Effects of refrigerated storage on hemostatic stability of four canine plasma products

Comparison of shelf-stable and conventional resuscitation products in a canine model of hemorrhagic shock

BACKGROUND

Treatment of severe hemorrhagic shock typically involves hemostatic resuscitation with blood products. However, logistical constraints often hamper the wide distribution of commonly used blood products like whole blood. Shelf-stable blood products and blood substitutes are poised to be able to effectively resuscitate individuals in hemorrhagic shock when more conventional blood products are not readily available.

METHODS

Purpose-bred adult dogs (n = 6) were anesthetized, instrumented, and subjected to hemorrhagic shock (mean arterial pressure <50 mm Hg or 40% blood volume loss). Then each dog was resuscitated with one of five resuscitation products: (1) lactated ringers solution and hetastarch (LRS/Heta), (2) canine chilled whole blood (CWB), (3) fresh frozen plasma (FFP) and packed red blood cells (pRBC), (4) canine freeze-dried plasma (FDP) and hemoglobin-based oxygen carrier (HBOC), or (5) HBOC/FDP and canine lyophilized platelets (LyoPLT). Each dog was allowed to recover after the hemorrhage resuscitation event and was then subjected to another hemorrhage event and resuscitated with a different product until each dog was resuscitated with each product.

RESULTS

At the time when animals were determined to be out of shock as defined by a shock index <1, mean arterial pressure (mmHg) values (mean ± standard error) were higher for FFP/pRBC (n = 5, 83.7 ± 4.5) and FDP/HBOC+LyoPLT (n = 4, 87.8 ± 2.1) as compared with WB (n = 4, 66.0 ± 13.1). A transient increase in creatinine was seen in dogs resuscitated with HBOC and FDP. Albumin and base excess increased in dogs resuscitated with HBOC and FDP products compared with LRS/heta and CWB ( p < 0.01).

CONCLUSION

Combinations of shelf-stable blood products compared favorably to canine CWB for resolution of shock. Further research is needed to ascertain the reliability and efficacy of these shelf-stable combinations of products in other models of hemorrhage that include a component of tissue damage as well as naturally occurring trauma.

In vitro evaluation of hyperosmotic canine plasma suitable for infusion

OBJECTIVE

To determine the characteristics of canine freeze-dried plasma (cFDP) as it is serially diluted with sterile water.

DESIGN

In vitro experimental study.

SETTING

Government blood and coagulation research laboratory.

ANIMALS

cFDP from a commercial manufacturer.

INTERVENTIONS

Ten units of cFDP were reconstituted to 100%, 90%, 80%, 70%, 60%, 50%, and 40% of the recommended volume with sterile water. The resultant solutions were analyzed for coagulation factor activity (factors II, V, VII, VIII, IX, X, and XII as well as antithrombin), fibrinogen concentration, prothrombin time, activated partial thromboplastin time, viscosity, osmolality, and kaolin-activated thromboelastography.

MEASUREMENTS AND MAIN RESULTS

Viscosity, osmolality, and turbidity properties of plasma were increased in a reconstitution volume-dependent manner, with the 40% suggested volume generating approximately 2-fold increases in each. Similarly, factor activity levels and fibrinogen concentration increased by approximately 2-fold over this range in a concentration-dependent manner. Prothrombin time declined from 11.4 seconds at 100% volume to 10.9 seconds at 70% before increasing to 11.9 seconds at 40%. Activated partial thromboplastin time increased exponentially from 21.8 seconds at 100% rehydration to 100.0 seconds at 40%. R-time on TEG increased from 3.1 to 13.9 minutes at 50% rehydration, while alpha angle declined from 61.3° to 24.7° over the same range, and the maximum amplitude initially increased from 13.2 mm at 100% water to 18.6 mm at 70% water before dropping back down to 14.6 mm at 50% water. No clotting was observed with 40% rehydration.

CONCLUSIONS

The creation of hyperosmotic plasma from cFDP appears feasible with preservation of concentrated coagulation factors, although there are some unexplained effects that happen to coagulation functions at the highest concentrations tested using only 40%-50% of recommended rehydration volume. Further studies are needed to evaluate the hyperosmotic product in vivo.

