Week 9 - Blood and Blood Component Therapy Flashcards
What is the maximum allowable blood loss formula?
MABL = EBV x (initial Hct - lowest acceptable Hct) / initial Hct
Visual blood loss estimates for a fully soaked surgical sponge and a fully soaked laparotomy sponge?
10 mL, 100 - 150 mL
Rapid interventions of ________ and _________ point of care monitoring has become popular, however it doesn’t estimate the amount of blood loss.
Hct, Hgb
Physiological responses suggestive of anemia or intra operative hemorrhage?
Tachycardia, decreased blood pressure and eventually decreased oxygen saturation
What are various assessments monitoring vital organ perfusion?
Echocardiography, urine output, cerebral oximetry, ABG, and mixed venous oxygen saturation, near infrared spectroscopy (NIRS)
What should be monitored if anemia is suspected?
Hgb and Hct
How can coagulopathy be assessed?
Monitoring platlets, fibrinogen, thromboelastography (TEG), INR, and aPTT
What emerging technology can aid in discerning coagulation dynamics?
Ultrasound technique called sonic estimation of elasticity via resonance (SEER Sonorheometry)
What are some commonly practiced “transfusion triggers”?
Hgb less than 6 –> Almost always transfuse
Hgb 6 - 10 –> Transfusion based on specific patient factors
Hgb 10 or more –> “Never transfusing”
What are some specific patient factors aiding in your decision to transfuse blood product?
Consideration of cardiopulmonary reserve, experienced and expected blood loss, O2 consumption (reflected in indices such as arterial and mixed venous oxygen saturation) and the presence of atherosclerotic disease.
Withholding transfusions with Hgb as low as ______ g/dL is considered justifiable practice in patients with no cardiac, renal, or hematologic disorders
7
What is the purpose of the patient blood management strategy developed by AABB (American Association of Blood Banks)?
Optimize patient outcomes while helping guarantee blood components are available for those in need
What are the three strategies of patient blood management?
- Optimizing the patient own red blood cell mass
- Minimizing blood loss
- Treatment of anemia
What is the average blood volume of a premature infant?
90-105 mL/kg
What is the male average blood volume?
70 mL/kg
What is the female average blood volume?
65 mL/kg
What is the average blood volume of a term newborn infant?
80-90 mL/kg
Endogenous erythropoietin increases in responses of __________ and ___________
hypoxia, anemia
Erythropoietin production is blunted in ___________ __________
Critical illness
What are the two forms of oxygen in the human body?
- Dissolved O2 –> Physical form
- O2 combined with hemoglobin –> Chemical form (most important)
Minimal blood loss can be accomplished successfully with volume replacement of what fluids?
Crystalloids 1:3 (Give LR 1st choice, NS 2nd –> Due to risk of hyperchloremia) and colloids 1:1 or 1:2
If blood losses are hemorrhagic, generally replacement therapy should include __________ and ____________ ____________
blood, blood components
What is considered a safe Hgb threshold for blood replacement?
7 g/dL
What is the oxygen carrying content equation?
CaO2 = (SaO2 x Hgb x 1.34) + 0.003(PaO2)
CaO2 –> Oxygen carrying content
1.34 mL of O2 is bound to each gram of Hgb
What does the oxygen carrying content equation tell us about dissolved blood vs bound blood?
Only a fraction of O2 in blood is dissolved compared to bound O2
Why may blood loss formulas (MABL) not be accurate in determining estimated blood loss?
They consistently over estimate and under estimate blood loss
What traditional transfusion indicators have been abandoned due to causing unnecessary transfusions and reactions?
Hgb of 10 and Hct of 30%
What should transfusion determination be based upon?
Multiple factors –> This includes Hgb and Hct levels, as well as patients condition, vital organ perfusion, and anticipated blood loss during case
What does the AABB (American Association of Blood Banks) recommend as far as transfusion based decisions?
Evidence from multiple critical elements instead of one single factor
What does the ASA recommend clinicians doing in regard to bleeding risk?
Evaluate the patient throughout the entire perioperative period for bleeding
Erythropoietin is excreted by the ___________
kidneys
What alternative to blood replacement has shown a significant decrease in the need for allogenic blood transfusions across all surgical procedures?
