Stored platelet number and viscoelastic maximum amplitude are not altered by warming or rapid infusion

The safety of ABO minor incompatible platelets transfusions using a rapid infuser

BACKGROUND

Administering platelets through a rapid infuser is proven to be safe. However, the clinical significance of infusing ABO-incompatible platelets with red blood cells (RBCs) in a rapid infuser remains unclear. There is a theoretical risk that isoagglutinin in the plasma of a platelet unit can interact with RBCs and induce hemolysis.

MATERIALS AND METHODS

Seven in vitro studies were performed including five cases (type A RBCs and type O platelets) and two controls (type A RBCs and platelets). Anti-A titers were measured in platelet units. An RBC unit and a platelet unit were mixed in the rapid infuser reservoir and incubated for 30 min. The primary outcome was the presence of hemolysis based on the following parameters: free hemoglobin concentration, hemolysis check, direct antiglobulin test (DAT), and direct agglutination.

RESULTS

The post-mix DAT was positive for IgG in all test samples (5/5), and weakly positive for complement in 3/5. The changes in free Hb in test cases between measured and calculated post-mix spanned -2.2 to +3.4 mg/dL. Post-mix hemolysis check was negative in 3/5 and slightly positive in 2/5 cases, with no significant differences compared to the control case. Anti-A titers ranged from 16 to 512 and were not associated with hemolysis. All samples were negative for direct agglutination.

CONCLUSION

Our study suggested that mixing ABO-incompatible platelets with RBCs in a rapid infuser does not induce in vitro hemolysis. These findings support the use of rapid infusers regardless of platelet compatibility in support of hemostatic resuscitation.

Cold platelet transfusion: The effects of a fluid warmer on platelet function

BACKGROUND

Recently the US Food and Drug Administration has granted variances to select blood centers to supply cold-stored platelet components (CSP). In hemorrhage resuscitation warming of blood components with approved fluid warming devices is common.

STUDY DESIGN AND METHODS

Pathogen-reduced apheresis platelet units were collected and stored in one of two ways: (1) CSP-I, (2) CSP-D. CSP-I were collected and immediately stored at 1-6°C until used. CSP-D were collected and stored at 20-24°C for 5 days and transferred to storage at 1-6°C until use. Aggregometry using arachidonic acid (AA), adenosine diphosphate (ADP) and collagen as agonists was performed on the unit samples before and after the units were infused through a Ranger blood-warming device.

RESULTS

CSP-I, 23 units, had very high aggregation responses to all agonists (all ≥47.6 ± 20.7). There was a statistically significant reduction in ADP-induced aggregometry results from 55.1 ± 23.2 before compared to 33.5 ± 14.6 following infusion of the PLT through the blood warmer (p < .001). There were no differences in AA and collagen aggregometry results before and after the infusion of the platelets through the blood warmer. CSP-D had 5 of the 15 units with visible clotting in the bag. The 10 CSP-Ds studied had lower aggregation than all agonists before and after infusion through the blood-warming device (all ≤49.9 ± 35.9).

CONCLUSION

We detected a statistically significant reduction in ADP-induced aggregometry in CSP-I run through a Ranger blood-warming device with no change with AA or collagen agonist aggregometry.

The effect of the Belmont rapid infuser on cold stored whole blood coagulability

INTRODUCTION

With the large-scale use of whole blood in massive transfusion using rapid infusers/fluid warmers such as the Belmont, questions remain as to whether coagulation potency, platelet number and function are preserved.  We aimed to study functional coagulation capacity and cell counts in whole blood before and after infusion through the Belmont rapid infuser utilizing TEG analysis and complete blood counts.

METHODS

We evaluated 10 whole blood units before and after infusion through a Belmont Fluid Management System at a set rate of 200 mL/min and a temperature of 37.4 °C.  Cell counts and thromboelastography function of the specimens were measured. Parameters were compared utilizing paired Student's t-tests and paired Wilcoxon Rank Sign tests.

RESULTS

Platelet count, R time, and Maximum amplitude showed significant decreases (defined as p<0.05) after being infused through the Belmont. Hemoglobin, hematocrit, MCV, and alpha angle were not statistically different before and after infusion.

CONCLUSION

Infusion of cold stored whole blood in a Belmont infuser, appeared to decrease platelet counts and function as well as activate clotting factors as demonstrated by a shorter R time while not affecting red cell counts or fibrin cross-linking as measured by TEG parameters and cell counts. This suggests that while it is possible to transfuse whole blood through a rapid infuser, platelet quantity and function may be negatively impacted.

Portal vein thrombosis associates with high platelet-fibrin clot strength and platelet activation in decompensated cirrhosis: A retrospective study

BACKGROUND AND AIMS

Alteration of platelet status associates with decompensation and death in cirrhosis, while its effect on portal vein thrombosis (PVT) remains unclear. We aimed to retrospectively investigate whether PVT associates with platelet-fibrin clot strength and platelet activation in decompensated cirrhosis.

METHODS

Platelet-fibrin clot strength (G) was measured by thromboelastography (TEG). Platelet activation was reflected by plasma concentrations of soluble p-selectin (sPs) and a platelet aggregation test adjusted for platelet counts.

