Effects of pathogen reduction technology and storage duration on the ability of cryoprecipitate to rescue induced coagulopathies in vitro

Background

Fibrinogen concentrates and cryoprecipitate are currently used for fibrinogen supplementation in bleeding patients with dysfibrinogenemia. Both products provide an abundant source of fibrinogen but take greater than 10 min to prepare for administration. Fibrinogen concentrates lack coagulation factors (i.e., factor VIII [FVIII], factor XIII [FXIII], von Willebrand factor [VWF]) important for robust hemostatic function. Cryoprecipitate products contain these factors but have short shelf lives (<6 h). Pathogen reduction (PR) of cryoprecipitate would provide a shelf‐stable immediately available adjunct containing factors important for rescuing hemostatic dysfunction.

Study Design and Methods

Hemostatic adjunct study products were psoralen‐treated PR‐cryoprecipitated fibrinogen complex (PR‐Cryo FC), cryoprecipitate (Cryo), and fibrinogen concentrates (FibCon). PR‐Cryo FC and Cryo were stored for 10 days at 20–24°C. Adjuncts were added to coagulopathies (dilutional, 3:7 whole blood [WB]:normal saline; or lytic, WB + 75 ng/ml tissue plasminogen activator), and hemostatic function was assessed by rotational thromboelastometry and thrombin generation.

Results

PR of cryoprecipitate did not reduce levels of FVIII, FXIII, or VWF. PR‐Cryo FC rescued dilutional coagulopathy similarly to Cryo, while generating significantly more thrombin than FibCon, which also rescued dilutional coagulopathy. Storage out to 10 days at 20–24°C did not diminish the hemostatic function of PR‐Cryo FC.

Discussion

PR‐Cryo FC provides similar and/or improved hemostatic rescue compared to FibCon in dilutional coagulopathies, and this rescue ability is stable over 10 days of storage. In hemorrhaging patients, where every minute delay is associated with a 5% increase in mortality, the immediate availability of PR‐Cryo FC has the potential to improve outcomes.

In vitro effects of lactated Ringer's solution, hypertonic saline, hydroxyethyl starch, hypertonic saline/hydroxyethyl starch, and mannitol on thromboelastographic variables of canine whole blood

OBJECTIVE

To assess the in vitro effects of crystalloid and colloid IV fluids on the thromboelastographic (TEG) variables of canine whole blood.

DESIGN

In vitro experimental study.

SETTING

Veterinary teaching hospital.

ANIMALS

Twenty-two healthy dogs.

INTERVENTION

Citrated whole blood samples collected from healthy dogs were diluted with 3.4% hypertonic saline (HTS 3.4), 7% hypertonic saline (HTS 7), and 20% mannitol at 8% and 16% dilutions; hydroxyethyl starch 130/0.4 (HES 130/0.4) at 16% dilution; lactated Ringer's solution (LRS) at 16%, 33%, and 66% dilutions; and HTS 7-HES 130/0.4 at 25% and 50% dilutions. Kaolin-activated TEG analysis was concurrently performed on diluted and control (undiluted) samples.

MEASUREMENTS AND MAIN RESULTS

Dilution of canine whole blood with LRS compared to control reduced α angle and MA at both 33% (P = 0.009 and P = 0.011, respectively) and 66% dilution (P < 0.001 and P < 0.001, respectively), and prolonged K time at 66% dilution (P = 0.003). At 16% dilution, HTS 3.4, prolonged R time (P = 0.007), while mannitol, a fluid iso osmolar to HTS 3.4, prolonged K time (P = 0.006), reduced α angle (P < 0.001), MA (P = 0.046), and LY60 (P = 0.015). At 8% dilution, HTS 7, a fluid of high osmolarity and tonicity, prolonged R time (P = 0.009) and reduced MA (P = 0.015), while all measured TEG variables were altered at the 16% dilution (P < 0.01 for all variables). HES 130/0.4 reduced α angle (P = 0.031) and MA (P = 0.001) and increased LY60 (P < 0.001) at 16% dilution. Comparing different fluid types, HES 130/0.4 and HTS 3.4 had no to minor, mannitol intermediate, and HTS 7 profound effects on TEG variables (P < 0.05) when compared to LRS at the same dilution.

