topic 8 Flashcards
Avg #of units required:
Car Accident
50 units of blood
Avg #of units required:
Heart Surgery
6 units of blood
6 units of platelets
Avg #of units required:
Organ Transplant
40 units of blood
30 units of platelets
20 bags of Cryo
25 units FFP
Avg #of units required:
Bone Marrow Transplant
120 units of platelets
20 units of blood
Avg #of units required:
Burn
20 units of platelets
% of open heart patients that require transfusions
30-70%
Leads to 2-4 donor exposures
Percentage of all RBC units transfused in US occur during CABG procedures.
10%
Blood usage in US is significantly ________ than other Western countries
higher
Blood is a
liquid transplant
Blood transfusions cause
changes in the immune system
new transfusion=
new donor
Blood transfusions lead to complications such as
Post op infections
Ventilator-acquired pneumonia
Central line sepsis
Increased LOS, mortality rates.
Transfusion risks- infections
Bacterial
Hepatitis
HIV
Transfusion risks non-infectious:
Febrile Fever=
- Fever, chills
- Pt antibodies are reacting with white cell antigens or white cell fragments in the transfused blood products.
- OR- due to cytokines which accumulate during storage.
- Most common with platelet transfusions
Transfusion risks non-infectious:
Uticarial (Allergic) Reactions=
1%
Urticaria, itching , flushing
Caused by foreign proteins
Transfusion risks non-infectious:
Anaphylactic Reactions
Hypotension, tachycardia, cardiac arrhythmia, shock, cardiac arrest
- caused by patients who have IgA deficiency who have anti-IgA antibodies.
- Require special washed/ tested blood products
Transfusion risks non-infectious:
Acute Hemolytic Reactions
- Caused by transfusion of ABO incompatible blood
- Chills, fever, pain, hypotension, dark urine, uncontrolled bleeding due to DIC
Transfusion risks non-infectious:
Hyopthermia
Caused by transfusion of too many cold blood products
Transfusion risks non-infectious:
Volume…
overload
Transfusion risks non-infectious:
Citrate Toxicity
- Metabolized by liver
- Rapid transfusion of large quantity of blood products
- Binds calcium and magnesium – depleting stores
- Myocardial depression
- Coagulopathy
Transfusion risks non-infectious:
Potassium Effects
- Stored RBC leak K+
- Irradiation increased the rate of leak
- Cardiac effects
Transfusion Related Acute Lung Injury
◦Symptoms
Similar to ARDS
-Hypotension, Fever, Dyspnea, Tachycardia
Transfusion Related Acute Lung Injury (TRALI) =
Non-Cardiogenic pulmonary edema with diffuse bilateral pulmonary infiltrates on CXR
◦Occurs within 6 hours of tx- Most cases present w/in 1-2 hours
◦All blood products are culprits
◦Occurs 1/2000 transfusions
TRALI is attributed to
HLA Antibodies
Granulocyte antibodies
Biologically active mediators in the blood.
TRALI treatment
Ventilator support for ~96 hours
TRALI mortality
5-10%
Clinically, transfusions are associated with
Longer hospital stays
Longer time to extubation
Morbidity
Mortality
9 techniques to minimize blood usage
- Autologous transfusion
- Pre-bypass autologous donation
- Intraoperative Cell Saver use
- Shed mediastinal blood recovery
- Accept lower hematocrit
- Retrograde Autologous Priming
- Hemoconcentration
- Plasma/Platelet Pheresis
- Mini-circuits
Bloodless medicine=
MULTIMODALITY and MULTIDISCIPLINARY approach to patient care without the use of allogenic blood.
