Platelets show a rapid reduction in their responsiveness to aggregating agents during storage for transfusion, but little is known about reversal of this defect in vivo after transfusion. In this study, fresh and stored platelets from the same donor (n = 12) were labelled with 111In or 51Cr, respectively, mixed, and simultaneously infused. Blood samples were taken for up to 5 d post-infusion, and the functional behaviour of the labelled platelets ex vivo was measured by retention on glass bead columns, and by whole blood aggregability to ADP, epinephrine and ristocetin. Aggregation was determined by filtering aggregated samples through a column of cotton wool to remove the aggregates, and quantitated as per cent decrease in radioactive counts. The study showed that, although infused radiolabelled 5 d stored platelets had a significantly lower aggregability towards ADP and epinephrine immediately (1 h) after infusion (32% and 29%, respectively, of fresh platelet values), a complete restoration to fresh platelet levels was found 24-72 h post-infusion, with no further change observed over the ensuing 5 d with either fresh or stored labelled platelets. A slightly (6-9%) lower adhesion to both uncoated and collagen-coated beads was found for the stored platelets throughout the 5 d period of study post-infusion. In conclusion, these studies show that, with ex vivo testing, platelets stored for 5 d quickly recovered adhesion and aggregability capabilities similar to that of fresh platelets, suggesting that the functional lesion developed during storage is quickly and completely reversed after infusion.

Two techniques for the preparation of platelet concentrate (PC), the standard platelet-rich plasma (PRP) and buffy coat (BC) methods, were compared in nine paired studies with regard to platelet harvest, white cell (WBC) contamination, and PC quality after 5 days of 22 degrees C storage. Platelet harvest using the BC method averaged approximately 56 percent of the whole blood level (6.2 x 10(10)/concentrate), which was less than the 76 percent achieved with the PRP-PC method (8.7 x 10(10)/concentrate). An additional 5 units collected into an experimental siphon bag for BC-PC processing showed improved platelet harvest (6.7 x 10(10)/concentrate, or approx. 70% of whole blood). WBCs remaining in the BC-PC averaged 0.19 x 10(8) per unit compared to 3.6 x 10(8) per unit for PRP-PC. Buffy coat processing produced red cell (RBC) units with 50 percent of the WBC contamination of conventionally prepared units (9.8 +/- 6.2 x 10(8)/unit vs. 18.9 +/- 7.1 x 10(8)/unit). The siphon bag further reduced WBC levels in the AS-3 RBC units (6.4 +/- 3.7 x 10(8)/unit). In vitro studies performed on Days 1 and 5 after collection showed no significant differences in platelet metabolic and biologic function or cell integrity. Beta-thromboglobulin and surface glycoprotein levels, indicators of platelet activation and membrane alteration, respectively, did not differ significantly in the PRP-PC and BC-PC; nor was lactate production higher in PRP-PC, despite the substantially higher WBC counts. Autologous in vivo platelet viability determinations were performed by using concurrent transfusion of 111In-labeled freshly drawn platelets and 51Cr-labeled stored platelets.(ABSTRACT TRUNCATED AT 250 WORDS)

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Pain continues to be a very formidable foe in the care of the hospice patient. The incidence among hospice admissions may range from 50 to 80 percent. With such a high initial incidence of pain, the rapidity with which pain can be controlled becomes a very high priority for the hospice effort. The assessment and management of pain in a home-based hospice program presents some unique problems--and opportunities, in that much of this work is done by hospice nurses on site, rather than by the physician, who might remain quite removed from the process. In the study described below, 250 consecutive admissions to either a hospice, or pre-hospice (bridge) program were assessed for pain on admission. Those with pain scores of 5 or greater (on a 1 to 10 scale) were followed daily for 15 days by phone to reassess pain and treatment effects. Of the 250 consecutive patients surveyed, 41 (16 percent) gave pain scores of 5 or greater. Mean pain scores for the 41 patients dropped to < 5 within 24 hours of admission.

The technique of freezing blood platelets has proven very useful in transfusion support of some patients who have become alloimmunized by prior transfusions. Although transfused frozen platelets have an acceptable life span in vivo, functional defects have been found when these cells were tested in vitro. The adhesive properties of frozen platelets were investigated by use of a modified Baumgartner chamber to perform paired perfusion studies of fresh versus frozen platelets or fresh versus 5-day-stored platelets from the same whole blood unit. Platelets were either frozen in liquid nitrogen with dimethyl sulfoxide as the cryopreservative or stored under standard blood bank conditions for 5 days. The freeze-thaw recovery of platelets was 73 +/- 8 percent. Frozen platelets exhibited a significant decrease in platelet adhesion as compared to fresh platelets from the same unit; adhesion of frozen platelets was only 53 percent of that of fresh platelets (p = 0.04). A slight, but insignificant decrease was noted with platelets stored for 5 days (86%, p = 0.197). These findings indicate that frozen-thawed platelets have a significant defect in adhesive capacity as compared to fresh platelets, and that platelets stored under blood bank conditions for 5 days maintain adhesive capacity well.

Thrombotic thrombocytopenic purpura (TTP) is a potentially lethal disease that may respond favorably to plasma infusion or therapeutic plasma exchange (TPE) with frozen plasma (FP) as the exchange fluid. Frozen plasma from which the cryo-precipitated fraction has been removed (cryopoor plasma, CP) has reportedly been useful in refractory cases in which a response to FP is not being observed. We report a retrospective analysis of all cases of TTP treated by TPE with either FP (1985-1989) or CP (1989-1993) as exchange fluid at a large tertiary care hospital between the years 1985 and 1993. A severity score index was compiled for each patient using the platelet count, mental status, hematocrit, and renal function at the time of diagnosis. Nineteen patients were treated with FP (group 1) and 18 patients with CP (group 2). Groups did not differ in age, gender, race, hematologic parameters, or severity scores. Patients treated with CP, however, had more plasma exchange (14 +/- 10 vs. 12 +/- 8, respectively) and more fluid exchanged than these treated with FP (50 L +/- 36 vs. 37 L +/- 40, respectively). Survival was 72% in the CP group and 47% in the FP group. Although a survival advantage for the use of CP as exchange fluid in the treatment of TTP is suggested by our observations, the retrospective nature of the study, lack of randomization, and sequential rather than concurrent use of FP and CP indicates caution in interpretation. The data do indicate, however, that use of CP is acceptable as the initial exchange fluid in TTP.