24 degrees C and 40 degrees C. In separate experiments, a container was opened and a RBC unit removed. RESULTS: One container weighing 10 pounds with four units of RBCs was capable of maintaining the temperature of the units between 1 and 10 degrees C for over 78 hours, 96 hours, and 120 hours at 40 degrees C, -24 degrees C, and 23 degrees C, respectively. Opening the container decreased these times by 2 to 3 hours. CONCLUSIONS: An energy-efficient and lightweight container that maintains RBCs at 1 to 10 degrees C under austere environments for over 78 hours is now available. This container, known as the Golden Hour container (GHC), will facilitate transport of RBCs. The GHC will have additional applications (transport and/or storage of vaccines, other biologics, organs, reagents, etc).

Physical and thermal properties of blood storage bags: implications for shipping frozen components on dry ice.

BACKGROUND: Frozen blood components are shipped on dry ice. The lower temperature (-70 degrees C in contrast to usual storage at -30 degrees C) and shipping conditions may cause a rent in the storage bag, breaking sterility and rendering the unit useless. The rate of loss can reach 50 to 80 percent. To identify those bags with lower probability of breaking during shipment, the thermal and physical properties of blood storage bags were examined. STUDY DESIGN AND METHODS: Blood storage bags were obtained from several manufacturers and were of the following compositions: PVC with citrate, di-2-ethylhexylphthalate (DEHP), or tri-2-ethylhexyl-tri-mellitate (TEHTM) plasticizer; polyolefin (PO); poly(ethylene-co-vinyl acetate) (EVA); or fluorinated polyethylene propylene (FEP). The glass transition temperature (Tg) of each storage bag was determined. Bag thickness and measures of material strength (tensile modulus [MT] and time to achieve 0.5 percent strain [T0.5%]) were evaluated. M(T) and T0.5% measurements were made at 25 and -70 degrees C. Response to applied force at -70 degrees C was measured using an impact testing device and a drop test. RESULTS: The Tg of the bags fell into two groups: 70 to 105 degrees C (PO, FEP) and -50 to -17 degrees C (PVC with plasticizer, EVA). Bag thickness ranged from 0.14 to 0.41 mm. Compared to other materials, the ratios of M(T) and T0.5% for PVC bags were increased (p < or = 0.001) indicating that structural changes for PVC were more pronounced upon cooling from 25 to -70 degrees C. Bags containing EVA were more shock resistant, resulting in the lowest rate of breakage (10% breakage) when compared with PO (60% breakage, p = 0.0573) or PVC (100% breakage, p = 0.0001). CONCLUSIONS: Blood storage bags made of EVA appear better suited for shipping frozen blood components on dry ice and are cost-effective replacements for PVC bags. For the identification of blood storage bags meeting specific storage requirements, physical and thermal analyses of blood storage bags may be useful and remove empiricism from the process.

Characterization of the main phase transition in 1,2-dipalmitoyl-phosphatidylcholine luvs by 1H NMR.

The main phase transition (Tm) of 100 nm large unilamellar vesicles (LUVs) of 1,2-dipalmitoylphosphatidylcholine (DPPC) was investigated using 1H NMR (proton magnetic resonance) in deuterium oxide, and both DSC (differential scanning calorimetry) and IR (infrared) spectroscopy in water and deuterium oxide. The ability of 1H NMR to determine Tm was demonstrated and the values obtained were in general agreement with those observed with DSC and IR. However, the temperature range of the transition observed by NMR was significantly broader than that observed with either DSC or IR. The effect of deuterium oxide on Tm was studied by comparing results obtained in water and deuterium oxide with DSC and IR. The results showed no significant difference in Tm or temperature range of transition determined in these solvents.