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119 Cards in this Set
- Front
- Back
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Why is an auto-transfusion performed?
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Oxygen carrying capacity and/or delivery to tissues
Coagulation deficits Intravascular volume |
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Steps in an auto-transfusion
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Determine blood type of recipient and donor
Identify antigens |
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What is an antibody?
What is an antigen? |
An antibody is a protein produced by a host to bind to, and thus inactivate, foreign particles.
The particle is called the antigen. |
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Antibodies related to blood type,
A, B, Rh Antigens are on the surface of RBCs |
Antibodies Occur naturally
-Anti-B, anti-A formed when surface of RBCs lack A and/or B antigens These antibodies can rapidly destruct RBCs if corresponding antigens exit |
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What is a major cross-match?
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Major cross-match
Donor’s RBCs are incubated with patient’s plasma Also checks for immunoglobulin G antibodies (if incompatible agglutination occurs) |
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What is a Minor cross-match?
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Patient's RBCs are incubated with donor’s plasma
(if incompatible, agglutination occurs) |
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Type Specific Blood
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Only ABO-Rh type is determined
1:1000 chance of a significant hemolytic transfusion reaction occurring in type-specific blood |
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List the best blood product choice if time does not allow for compatibility testing
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Best choice is transfuse type-specific, partially cross-matched blood
Usually takes about 5 min (depends on lab) 2nd choice is type-specific, not cross-matched blood Last choice is O-negative PRBCs (Universal donor) |
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O-negative Whole Blood
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This is not an option because it may contain high titers of anti-A and anti-B hemolytic antibodies
After giving 2 units of 0- PRBCs, should not give patient’s blood type but continue with 0- PRBCs |
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Type and Screen
What is included in a T & S? When is a T & S commonly done? |
Blood that has been typed for A, B, Rh antigens and screened for common antibodies
Type and Screen is often ordered when it is unlikely that surgical procedure will require transfusion, but would like to obtain blood quickly if needed |
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Why is a T & S cost effective?
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More efficient use of resources b/c T&S allows stored blood to be available to more than one patient
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What is the chance of a significant hemolytic reaction from a T & S?
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1:10,000
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Blood storage and preservative
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Variety of solutions containing
Dextrose, phosphate, sometimes adenine Stored temperature 1-6o C Time stored approx 21-35 days Changes w/n blood are a result of type of preservative & time stored In critically ill patients, often “fresher” blood (< 5 days storage) provides better oxygen delivery to tissues |
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What temperature is blood stored at?
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1-6 degrees C
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Why is blood stored less then 5 days preferred for critically ill patients?
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fresher blood provides better oxygenation
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What are indicators that a transfusion is recommended?
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Visual estimation of intraoperative blood loss
Laps (100-150 ml), sponges (10ml), suction, cell-saver Correct interpretation of monitor data indicating signs of inadequate organ perfusion Heart rate (insensitive indicator) but should be evaluated for volume depletion, light anesthesia, pain Systemic blood pressure Central venous pressure (if available) 6-12 mm Hg may suggest adequate volume Urinary output Decrease occurs when moderate to severe hypovolemia exists Arterial pH Acidosis occurs with severe hypovolemia |
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What factors make Heart Rate an insensitive indicator of the need for a transfusion?
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volume depletion
light anesthesia pain |
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What changes are seen in Arterial pH (pHa) when hypovolemia (needing a transfusion occurs)?
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Acidosis
occurs with severe hypovolemia |
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What risks should be evaluated when deciding to transfuse?
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1.)Anemia and its implications for patient
2.)Ability of patient to compensate for decreased oxygen-carrying capacity 3.) Potential disease transmission Must balance risks with perceived benefit(s) |
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Is there an auto-transfusion trigger?
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Doesn’t exist
– practitioners assessment and decision |
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What guidelines do practitioners follow when deciding to transfuse?
