Preparation and storage of white blood cell-reduced split apheresis platelet concentrates for pediatric use

BACKGROUND: White blood cell (WBC) reduction and bacterial screening induce unacceptable product loss when platelet (PLT) concentrates (PCs) for pediatric transfusion are prepared from whole blood. The aim was to investigate PCs, WBC reduced and bacterially screened, from single-donor apheresis procedures, divided in 3 or 4 pediatric units and stored up to 5 days. STUDY DESIGN AND METHODS: PCs were collected with an apheresis machine and WBC reduced by in-process filtration. The PCs were sampled for bacterial screening and subsequently divided in 70-mL products. Initially, storage characteristics of split units in 400-mL polyvinylchloride (PVC) bags with 17 split PCs originating from five apheresis donations were studied. When a 600-mL container made of the more gas-permeable polyolefin became available, a paired comparison was performed with 9 split PCs from nine donations and with a higher-yield PLT collection procedure. RESULTS: Split PCs contained 69 x 10(9) +/- 14 x 10(9) PLTs in 69 +/- 1 mL of plasma, and storage in the PVC containers gave a pH value of 6.86 +/- 0.10 on Day 6 (mean +/- SD, n = 17). When comparing the containers, the PVC bag contained 98 x 10(9) +/- 15 x 10(9) PLTs in 72 +/- 4 mL versus 102 x 10(9) +/- 18 x 10(9) PLTs in 74 +/- 8 mL for the polyolefin bag (n = 9, not significant). This gave pH values on Day 6 of 6.12 +/- 0.50 in the PVC container, whereas pH remained acceptable in the polyolefin container: 6.85 +/- 0.10 on Day 6 (p < 0.01). CONCLUSION: PCs for pediatric use from split single-donor apheresis concentrates, WBC reduced and bacterially screened, can be stored for up to 5 days in a 600-mL polyolefin container with maintenance of good in vitro storage variables.     

Extension of platelet concentrate storage

Extension of the storage time of platelet concentrates in a satellite bag which is part of a new blood bag system was studied by reinfusing autologous 51Cr-labeled platelets into normal volunteers, and measuring postinfusion platelet counts and bleeding times in patients requiring platelet transfusions. This satellite bag, made of polyvinylchloride plasticized with a new agent, was found to protect platelet concentrates against fall of pH better than other containers studied. This protection was felt to be due to the greater gas permeability of the new plastic. Mean in vivo recovery and half-life (greater than 31% and 3.3 days, respectively) of autologous reinfused platelets were satisfactory following 5 days of storage. Following 7 days of storage, mean recovery was 41 percent and half-life was 2.8 days. Peripheral platelet count increments in patients following platelet transfusions with concentrates stored 4 to 7 days in the new plastic were comparable to increments following transfusion of platelets stored 2 to 3 days in the other plastics studied. Bleeding times shortened in three of four patients receiving platelet concentrates stored from 4 to 6 days in the new plastic. Platelet concentrates stored in the new bag at 20 to 24 degrees C with flat-bed or elliptical agitation could be transfused for up to 5 days following phlebotomy with acceptable clinical results. The new plastic container is promising for storage of platelet concentrates for up to 7 days. Due to the higher pH of 50-ml platelet concentrates stored in bags made with the new plastic, the concentrates were superior at any storage interval to those stored in bags made of the other plastics studied.     

A new polyvinylchloride blood bag plasticized with less-leachable phthalate ester analogue, di-n-decyl phthalate, for storage of platelets