-AKA: Transfusion-Free Medicine
Blood conservation=
Global concept aimed at reducing patient exposure to allogenic blood products. Does not exclude use
Denton Cooley (Early 1960’s)=
Published article in the American Journal of Cardiology (1964) titled Open heart surgery in the Jehovah’s Witness”
- Described his techniques for treating these patients
- 1977 – reported experience with 500 JW patients
World War 1=
Blood Anticoagulation
- Allowed for transport of blood to the wounded
- PROBLEM: Storage
World War 2=
Storage problem overcome with the advent of blood banks
1953=
Use of blood alternatives
- Switched from plasma to Dextran (volume expander)
- Sugar substrate
- Due to incidence of hepatitis transmittal
1985=
Started looking into “blood substitutes”
Searched for oxygen carrier
Introduction of cell savers
Surgeon Gerald Klebanoff (Vietnam Vet) introduced the first cell saver in a military hospital
Recombinant Factor VIIa
- Hemopheliacs
- Israeli army discovered potential to stop life threatening hemorrhage
Currently, there are more than ___ organized bloodless programs in the US
100
There is a huge demand
-Patients are asking for it
Pre-op history: Age
tolerance of anemia is age dependent
Elderly don’t tolerate
As age increases, risk of transfusion increases
Pre-op history: Gender
- women are more likely than men to get transfused
- Lower hct and prone to blood loss with menses
Pre-op history: Height/weight
- required to do calculations
- Small patients and obese patients are at risk for transfusion
Pre-op history: race/ethnicity
Anemia and Coagulation disorders are associated with certain races
Ask about patient-related obstacles to transfusion-free therapy:
◦Anemia ◦Hemostatic disturbances ◦Medical conditions increasing perioperative blood loss ◦Obstacles to surgical hemostasis ◦Factors decreasing anemia tolerance
Pre-op lab work
Hgb
PT/INR / PTT
Platelet Count and Platelet Function Tests
Pre-op treat any:
- coagulopathies
- anemia: Optimize Hgb prior to surgery
Pre-op treat polycythemia
- Risk of hemorrhage during surgery (hyperviscosity)
- Plebotomy
Pre-op avoid pharmacological coagulopathies
Drugs (not anticoagulants) than have increased bleeding risk
-NSAIDs, PCN, NTG, High dose Vitamin C, St. John’s Wort, Ginger, Garlic, etc.
Anesthesiologist is a good resource to help detect any
obstacles in blood management
Anesthesia helps to
- correct any coagulopathies/anemia preop.
- Help position the patient to decrease blood loss
- Provide controlled hypotension
Keeping the patient
Optimizes clotting
Anesthesia Timing of fluid administration
- Restrict until surgical hemostasis is achieved
- Intravascular pressure is not too high
Autologous Donation=
Donation where the donor and recipient are identical
- Patient donates blood to be used on themselves during surgery.
- Avoids use/ risks of donor blood
Auto donation Requires a hematocrit of
33%
Auto donation contraindications:
Recent MI CHF Aortic Stenosis Transient Ischemic Attacks Hypertension Unstable Angina Bacteremia
Auto Donation:
Donation of whole blood can be split
- Allows not only donation of RBC, but also FFP
- Requires special order from physician
Auto Donation:
Plateletpheresis and Plasmapheresis
Allows the donation of platelets and plasma
Prebypass autologous normovolemic hemodiultion=
- Used to remove blood from the patient pre-bypass for transfusion later in the case.
- Removed volume is replaced with crystalloid
Prebypass autologous normovolemic hemodiultion Spares platelets from bypass and requires a hct of
35%
Prebypass autologous normovolemic hemodiultion: remove about
500-1000mL (1-3 units) ◦Depends on starting hct ◦Depends on age of patient ◦Depends on BSA ◦Depends on coexisting conditions
Prebypass autologous normovolemic hemodiultion: Blood is placed in a bag with
anticoagulant
◦Usually CPD
Prebypass autologous normovolemic hemodiultion: Reinfused after
protamine is administered
Prebypass autologous normovolemic hemodiultion: contraindications
◦COPD ◦CHF ◦CAD ◦Unstable Angina ◦Renal Insufficiency ◦Severe Aortic Stenosis ◦Coagulopathy
Dry Venous Line=
- Requires the use of VAVD
- Venous line is emptied prior to connection to the venous cannula
- Volume is removed to a bag and discarded or sequestered
- Eliminates about 400-1000mL
Dry Venous Line cautions=
- Only works if patient has adequate volume pre-op
- If patient is dry, will need the volume anyways
Mini Circuit=
AKA: Miniaturized Extracorporeal Circuits
Decreases foreign surface area
Decreases prime volume
Decreases blood-air contact
Mini Circuits attempt to:
- Decrease hemodilution
- Decrees inflammatory response
- Decrease volume shifts
Mini Circuit setup
Closed A-V Loop with centrifugal pump, membrane oxygenator, coated tubing
◦No venous reservoir
◦No cardiotomy
◦Often no heat exchanger or arterial line filter
◦Centrifugal pump provides kinetic assisted venous drainage and blood flow
Mini Circuit prime volume
500mL
◦Can be decreased with RAPing
Mini Circuits are mainly used for
CABGs
◦Some valves have been done
Mini Circuits- 2 types=
Totally Integrated Devices
Combination of components
Mini Circuit: Totally Integrated Devices
Include air handling and elimination systems, centrifugal pump and membrane oxygenator.