Administration of erythropoietin preoperatively
What congenital or acquired diseases have shown increased complications with blood transfusions?
Sickle cell anemia, Factor VIII deficiency, liver disease, and idiopathic thrombocytopenia
Aspirin should be discontinued ____________ days prior to surgery
7-10
Warfarin should be discontinued _________ days prior to surgery
5
Certain procedures that anticipate significant blood loss may benefit from an _______________
antifibrinolytic (tranexamic acid) –> prevents the breakdown of clots by inhibiting plasminogen from turning into plasmin
What is an autologous transfusion?
A re infusion of the patients own blood or blood components that were salvaged during surgery or donated prior to
What are the three types of autologous donations?
Preoperative autologous donation, acute normovolemic hemodilution, and cell salvage (cell saver)
What is a preoperative autologous donation (PAD)?
Involves blood collection prior to surgery of the patients own blood –> Should be AT least 48-72 hours prior to allow for the patient to equilibrate
When can oral or intravenous iron be given?
During preoperative autologous donation to maintain proper erythropoiesis when patient has donated their blood.
What are contraindications to preoperative autologous donation (PAD)
Preexisting anemia, cyanotic heart disease, ischemic heart disease, aortic stenosis, or uncontrolled HTN
What are some complications of preoperative autologous donation (PAD)?
Bacterial contamination, increased costs, and 50% of collected blood is wasted because it is unused
What is acute normovolemic hemodilution?
Takes place in the OR –> patients blood in withdrawn here and replaced with crystalloids or colloids. Blood is given back toward the end of surgery or when hemostasis is achieved.
What is the working theory behind acute normovolemic hemodilution?
You dilute the blood so blood loss is minimized during surgery
What is the goal Hct level in acute normovolemic hemodilution?
20%
What is a potential complication in acute normovolemic hemodilution?
Hemodynamic instability due to a significant decrease in Hct
What are contraindications for acute normovolemic hemodilution?
Patients at risk for MI or those with significant organ damage that relies on stable Hct and Hgb
What is cell salvage?
The collection of the patients blood during surgery from suction and surgical drains –> This is filtered and washed and then re infused into the patient
What is an advantage to cell salvage?
Provides a supply of RBCs in proportion to the amount being lost.
What religious group may accept cell salvage therapy
Jehovah’s witnesses
Cell salvage can help reduce what 2 things?
Allogenic blood transfusions and postoperative anemia
Cell salvage should be used if blood loss of ____________ is anticipated
500 mL
What cell salvage filter should be used in cancer surgery?
leucodepletion filter
Trained personnel and equipment should be available ___________ a day in regard to cell salvage therapy
24 hours
When is cell salvage contraindicated?
In patients with sepsis or some cancer surgeries
What are some complications of cell salvage?
Electrolyte disturbances, dilutional coagulopathy, and DIC
Using cell salvage can reduce the need of allogenic blood transfusions by __________
40%
What is a direct donor transfusion?
Blood being donated from a family member or friend of the patient –> This can reduce the risk of transmission of diseases
When should direct donor blood be collected?
At least 5 days prior to the patients procedure
What are the two prerequisites prior to any blood transfusion?
ABO blood type and Rhesus antigen testing (usually antigen D)
What antibodies are present in type O blood?
Anti-b and anti-a antibodies
What antigens are present on type O blood?
NONE
What does it mean if someone carries the Rhesus antigen?
They are + for whatever their blood type is –> A+, B+, AB+, or O+
How is blood type determined?
By the presence or absence of antigens on the RBC
Present –> A, B, or AB
Absent –> O
Where can the Rh antigen be found of the RBC?
Transmembrane protein that can be found on the surface of the RBC
What Rh antigen is the most common?
Antigen D, this is also immunogenic
What antibodies would you expect in a patient with type A+ blood?
Anti-B antibodies
What antibodies would you suspect in a patient with type AB- blood?
None
What does a type and screen test for?
Determines ABO type, presence of Rh D antigen, and other commonly known antibodies
What does a crossmatch test?
Tests the patients blood against the prospective donor’s blood to determine if an adverse reaction occurs. “trial transfusion”
What blood type is considered the universal donor?
O -
What blood type is considered the universal recipient?
AB +
In an emergency transfusion, what blood should be given?