To compare changes in platelets stored in the new di-n-decyl phthalate (DnDP)-plasticized polyvinyl chloride (PVC) bag with those in a di-(2-ethylhexyl) phthalate (DEHP)-plasticized PVC bag, single-donor apheresis platelet concentrates (PCs), 133 +/- 11 x 10(7) platelets per ml (n = 7), were stored with 94 +/- 3 ml of plasma in a new 1-liter bag with a surface area of 44 +/- 7.1 cm2 per 10(10) platelets. Oxygen and carbon dioxide gas diffusion properties of PVC-DnDP films were respectively, 1.6 and 2 times those of standard PVC-DEHP films. The amounts of DnDP leaked into the plasma of PCs were low at 0.58 +/- 0.06 mg per bag after 5-day storage, which is about one-eightieth the amount of DEHP leaked. The pH of PCs in PVC-DnDP bags amounted to 6.99 +/- 0.03 after 5-day storage, with glycolysis accelerated somewhat in the new bags. However, the platelet oxygen consumption was no different from that in the PVC-DEHP bags. Platelet aggregation and responses to hypotonic shock were significantly better in the new bags at the end of storage. Shape changes of platelets into spherical forms with dendrites were more frequently observed in PVC-DnDP bags than in PVC-DEHP bags. The study indicated that platelets stored in the new DnDP-plasticized PVC bags have retained aggregation and responses to hypotonic shock more than platelets in the PVC-DEHP bags, but spherical forms and anaerobic metabolism increased in the new bags.     

Storage of single donor platelet concentrates: Paired comparison of storage as single or double concentrates

Modern cell separators allow the collection of two plateletpheresis concentrates (PCs) at one session. This study evaluates the quality of PCs stored as double concentrates in standard storage containers of two manufacturers. We collected 20 PCs that contained 4.5 × 10¹¹ platelets in 375 ml plasma (10 using the COBE Spectra and 10 using the Fresenius AS.TEC 204 with 500 ml bags) that were split into one unit of 3.0 × 10¹¹ platelets in 250 ml (3.0‐PC) and one of 1.5 × 10¹¹ platelets in 125 ml (1.5‐PC). Storage of one 3.0‐PC per bag of a two‐bag system corresponded to storage conditions for double PCs and storage of one 1.5‐PC per bag to storage conditions of single PCs. Cell counts, blood gas analysis, glucose and lactate levels, platelet aggregation, and activation and plasma levels of β‐ thromboglobulin (β‐TG) and complement factor 3a (C3a) were measured before storage and again on days 3 and 5. COBE 3.0‐PCs demonstrated less pH rise, lactate production, CD 62P expression and β‐TG plasma levels, and better aggregability after storage than COBE 1.5‐PCs. Fresenius 1.5‐PCs had similar platelet quality to COBE 3.0‐PCs. Fresenius 3.0‐PCs showed a fall of pH (day 5: 6.22 ± 0.56), the highest amount of anaerobic glycolysis compared to all other storage conditions investigated, high CD 62P‐ expression and β‐TG plasma levels, and impaired aggregability on days 3 and 5. The highest C3a levels were found in COBE 1.5‐PCs. 3.0 × 10¹¹ platelets in 250 ml plasma should be stored either in one bag of the COBE system or in two 500 ml bags of the Fresenius system. The COBE two‐bag system allows the storage of two PCs without loss of platelet quality. Two PCs should not be stored in the Fresenius C4L 500 ml storage containers. J. Clin. Apheresis. 16:148‐154, 2000. © 2001 Wiley‐Liss, Inc.     

Storage of pools of six and eight platelet concentrates

Platelet concentrates (PCs) prepared from units of whole blood are routinely stored singly at 20 to 24 degrees C and pooled prior to transfusion. Studies have been conducted to evaluate the in vitro properties of pools of six (n = 19) and eight (n = 17) ABO-identical PCs after storage, with comparative studies involving single units (n = 33). The pools were prepared using the sterile connecting device. One- day-old and 3-day-old PCs were pooled and stored for a total of 5 days in a container system consisting of two 1000-mL polyolefin containers. The pooled platelet suspension was divided approximately equally between the two containers. The platelet count was reduced by less than 5 percent during storage of the pools, which is similar to the reduction found with storage of control units of single PCs. The volume loss due to pooling was 9.6 +/− 1.9 percent (mean +/− 1 SD). The pH of the PC pools was approximately 7.0 after 5 days of storage, with no pool having a pH below 6.2. In vitro platelet properties, such as morphology score, extent of shape change induced by ADP, total ATP, aggregation response to ADP and collagen, response to hypotonic stress, lactate dehydrogenase discharge, and beta-thromboglobulin release, were similar for pools and control single PCs. In addition, comparable low levels of thymidine uptake were detected in the mononuclear leukocyte fraction of pooled and unpooled PCs that were stored for 5 days at 20 to 24 degrees C, which indicates that the mixing of lymphocytes in the pool did not stimulate in vitro immunologic reactions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Improvement of platelet storage conditions by using new polyolefin containers

