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Keywords:

  • Cell separator;
  • Donor safety;
  • Double-dose platelet;
  • Plateletpheresis

SUMMARY

  1. Top of page
  2. SUMMARY
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONCLUSIONS
  8. REFERENCES

The practice of high-yield or double-dose platelet (DDP) collection through automated apheresis is gradually increasing. Very few studies have examined donor safety issues in DDP collection. The present study highlights the process of DDP donor selection as well as the product quality and donor safety issues on 67 donors. All procedures were performed following the departmental standard operating procedure. We observed a significantly higher mean platelet yield with the Amicus separator than the Fresenius separator (5.4 × 1011vs. 5.1 × 1011, P = 0.03). The Fresenius separator processed a mean blood volume of 3974 mL and collected a mean platelet amount of 444.9 mL, and these were significantly higher when compared with Amicus (P < 0.0001). Mean values of procedure-related parameters, such as acid-citrate-phosphate volume, donation time, needle time, processing time and whole blood processed, and donor-related parameters, like citrate toxicity and vasovagal reactions, were significantly higher during DDP than single-dose platelet collection (P < 0.05). We conclude that obtaining eligible donors for DDP from a shrinking donor population with low normal platelet values is a difficult task. Therefore, each transfusion service should set their own guidelines for DDP collection with the objectives of donor safety and optimal product quality.


INTRODUCTION

  1. Top of page
  2. SUMMARY
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONCLUSIONS
  8. REFERENCES

Development in medical sciences, including transplantation programs, has significantly increased the demand for platelets (PLT).1,2 The last two decades have observed an inclination toward the use of apheretic PLT rather than random donor PLT.3 The more stringent exclusion criteria for whole-blood donation in general and PLT donation in particular have made donor recruitment and retention all the more difficult.4,5 In addition, the non-availability of apheresis machines in most blood centers or the increasing cost of apheretic PLT restricts many eligible donors from donating PLT in the developing nations. To counteract these problems and reduce the cost and inherent risk of allogeneic transfusion, the practice of high-yield or double-dose platelet (DDP) collection through automated apheresis is gradually increasing.6–9 Normal PLT count in the healthy population varies from region to region. The low normal PLT count (< 180 × 109/L) in this part of India has previously been discussed.10 This creates difficulty in obtaining high-yield PLT products from our plateletpheresis donor population. Today, more emphasis is placed on introducing new-generation machines that can guarantee consistent product quality with optimum leukoreduction. However, these machines have been shown to cause relatively high rates of citrate reactions, which may be of greater significance while collecting DDP.11,12 Although such collections from eligible donors have optimized the availability of PLT and their transfusions, blood centers should also emphasize on donor safety in parallel to product quality while performing these procedures.

We, at our blood center, have started DDP collections from eligible donors using the last-generation Amicus and Fresenius systems. The present study will highlight the donor selection process, the quality of products and donor comfort and safety issues while collecting DDP from a healthy donor population with low normal PLT count.

MATERIALS AND METHODS

  1. Top of page
  2. SUMMARY
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONCLUSIONS
  8. REFERENCES

Donors and procedures

All donors intended to undergo plateletpheresis were directed to the apheresis unit by various clinical specialties for motivation, screening and PLT donation. On screening, only those donors who satisfied the departmental standard operating procedure (SOP) for DDP collection were considered for such procedures. This prospective study conducted on DDP collection included 67 plateletpheresis procedures performed on eligible donors aged between 21–52 years from February 2007 to March 2008 after obtaining informed consent. All procedures were performed by the same team of resident doctors. No prophylactic calcium supplementation was provided to any of the donors. A total of 32 and 35 such procedures were performed on the Fenwal Amicus double-needle (DN) separator (Baxter Healthcare Corporation, Deerfield, IL, USA) and the Fresenius DN separator (COM.TEC) (Fresenius HemoCare GmbH, Bad Homburg, Germany), respectively. Donor selection and plateletpheresis procedures were performed following the departmental SOP for DDP collection as described in Figure 1, using closed-system apheresis kits and ACD-A anticoagulant in the proportion of 1:12. The Amicus separator was operated using the software version 2.5 and Fresenius separator using the version 4.00.xx with blood flow rate automatically adjusted to a maximum of 80 mL/minute. The end point of each procedure was based on the target yield of 5.5 × 1011 PLT per bag. Donors' general details, such as age, gender, weight and height, and plateletpheresis procedure details, such as blood volume processed, total anticoagulant used, time taken, etc., were recorded for each procedure from the procedure register. Any adverse donor reactions, including symptoms of hypocalcaemia, were also recorded. To make a prospective comparison of DDP collection with single-dose platelet (SDP) collection with respect to the procedure details and donor safety issues, we prospectively considered 49 and 45 procedures of SDP collection by Amicus DN and Fresenius DN, respectively, as controls.

image

Figure 1. Operational flow chart for double-dose plateletpheresis. ACD, acid-citrate-phosphate; BFR, blood flow rate; BP, blood pressure; Hb, hemoglobin; WB, whole blood; EDTA, ethylene diamine tetra acetic acid; PLT, platelet; SOP, standard operating procedure.