O + –> People of childbearing age and have never received a O + blood transfusion in the past
O - –> When you are unaware of the patients transfusion history OR to a female of childbearing age
If a patient is receiving type O blood in an emergency transfusion, when can they be switched back to their primary ABO blood type?
All 3 of these must occur
- When inventory permits
- When bleeding has slowed or stopped
- MOST IMPORTANTLY a recent crossmatch indicates compatibility with a sample of the patients blood
What accounts for 50% of deaths after trauma?
Hemorrhage, within the first 24 hours of injury
What three things determine a massive transfusion?
- 10 units of PRBC’s in 24 hours
- 5 units of RBC’s in 4 hours
- Loss of one blood volume
What has improved mortality in patients suffering from traumatic hemmorhage?
Early and rapid delivery of blood products and with a primary goal of treating acute coagulopathy.
What blood product maintains tissue oxygenation?
PRBCs
What blood product addresses coagulation issues?
FFP, platelets, and cryoprecipitate
What is the plasma to RBC ratio for replacing depleted blood volume in massive transfusion protocols?
1:1 or 1:2
You should transfuse at least 1 unit of platelets for every ________ units of RBC’s when following massive transfusion protocols
6
More recent studies have lead massive transfusion protocols to infuse what three things to aid in clot formation?
- Calcium chloride (factor 4)
- Tranexamic acid (prevents clots from being dissolved via plasmin)
- Cryoprecipitate
What is the benefit to administering parts of blood (RBCs, FFP, platelets, cryo) opposed to whole blood?
Allows for targeting specific patient needs
What blood product should be given for urgent reversal of anticoagulation?
FFP –> Contains ALL clotting factors
What is an indication to transfuse cryoprecipitate?
Hypofibrionogenemia or consumptive coagulopathy
Why would you want to transfuse PRBCs?
To improve hemoglobin concentrations and oxygen carrying capacity
How long are RBCs good for if stored if a refrigerator properly?
42 days –> 300 mL total volume with a Hct of 65%
How much you expect Hbg and Hct to change when giving 1 unit of PRBCs?
1 unit = 1 g/dL increase in Hgb and a 2-3% increase in Hct
What blood product is generally administered at 1 mL for every 2 mL of blood loss in adults?
PRBCs –> 600 mL blood loss = 1 unit of PRBCs (300mL)
Pediatric patients experiencing blood loss should receive PRBC at an amount of __________ mL per kg and infants at __________ mL per kg
10-15, 15 –> Infants have larger blood volumes per kg than adults
What are platelets essential for? When should they be transfused?
Hemostasis, transfused for platelet dysfunction ot thrombocytopenia
What are alloantibodies? What if a patient has to receive a platelet transfusion but they have developed alloantibodies?
Alloantibodies are immune antibodies that are only produced following exposure to foreign red blood cell antigens
The patient will need single donor apheresis platelets, this comes at an increased expense –> compared to the normal method which it is separated from whole blood and collected from 6-10 donors
After transfusing 1 unit of platelets, how would you suspect the patients platelet level to change?
Increase by 5-10,000
Is ABO matching needed for transfusing platelets?
No, but is preferred because incompatibility can lead to shortened survival or plts and a small degree of hemolysis
At what platelet count should platelets be transfused?
10,000 or less –> Who are stable and not bleeding to prevent spontaneous bleeding (20,000 per Reed’s slides)
50,000 or less –> For patients actively bleeding
How long are platelets good for?
24 hours if open at room temp with continuous agitation
5 days if closed at room temp with continuous agitation
How long are frozen RBC’s good for?
10 years at -80C
What does FFP contain?
ALL CLOTTING FACTORS
What is the most commonly used plasma product?
FFP
How long can FFP be stored for?
1 year at -8 to -30 C if frozen within 8 hours
What happens if FFP is not transfused within 24 hours of being thawed?
Factors V and VIII begin to decline
What amount of FFP should be used for urgent warfarin reversal?
5-8 mL/kg
When 10 - 20 mL per kg of FFP is transfused, how will coagulation levels change?
Increase by 20 - 30%
What are the 4 Variables in the ABC score assessment for MTP?
