Macroaggregate Formation in Optimal Additive Red Cells

Abstract

The formation of macroaggregates weighing up to 9 g was observed in optimal additive red cells. Such aggregates, with a mean wet weight of 3 g, formed progressively during storage and were present in up to 85% of units. They were composed of leucocyte and platelet debris, together with some fibrin. Macroaggregates formation was halved by less stringent centrifugation during preparation and was reduced by use of an optimal additive system in which the additive solution contained citrate. Extra mixing during transfer of the additive solution only delayed aggregate formation. Partial leucocyte depletion or addition of 200,000 KIU of the enzyme inhibitor aprotinin did not prevent macroaggregate formation.

Studies on the Procurement of Blood Coagulation Factor VIII in vitro Studies on Blood Components Prepared in Half-Strength Citrate Anticoagulant

“…Assessment of the red cell units after 5 weeks storage showed no visual evidence of clotting, no bacterial contamination and only one 0.5-CPD.A2 unit contained a macroaggregate, of the type observed at high frequency in optimal-additive-stored red cells [32], Table IV shows results for red cell products stored at differing haematocrits and confirms that for 0.5-CPD. A2 these are acceptable.…”

White Thrombus Formation in Blood Tubing Lines in a Chronic Hemodialysis Unit

“…This phenomenon has not previously been described in the public domain; however, a similar white particulate matter was described in blood products stored ex vivo in plasticized containers (1)(2)(3)(4). This phenomenon seemed to abate after change of dialysis blood lines, and returned immediately after temporary reinstatement of prior dialysis blood lines.…”

What is the ‘Optimum’ Optimal Additive Solution?

“…No special attention has been paid to the mixing of blood with anticoagulant during collection as was investigated by Robertson et al [3] in their study of this phenomenon. These workers showed that Tuta optimal additive packs which do contain citrate, but at around 25% of that in our additive '3' contained around 30% less clot than Fenwal packs.…”

“…The Transfusion Service benefits because their use enables the collection of the maximum volume of plasma for other therapeutic purposes whilst for clin ical staff the excellent flow properties and reduced microaggregate content of cell sus pensions are welcome features [1,2], Despite their reduced microaggregate con tent optimal additive red cell packs appear to have an increased tendency towards forma tion of amorphous diffuse clots [3]. These are occasionally so conspicuous as to cause the red cell packs to be returned from hospitals as unsuitable for use.…”