BACKGROUND : Storage of pooled platelet concentrates (PCs) with yields above 3.0 × 10¹¹ platelets per unit in a 1-L PL-732 polyolefin container for 5 days often results in a drop in pH to below 6.0. Recently, new oxygen-permeable platelet containers (1-L PL-2410, 1-L and 1.5-L Compoflex) have been developed. The maximal platelet storage capacities of the new containers and the PL-732 were compared. STUDY DESIGN AND METHODS : Large platelet pools (n = 27) with platelet concentrations between 1.2 and 1.4 × 10¹¹ per L were made from 3 to 5 PCs prepared from buffy coats. The pools were divided in equal volumes among the PL-732 and the three new platelet containers. Platelet counts in the PCs ranged from 1.0 to 5.0 × 10¹¹ per unit. All PCs were stored on a flatbed shaker at 22 ± 2°C and evaluated on Days 1, 3, 5, and 7 by measuring platelet count, pH, pO₂, pCO₂, HCO₃-, glucose, lactate, platelet swirling, and soluble p-selectin. RESULTS : Day 7 storage of PCs (n = 6) with yields between 3.0 and 4.0 × 10¹¹ platelets in PL-732 showed mean ± SD pH values of 5.93 ± 0.05 and lactate values of 32.3 ± 7.9 mmol per L; in 4 of these 6 PCs, pH was below 6.0. In contrast, storage of these PCs in 1-L PL-2410 and 1.5-L Compoflex containers and of 2 of these 6 PCs in 1-L Compoflex containers showed pH values above 6.8. Lactate values were 15.5 ± 1.3, 15.3 ± 1.8, and 19.5 ± 4.7 mmol per L, respectively (p < 0.001 vs. PL-732). The platelet storage capacity of the new containers with platelet yields between 4.0 and 5.0 × 10¹¹ per unit (n = 6) was evaluated. Day 7 storage of these PCs in the 1.5-L Compoflex showed an average pH value of 6.74 ± 0.20; in 2 of 6 PCs, pH was below 6.8. The average pH value in the PL-2410 was 6.38 ± 0.31, and in all PCs, pH was below 6.8. Average lactate values were 17.8 ± 5.7 and 25.8 ± 5.6 mmol per L (p < 0.05), respectively. Soluble p-selectin values on Day 7 of storage increased approximately twofold in all PCs. CONCLUSION : The new oxygen-permeable containers showed platelet quality comparable to that with the PL-732 and for longer storage periods and at higher platelet counts.     

Volume-reduced platelet concentrates: optimization of production and storage conditions

BACKGROUND: Plasma can be removed from platelet (PLT) concentrates (PCs) when volume reduction for PLT transfusion is indicated. Volume‐reduced PCs are currently produced from pooled buffy coat (BC) PCs or apheresis PCs by pretransfusion volume reduction, followed by transfer to a syringe for immediate transfusion. We evaluated the maximal storage time of the volume‐reduced PCs in gas‐permeable containers. STUDY DESIGN AND METHODS: Volume‐reduced PCs were produced from BC‐derived and apheresis PCs by hard‐spin centrifugation. Supernatant was removed and the PLTs were resuspended in 20 mL of retained original PC and had PLT concentrations ranging from 10.8 × 10⁹ to 13.8 × 10⁹ PLTs/mL. Volume‐reduced PCs were stored either in syringes or in containers made from diethylhexyl phthalate (DEHP)‐polyvinylchloride (PVC) or butyryl trihexyl citrate (BTHC)‐PVC plastic. Units were sampled at t = 0, 1, 3, and 6 hours for in vitro measurements. RESULTS: When prepared from 2‐day‐old PCs (n = 4), volume‐reduced PCs from BCs in a syringe had a pH_37°C of 5.76 ± 0.04 at t = 6 hours after volume reduction. In the DEHP‐PVC container, pH was 5.85 ± 0.15 (not significant), and in the BTHC‐PVC, 6.34 ± 0.16 (p < 0.001), at t = 6 hours. When made from 7‐day‐old PCs, pH was lower for all storage conditions: 5.68 ± 0.06 in the syringe, 5.70 ± 0.09 in the DEHP‐PVC container (not significant), and 6.07 ± 0.24 in the BTHC‐PVC container (p < 0.01) at t = 6 hours. Volume‐reduced 2‐day‐old apheresis PCs had a pH of 6.47 ± 0.20 at t = 6 hours. CONCLUSIONS: Adult‐dose PCs derived from BC or apheresis can be volume‐reduced to approximately 20 mL in a closed gas‐permeable system. Volume‐reduced PCs in BTHC‐PVC containers retain a mean pH of more than 6.0 up to 6 hours after production. Syringes allow only 3 hours of storage.     