*Pulse< 120bpm
*SBP< 90mmHg
*FAST- Focused Assessment with Sonography in Trauma
*Penetrating Torso Injury
What does cryoprecipitate contain?
100 units of factor VIII, 200 mg of fibrinogen, fibronectin, and von Willebrand factor
How is cryoprecipitate collected?
Thawing FFP to 4 C and collecting the precipitate via centrifuge
When should cryoprecipitate be administered?
3 indications
Only patients actively bleeding with von Willebrand disease, fibrinogen levels less than 80-100 mg per dL, and prophylactically in patients with congenital fibrinogen deficiencies or von Willebrand disease who are unresponsive to desmopressin (DDAVP)
What changes occur during blood stroage?
Blood undergoes structural and functional changes over time –> ATP and 2,3-diphosphoglycerate decrease while potassium levels increase. Acidosis and oxidative damage …
Using RBCs after _____________ of collection, patients experienced reduction in short term and long term survival
2 weeks
What is added to stored blood to prevent clotting?
citrate phosphatase dextrose (CPD) –> Can cause hypocalcemia
What is the suggested platelet count prior to most surgical procedures?
At least 50,000
What platelet count should a patient have prior to an endoscopy?
At least 30,000
What are the most common reactions after receiving blood, although rare?
Fever and allergic reactions
Acute vs delayed blood transfusion reactions?
Acute –> Generally more severe and occur within 24 hours of transfusion
Delayed –> Occurs days, months, and even years after transfusion
What is the most susceptible blood product to bacterial contamination?
Platelets
Blood product contamination increases in likely hood with ________________
Increased length of time blood is stored
When administering blood in the OR, what can be masked by general anesthesia?
Acute hemolytic reactions –> unexplained hypotension, hemoglobinuria, or a hemorrhagic episode shortly after the start of the transfusion
What is a hemolytic blood transfusion reaction?
The patients antibodies destroy the donors RBCs
What are the presenting symptoms of an acute hemolytic reaction?
Pain at infusion site, fever, chills, back pain, substernal pain, altered LOC, dyspnea, hypotension, hemoglobinuria, tendency to bleed
Acute hemolytic reactions are rare, but can lead to what?
Shock or DIC
What should be done if patient experiences an acute hemolytic reaction?
Stop transfusion and provide hemodynamic support and fluids management with NS –> Severe reactions may need FFP, cryo, and platelets to counteract coagulopathies
What is a delayed hemolytic reaction?
Much more common blood transfusion reaction occurring with a mild symptoms –> jaundice, decreased Hgb levels, and hemoglobinuria
What patient population is at increased risk for developing delayed hemolytic reactions?
Obstetric patients and those who have received transfusions in the past.
What is TRALI?
Transfusion related acute lung injury –> Occurs when alloreactive plasma antibodies within blood products lead to clumping and activation of leukocytes –> This causes acute lung injury and non cardiogenic pulmonary edema.
What are symptoms of TRALI?
New acute lung injury within 6 hours of the transfusion –> Hypoxemia, ARD, increased peak airways, hypotension, and fever
What is TACO?
Transfusion associated circulatory overload –> Leading cause of death in transfusion complications since 2016!
Pulmonary edema occurs due to large volumes of transfused products over a short period of time.
What are some symptoms of TACO?
Respiratory distress or HTN within 6-12 hours after completing a transfusion
Other symptoms include hypoxemia, tachycardia, widened pulse pressure, JVD, rales and wheezing in the lungs.
What is the primary treatment for TACO?
Supplemental O2 and fluid mobilization via diuretic therapy, as well as ventilatory support
Symptoms of an IgE related reaction
Allergic reaction –> usually minor and limited to urticaria and erythema –> Treated with diphenhydramine
The patient will have a more severe allergic blood transfusion reaction if _______ deficient
IgA
When would an IgA deficient patient develop a severe blood transfusion reaction?
Upon second exposure to IgA containing blood products –> First exposure would cause patient to develop IgE antibodies to IgA
What type of blood should be given to patients who have experienced an anaphylactic reaction in the past?
Washed blood, which removes IgA
In a severe, IgA mediated reaction to a blood transfusion, what symptoms would you expect the patient to present with?
Anaphylaxis –> bronchospasm, dyspnea, and hypotension –> Can occur with a little as a few mL of blood
