Currently, platelet concentrates are stored in 50 to 60 ml of plasma. A major drawback to storage in plasma is the considerable loss of platelet function which occurs during storage. A modified Tyrodes medium has been developed for storage of platelets. A comparison between platelet concentrates stored in this medium and in plasma showed that platelet aggregation and release responses to synergistic pairs of stimuli were equivalent for both types of concentrates on the day of preparation and after 72 hours. Platelet aggregation and release responses to single stimuli, the content of membrane glycoproteins, and the pH declined during storage but were similar for both preparations. The data show that plasma is not required to maintain in vitro platelet function during storage of platelet concentrates, but in vivo functions remain to be determined. The use of an artificial medium has the advantages of decreasing patient exposure to plasma contaminants, generating additional plasma for fractionation, and controlling more exactly the storage environment.

Optimal conditions for the storage of platelet concentrates were studied by changing 5 environmental parameters: bag composition (PL 146 vs. PL732), volume of plasma (60 vs. 30 ml), anticoagulant (CPDA^-1 vs. heparin), nutrient (glucose vs. fructose) and medium (plasma vs. artificial medium). A full bilevel factorial study was conducted to evaluate each variable alone and in combination with the other variables for their effects on platelet aggregation and release in response to single and pairs of stimuli. Serotonin uptake, pCO(2), platelet count, lactate, glucose, pO(2), pH and white blood cell concentration were also measured after 3 and 5 days of storage. Platelets that were stored in PL146 bags had reduced responses to stimulation by 3 days and markedly impaired responses after 5 days relative to platelets that were stored in PL732 bags. There was a large drop in pH and platelet responsiveness when platelets were stored in a volume of 30 ml in PL146 bags; these were not found when platelets were stored in 30 ml in PL732 bags. Replacing plasma with an artificial medium or adding fructose or heparin and calcium to plasma yielded platelets that were equally functional as routine controls in CPD-A1 plasma. It was concluded that replacement of plasma with 60 ml of artificial medium or a reduction of plasma volume with storage in PL732 bags are two possible mechanisms of obtaining more plasma from blood donations without compromising maximum platelet storage life.

Optimal conditions for the storage of platelet concentrates were studied by changing 5 environmental parameters: bag composition (PL146 vs. PL732), volume of plasma (60 vs. 30 ml), anticoagulant (CPDA-1 vs. heparin), nutrient (glucose vs. fructose) and medium (plasma vs. artificial medium). A full bilevel factorial study was conducted to evaluate each variable alone and in combination with the other variables for their effects on platelet aggregation and release in response to single and pairs of stimuli. Serotonin uptake, pCO2, platelet count, lactate, glucose, pO2, pH and white blood cell concentration were also measured after 3 and 5 days of storage. Platelets that were stored in PL146 bags had reduced responses to stimulation by 3 days and markedly impaired responses after 5 days relative to platelets that were stored in PL732 bags. There was a large drop in pH and platelet responsiveness when platelets were stored in a volume of 30 ml in PL146 bags; these were not found when platelets were stored in 30 ml in PL732 bags. Replacing plasma with an artificial medium or adding fructose or heparin and calcium to plasma yielded platelets that were equally functional as routine controls in CPD-A1 plasma. It was concluded that replacement of plasma with 60 ml of artificial medium or a reduction of plasma volume with storage in PL732 bags are two possible mechanisms of obtaining more plasma from blood donations without compromising maximum platelet storage life.

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