Storage of platelets on flatbed agitators in polyvinyl chloride blood bags plasticized with tri(2-ethylhexyl) trimellitate

Data are presented showing that platelets in polyvinyl chloride blood bags plasticized with tri(2-ethylhexyl) trimellitate can be stored on flatbed agitators (shakers) without the pH falling below 6.0. The lowest pH seen after 7 days of storage in 46 units with platelet yields ranging from 3.6 to 13.3 X 10(10) per unit was 6.43. These bags have a O2 transmission rate of 13.3 mumol per hour per bag. Platelet bags with a O2 transmission rate of 7.9 mumol per hour per bag experience a pH fall after 5 days of storage on the shaker in units whose platelet yield on average exceeds 10 X 10(10). Platelets can be stored on first-generation shakers (70 cycles/min, stroke = 1 inch) without an attempt at manual resuspension of the platelet button. The count after 30 minutes on the shaker averaged 89 +/- 15 percent of the expected count, indicating that resuspension was nearly complete after a relatively short period. Red cells, but not platelets, settled out during storage on the shaker.     

The effect of the interruption of agitation on platelet quality during storage for transfusion

BACKGROUND: A considerable amount of data and the CFR suggest that platelet concentrates (PCs) should be stored with continuous, gentle agitation before transfusion. However, there are only limited data concerning the mechanisms of platelet damage that may occur when agitation is interrupted, and there are no CFR guidelines concerning shipment between periods of storage. STUDY DESIGN AND METHODS: PCs were prepared by the platelet-rich plasma method and stored for 5 days at 20 to 24 degrees C; agitation was interrupted for 1 to 3 days either by simply stopping the agitator or by placing the PCs in a stationary shipping container. Measurements of platelet metabolism and quality were made during storage and on Day 5. RESULTS: With interruption on the agitator, the production of lactic acid was increased during the interruption in proportion to the number of platelets in the PC and the duration of the interruption. The pO(2) was increased during agitation interruption, which suggested a decline in oxygen utilization. With the use of the hypotonic shock response and the extent of shape change as reflections of platelet quality, there was no evidence of platelet damage unless the pH fell to or below 6.5. No PC reached this level after an interruption of agitation for only 1 day, irrespective of which day was chosen for interruption. PCs whose agitation was interrupted for 2 and 3 days were at risk of having a pH less than 6.5 if their contents were greater than 1.25 x 10(11) and 0.75 x 10(11) platelets, respectively. Interruption of agitation for 1 day in the shipping container produced results essentially identical to those produced by interruption on the agitator. CONCLUSION: Interruption of agitation of PCs for 1 day, either on the agitator or in the shipping container, produces no platelet damage measurable by these in vitro techniques. However, an interruption of agitation for 2 days can result in significant damage in some components. Further studies will be required to learn more about the mechanisms that lead to the metabolic changes described and to determine if the same generalizations apply to apheresis PCs and PCs prepared from pooled buffy coats.     

