Patient Blood Managment: Transfusion Therapy Flashcards
indications for transfusions
increased oxygen carrying capacity in the only true reason for RBC transfusion
oxygen delivery equation
oxygen delivery = CO x arterial O2 content
normal O2 deliery exceeds O2 consumption by __ fold
4
ways that the body compensates for anemia
- erythropoesis (make more hgb)
- rightward shift of ODC
- increase CO
normal oxygen delivery is
1 L/min
oxygen extraction ratio
VO2/DO2
normal O2 consumption is
250mL/min
critical Hgb
the threshold below which the body’s O2 consumption becomes dependent on O2 delivery
Class I acute hemorrhage
750cc
15% of blood volume
HR 100
BP normal
PP normal or increased
cap refill normal
RR 14-20
UO 30mL/hr
CNS: slightly anxious
fluid replacement: crystalloid
Class II Acute hemorrhage
750-1500cc
15-30% of blood volume
HR 100
BP normal
PP decreased
cap refill positive
RR 20-30
UO 20-30mL/hr
CNS: mildly anxious
fluid replacement: crystalloid
Class III Acute hemorrhage
1500-2000cc
30-40% of blood volume
HR 120
BP decreased
PP decreased
cap refill positive
RR 30-40
UO 5-10mL/hr
CNS: anxious/confused
fluid replacement: crystalloid + blood
Class IV Acute hemorrhage
2000cc or more
40% or more of blood volume
HR 140 or higher
BP decreased
PP decreased
cap refill positive
RR 35
UO negligible
CNS: confused/lethargic
fluid replacement: crystalloid + blood
the decision to transfuse should be based on the overall status of the pateint
- inadequate perfusion to tissue organs
- anticipated blood loss
- estimated blood loss
- amount of fluid given
- Hgb
- Transfusion indicators
monitoring for inadequate perfusion and oxygenation of vital organs
- hemodynamics: HR as an insensitive indicator of hypovolemia
- U/O: declines during moderate to severe hypovolemia
- ECG
- O2 sats: not a good indicator
- ABGs: pH decreased during severe hypo perfusion
- mixed venous oxygen saturation
monitoring for blood loss
- visual estimation
- based on suction devices, sponges, and drapes
- a study in patients undergoing spinal surgery showed that anesthesiologists tended to overestimate blood loss by as much as 40%
allowable blood loss (ABL) equation
EBV x (Hi-Hf) / Hi
EBV women
65 mL/kg
EBV men
70 mL/kg
what is spectrophotometric finger technology?
standard parameters: pulse ox, pulse rate, perfusion index
optional parameters: pleth variability index, total hgb, methemoglobin saturation, carboxyhemoglobin
1988 NIH consensus conference
- Hgb >10: rarely require transfusions
- Hgb < 7: almost always require transfusions
- Hgb 7-10: decision to transfuse should be based on patients risk for complications of inadequate oxygenation
TRICC Trial
Research question: among critically ill patients, how does a restrictive transfusion strategy (hgb 7-9) compare to a liberal transfusion strategy (hgb 10-12) in decreasing mortality?
Restrictive: hgb maintained at 7-9, avg 2.6 unit pRBC’s
Liberal: hgb 10-12, avg 5.6 units pRBCs
bottom line: restrictive strategy is associated with less mortality
transfusion requirements in critically care
replacement ratio for blood w/ crystalloid
1:3 (LR or NS)
replacement ratio for blood w/ colloid
1:1 (albumin, plasmanate, dextran)
replacement ratio for blood w/ whole blood
1:1
types of blood collection
- allogenic (homologous)
- Autologous
- perioperative blood salvage
- acute normovolemic hemodilution
replacement ratio for blood w/ pRBCs
1:1
allogenic blood collection
taken from different individuals of the same species
bank blood additives increase
storage time
Blood preservatives- CPDA
- citrate: prevents clotting by binding with calcium
- phosphate: buffer
- dextrose: RBC energy source
- adenine: allows RBCs to resynthesize ATP, extends storage time (35 days)
adsol(AS-1): adenine, glucose, mannitol NaCl, increases storage time to 42 days
past generation additives
- CPD: citrate, phosphate, dextrose (21 days)
- CPD-A: adenine added (35 days/5 weeks)
current generation additives (storage time = 42 days)
- AS-1(Adsol): adenine glucose, mannitol, and sodium chloride
- AS-3 (Nutricel): glucose, adenine, citrate, phosphate & NaCl
- AS-5 (optisol): glucose, adenine, NaCl and mannitol
ABO blood typing
blood typing-looks at what is in the plasma to see if it will react with the RBCs that you are giving
antigens- surface markers (RBCs), able to trigger an immune response
antibodies- in the plasma
if you are giving antibodies, you are giving?
giving plasma
if you are giving antigens, you are giving?
pRBCs
Rh factor
are another group of antigen found on the surface of RBCs
Rh Isoimmunization
- Rh-neg woman and a Rh-pos man conceive a child
- Rh-neg woman with Rh-pos fetus
- cells from Rh-pos fetus enter the woman’s bloodstream
- woman becomes sensitized - antibodies form to fight Rh-positive blood cells
- in the next Rh-pos pregnancy, maternal antibodies attack fetal RBCs
what is the main Rh+ factor?
