New additive solutions for red cells

Shortly after the introduction of component therapy in the 1960s, the first additives for red cell concentrates (RCC) were introduced. This development resulted in prolongation of RCC shelf life from 21 to 35 or 42 days. Over the years, some new solutions were developed, but still SAGM (Europe) and AS-1 (United States) are the standard, nearly exclusive in combination with CPD as anticoagulant. Most of these new solutions were minor variations on SAGM or AS-1, with limited improvement of in vitro quality of erythrocytes. Development of new concepts, resulting in improved quality of RCC, was in first instance focused on achieving longer storage time. However, as a result from the concern about possible negative side effects caused by transfusion of older units, the research on new additive solutions is more focused on having a better quality during the currently accepted maximum storage time of 35–42 days. Around 1990, Meryman developed the concept of the so-called chloride shift. Through replacement of chloride by impermeable solutes, it is possible to manipulate the intracellular pH of erythrocytes, resulting in high 2,3-DPG and/or ATP values throughout storage. During the past 15–20 years, several research groups, with the group of Greenwalt and Hess as pioneers, developed new additive solutions based on the Meryman concept. Recently, the first commercial product from these studies was launched, with an improved in vitro quality parameter profile and improved in vivo recovery data. Finally, some recent developments are discussed with respect to alkaline additive solutions and anaerobic storage of erythrocyte concentrates.