Comparative analysis of platelet concentrates prepared after two hours and overnight storage of buffy coat at room temperature

IntroductionThe overnight storage of the buffy coat (BC) at room temperature has logistic and operational advantages for the blood centre. The present study aimed to evaluate the impact of an overnight hold (stored) of BC at room temperature in comparison with the 2-hour hold (fresh) of buffy coats on the platelet concentrate (PC) characteristics.MethodsA total of 60 BCs were included in the study, 30 PCs (fresh) were prepared after two hours holding time of the BCs and the other 30 PCs (stored) were prepared after the overnight BC storage at room temperature. The primary endpoint of PCs evaluation was the platelet yield, volume, pH, WBC count, RBC count, and platelet swirling in the PC and the secondary endpoints were glucose concentration, lactate, LDH, and sterility of the PCs. All the tests were performed on the day+1 of the blood collection.ResultsThere was no difference concerning the volume, RBC count, and swirling between the two groups (P>0.05). The PCs from the fresh BC had higher pH and glucose concentration (P<0.05). On the other hand, the overnight hold of BC produced higher platelet counts, WBC counts, lactate, and LDH levels (P<0.05). All the 60 PCs did not record any bacterial growth on the culture media for the sterility results.ConclusionThe overnight hold of BC produces a higher platelet yield with higher storage lesions. This may also allow better supervision, ensuring better quality control.     

WBC-reduced platelet concentrates from pooled buffy coats in additive solution: an evaluation of in vitro and in vivo measures

BACKGROUND: The use of a platelet additive solution (PAS-II, Baxter) may have benefits over plasma for storage of platelets. It was the aim of this study to develop a method to produce WBC-reduced platelet concentrates (PCs) in PAS-II with >240 x 10(9) platelets and <1 x 10(6) WBCs per unit, which can be stored for 5 days at pH >6.8 and that will give sufficient platelet increments after transfusion: a 1-hour CCI of >7.5 and a 20-hour CCI of >2.5. STUDY DESIGN AND METHODS: PCs were made from five pooled buffy coats and 250 g of PAS-II. After centrifugation the PCs were WBC-reduced with a filter (Autostop BC, Pall Biomedical) and stored in a 1000-mL polyolefin container. CCIs were assessed in stable hemato-oncologic patients after 5-day old PCs were transfused. RESULTS: Routinely produced PCs contained a median of 310 x 10(9) platelets (n = 5,363) with 3.5 percent containing <240 x 10(9) platelets, in a median volume of 320 mL (n = 11,834). The median number of WBCs was <0.03 x 10(6) (n = 694). The WBC count exceeded 1 x 10(6) in three PCs, but it was always <5 x 10(6), giving 99-percent confidence that more than 99.5 percent of the units will contain <1 x 10(6) WBCs. The pH remained >6.8 on Day 8, provided the concentration was below 1.1 x 10(9) platelets per mL (n = 32). After 28 transfusions in 28 patients, the 1-hour CCI was 12.6 +/- 4.3 (mean +/- SD, with 2/28 CCIs <7.5) and the 20-hour CCI was 8.9 +/- 5.6 (with 4/28 CCIs <2.5). Limitations of this study include the absence of a control group of patients receiving platelets stored in plasma and of in vivo radiolabeled survival studies, but a comparison of these data with previously published data suggested that the in vivo survival of platelets stored in PAS-II is less than that of platelets stored in plasma. CONCLUSION: The WBC-reduced PCs conformed to specifications. These WBC-reduced PCs could be stored at least 5 days with maintenance of pH, and they gave sufficient increments after transfusion to patients.     

Noninvasive measurement of pH in platelet concentrates with a fiber optic fluorescence detector

BACKGROUND: Stored platelets (PLTs) are metabolically active, resulting in a decrease of pH during storage. The pH of PLT concentrates (PCs) is recognized as a measure of quality, and pH limits are set by regulatory bodies. A pH sensor was built into a PLT storage container, and the feasibility of testing pH using a noninvasive fluorescent measurement method was evaluated.
STUDY DESIGN AND METHODS: A citrated polyvinylchloride (PVC) PLT storage container with pH sensor insert was made and evaluated for biocompatibility during PLT storage and on pH reading accuracy, reproducibility, and durability. A noninvasive fluorescence reader was tested versus syringe-based sampling and subsequent measurement with a blood gas analyzer (BGA). The effect of interfering substances in plasma on the accuracy of this optical measurement was tested. Calibration and accuracy of the pH sensor were determined in both phosphate-buffered saline and in PCs.
RESULTS: The citrated PVC storage container with pH sensor insert showed good storage properties for 300 mL of pooled buffy coat PLTs in plasma over 7 days. The pH sensor was easy to use and tracked pH₂₂ in the range of 6.2 to 7.8 over 11 days of storage. Accuracy in PCs was 0.08 pH units measured at 22°C when calibrated against a BGA.
CONCLUSION: The storage container with integrated pH sensor and noninvasive reader allows pH of PCs to be tracked over time in a noninvasive manner.     

