Improvement of platelet storage conditions by using new polyolefin containers

BACKGROUND : Storage of pooled platelet concentrates (PCs) with yields above 3.0 × 10¹¹ platelets per unit in a 1-L PL-732 polyolefin container for 5 days often results in a drop in pH to below 6.0. Recently, new oxygen-permeable platelet containers (1-L PL-2410, 1-L and 1.5-L Compoflex) have been developed. The maximal platelet storage capacities of the new containers and the PL-732 were compared. STUDY DESIGN AND METHODS : Large platelet pools (n = 27) with platelet concentrations between 1.2 and 1.4 × 10¹¹ per L were made from 3 to 5 PCs prepared from buffy coats. The pools were divided in equal volumes among the PL-732 and the three new platelet containers. Platelet counts in the PCs ranged from 1.0 to 5.0 × 10¹¹ per unit. All PCs were stored on a flatbed shaker at 22 ± 2°C and evaluated on Days 1, 3, 5, and 7 by measuring platelet count, pH, pO₂, pCO₂, HCO₃-, glucose, lactate, platelet swirling, and soluble p-selectin. RESULTS : Day 7 storage of PCs (n = 6) with yields between 3.0 and 4.0 × 10¹¹ platelets in PL-732 showed mean ± SD pH values of 5.93 ± 0.05 and lactate values of 32.3 ± 7.9 mmol per L; in 4 of these 6 PCs, pH was below 6.0. In contrast, storage of these PCs in 1-L PL-2410 and 1.5-L Compoflex containers and of 2 of these 6 PCs in 1-L Compoflex containers showed pH values above 6.8. Lactate values were 15.5 ± 1.3, 15.3 ± 1.8, and 19.5 ± 4.7 mmol per L, respectively (p < 0.001 vs. PL-732). The platelet storage capacity of the new containers with platelet yields between 4.0 and 5.0 × 10¹¹ per unit (n = 6) was evaluated. Day 7 storage of these PCs in the 1.5-L Compoflex showed an average pH value of 6.74 ± 0.20; in 2 of 6 PCs, pH was below 6.8. The average pH value in the PL-2410 was 6.38 ± 0.31, and in all PCs, pH was below 6.8. Average lactate values were 17.8 ± 5.7 and 25.8 ± 5.6 mmol per L (p < 0.05), respectively. Soluble p-selectin values on Day 7 of storage increased approximately twofold in all PCs. CONCLUSION : The new oxygen-permeable containers showed platelet quality comparable to that with the PL-732 and for longer storage periods and at higher platelet counts.