Clinical Use of Canine Thawed Refrigerated Plasma: A Historical Case Series

Thawed plasma (TP) refers to defrosted fresh frozen plasma stored refrigerated. TP is used in human medicine for the rapid provision of coagulation factors and resuscitation of haemorrhagic shock, but its use in dogs is poorly described. The objectives of this historical case series were to describe the reasons for TP transfusion, treatment outcomes, and adverse events associated with canine TP transfusions in a veterinary teaching hospital. We hypothesised that TP would be used most commonly for the treatment of haemorrhage secondary to anticoagulant rodenticide intoxication and trauma. Blood bank plasma transfusion logs were searched to identify dogs that received at least one unit of TP between December 2015 and June 2021. Briefly, 166 dogs received a total of 262 units of TP. Anticoagulant rodenticide intoxication (37/166, 22.3%) was the most common reason for transfusion, followed by traumatic haemorrhage (23, 13.9%) and spontaneous haemoperitoneum (22, 13.2%). The majority of dogs received one unit of TP (111/166, 67.1%) and pRBCs were commonly simultaneously transfused with TP (65, 39.2%). Severe prolongations of prothrombin time and activated partial thromboplastin time were reduced following TP transfusions. Allergic reactions were the most common transfusion reaction (19/166, 11.4%). Most dogs survived to discharge (101/166, 60.8%).

The hemostatic profile of cold-stored whole blood from non-greyhound and greyhound dogs over 42 days

Objectives

To compare the hemostatic characteristics of cold-stored whole blood (CSWB) from non-greyhound dogs (NGD) and greyhound dogs (GD) over 42 days of storage, notably, platelet closure time (PCT) (NGD only), manual platelet count (PLT) (GD only), ellagic acid (INTEM) and tissue factor activated (EXTEM) rotational thromboelastometry, prothrombin (PT) and activated partial thromboplastin time (aPTT), fibrinogen concentration (FIB), and the activities of factors (F) FII, FV, FVII, FVIII, FIX, FX, FXIII antigen (FXIII:Ag), and von Willebrand factor antigen (vWF:Ag).

Design

Whole blood from 10 NGD and 10 GD, was refrigerated in CPD blood bags at 4°C for 42 days. Blood was analyzed before refrigeration (day 0) and at day 1 (d1), 3, 5, 7, 10, 14, 17, 21, 24, 28, 31, 35, 38, and 42. Multivariate linear mixed effects models were created to evaluate coagulation parameters over time and compare NGD and GD. Data are summarized as estimated marginal means with 95% confidence intervals. Significance was set at P < 0.05.

Results

The PCT for all NGD CSWB was above the device limit by d7. The PLT for GD CSWB did not change during storage. The mean alpha-angle for INTEM and EXTEM decreased to <50% of baseline at d38 and d31 for NGD, and d31 and d17 for GD CSWB. The mean maximum clot firmness (MCF) for INTEM and EXTEM reduced to <50% of baseline at d42 and d28 for both GD and NGD. PT and aPTT for NGD and GD increased over time. For NGD CSWB, the mean FVIII and vWF:Ag activities decreased to <50% of baseline at d7 and d28, respectively, and FIB reached 0.982 g/dL by d24. For GD CSWB, FVIII, FXIII:Ag and FV activities decreased to <50% of baseline by d3, d38, and d38, respectively, and FIB was 0.982 g/dL at baseline. Alpha-angle and MCF for both INTEM and EXTEM, and activities for FII, FV, FIX, FXIII:Ag were significantly lower, and vWF:Ag was significantly higher overall in GD CSWB compared with NGD. A significant difference in the pattern of change over time was detected between NGD and GD in EXTEM alpha-angle, INTEM and EXTEM MCF, FII, and FVIII activities.

Conclusions

The in vitro viscoelastic parameters of GD and NGD CSWB declines over 42 days, but numerous hemostatic parameters (INTEM and EXTEM alpha-angle and MCF, activity of FII, FV, FV, FVII, FIX, FX, FXIII:Ag, vWF:Ag, and FIB) remain within 50% of baseline for more than 14 days. CSWB from GD compared to NGD has reduced hemostatic activity overall, but a similar pattern of decline for most parameters over time.

Hemostatic Activity of Canine Never-Frozen Liquid Plasma Collected for Transfusion

This study measured the changes of hemostatic activity in liquid plasma (LP) over 7 days of storage. Five canine plasma units, divided into two aliquots were evaluated: one stored refrigerated at 2–6°C as never-frozen LP and one frozen at −18°C as fresh frozen plasma (FFP). Clotting times, coagulation activities of factor (F) V, VIII, X, XI, antithrombin (AT), and von Willebrand (vWF), fibrinogen and D-dimers (DD) content were assessed before storage (baseline value), and after 12, 24, 48 h and 7 days (D7) in LP stored refrigerated, and on day 7 in FFP. At baseline median values of all factor activity were greater than 80%, and for clotting times, AT, fibrinogen and DD content, were within the canine reference range. Some hemostatic parameters changed significantly over 7 days and at the end of storage in LP. However, median activities of FV, FVIII, FX and FXI, coagulation time, AT, fibrinogen and DD content remained within reference ranges at all time points. The only exception was for vWF which median activity was lower than reference range for all storage time points. Activity of FVIII was significant lower in LP at D7 when compared to activity in FFP, with values of 62 vs. 118%, respectively. DD content showed a median value higher than reference range in FFP at D7. Despite some statistically significant changes at the end of 7-day storage period, never-frozen LP maintained median factor activities >80% for most factors. The clinical impact of the drop over time of vWF activity is unknown.

