Effect of transient warming of red blood cells for up to 24 h: in vitro characteristics in CPD/saline-adenine-glucose-mannitol environment

Background and Objectives There are few studies on transient warming of red blood cells (RBCs). Occasional storage outside restricted temperature range often results in destroying of the RBC unit, even after a short period of time due to national guidelines. This study evaluates the in vitro effects associated with such accidental warming on RBCs stored in saline-adenine-glucose-mannitol (SAGM) and prepared within 8h after blood collection. Study Design and Methods This study includes both repeated short-term exposure of RBCs to room temperature for 6h as wells as warming for either 6, 12, 18 or 24h after 1week or after 3weeks of storage in two separate studies. RBCs were stored for 42days. We weekly measured pH, K+, glucose, lactate, haemolysis, red cell ATP and 2,3-diphosphoglycerate. Results The lowest individual ATP value observed in any of the groups of warmed units was 26mol/g haemoglobin. Increased haemolysis in warmed units was noted in two of the studies. None of the individual units exceeded the European maximum limit of 08% haemolysis. Conclusion Our results suggest that quality of RBCs after transient warming will be maintained at acceptable levels specified in standards and in previous studies. However, increased haemolysis was observed when transient warming occurred during the second part of the storage period of 6weeks suggesting that RBCs are more vulnerable to warming by the end of storage.