复方电解质注射液作添加液汇集血小板的研究

目的探讨复方电解质注射液作添加液（PAS）汇集多人份混合血小板的可行性。方法从400ml全血中分离白膜层（BC）,容量40～45ml,于22℃±2℃静置过夜,将ABO同型的6袋白膜汇集,加200ml复方电解质注射液稀释白膜,稀释后的白膜在温度22℃±2℃的离心机中,以900r／min离心10min。上层富含血小板悬液经白细胞过滤器去除白细胞,并转移到血小板保存袋内,即制备成1个成人治疗量的PAS汇集BC—PCs。结果共制备10个成人治疗量的PAS汇集BC—PCs,其容量、血小板含量、WBC混入量、RBC混入量分别为：（293±22）ml、（3．01±0．29）×10^11、（1．1±0．2）×10^6、（5．9±1．3）×10^3。保存8d后的pH、低渗休克反应率（HSR）、形变能力（ESC）、CD62P表达率、AnnexinV结合率分别为7．10±0．05、（65．6±7．1）％、（7．1±1．6）％、（27．4±3．3）％、（12．0±1．4）％。结论复方电解质注射液作为添加液汇集血小板的方法可行。     

In vitro analysis of platelet concentrates stored in the presence of modulators of 3',5' adenosine monophosphate, and organic anions

The storage of conventional platelet concentrates (PCs) under standard blood bank conditions is limited to five days, in part because longer storage periods lead to increasing damage in platelet integrity and functionality. The growing demand of PCs for clinical use, raises the interest to develop agents that would potentially permit a more extended period of storage. We have evaluated and compared the in vitro quality of PCs treated with: (1) Modulators of levels of cAMP (PGE1, foskolin, theophylline and isobutyl-methyl-xanthine [IBMX]); and (2) organic anions that function as alternative substrates of platelets (pyruvate and acetate). Platelet rich plasma (PRP) from pools (n = 6) of PCs was distributed into storage bags, and the agents to be tested were added, using saline as a control substance. PCs were stored at 22 degrees C with continuous agitation for up to 10 days. At 0, 5 and 10 days of storage, samples were analyzed for platelet counts, mean platelet volume (MPV), metabolic markers, and expression of glycoproteins (GPs). The addition of modulators of levels of cAMP, at the concentration used in the study, did not lead to substantial improvement in the parameters being evaluated, with respect to those in control units. The supplementation with organic anions, while not affecting the surface levels of GPs, favored the maintenance of metabolic values, such as pH, PCO2, and bicarbonate concentrations, as well as the preservation of MPV (p values < 0.05 respect to control units both at 5 and 10 days of storage). Our results indicate that while the use of modulators of levels of cAMP do not provide substantial benefit in the prevention of platelet storage lesions, organic anions have some advantageous effect in the storage promoted metabolic changes of PCs. These data might be considered when designing strategies to improve PC storage.     

Extended storage of single-donor platelet concentrate collected by a blood cell separator