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Sampling

Donors' pre-donation hematological values

To measure the pre-donation hematological values of all donors as a part of screening process, whole-blood samples in ethylene diamine tetra acetic acid (EDTA) vials were collected before the plateletpheresis procedure and parameters such as PLT, hemoglobin concentration (Hb), hematocrit (Hct), red blood cell (RBC) count and white blood cell (WBC) count were measured.

Sampling from bag

Following collection of PLT, each unit was allowed to rest for 1 hour ensuring optimum disaggregation of PLT before sampling. Then approximately 1 mL sample from each bag was collected in EDTA (K2 EDTA) after thorough stripping of segment to ensure representative product of the bag. The samples were then mixed thoroughly by means of mechanized blood mixer (Techno FAB, Vadodara, India) for 15 minutes and then subjected to measurements of various parameters, such as pH, Hct, PLT count, RBC counts and WBC counts.

Measurements

Hematological values of both donor and bag samples were obtained using a routinely calibrated automated cell counter (Micros 60, ABX diagnostics, Montpellier, France). Residual WBC content in the bag was measured by Nageotte chamber hemocytometer counts as described previously.13 The pH of all PLT units was measured using a calibrated portable pH meter (Toshniwal Inst. Mfg. Pvt. Ltd, Ajmer, India) according to the departmental SOP. Swirling in PLT units was assessed visually on the third or fourth day of storage and documented as ‘present’ or ‘absent’.

Statistical analysis

Statistical analysis was done using the spss statistical package (version 13, SPSS, Chicago, IL, USA). All results were depicted as mean ± SD and a P value < 0.05 was considered statistically significant. Mean values were compared using the unpaired or paired Student's t-test as appropriate. Definitions, abbreviations and formulae used in the study to obtain donor and procedure details are described in Table 1.

Table 1.  Definitions, abbreviations and formulae used in the present study
ParametersAbbreviationSI unitDefinitions/formulae
  1. ACD, acid-citrate-phosphate; PLT, platelet.

Pre-donation timepminTime for kit installation, priming & programming
Donation timeDTminTime from start until reinfusion
Needle timeNTminDT + reinfusion time + post-procedure sample collection time
Processing timePTminTime from set-up to final product (PT) = NT + p
Whole blood processedWBPmLVolume processed from start until reinfusion – citrate volume
Total ACD usedACDmLTotal ACD consumed during the procedure as displayed by machine
Collection efficiency of machineCE%PLT yield/total PLT processed × 100

RESULTS

  1. Top of page
  2. SUMMARY
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONCLUSIONS
  8. REFERENCES

Of the 487 donors screened for plateletpheresis during the study period, only 373 (76.6%) donors could fulfill the selection criteria of a single- or double-PLT donation. The major causes of deferral were the patient's blood group (44%), followed by low PLT count (< 150 × 109/L) (28%), anemia (< 12.5 g/dL) (9%), poor venous access (7%), less weight (< 45 kg) (4%), needle phobia (3%), drug ingestion (3%) and a reactive transfusion-transmitted infection test (2%). Out of the 373 accepted donors, only 74 (19.8%) could be selected for DDP procedures as per the SOP.

A comparable donor general and hematological characteristic was observed with both cell separators. We also observed a significantly higher mean PLT yield with the Amicus than with the Fresenius separator (5.4 × 1011vs. 5.1 × 1011; P = 0.03). The Fresenius separator processed a mean blood volume of 3974 mL and collected a mean PLT amount of 444.9 mL and these were significantly higher when compared with Amicus (P < 0.0001) (Tables 2 and 3). As shown in Table 3, both procedure- and donor-based safety issues were comparable with both machines during DDP collection. However, whole blood processed by the Fresenius separators was significantly higher when compared with Amicus (P = 0.00). Mean values of procedure-related parameters, such as acid-citrate-phosphate volume, donation time (DT), needle time (NT), processing time and whole blood processed, and donor-related side effects were significantly higher with DDP (P < 0.05) than with SDP, thereby suggesting that the latter is a safer procedure. As depicted by the collection efficiencies, the efficacy of both cell separators was comparable (59.7% and 55.8% for Amicus & Fresenius, respectively; P = 0.19). On analyzing the donor-related side effects, citrate toxicity was 11.4% with Amicus and 9.4% with Fresenius during DDP as compared with only 6.1% and 4.4%, respectively, during SDP. Similarly, vasovagal reactions were also higher during DDP (8.6% and 9.4% with Amicus and Fresenius, respectively). While one DDP donor on Amicus complained of pain at the site of phlebotomy, another developed a hematoma on the Fresenius (2.8% and 3%, respectively). Although the adverse reactions with SDP (10 out of 94, 10.6%) were less compared with DDP (15 out of 67, 22.4%), the difference was not statistically significant (P = 0.13). Therefore, with regard to donor-related side effects SDP donors seemed to be safer than DDP. Although a post-donation hematological drop was observed in all donors (Figure 2), none of the parameters except Hb showed a significant drop with either of the cell separators. Hb decrement after plateletpheresis was significantly higher with the Amicus (P = 0.03).