Rh(D)
85% of ppl have these antigens are Rh+
unlike ABO system, antibodies to Rh factor are not developed until you are exposed
giving plasma =
giving antibodies
selection of donor plasma according to ABO group
AB
A
B
O
AB 1st
A 1st AB 2nd
B 1st AB 2nd
O 1st A 2nd B 3rd AB 4th
Type and screen
- to ‘type’ blood: mix with serum from O blood (known to have anti-A and anti-B antibodies). also treated with anti-D antibodies to determine Rh status
- to ‘screen’ blood (called indirect Coomb’s test): mix the patient’s serum with the most commonly known antibodies
when is a T/S needed?
- performed with the scheduled procedure is unlikely to require blood transfusions, blood should still be available
- most cost-effective use of stored blood
- blood is available to more than one patient
type and cross
- mimics the transfusion
- donor cells are mixed with the recipient’s serum
- detects the presence of less common antibodies not usually tested for in a screen
- performed for elective surgeries when the risk of transfusion is high
major cross-match
- 2 drops of patient serum with 1 drop of 5% of donor RBC –> incubation at 37 degrees C for 1 hr
- then into the centrifuge with 2 drops of AHG… will have (2) outcomes.. agglutination which is not compatible or no agglutination which is compatible
infectious disease testing for blood transfusions
conservative measures
- no donations taken from exposed or symptomatic patients
- wait 14 days after symptom resolution to donate blood
- if donated blood and develop symptoms within 28 days of donation, blood is discarded
are we testing for COVID?
autologous blood collection is?
the patients own blood
3 types of autologous blood transfusions
1.) preoperative autologous donation
2.) Acute normovolemic hemodilution
3.) Intraoperative and postoperative blood salvage
Preoperative autologous donation considerations
- patient scheduled for elective surgery predonates blood
- Hgb concentration must be greater than 11
- most patients can donate 10.5 mL/kg blood 5-7 days before surgery with a max of 2-3 units
- last unit must be collected 72 hours before surgery
- permits restoration of plasma volume
- PO iron may be given within a few days of surgery
not everyone can pre-donate blood
list contraindications
- evidence of infection and risk of bacteremia
- scheduled surgery to correct aortic stenosis
- unstable angina
- active seizure disorder
- MI or CVA within 6 months of donation
- high-grade left main CAD
- cyanotic heart failure
- uncontrolled htn
acute normovolemic hemodilution involves withdrawal of blood early in the intraoperative period
- loss of blood with low hematocrit
- replace withdrawn blood with 3cc crystalloid for every cc of blood
- Hct endpoint = 27-33%
- depends on pt’s CV and respiratory reserve
- reinfusion- use 40-micron filter to avoid palette elimination
Intraoperative blood salvage
“cell saver”
what is the process of the cell saver?
involves “washing” of salvaged material and return of only RBCs (hct = 50-60%)
where does the blood collect from?
surgical field and would drians
when is the cell saver re-infused?
post-surgery
T/F Autologus blood is not used much anymore
true
potential complications with autologous blood
- anemia d/t lack of time for RBC reconstitution
- possible reinfusion of fat, micro aggregates (platelets, WBCs, air, red cell stroma, bacteria, etc.)
- massive air embolism
- dilutional coagulopathy r/t large transfusions
- no clotting factors: all clotting factors and platelets are removed by washing process (ANH-exception)
- reinfusion of excessive anticoagulant (heparin)
- HD
- DIC
whole blood is separated into components, and when whole blood is centrifuged turns into what?
packed red blood cells
- frozen red cells (freeze -80 deg C)
- leukocyte-poor red cells
whole blood is separated into components, and when platelet-rich plasma is centrifuged at 20 deg C, turns into what?
platelets
whole blood is separated into components, and when platelet-poor plasma is frozen at -20 deg C turns into what?
fresh frozen plasma
whole blood is separated into components, and when platelet-poor plasma is frozen at -70 deg C and then thawed it is?
Cryoprecipitate
whole blood is separated into components, and when platelet-poor plasma is frozen at -70 deg C what is it?
Factor VIII- poor plasma
1 unit of pRBCs will increase the hct by how much?
