Stiffness increase of red blood cells during storage

In transfusion medicine,the deformability of stored red blood cells(RBCs)changes during storage in blood banks.Compromised RBC deformability can reduce the transfusion efficiency or intensify transfusion complications,such as sepsis.This paper reports the microfluidic mechanical measurement of stored RBCs under the physiological deformation mode(that is,folding).Instead of using phenomenological metrics of deformation or elongation indices(DI or EI),the effective stiffness of RBCs,a flow velocityindependent parameter,is defined and used for the first time to evaluate the mechanical degradation of RBCs during storage.Fresh RBCs and RBCs stored up to 6 weeks(42 days)in the blood bank were measured,revealing that the effective stiffness of RBCs increases over the storage process.RBCs stored for 1 week started to show significantly higher stiffness than fresh RBCs,and stored RBC stiffness degraded faster during the last 3 weeks than during the first 3 weeks.Furthermore,the results indicate that the time points of the effective stiffness increase coincide well with the degradation patterns of S-nitrosothiols(SNO)and adenosine triphosphate(ATP)in RBC storage lesions.

Perioperative Red Blood Cell Transfusion： What We Do Not Know

Objective： Blood transfusion saves lives but may also increase the risk of injury. The objective of this review was to evaluate the possible adverse effects related to transfusion of red blood cell （RBC） concentrates stored for prolonged periods. Data Sources： The data used in this review were mainly from PubMed articles published in English up to February 2015. Study Selection： Clinical and basic research articles were selected according to their relevance to this topic. Results： The ex vivo changes to RBC that occur during storage are collectively called storage lesion. It is still inconclusive if transfusion of RBC with storage lesion has clinical relevance. Multiple ongoing prospective randomized controlled trials are aimed to clariI~~ this clinical issue. It was observed that the adverse events related to stored RBC transfusion were prominent in certain patient populations, including trauma, critical care, pediatric, and cardiac surgery patients, which leads to the investigation of underlying mechanisms. It is demonstrated that free hemoglobin toxicity, decreasing of nitric oxide bioavailability, and free iron-induced increasing of inflammation may play an important role in this process. Conclusion： It is still unclear whether transfusion of older RBC has adverse effects, and if so, which factors determine such clinical effects. However, considering the magnitude of transfusion and the widespread medical significance, potential preventive strategies should be considered, especially for the susceptible recipients.