Table 2.  Characteristics of donor and quality of platelets in double-dose and single-dose (controls) collections
ParametersDouble-dose plateletP valueSingle-dose platelet (controls)
Amicus (n = 35)Fresenius (n = 32)Amicus (n = 49)Fresenius (n = 45)
  1. Hb, hemoglobin; Hct, hematocrit; RBC, red blood cell; WBC, white blood cell.

Donor characteristics
Age (range) (years)33.2 (18–55)30.1 (22–42)0.1329 (19–55)31 (18–52)
Gender (M : F)9:111:119:114:1
Weight (kg)72.2 ± 13.170.5 ± 9.10.5467.4 ± 10.4568.2 ± 12.1
Platelet count (×109/L)282.2 ± 38.4278.6 ± 38.20.71213 ± 65.5201 ± 55.5
WBC count (×109/L)8.3 ± 2.58.6 ± 1.70.637.9 ± 1.57.3 ± 1.9
Hb (g/dL)13.8 ± 1.213.7 ± 1.20.9613.6 ± 1.313.3 ± 1.2
Hct (%)43.9 ± 5.143.5 ± 4.10.7242.7 ± 4.643.1 ± 4.2
Product quality
Volume (mL)411.2 ± 31.6444.9 ± 51.10.000243.5 ± 40.7252 ± 29.9
pH7.06 ± 0.067.05 ± 0.050.317.03 ± 0.517.02 ± 0.33
Platelet yield (×1011/unit)5.4 ± 0.65.1 ± 0.90.033.6 ± 1.13.2 ± 1.5
WBC (×108/unit)3.2 ± 1.52.9 ± 1.10.572.7 ± 0.91.9 ± 0.7
RBC (mL/unit)0.6 ± 0.30.5 ± 0.40.440.8 ± 0.50.9 ± 0.4
Hct (%)0.34 ± 0.20.27 ± 0.10.120.33 ± 0.30.31 ± 0.4
Table 3.  Donor safety issues in DDP collection (n = 67)
Para-metersDouble-dose plateletsSingle-dose platelets (controls)DDP vs. SDP
Amicus (n = 35)Fresenius (n = 32)P valueAmicus (n = 49)Fresenius (n = 45)P valueP value
  1. *Significant with both machines. Significant with Fresenius only. Not significant with either machines. ACD, acid-citrate-phosphate; CE, collection efficiency; DT, donation time; NT, needle time; PT, processing time; TDR, total donor reactions; WBP, whole blood processed.

VeinsDoubleDoubleDoubleDouble
ACD354 ± 66.9360 ± 70.10.73313.3 ± 61.2310 ± 63.70.82< 0.05*
DT70.1 ± 13.275.2 ± 14.50.1461.9 ± 14.265.3 ± 14.40.23< 0.05*
NT81.5 ± 13.186.4 ± 15.70.1770.2 ± 12.873.1 ± 13.10.32< 0.05*
PT96.2 ± 13.497.4 ± 16.40.7584.3 ± 10.787.3 ± 10.20.51< 0.05*
WBP3189 ± 7073974 ± 7540.003057 ± 5933170 ± 7330.11< 0.05
CE59.7 ± 4.755.8 ± 4.90.1964.9 ± 5.263.6 ± 4.90.42> 0.05
TDR (%)8 (22.8)7 (21.8)6 (12.2)4 (8.9)
image

Figure 2. Box plot showing effect of cell separators on decrement in donor's hematological values (n = 67). Post-donation Hb decrement significant with Amicus, P = 0.03. (inline image) Fresenius. (inline image) Amicus. Hb, hemoglobin; Hct, hematocrit; WBC, white blood cell.