Hemorrhagic shock and hemostatic resuscitation in canine trauma

Hemorrhage is a significant cause of death among military working dogs and in civilian canine trauma. While research specifically aimed at canine trauma is limited, many principles from human trauma resuscitation apply. Trauma with significant hemorrhage results in shock and inadequate oxygen delivery to tissues. This leads to aberrations in cellular metabolism, including anaerobic metabolism, decreased energy production, acidosis, cell swelling, and eventual cell death. Considering blood and endothelium as a single organ system, blood failure is a syndrome of endotheliopathy, coagulopathy, and platelet dysfunction. In severe cases following injury, blood failure develops and is induced by inadequate oxygen delivery in the presence of hemorrhage, tissue injury, and acute stress from trauma. Severe hemorrhagic shock is best treated with hemostatic resuscitation, wherein blood products are used to restore effective circulating volume and increase oxygen delivery to tissues without exacerbating blood failure. The principles of hemostatic resuscitation have been demonstrated in severely injured people and the authors propose an algorithm for applying this to canine patients. The use of plasma and whole blood to resuscitate severely injured canines while minimizing the use of crystalloids and colloids could prove instrumental in improving both mortality and morbidity. More work is needed to understand the canine patient that would benefit from hemostatic resuscitation, as well as to determine the optimal resuscitation strategy for these patients.

Lessons Learned From the Battlefield and Applicability to Veterinary Medicine - Part 2: Transfusion Advances

Since the inception of recent conflicts in Afghanistan and Iraq, transfusion practices in human military medicine have advanced considerably. Today, US military physicians recognize the need to replace the functionality of lost blood in traumatic hemorrhagic shock and whole blood is now the trauma resuscitation product of choice on the battlefield. Building on wartime experiences, military medicine is now one of the country's strongest advocates for the principle of hemostatic resuscitation using whole blood or balanced blood components as the primary means of resuscitation as early as possibly following severe trauma. Based on strong evidence to support this practice in human combat casualties and in civilian trauma care, military veterinarians strive to practice similar hemostatic resuscitation for injured Military Working Dogs. To this end, canine whole blood has become increasingly available in forward environments, and non-traditional storage options for canine blood and blood components are being explored for use in canine trauma. Blood products with improved shelf-life and ease of use are not only useful for military applications, but may also enable civilian general and specialty practices to more easily incorporate hemostatic resuscitation approaches to canine trauma care.

Fluids of the Future

Fluids are a vital tool in the armament of acute care clinicians in both civilian and military resuscitation. We now better understand complications from inappropriate resuscitation with currently available fluids; however, fluid resuscitation undeniably remains a life-saving intervention. Military research has driven the most significant advances in the field of fluid resuscitation and is currently leading the search for the fluids of the future. The veterinary community, much like our civilian human counterparts, should expect the fluid of the future to be the fruit of military research. The fluids of the future not only are expected to improve patient outcomes but also be field expedient. Those fluids should be compatible with military environments or natural disaster environments. For decades, military personnel and disaster responders have faced the peculiar demands of austere environments, prolonged field care, and delayed evacuation. Large scale natural disasters present field limitations often similar to those encountered in the battlefield. The fluids of the future should, therefore, have a long shelf-life, a small footprint, and be resistant to large temperature swings, for instance. Traumatic brain injury and hemorrhagic shock are the leading causes of preventable death for military casualties and a significant burden in civilian populations. The military and civilian health systems are focusing efforts on field-expedient fluids that will be specifically relevant for the management of those conditions. Fluids are expected to be compatible with blood products, increase oxygen-carrying capabilities, promote hemostasis, and be easy to administer in the prehospital setting, to match the broad spectrum of current acute care challenges, such as sepsis and severe systemic inflammation. This article will review historical military and civilian contributions to current resuscitation strategies, describe the expectations for the fluids of the future, and describe select ongoing research efforts with a review of current animal data.