CONCLUSIONS

In vitro dilution of canine whole blood with commonly used IV fluids leads to thromboelastographic changes consistent with hypocoagulability in a dose dependent manner for all fluid types tested. Viscoelastic changes are also influenced by fluid characteristics, specifically tonicity and osmolarity.

Elevated fibrinogen, von Willebrand factor, and Factor VIII confer resistance to dilutional coagulopathy and activated protein C in normal pregnant women

BACKGROUND

Gestational changes in coagulation factor concentrations include elevations in fibrinogen, Factor VIII, and von Willebrand factor (vWF). We hypothesised that blood samples from term pregnant (TP) subjects are less prone to coagulation disturbances from haemodilution compared with those from non-pregnant (NP) females.

METHODS

Blood samples were collected from 15 NP and 15 TP subjects. In vitro haemodilution with normal saline was assessed by modified Clauss fibrinogen assay, factor activity, flow-chamber assay, and thromboelastometry. The impact of human fibrinogen concentrate (hFC), cryoprecipitate, and vWF/Factor VIII (FVIII) concentrate replacement in diluted TP and NP blood was compared. Thrombin generation and activated protein C sensitivity were assessed.

RESULTS

TP blood contained twice the concentrations of fibrinogen, FVIII, and vWF relative to NP blood (P<0.0001). Platelet thrombus formation (PTF) under flow was reduced by 99.2% and 69.2% in diluted NP and TP blood, respectively. Platelet thrombus formation was partially restored by adding vWF/FVIII, but not hFC or cryoprecipitate. Fibrin clot firmness approached the threshold of 10 mm in diluted NP blood, and clot firmness was effectively restored by hFC, but not by vWF/FVIII. In the presence of thrombomodulin, peak thrombin generation was decreased by 86.7% in NP plasma, but by 31.8% in TP plasma (P<0.0001 vs NP plasma), indicating reduced activated protein C sensitivity in TP plasma. Both elevated FVIII and haemodilution contributed to activated protein C insensitivity.

CONCLUSIONS

Our in vitro model showed relative resistance of TP blood to dilutional coagulation changes with respect to platelet adhesion, fibrin polymerisation, and thrombin generation. Careful therapeutic monitoring for different pro-haemostatic agents in pregnant women is warranted.

Importance of fibrinogen in dilutional coagulopathy after neurosurgical procedures: A descriptive study

BACKGROUND AND AIMS

The routine management of coagulopathy during surgery involves assessing haemoglobin, prothrombin time (PT), activated partial thromboplastin time (aPTT) and platelets. Correction of these parameters involves administration of blood, fresh frozen plasma and platelet concentrates. The study was aimed at identifying the most common coagulation abnormality during neurosurgical procedures and the treatment of dilutional coagulopathy with blood components.

METHODS

During 2 years period, all adult patients undergoing neurosurgical procedures who were transfused two or more units of red cells were prospectively evaluated for the presence of a coagulopathy. PT, aPTT, platelet count and fibrinogen levels were estimated before starting a component therapy.

RESULTS

After assessing PT, aPTT, platelet count and fibrinogen levels following two or more blood transfusions, thirty patients were found to have at least one abnormal parameter that required administration of a blood product. The most common abnormality was a low fibrinogen level, seen in 26 patients; this was the only abnormality in three patients. No patient was found to have an abnormal PT or aPTT without either the fibrinogen concentration or platelet count or both being low.

CONCLUSION

Low fibrinogen concentration was the most common coagulation abnormality found after blood transfusions for neurosurgical procedures.

Effects of in vitro hemodilution with crystalloids, colloids, and plasma on canine whole blood coagulation as determined by kaolin-activated thromboelastography

OBJECTIVE

To investigate the effects of in vitro hemodilution with lactated Ringers solution (LRS), hetastarch (HES), and fresh frozen plasma (FFP) on whole blood coagulation in dogs as assessed by kaolin-activated thromboelastography.

DESIGN

In vitro experimental study.

SETTING

University teaching hospital.

ANIMALS

Six healthy client-owned dogs.

INTERVENTIONS

Whole blood was collected and diluted in vitro at a 33% and 67% dilution with either LRS, HES, or FFP.

