Massive transfusion Flashcards
massive transfusion definition:
1 or more blood volumes w.in 24-hr period
>1.5ml/kg/min in 20 min
1/2 blood volume in 3 hrs
survival with massive transfusion
humans 25% to 84%
dog one study 27%
adverse effects:
Electrolyte abnormalities Hypocalcemia Hypomagnesemia Hyperkalemia Hemostatic defects Thrombocytopenia Secondary coagulopathy Hypothermia Metabolic acidosis Immunosuppression Transfusion-related acute lung injury Other transfusion reactions
MoA hypoCa hypoMg
citrate binds rapidly to both calcium and magnesium with equal affinity, resulting in decreases in ionized calcium and magnesium levels
1 veterinary study, ionized hypocalcemia was documented in 100% of cases after massive transfusion, severe hypocalcemia (<0.7 mmol/L) noted in 20%
tx:
ECG abnorm.:
- resolve quickly once perfusion is restored
- citrate is metabolized rapidly by the liver - Tx calcium gluconate if severe or CS: hypotension, muscle tremors, arrhythmias, or prolonged QT interval manifest
HYPERK+ MoA:
is this a concern in vetmed? why?
which breeds is it?
but it still is a concern in vetmed why
cold temp of transfusion inactivation of the sodium-potassium ATPase pump
most dogs lack significant intracellular quantities of potassium in RBC
= >K levels are not observed in stored RBC
except
Akitas and Shiba Inus RBC Na/K ATPase pump
shift with acidosis,oliguria, tissue damage
Thrombocytopenia after massive transfusion MoA 3:
severity:
why:
blood loss and dilution
1.blood products become devoid of platelets after 2 days of storage because the cold storage temperatures cause cell oxidation and death
- admin large volumes of these platelet-free blood products, especially after aggressive fluid resuscitation, can result in a dilutional thrombocytopenia
generally less severe than the level that would have been predicted by the degree of dilution (i.e., the loss and replacement of 50% of a patients blood volume does not result in a 50% decrease in platelet count)
because platelets are released from stores in the lungs and spleen
- consumptive
- dysfunc with hypothermia
Hemostasis is generally maintained as long as clotting factors are at least:
30% of normal
PT and aPTT <1.5 times
should transfusions of up to 1 blood volume be associated with abnormal bleeding tendencies:
Exchange transfusion models predict that loss and replacement of 1 blood volume removes slightly less than 70% of circulating factors in the plasma, and only need 30% or normal so no
acute coagulopathy of trauma (ATC) def:
triggered by 2:
5:
MoA 3:
endodenous hypocoaguable condition <1h post trauma 1. hypoperf 2. severe tissue injury 3 endothelial damage 4. inflamm 5. acidosis 6. hypothermia 7. hemodilution
- DIC w hyperfibrinolytic phenotype
- thrombin-thrombomoduli activated protein C
- catecholamine induced endothelial damage
TIC
trauma induced coagulopathy
hypothermia
acidosis
hemodilution
ATC:
and transfusions
hyperfibrinolysis and release of activated protein C secondary to tissue injury, hypoperfusion, and acidosis
increased transfusion requirements
ATC has been documented before fluid resuscitation and has been associated with increased transfusion requirements, hospital stays, and mortality
coagulopathy after trauma has also been documented in dogs and has similarly been associated with injury severity, transfusion requirements, and outcome
sequ. hypothermia:
MoA:
strong association bw. severity of hypothermia and the likelihood of developing
MoA 3: little effect on clotting factor levels, it has been
importance of hypothermia overlooked often - why?
observed in 69% of massively transfused dogs
shock + cold blood products
microvascular bleeding
- shown to inactivate the enzymes
- & enhance fibrinolysis
- decreased platelet activity.20, 28
coagulation testing performed at 37° C in the laboratory vs patient’s body T
immunosuppression MoA:
incompletely understood
donor leukocytes are believed to exert immunosuppressive effects through alloimmunization, induction of tolerance in recipient lymphocytes, and release of humoral factors that suppress immune cell function
TRALI MoA:
- develops microaggregates of platelets, white blood cells, and fibrin only partially removed 170-micron blood filter
- Embolization to the alveolar capillary beds has been shown experimentally to occur
- In human medicine, antileukocyte antibodies in the donor blood have been implicated as one of the primary causes of in vivo agglutination and subsequent embolization of recipient neutrophils to the pulmonary vasculature, although this mechanism has not yet been identified in dogs
Human leukocyte antibody (HLAb) attached o recipients own WBC and embolize in lungs