3%
1 unit of pRBCs will increase the hgb by how much?
1gm/dL
1 unit pRBCs
- plasma is removed
- 250-350 mL volume with a 60% hct (whole blood has a hct of 40%)
- same amount of hgb as whole blood
- stored 21-43 days @ 1-6 deg C
- any crystalloid that contains calcium will cause clotting
- infusion with any crystalloid that contains Ca will cause clotting
how long should you wait to check a hgb?
- takes 24 hours for full equilibrium
- earlier measures reflect steady-state values in persons who have not bled recently
- only 6% of patients had a statistically significant between hgb/hct levels drawn at 15 mins and 24 hrs
ASA 2015 Practice Guidelines
1.) rarely need transfusion when hgb > 10 and always need when < 6
2.) A restrictive strategy (hgb > 8) should be used
3.) Multimodal protocols should be used to reduce intraop blood loss. should chk hgb between units
4.) Consider factors other than hgb when deciding to transfuse. remember pRBCs are given to increase O2 carrying capacity
5.) use blood salvage, acute normovolemic hemodilution and other measures to decrease blood loss when possible
one unit of platelets increase platelet count how much?
7,000-10,000 cells/mm^3
how long are platelets good for?
7 days
but risk for sepsis goes up at the end of this time, so try to use earlier
recommend 2.5 - 3 days
how many pooled donors does it take to make 1 unit of platelets?
4-6 donors
or apheresis from one donor
what is the only blood product stored at room temp?
platelets
stored at 20-24 deg C
what is the third leading cause of transfusion-related deaths?
bacterial contamination (mainly from platelets)
guideline for platelet transfusion
- prophylactic platelet transfusions are rarely indicated when platelets are > 100 x 10^9 and are usually indicated when platelets are < 50 x 10^9
- adequate plt count but known plt dysfunction (with antiplt agents and CPB). consider desmopressin first
- pts with severe thrombocytopenia ( < 20,000) and clinical signs of bleeding
- HELLP & neuraxial anesthesia - 70,000 plts (UpToDate)
- should be ABO compatible
FFP contains all coagulation factors except
platelets
what is the most frequently used plasma product?
FFP
what does FFP have?
- factor V and VIII
- fluid portion contained from a single unit of whole blood
- frozen within 6 hrs of collection
- stored for 5 days*
2 units of FFP (10/15 mL/kg) achieve __ factor activity
30%
effective coagulation occurs with clotting facotr levels of
20-30% normal
guidelines for FFP transfusion
- transfuse if INR > 2 in the absence of heparin
- transfuse if the pt has been transfused with pRBCs > 1 total blood volume (70cc/kg)
- transfuse for urgent reversal of warfarin therapy when prothrombin concentrate complex is not available
- prior to the administration of FFp, obtain coag studies
Cryoprecipitate is
fraction of plasma that precipitates when FFP is thawed
coagulation factors in cryo
- factor VIII: C (procoagulant activity)
- factor VIII: vWF
- Fibrinogen (cryo has the highest content of fibrinogen)
- factor XIII (fibrin stabilizing pattern)
- fibronectin (helps clean up foreign particles and bacteria from the blood)
cryo is rarely indicated when fibrinogen is >
150 mg/dL
indications for cryo
- fibrinogen < 80 -100 in the presence of excessive bleeding
- OB patients experiencing excessive bleeding despite fibrinogen level > 150
- massive transfusions (best to measure fibrinogen, but if you can’t it is ok to give cryo)
- bleeding in von Willebrand dx who don’t respond to desmopressin or vWF/factor VIII concentration
how to give cryo
- through a filter
- as rapid as possible (at least 200mL/hr)
- complete the infusion within 6 hrs of thawing
- 10 units of cryo will increase fibrinogen 70 mg/dL
does cryo need to be ABO compatible?
cryo contains extremely low concentrations of antibodies so probably not very important
physiologic effects of massive transfusions
- alkalosis: d/t citrate metabolism to bicarb in the liver
- hypothermia: d/t transfusion of cold blood
- hyperglycemia: d/t dextrose additive
- hypocalcemia: d/t binding of calcium to citrate
- hyperkalemia: d/t administration of older blood and leaky K (caution in neonates and RF)
Rh factor with cryo:
if cryo from Rh + pt is given to Rh - pt, could sensitize the patient
fibrin glue
made from cryo b/c of a large amount of fibrinogen. thrombin is added to make it work
what happens to blood with decreased storage
decreased with storage: pH, Ca, Factor V & VIII, (2,3 DPG)
what happens to blood with increased storage
increased with storage: K, Hgb, LA & CO2, fragility of RBC –> cell lysis
citrate intoxication manifests as
hypocalcemia
increased risk of citrate intoxication
- peds
- with hyperventilation
- liver dx/transplant
citrate intoxication occurs when
giving blood rapidly ( 1 > unit every 10 mins)
even with giving blood quickly you do not bind enough Ca ro cause bleeding problems
signs of hypocalcemia
- hypotension
- narrow pulse pressure
- increased CVP and intraventricular EDP
giving blood products increases the patient’s risk for?