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DISCUSSION

  1. Top of page
  2. SUMMARY
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONCLUSIONS
  8. REFERENCES

Collection of PLT by apheresis has been a major advance in transfusion medicine. Such practice allows supply of a therapeutically beneficial component ensuring leukocyte reduction, limited donor exposure and reduced infectious complications.14,15 In addition, collection of DDP has contributed to the optimum availability of PLT even under a situation of limited human resources and shrinking donor population.16

In the present study we shared our experience of difficulties in obtaining high-yield PLT from low normal PLT count but otherwise eligible donors. Collection of DDP is challenging in our region because of the prevalence of low normal PLT counts in North Indian blood donors.10 It was observed that despite high PLT count in the female donors (250–300 × 109/L), they were mostly deferred because of either low Hb or poor venous access. A substantial number of such donors could have been accepted if existing Hb cutoff of 12.5 g/dL would have been lowered to 11.5 g/dL. However, this is not permitted by our national guidelines. Pre-apheresis hematological values of donors, such as Hb, PLT and WBC count, were comparable with both apheresis machines used in the study. The Drugs and Cosmetic Act of India, which is the national regulatory agency for safe blood transfusion practice, has no established guidelines on collection of DDP products; therefore, we prepared our own SOP as detailed in Figure 1. A minimum donor weight of 55 kg has been accepted to ensure an optimum donor blood volume that will prevent hypovolemia and other related side effects in donors undergoing DDP collections. The American Association of Blood Banks requires a minimum pre-donation PLT count of 300 × 109/L for a DDP collection (≥ 6 × 1011/unit).17 In context to our population, only 4% of screened donors had a PLT count of ≥ 300 × 109/L, which greatly restricted the expansion of our DDP registry. Therefore, a pre-donation PLT cutoff of 250 × 106/L was considered to obtain an optimized DDP (5.5 × 1011/unit) without inducing donor thrombocytopenia and at the same time maintaining an effective donor registry for such procedures.

Cellular contamination of product, such as WBC or RBC content, was comparable with both the machines. Mean PLT yield by the Amicus was significantly higher than the Fresenius (5.4 vs. 5.1 × 1011 /unit; P = 0.03). This could be due to different PLT collection protocol in the two machines. The Amicus collects hyper-concentrated PLT that can be subsequently reconstituted in the dedicated amount of collected plasma; on the other hand, the Fresenius collects PLT and plasma simultaneously in the dedicated PLT collecting bag. However, the collection efficiencies of both the cell separators were comparable (59.7% vs. 55.8%; P = 0.19). Higher collection efficiency in the latest apheresis machines has also been discussed previously.18,19 We observed a non-significant but higher collection efficiency of both machines while collecting DDP and this might be caused by the significantly high volume of blood/PLT processed during such collections. As per our SOP, only those units that yielded ≥ 5 × 1011 PLT per bag were divided into two halves. This was done to comply with the Council of Europe 2007 recommendation of one hemostatic PLT dose containing ≥ 2 × 1011 PLT.20 Seven undercollected PLT products (< 5 × 1011/bag) were not included in the study, including control data in Table 3. Briefly, all these seven units had a PLT count in the range of 3.8–4.8 × 1011 and four of these units were collected on the Fresenius.

The present study also observed higher citrate-related side effects and vasovagal reactions by both machines, when compared with single-dose collection. This could be explained by the higher volume of acid-citrate-phosphate infused, whole-blood volume processed and significantly increased NT during DDP collection. Prophylactic calcium was not given to any donors; such prophylaxis could be implemented and recommended to prevent hypocalcemia as also suggested by other authors previously.21,22 Moreover, we observed that information to donors about DDP increased anxiety, apprehension and thereby donor reactions. This was observed in 8 of the total 15 affected donors, which ultimately culminated into either a vasovagal reaction or citrate toxicity. Whether such donor information should be explained or concealed should be addressed in details, because concealing facts may reduce donor reactions, but such a practice is not permitted by our regulatory authorities.

As donation time, NT and processing time directly affect the apheresis donors, these are important parameters to evaluate safety and comfort of healthy donors. In our experience, all these procedure-related parameters were prolonged in DDP collection. Although all donors experienced a post-donation hematological drop, unexplained significant reduction in Hb was observed with the Amicus as compared with Fresenius (P = 0.03). Drop in Hb and Hct with Fenwal CS 3000 plus and Fresenius AS-204 machines as compared with the COBE spectra were also observed by other authors.23

CONCLUSIONS

  1. Top of page
  2. SUMMARY
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONCLUSIONS
  8. REFERENCES

While collection of DDP contributed greatly to the PLT inventory of a transfusion service, obtaining these eligible donors from a shrinking donor population with low normal PLT values seemed to be a challenging task. Even more challenging would be the collection of triple-dose PLT because such practice may not be possible in India because of a population with relatively low body weight and PLT counts. Therefore, it is incumbent upon all transfusion services to prepare their own SOP based on demographic, general and hematological characteristics of their donor populations. This practice will definitely ensure donor safety, product quality and an effective donor registry.

REFERENCES

  1. Top of page
  2. SUMMARY
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONCLUSIONS
  8. REFERENCES