MEASUREMENTS AND MAIN RESULTS

Kaolin-activated thromboelastography was performed on each sample as well as a control. Thromboelastographic parameters R (min), alpha (deg), K (min), and MA (mm) were measured and compared to the sample control for each dilution using mixed model methodology. Prolongation in coagulation times were seen at both dilutions with LRS and HES. There was no significant difference in R times at the 33% dilution, but R time was significantly prolonged at the 67% dilution with HES (P = 0.004). MA was significantly decreased for LRS at both dilutions (P = 0.013, P < 0.001) and more profoundly decreased for HES (P < 0.001, P = 0.006). No significant difference in any parameter was found for FFP.

CONCLUSIONS

In vitro hemodilution of whole blood with both LRS and HES but not FFP resulted in significant effects on coagulation with HES having a more profound effect. In vivo evaluation of changes in coagulation with various resuscitation fluids is warranted and may be clinically relevant.

Comparison of the in vitro effects of saline, hypertonic hydroxyethyl starch, hypertonic saline, and two forms of hydroxyethyl starch on whole blood coagulation and platelet function in dogs

OBJECTIVE

To compare the in vitro effects of hypertonic solutions and colloids to saline on coagulation in dogs.

DESIGN

In vitro experimental study.

SETTING

Veterinary teaching hospital.

ANIMALS

Twenty-one adult dogs.

INTERVENTIONS

Blood samples were diluted with saline, 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH), 7.2% hypertonic saline (HTS), hydroxyethyl starch (HES) 130/0.4 or hydroxyethyl starch 600/0.75 at ratios of 1:22 and 1:9, and with saline and HES at a ratio of 1:3.

MEASUREMENTS AND MAIN RESULTS

Whole blood coagulation was analyzed using rotational thromboelastometry (extrinsic thromboelastometry-cloting time (ExTEM-CT), maximal clot firmness (MCF) and clot formation time (CFT) and fibrinogen function TEM-CT (FibTEM-CT) and MCF) and platelet function was analyzed using a platelet function analyzer (closure time, CTPFA ). All parameters measured were impaired by saline dilution. The CTPFA was prolonged by 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH) and HTS but not by HES solutions. At clinical dilutions equivalent to those generally administered for shock (saline 1:3, HES 1:9, and hypertonic solutions 1:22), CTPFA was more prolonged by HH and HTS than other solutions but more by saline than HES. No difference was found between the HES solutions or the hypertonic solutions. ExTEM-CFT and MCF were impaired by HH and HTS but only mildly by HES solutions. At clinically relevant dilutions, no difference was found in ExTEM-CFT between HTS and saline or in ExTEM-MCF between HH and saline. No consistent difference was found between the 2 HES solutions but HH impaired ExTEM-CFT and MCF more than HTS. At high dilutions, FibTEM-CT and -MCF and ExTEM-CT were impaired by HES.

CONCLUSIONS

Hypertonic solutions affect platelet function and whole blood coagulation to a greater extent than saline and HES. At clinically relevant dilutions, only CTPFA was markedly more affected by hypertonic solutions than by saline. At high dilutions, HES significantly affects coagulation but to no greater extent than saline at clinically relevant dilutions.

Transfusion ratios for postpartum hemodilutional coagulopathy: an in vitro thromboelastographic model

OBJECTIVE

A 1:1:1 ratio of packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelets (PLT) has been advocated for trauma hemorrhage, but the effectiveness of this ratio for postpartum hemorrhage is unknown. We created an in vitro hemodilutional model to investigate this strategy.

STUDY DESIGN

Blood from 20 parturients at term was diluted 50% with 0.9% normal saline. Diluted samples were reconstituted with 1:1 PRBC:FFP or 3:1 PRBC:FFP. In 10 samples, PLT were also added. Baseline, diluted, and reconstituted sample thromboelastographic values were compared.

RESULTS

Maximum amplitude (MA) was lower compared to baseline values in both groups after 50% dilution with normal saline (P < .001) and remained lower than baseline despite reconstitution with 3:1:0 or 1:1:0 PRBC:FFP:PLT (P < .0001) or 3:1:1 PRBC:FFP:PLT (P < .01). MA approached baseline (P = not significant) in the samples with 1:1:1 PRBC:FFP:PLT.

CONCLUSION

The addition of PLT to 1:1 PRBC:FFP optimized MA in this in vitro hemodilutional model of postpartum hemorrhage.