what does it do to the heart?
hypothermia
- it can cause cardiac irritability and interfere with coagulation
- if the body temp falls < 30, ventricular irritability/cardiac arrest may occur
blood is stored at
4-6 deg C
coagulation abnormalities
- DIC-like syndrome (called consumptive coagulopathy in Miller) is caused by tissue hypoperfusion
- Thrombocytopenia (defined as plts < 150)
- low levels of fibrinogen, factor V & factor VIII
- these coagulation abnormalities are often seen with the administration of large amounts of blood (6-10 units)
signs of dilutional coagulopathy
- oozing into the surgical field
- hematuria
- gingival bleeding
- petechial bleeding from venipuncture sites
- ecchymosis
DIC-like syndrome
- deranged clotting system leading to disseminated fibrin deposition
- un-clottable blood (severe hemorrhagic diathesis)
- severely altered microcirculation leading to ischemic necrosis in various organs (esp. kidney)
most frequent infection associated with blood transfusions
Hepatitis (viral) risk: 1:103,000
cryo is most likely blood product to transmit hepatitis
TRALI means
transfusion related acute lung injury
1 cause of transfusion-related fatalities (TRALI) ?
- respiratory distress syndrome occurring within 6 hours after transfusion of pRBC’s or FFP
manifests like non-cardiogenic pulmonary edema
BUT no excessive intravascular volume and no cardiac failure
causes: all blood products, highest risk FFP
S/S of TRALI
- fever
- dyspnea
- fluid in endotracheal tube
- severe hypoxia
- during Ga - persistent decrease in blood O2 saturation
how to diagnose TRALI
- pulm edema in the absence of HF / circulatory overload
- pulm fluid has high protein content
treatment of TRALI
- stop transfusion
- support VS
- determine protein concentration of pum edema fluid via ETT
- obtain CBC & CXR
- notify blood bank (quarantine-associated units)
what does TACO mean
transfusion related circulatory overload
unlike TRALI, TACO is __ __ with excessive intravascular volume
pulmonary edema
high volume or rate of transfusion exceeds ability of patients cardiovascular system to handle additional workload
at risk for TACO
- cardiopulmonary dx
- RF
- extremes of age
TACO symptoms: (signs of overload)
- dyspnea, orthopnea
- hypoxemia
- pulmonary edema
- HTN ( > 50 mmhg in SBP)
- increased CVP
3 types of transfusion reactions
- febrile
- hemolytic
- allergic
what adverse transfusion reaction is the most common?
febrile reaction
febrile reaction S/S
fever, chills, headache, myalgia, nausea, non-productive cough
less frequently: hypotension, chest pain, dyspnea
cause of febrile reaction
the release of intracellular contents of donor leukocytes causes symptoms. the use of Leuko-reduced blood lowers the incidence of febrile reactions
treatment of febrile reaction
slowly infuse blood (but no clear consensus if the transfusion should be stopped)
allergic reaction can be
minor, anaphylactic, or anaphylactoid
allergic reaction S/S
- uticaria (most common)
- increased temp
- pruritus
cause of allergic reaction
- can be anaphylactoid or anaphylactic
- anaphylactic reactions are caused by transfusion of IgA to patients who are IgA deficient and have developed antibodies
- there is no cell destruction
treatment of allergic reaction
- IV antihistamines
- severe cases –> d/c blood
- observe urine for free hgb to rule out hemolytic reactions
what type of allergic reaction is a hemolytic reaction?
type II allergic reaction
cause of hemolytic reaction
administration of wrong blood type (ABO incompatibility), most times it is d/t a clerical error
s/s of hemolytic reaction
classic signs: fever, chills, chest pain, flank pain, nausea
S/s of hemolytic reaction under A
- hemoglobinuria (usually a persisting sign)
- hypotension
- bleeding diathesis
what to do with hemolytic reaction
- stop the transfusion
- maintain UO (75-100mL/hr) give fluids/maybe mannitol–> last case lasix if the other 2 don’t work
- alkalinize the urine: b/c bicarb is preferentially excreted in the urine, give bicarb drip to bring urine pH to 8
- assay urine and plasma hgb concentrations
- determine plt count, partial thromboplastin time, and serum fibrinogen level
- return unused blood to blood bank for repeat crossmatch
- send pt.s blood and urine to blood bank for examination
- prevent hypotension to ensure adequate renal blood flow
