The effect of temperature and mode of agitation on the resuspension of platelets during preparation of platelet concentrates

[Obtaining blood components in blood banks]

After the first successful blood transfusion, different difficulties of a liquid tissue were overcome; this liquid required special conditions to keep its characteristics with minimal alterations and, thus, to be able to be used in patients who needed it. Subsequently, techniques that also made possible to separate this liquid into its different components for its use were discovered, allowing a more specific treatment of the deficiencies of patients when administering cellular or non-cellular elements. With this, a new area arose within the blood banks to obtaining components. This area became the central point of convergence of all the processes involved in obtaining components, which include the biological qualification of each one of the units, as well as their labeling and release for the different distribution in transfusion services. It is important to highlight that the main source of components is obtained from whole blood; its processing for several decades was an artisanal operator-dependent process; however, with the evolution of technology, now it is possible to carry it out in an automated manner; likewise, today it is possible to obtain components directly from the donor's whole blood by separating it in real time by means of apheresis, which allows obtaining the component of interest and returning the remainder to the donor.

Reevaluation of the resting time period when preparing whole blood-derived platelet concentrates with the platelet-rich plasma method

BACKGROUND

The resting of platelet (PLT) pellets during the preparation of whole blood-derived PLT concentrates (PCs) is considered an essential step. A reevaluation of the rest period was conducted because preparation and storage conditions have been modified during the past 20 years.

STUDY DESIGN AND METHODS

A two-site in vitro study (Study 1) was conducted with rest times of 0 to 5 minutes, 1 hour, and 4 hours (n = 31-33 per rest period). Leukoreduced PCs were stored for 5 days. A second study (Study 2) measuring in vivo viability was conducted at a third site (14 paired studies). PCs were prepared from 2 units of whole blood on the same day to simultaneously compare viability following storage and radioisotopic labeling.

RESULTS

In Study 1, comparable in vitro parameters and swirling were observed with the three rest periods. The mean (+/-1 SD) values after storage for the extent of shape change and hypotonic stress parameters were 0 to 5 minutes, 16.7 +/- 7.2 and 66.0 +/- 15.7%; 1 hour, 19.1 +/- 6.9 and 69.3 +/- 17.9%; and 4 hours, 17.6 +/- 5.5 and 64.1 +/- 11.3%. In Study 2, the in vivo recovery was 49.9 +/- 15.3 and 50.9 +/- 20.2% with 0- to 5-minute and 1-hour rest periods, respectively. The corresponding survival time was 111.2 +/- 50.7 and 114.9 +/- 43.8 hours.

CONCLUSION

These studies indicate comparable in vitro and in vivo viability properties with 0- to 5-minute and 1-hour rest periods and at 4 hours (in vitro only).

Platelet thermophysiology: a new field of investigation dependent upon an improved sub-ambient platelet aggregometer

Studies of platelet aggregation are normally performed at 37 degrees C. However, in hypothermia during certain surgical procedures (for example, cardiopulmonary bypass) efficient aggregation may be needed at temperatures below 37 degrees C: therefore, assessment of platelet aggregation at temperatures below 37 degrees C may be relevant. This paper describes a sub-ambient aggregometry system developed for this purpose. The effect of temperature (range of 4.5 degrees-37.0 degrees C) upon ADP-induced and spontaneous aggregation of platelets from normal subjects was studied. Platelet aggregation was found to be maximal at room temperature, and may represent 'pure' aggregation. At higher temperatures platelet disaggregation becomes measurable, and at lower temperatures, cold-induced platelet shape-change predominates. These parameters are briefly discussed in terms of their relevance to future research into the physiology of platelet storage and clinical haemostasis.