RESULTS

Among 166 patients, 45 had PVT. The platelet count was significantly lower in PVT. While the G value was positively correlated with platelet count (ρ = 0.74, P < 0.01), increased G was associated with PVT after adjusting for platelet count in the logistic regression (P = 0.04). The normalized G value according to the linear relation with platelet count was calculated as follows: G_platelet = [(G - 2622)/platelet count]. This coefficient had no correlation with platelet count and was an independent risk factor of PVT (OR = 1.03, CI_95%: 1.01-1.05, P = 0.012). In two subanalyses, the collagen-induced platelet aggregation (n = 37, P = 0.029) and plasma concentration of sPs (n = 56, P = 0.001) adjusted for platelet count were significantly higher in PVT.

CONCLUSION

This study showed a positive correlation of high platelet-fibrin clot strength detected via TEG and platelet activation with PVT in decompensated cirrhosis.

Advances in hemorrhage control resuscitation

PURPOSE OF REVIEW

Despite significant advances in trauma management over the last twenty years, uncontrolled hemorrhage remains the leading cause of preventable death in trauma. We review recent changes affecting hemorrhage control resuscitation.

RECENT FINDINGS

Early blood product usage has become well established as a standard of care in trauma hemorrhage control. To enable this, low titer group A liquid plasma and group O whole blood are increasingly utilized. Single donor apheresis platelets have now replaced pooled donor platelets in the USA and are often pathogen reduced, which has implications for trauma resuscitation. Further work is examining timing and dosing of tranexamic acid and the debate in factor concentrate usage in trauma induced coagulopathy continues to evolve. The 'Stop the bleed' campaign has highlighted how important the use of hemostatic dressings are in hemorrhage control, as too is the expanded use of endovascular aortic occlusion. We highlight the ongoing research into desmopressin use and the undetermined significance of ionized calcium levels in trauma. Finally, we discuss our own hospital experience with coagulation testing and the paucity of evidence of improved outcomes with viscoelastic testing.

SUMMARY

Improving trauma coagulopathy diagnostics and hemorrhage control are vital if we are to decrease the mortality associated with trauma.

Efficacy of platelet transfusion in cardiac surgery

Massive diffuse bleeding is still a problem in cardiovascular surgery. The first line treatment is platelet concentrate transfusion, although there is still insufficient information regarding efficacy, quantity, and timing. The objective of this prospective cohort study was to find out whether the amount of 4 apheresis platelet concentrates could reduce intraoperative bleeding and improve viscoelasticity and aggregometry.10 patients were enrolled intraoperatively because of life-threatening diffuse bleeding after cardiopulmonary bypass and received 4 apheresis platelet concentrates back-to-back. The units were given every 5 minutes. After every unit, thromboelastometry, performed by ROTEM®, and aggregometry, performed by Multiplate®, were done together with Hematocrit, Hemoglobin, and Platelet Count.Hematocrit and Hemoglobin showed a statistically significant decrease of 14%, whereas Platelet Count showed a statistically significant increase of 205%. MCE-EXTEM increased statistically significant: 46%. There was no statistically significant increase in both ADP and COL results.Even a series of 4 platelet concentrates did not comprehensively improve both essential components of an adequate hemostasis: viscoelasticity and aggregation. Just the transfusion of platelet concentrates alone did not build a sufficient strategy improving hemostasis and reducing bleeding. A positive effect of surgical packing on stopping the bleeding could be seen.

Effects of a Single Rapid Infusion System on Platelet Function in Stored Whole Blood: An Ex Vivo Study

Introduction

Rapid infusion systems (RIS) are used to warm and rapidly infuse crystalloids and blood products. Current guidelines do not approve of platelet transfusion through a RIS, but data supporting these guidelines are scarce. Our hypothesis was that an infusion of whole blood through a RIS would degrade platelet quantity, impede viscoelastic clot strength, and inhibit platelet aggregation response to adenosine diphosphate pathway (ADP) activation.

Methods

Ten iterations of a simulated scenario of transfusing whole blood via a single brand and make of RIS (Belmont Fluid Management System 2000, Belmont Medical Technologies, Billerica, MA) were performed. Units of whole blood, which were two to nine days old, were leukoreduced prestorage. Blood was used to prime the RIS and then warmed and infused at 100 mL/min into a reservoir. Blood samples were collected before and immediately after infusion. Samples were tested for platelet count, size, and viscoelastic clot strength using thromboelastographic and aggregation assays.

Results

The study sample (n = 10) included platelets with an average age of 5.3 days. The infusion through the RIS had a detrimental effect on all the maximal amplitudes (MA) of viscoelastic testing: MA ADP (mean difference = −18.7 mm; 95% CI: −24.1 to −13.3, P = 0.004), MA rapid thromboelastography (MA rTEG) (mean difference = −6.0; 95% CI: −10.0 to −2.0, P = 0.008), MA TEG (mean difference = −7.1; 95% CI: −10.9 to −3.4, P = 0.004), mean platelet volume (MPV) (mean difference = −0.3; 95% CI: −0.6 to −0.1, P = 0.02), and platelet count (mean difference = −68.3 × 10³/µL; 95% CI: −86.9 to −49.7, P = 0.004).