(hemoglobin values and likely hood of transfusion) |
Healthy patients – hgb< 10g/dL
-Rarely require transfusion Healthy patients – hgb < 6g/dL -Often transfused Especially with continuous profuse bleeding & anemia exist congruently |
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(in deciding to transfuse)
Healthy patients – hgb < 6g/dL |
-Often transfused
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(in deciding to transfuse)
Healthy patients – hgb< 10g/dL |
-Rarely require transfusion
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(in deciding to transfuse)
Hemoglobin values Between 6-10 g/dL |
Not an automatic decision
Based on pts likelihood of complications d/t inadequate oxygenation e.g. CAD, chronic lung dz, large surgical blood loss |
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Evidence based literature suggest that with
Hemoglobin values between 6-10 g/dl |
Evidenced-based literature
Sparse with human subjects -Due to protection of human subjects (Institutional Review Boards) Some studies in animal models No evidence to support that mild to moderate anemia impairs healing, increases bleeding, or prolongs hospital stays |
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Why is maintaining appropriate intravascular fluid volume on a patient important?
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Ensure optimized: left ventricular filling pressure, cardiac output, systemic BP & O2 delivered to tissues
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what should be considered w/ fluid replacement?
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surgical considerations (blood loss, evaporate of lost, 3rd spacing)
preop volume status (where did it start?) NPO time pre-existing disease (comorbidities) effect of anesthetic drug on physiologic function |
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why does intravascular fluid volume matter?
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influences intra & post op morbidity & mortality (tissue & organ perfusion, less unstable hemodynamics)
there is no one perfect fluid intervention (tailor to patients needs) |
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What affects intravascular volume?
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NPO, bowel prep, vomiting, diarrhea, diaphoresis, hemorrhage, burns, inadequate intake, dehydration
intravascular volume w/o evidence of external factors (sepsis, ARDS, ascites, pleural effusions, bowel abnormalities) |
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Look at indirect determinants, which only are overall estimate of organ perfusion
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urine output (> 0.5 ml/kg/hr)
heart rate systemic BP *direct determinant (CVP)* |
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Other clues for intravascular fluid volume
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skin turgor
mucous membranes (dry or moist) strength of peripherial pulses resting heart rate systemic BP (w/ Orthostatic changes) urine concentration & volume |
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What labs do you look at?
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serial hematocrit
ABG w/ based deficit urine specific gravity or osmolality serum sodium serum creatinine-to-BUN ratio |
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effects of anesthetic technique: IV induction drugs - thiopental & propofol
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thiopental (decrease venous return)
propofol (decreased systemic vascular resistance, cardiac contractility, preload) Inducing volume depleted patients can lead to a drop in systemic BP & organ perfusion (SEVERE HYPOtension) |
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effects of anesthetic technique: IV induction drugs - ketamine
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--increases systemic BP, HR, cardiac output through stimulation of sympathetic nervous system & inhibiting reuptake of Norepi
--if catecholamine stores are depleted (CHF/Shock) cardiac depression may occur as seen w/ other induction drugs (propofol) |
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effects of anesthetic technique: IV induction drugs - neuromuscular blockers (NMB)
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no direct cardiovascular effects BUT may release histamine (SVR can decrease d/t vasodilation & subsequent venous pooling d/t loss of muscle tone = hypotension)
**mivacurium, atracurium |
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PRBC
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Usual volume 250-300 ml
Hematocrit within RBCs is ~ 70-80% |
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What is the goal of giving PRBC
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Goal is to increase O2 carrying capacity and tissue oxygenation
(Other products can increase intravascular volume -- colloid, crystalloid) |
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PRBC's continued
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1 unit can increase Hgb concentration by 1 g/dL
When transfusing, dilution with 50-100 ml NaCl can facilitate transfusion If mixed with lactated Ringer’s, clotting may occur due to presence of Ca++ |
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How can you facilitate PRBC transfusion?
Why don't you mix PRBC with LR? |
dilution with 50-100 ml NaCl
with LR clotting may occur due to presence of Ca++ |
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How much does giving 1 unit PRBC improve the hemoglobin?
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1 unit can increase Hgb concentration by 1 g/dL
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Acute blood loss
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1.5 – 2.0 liters
Approximately 30% of most adult’s blood volume Likely to observe tachycardia and hypotension However may be masked by anesthetic drugs Replacement with crystalloid or colloid does not aid in oxygen-carrying capacity May restore hemodynamic stability In large quantities may cause coagulation disorder |
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Crystaloids and colloids are effective for what?
ineffective for? and in large quantities put the patient at risk for what? |
May restore hemodynamic stability
does not aid in oxygen-carrying capacity In large quantities may cause coagulation disorder |
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Platelets
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Specifically treat thrombocytopenia while not infusing unnecessary blood components
Usually not required unless platelets <50,000 One unit of platelets will increase plt count by 5-10K within 1 hour of transfusion |
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When are Platelets required to treat Trombocytopenia?