- CorX (Cardiovention)
- Cobe Synergy
Mini Circuit: Combination of components
MECC System (Jostra)
MCPB
DeltaStream ERP (Medos)
Resting Heart System (Medtronic)
Mini Circuit benefits
- Less inflammatory reaction
- Less activation of coagulation and fibrinolysis
- Less hemodilution
- Less use of autologous blood
- Marginally improved renal and neurological function
Mini Circuit: variables impacting outcomes
steroids Aprotinin degree of heparinization type of tubing coating patient population
Mini Circuit Concerns
- Air handling
- Requires surgeon to take care to avoid air entrapment around the cannula
- More microemboli with MECCs compared to normal circuits
- No reservoir = no way to handle excess volume
- No immediate volume infusion
- No heat exchanger (on most)
- Use of separate cell saver (Delay in processing, loss of factors/platelets)
- Increased cost
- Adaptability when surgical complications/ need requires normal ECC
Things you can do instead of using mini circuits
- Cut lines short
- Get as close to the table as possible
- Elevate the reservoir: Use VAVD
- Put modular pump heads near outlet/inlet of oxygenator
- Dry venous line: Requires VAVD
- Go on with low prime volume
Ultrafiltration/hemoconcentors=
Filtration of water across a semipermeable membrane via hydrostatic pressure gradient
- Water crosses the membrane which creates a solute concentration gradient
- Solutes have a higher concentration in blood so they move to the water side which has a lower solute concentration
Ultrafiltration/hemoconcentors removes
water and electrolytes
Ultrafiltration/hemoconcentors: Z-BUFing
you need to make sure to add sodium bicarb to the normal saline you’re Z-BUFing with to avoid acidosis
Modified Ultrafiltration (MUF)=
- Withdrawing blood from the patient via the arterial line (post bypass)
- Running the blood through a hemoconcentrator
- Pumping the blood back into the patient via the venous line
Modified Ultrafiltration (MUF) is primarily used in
pediatrics
Modified Ultrafiltration (MUF): Can use the cardioplegia circuit
Make sure to flush out the cardioplegia solution with blood
◦Already have a roller pump, bubble trap, heat/exchanger, line pressure monitor, already connected to the arterial line.
◦Risk of air entrapment around the arterial cannula: Don’t transfuse up the arterial cannula once started MUF
◦Pump flow rate less than MUF flow rate.
Cell saving=
- Use heparinized saline or CPD as an anticoagulant
- Cells are separated from the fluid by a centrifuge
- RBC fall to the bottom, Plasma on top
- RBC washed with 3x bowl volume (min)
- Put in a reinfusion bag for administration
Cell saving removes
Fat air tissue debris potassium hormones bioactivators
Cell saving limitations
◦Delay in processing ◦Loss of plasma proteins ◦Loss of coagulation factors and platelets ◦Expense ◦Operator attention and time
Reinfusion of shed blood
- Blood collected from the mediastinum and pleural cavities post op can be reinfused
- Doesn’t clot due to defibrination
- Increased level of free Hgb
- Contains activated products
Cardiopat=
- Shed blood can be collected and processed
- Uses a dynamic disk to process.
- Processes a variable volume of blood
- Consistently delivers washed RBCs w/ hct of 70-80%
- Processes up to 2 liters per hour or as little as 5 mL of RBCs