Use of a sealless blood pathway in a blood cell separator (CS-3000, Fenwal) permits collection of platelets in a "closed system" when saline and anticoagulant solutions are integrally attached; this in turn allows storage of instrument-collected platelet concentrates (PCs) beyond 24 hours. To evaluate extended storage of high yield PCs, cells collected with the instrument were stored (200 ml plasma) for 8 days (flatbed agitation) in either 3-liter polyvinylchloride (PL 146) containers (n = 6), polyolefin bags (PL 732) (n = 8), or two 1-liter polyolefin (double PL 732) containers (n = 8). A mean of 4.45, 4.09, and 3.94 X 10(11) platelets were stored in PL 146, single PL 732, and double PL 732, respectively; total white cells per container averaged 0.3, 0.2, and 0.2 X 10(9) for the three container systems. By day 1, platelet pO2 dropped to 14 and 16 torr in PL 146 and PL 732 PCs (pCO2, 127, and 82 torr). In contrast, double PL 732 maintained high pO2 (approximately equal to 80 torr) and low pCO2 (approximately equal to 30 torr) through day eight. Glucose declined at faster rates in PL 146 and single PL 732 containers, while lactate increased more rapidly (338 and 197 mg/dl of lactate on day four vs. 116 mg/dl for double PL 732 units). Morphology scores dropped from 400 to 98 (PL 146) and 216 (PL 732) at day four (pH values of 6.3 and 7.0), while a score of 330 was seen in double PL 732 PCs.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of mode of agitation and type of plastic bag on storage characteristics and in vivo kinetics of platelet concentrates

We studied the characteristics of platelet concentrates stored for 5 days at 22 degrees C. Platelets were prepared in three plastic bags (PL 732, PL 1240, and CLX) and stored on one of four platelet agitators, 1- or 6-rpm elliptical and 2- or 6-rpm circular rotators. A total of 76 studies were divided among 12 groups, each group being composed of a different storage bag-rotator combination. In vivo recovery and survival were calculated using Indium-111 oxine-labeled platelets injected into autologous volunteers. Platelet recovery was assessed at 2 hours postinjection or as the y-intercept of the multiple-hit model survival curve. Survival was calculated using linear, exponential, and multiple-hit computer models. Linear T 1/2 also was calculated as an index of platelet survival. At 5 days, the pH of all concentrates was above pH 7.0 and platelet counts were above 5.5 X 10(10) per bag except for the PL 732 with the 6-rpm elliptical rotator, which was 4.6 X 10(10) per bag. This combination also showed a significantly higher poststorage lactic dehydrogenase (LDH) discharge compared to the mean of the other 11 groups (23.6 +/- 5.4% vs. 10.4 +/- 3.0%, p less than 0.05); however, the beta-thromboglobulin (beta-TG) release was not statistically different.(ABSTRACT TRUNCATED AT 250 WORDS)     

Amphotericin B-induced injury in stored human platelets

Administration of intravenous amphotericin B is a major factor in the reduction of the recovery of transfused platelet concentrates (PCs). For the study of possible drug-induced platelet lesions, fresh platelets and stored PCs were incubated with therapeutic concentrations of amphotericin B (10-50 micrograms/mL) and examined for membrane changes by scanning electron microscopy. Stored platelets demonstrated the formation of "pits" on the surface membrane, which were maximal immediately after preparation and gradually decreased with storage. The number of pits was significantly higher after exposure to amphotericin B. No increase was detected in fresh platelets following exposure to amphotericin B. The maximal effect of the drug was seen after 5 days of storage as PCs. Amphotericin B did not affect platelet shape or the number of pseudopodia. There was no correlation between pit formation and the pH, pO2, or pCO2 of the concentrates. Amphotericin B did not release 51Cr from prelabeled stored platelets after 2 hours' incubation at 37 degrees C. Thus, amphotericin B appears to exacerbate a membrane lesion induced by the preparation and storage of PCs.     

血小板保养液与血浆混合保存血小板的初步研究

目的探讨血小板保养液与不同比例血浆混合保存单采血小板的效果。方法选用枸橼酸钠、醋酸钠、磷酸钠和氯化钠等组成血小板保养液,(22±2)℃振荡条件下保存单采血小板7d;按保养液与血浆混合比例,实验组分为实验Ⅰ组(50%保养液+50%血浆)和实验Ⅱ组(80%保养液+20%血浆),分别于1、3、5、7d取样检测血小板数(Plt)、pH值、葡萄糖消耗量、乳酸产生量和血小板膜CD62p的表达情况,并与100%血浆保存的血小板(对照组)比较。结果血小板保存到5d时,实验组与对照组比较Plt差异无统计学意义(P>0.05),其pH值较对照组均有明显下降(P<0.05),但pH仍>6.0;实验组血小板膜CD62p阳性表达率分别为32%和36%,比对照组的28%略高(P<0.05)。血小板保存到第7天时,Plt、pH和血小板膜CD62p阳性表达率,实验各组较对照组为差(P<0.05);1—7d葡萄糖平均消耗量实验Ⅱ组比对照组和实验Ⅰ组为高(P<0.05),而乳酸平均产生量则实验各组较对照组明显为高(P<0.05)。结论采用血小板保养液与20%或50%比例的血浆混合,短期(5d)保存单采血小板的pH值和血小板数量与用100%血浆保存单采血小板的效果基本相同,但保存在保养液与血浆混合液中的血小板更易激活。     