Conclusions

Platelet quantity, viscoelastic clot strength, and platelet aggregation response to ADP each decline after infusion through a RIS. Further studies regarding microaggregates and platelet activation are required.

Whole Blood Administration: Comparison of In Vitro Platelet Function of Pressure Bag, Pressure Bag With Fluid Warming Device, and Rapid Infuser Methods

BACKGROUND

Use of low-titer group O whole blood for emergent transfusion of patients with unknown blood type became AABB approved in January 2018. Since that time, there is increasing use of whole blood in massive transfusion protocols. Whole blood stored at refrigerator temperature (2-4 °C) contains functional platelets that some research proposes may provide better clot dynamics than standard platelets, which are stored at room temperature (20-24 °C). Conventional teaching does not promote infusion of platelet products with pressure or warming, due to concerns of activation and subsequent inactivity of the infused platelets. Although a few reports found no significant changes in platelet function with warming or pressure during infusion of conventional room-temperature-stored platelets, there is limited data to support use of warming or pressure for infusion of whole blood products containing cold-stored platelets.

METHODS

This study design is to evaluate and compare three commonly used methods of administering blood products in a massive transfusion setting for their potential effects on platelets contained within whole blood units (pressure bag alone, pressure bag with fluid warming line, and rapid infuser).

RESULTS

Platelet function of 10 units tested pre- and post-infusion by thromboelastography (TEG) and platelet aggregation studies found no significant difference in platelet activity pre- and post-infusion with any of the three methods evaluated.

CONCLUSIONS

This study supports the use of rapid infuser or pressure bag devices (with or without warming) as acceptable for infusion of whole blood products. Infusion of whole blood with warming is preferable to prevent potential transfusion-associated hypothermia.

Platelet transfusion: The effects of a fluid warmer on platelet function

Platelet (PLT) transfusions are an important component of hemostatic resuscitation. The AABB has published several guidelines recommending that PLT units should not be infused through blood warming devices.

STUDY DESIGN AND METHODS

Thirty-one units of hospital blood bank apheresis PLTs were obtained. PLT-rich plasma (PRP) aggregometry and thromboelastography (TEG) were performed on the unit samples before and after the units were infused through a Ranger blood/fluid warming device.

RESULTS

There were no differences in any of the aggregometry results before and after infusion of the PLTs through the blood warmer (all P > .32). There was a significant reduction in the TEG maximum amplitude (MA) of 69.8 ± 7.9 mm before and 66.0 ± 8.8 mm after (P < .001) infusion of the PLTs through the blood warmer and α angle 61.8 ± 9.4° before and 59.3 ± 8.2° after (P = .044) infusion of the PLTs through the blood warmer, although both mean values were within normal range for the TEG and not clinically significant. There were very good correlations of aggregometry and TEG results before and after infusion of the PLTs through the blood warmer device.

CONCLUSION

This study did not demonstrate significant deleterious effect on PLT function from infusing apheresis PLT units through a blood warming device by PRP aggregometry. We did detect a statistically significant-but not clinically significant-reduction in TEG MA and α angle. The prohibition of transfusing PLT units though the Ranger blood warming device is not indicated.

Warming blood products for transfusion to neonates: In vitro assessments

BACKGROUND

Blood products may be transfused into neonates at temperatures at or below room temperature. The benefits and risks of warming blood to 37°C are not defined in this population or with the equipment used in neonates. Physiologic warming might enhance product effectiveness or decrease transfusion-associated hypothermia.

STUDY DESIGN AND METHODS

We utilized an in vitro model of neonatal transfusions, with a syringe pump, blood tubing, and 24-gauge catheter and compared current practice (cold products) vs an inline blood warmer. Transfusions were performed rapidly (30 minutes) and slower (120 minutes) to model emergent vs routine situations. We tested red blood cells, fresh-frozen plasma, apheresis platelets (PLTs), and cold-stored low-titer group O whole blood. We used infrared detectors and inline probes to measure temperatures at the origin and at the simulated patient. We assessed warmer-induced damage by measuring plasma hemoglobin and hematocrit (seeking hemolysis), fibrinogen (seeking activation of coagulation), and PLT count and TEG-MA (seeking PLT destruction or dysfunction).

RESULTS

The cold-stored products were 4.2 ± 1.0°C (mean ± SD) at the origin and 21.5 ± 0.1°C at the patient. With the inline warmer, products were 37.8 ± 0.6°C at the warmer and 32.6 ± 1.7°C at the patient during a 30-minute infusion, but were 34.5 ± 2.1 with a foil sheath covering the terminal tubing. We found no warmer-induced damage using any metric.

CONCLUSION

In simulated neonatal intensive care unit (NICU) transfusions, an inline blood warmer can deliver blood products at near-physiologic temperatures with no detected damage. We suggest in vivo testing of warmed NICU transfusions, assessing product effectiveness and hypothermia risk reduction.