Aplin Kate, Pitt Tyrone, Allen Jennifer, Roy Anjana, Tidey Katrina, Ball Joanne, McDonald Carl Peter
National Bacteriology Laboratory, NHS Blood and Transplant, London, UK.
Vox Sang. 2019 Apr;114(3):189-197. doi: 10.1111/vox.12747. Epub 2019 Mar 4.
In the UK, a significant proportion of red cell units is discarded due to the 30-min rule governing out of temperature control. Studies have shown that repeated warming to ambient temperature has little impact on red cell quality or bacterial growth. We aimed to validate extension of the rule to 60 minutes by investigation of repeated same, and different, day exposures on bacterial growth.
Red cell units were seeded individually at 100-1000 cfu/ml with Yersinia enterocolitica, Serratia liquefaciens, Pseudomonas putida, Staphylococcus epidermidis, Enterobacter cloacae and Bacillus cereus. Test units were exposed to 30°C for 30 or 60 min on a single occasion at days 15, 17 and 21, or thrice on day 15 of a 35-day storage period. A 10-fold increase in bacterial counts in tests versus controls maintained in cold storage was considered indicative of significant bacterial proliferation.
Exposure of units to 30°C for up to 60 min had no substantial impact on the growth of bacteria and all mesophiles declined steadily in tests and controls. Only P. putida showed a near significant elevation in count on exposure for 60 min at day 35.
Extension of the out of temperature rule for red cells to 60 min will potentially not compromise patient safety, although exposures to ambient temperatures should be minimized. Units returned to storage must not be reissued for at least 6 hours and not be exposed to ambient temperatures on more than three occasions.
在英国，由于30分钟的温度控制规则，相当一部分红细胞单位被丢弃。研究表明，反复升温至环境温度对红细胞质量或细菌生长影响不大。我们旨在通过研究同一日和不同日反复暴露对细菌生长的影响，验证将该规则延长至60分钟的可行性。
将红细胞单位分别接种100 - 1000 cfu/ml的小肠结肠炎耶尔森菌、液化沙雷菌、恶臭假单胞菌、表皮葡萄球菌、阴沟肠杆菌和蜡样芽孢杆菌。测试单位在储存35天期间的第15、17和21天单次暴露于30°C 30或60分钟，或在第15天暴露三次。与冷藏中的对照相比，测试中细菌计数增加10倍被认为表明有显著的细菌增殖。
单位暴露于30°C长达60分钟对细菌生长没有实质性影响，所有嗜温菌在测试和对照中均稳步下降。仅恶臭假单胞菌在第35天暴露60分钟时计数有接近显著的升高。
将红细胞温度控制规则延长至60分钟可能不会危及患者安全，尽管应尽量减少暴露于环境温度的情况。退回储存的单位至少6小时内不得重新发放，且暴露于环境温度的次数不得超过三次。