一氧化氮供体改善血小板保存质量的初步研究

目的探讨一氧化氮(NO)供体S-亚硝基乙酰青霉胺(SNAP)对常温保存血小板过程中血小板质量的影响。方法离心法制备浓缩血小板共12人份,38~40 ml/份。将相同血型的2袋混合,加入复温后的冰冻血浆至约100 ml,混匀后均分、转移至2个血小板专用保存袋,分别为实验组:保存前加入终浓度10~5mol/L SNAP;对照组:加入等体积的无菌生理盐水。(22±2)℃振荡保存7 d,分别在d1、d3、d5、d7取样检测血小板计数、pH、血小板活化率及抗低渗性休克反应等指标。结果 2组血小板在保存过程中pH均保持在6.8以上;血小板活化率均不断升高,实验组从(5.93±1.43)%升高到(44.22±6.84)%,对照组从(8.22±1.33)%升高到(54.32±5.68)%,d1、d3、d5、d7 2组血小板之间活化率差异有统计学意义(P<0.05);d1、d5、d7实验组血小板抗低渗休克反应分别为(65.98±7.57%)、(53.1±8.44)%、(44.23±0.08)%,对照组为(50.92±4.48)%、(40.06±4.66)%、(35.28±0.04)%,d1、d5、d7实验组抗低渗休克反应能力高于对照组,差异具有统计学意义(P<0.05)。结论在血小板保存过程中加入NO供体SNAP一定程度上可以抑制血小板活化,改善血小板功能。     

The expression of p-selectin during collection, processing, and storage of platelet concentrates: relationship to loss of in vivo viability

BACKGROUND : Recent studies suggested that platelet activation with surface expression of p-selectin on stored platelets may be related to a loss of viability. At present, there has been no thorough investigation of the extent or significance of p-selectin expression during the collection, processing, and storage of platelet concentrates (PCs) under various conditions. STUDY DESIGN AND METHODS : Platelet surface expression of p-selectin (CD62) was determined on fixed platelet samples using fluorescein-conjugated monoclonal antibodies. Platelet viability was assessed by autologous transfusion of platelets stored for 5 days and labeled with either ⁵¹Cr or ¹¹¹in. RESULTS : Little (2–10%) platelet expression of p-selectin was found in whole blood and platelet-rich-plasma preparations, whereas PCs showed a substantial increase in p-selectin expression to levels of 20 to 30 percent. Both fresh PCs and those stored for 5 days, obtained with one cell separator (MCS, Haemonetics) showed substantially lower levels of p-selectin expression than PCs from two other cell separators (Spectra, COBE, and CS-3000 with TNX-6, Baxter Healthcare). Exposure of platelets to EDTA, cold, or a pH below 6.2, conditions that are known to result in the loss of viability upon transfusion, produced substantial and irreversible p-selectin expression. PCs with a pH of 6.2 to 6.8 (conditions in which no loss of viability has been demonstrated) also showed pronounced p-selectin expression, which returned to control values after incubation at 37° C in plasma at pH 7.0 to 7.2. With storage under current conditions the in vivo studies (n = 61) demonstrated a rather poor correlation between p-selectin expression and the percentage of recovery (r = ?0.25) but a somewhat better correlation with survival (r = ?0.42). Better correlations were observed with the extent of shape change, lactate, and hypotonic shock response. CONCLUSION : These studies show that p-selectin expression on the platelet surface is a predictor of platelet viability, although the extent of shape change and the hypotonic shock response may be more sensitive.