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Usually not required unless platelets <50,000
platelets are given to treat thryombocytopenia because they contain no unnecessary blood products |
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One unit of platelets will increase plt count
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by 5-10K within 1 hour of transfusion
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Risks related to Platelets
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1.) Sensitization reaction
2.) Transmission of infectious disease 3.) Bacterial contamination (stored 20-24oC) More likely in platelet concentrations Sepsis can be fatal & occurs in 1:5000 transfusions May be under-reported due to the acuity of patients receiving them |
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Fresh Frozen Plasma
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Fluid portion from unit of whole blood frozen within 6 hrs of collection
All coagulation factors except platelets are present Indicated if PT, PTT 1.5 X greater than normal Also used to reverse coumadin or in cases of heparin resistance |
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When is Fresh Frozen Plasma are given?
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Indicated if PT, PTT 1.5 X greater than normal
Also used to reverse coumadin or in cases of heparin resistance |
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Fresh Frozen Plasma contains
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All coagulation factors
except platelets are present |
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effects of anesthetic technique: IV induction drugs - inhale anesthetics
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decrease SVR & mildly depressed cardiac contractility & function (isoflurane, desflurane, sevoflurane)
positive pressure ventilation -- reduces preload by increasing intrathoracic pressure which decreases systemic BP if hypovolemia exists |
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effects of anesthetic technique: IV induction drugs - regional anesthesia
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Neuraxial blockade: blocks sympathetic nervous system fibers which innervate arterial & venous vascular smooth muscles
usually prevented by fluid bolus administration b/f beginning block |
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Perioperative fluid treatment -- therapy includes
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1. Replacement of pre-existing deficit
2. Replacement of normal losses 3. Replacement of surgical losses from incision (third space, actual blood loss) --all three are used in calculation to estimate hourly fluid requirements throughout duration of surgery |
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What is NPO time equal to?
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The actual time duration they have fasted
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How is NPO calculated?
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Calculated by multiplying the normal maintenance fluid rate (based on weight in kg) by the # hours they have been actually NPO
--Adults usually calculated at 1.5 ml/kg as a maintenance rate |
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Replacement of normal fluid losses.
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Maintenance rate per hour based upon pts weight for the duration of surgery & anesthesia time (If pt obese, may reduce the maintenance rate by ~30% --> 70 ml/hr instead of 100ml/hr)
--Replaced w/ crystalloid solutions (LR, NaCl) |
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How is actual blood loss is determined
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Look at suction canister
Occult bleeding in wound or drapes Laps (100-150 ml), sponges (10 ml) (if saturated count them & multiply it out) |
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Is blood loss diluted by irrigation, urine, amniotic fluid or ascitic fluid?
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Yes
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What is the KEY for replacement of surgical losses?
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Visual estimation b/c clinical (hypotension, tachy) & lab (low HCT, rising base deficit, acidosis) signs are evident later
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How do you replace blood loss?
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--Crystalloid w/ 3:1 ratio (lose 100cc blood, replaced w/ 300cc LR to maintain intravascular volume)
--Colloid or Blood w/ 1:1 ratio (packed RBC or Hespan/Albumin) |
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Cryoprecipitate
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Fraction of plasma that precipitates when FFP is thawed
-Treat hemophilia A unresponsive to desmopressin -Treat hypofibrinogenemia induced by PRBCs |
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Cryoprecipitate is used to treat (2)
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1) hemophilia A unresponsive to desmopressin
2) hypofibrinogenemia induced by PRBCs |
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Cryoprecipitate is
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Fraction of plasma that precipitates when FFP is thawed
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Albumin
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5%
Isotonic with pooled plasma Used when rapid expansion of blood volume is needed 25% solution Used with hypoalbuminemia Neither solution provides coagulation factors Heating (homogenation) reduces potential for transmission of hepatitis |
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5% Albumin
characteristic use |
Isotonic with pooled plasma
Used when rapid expansion of blood volume is needed |
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25% solution Albumin
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Used with hypoalbuminemia
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What does Albumin NOT do?
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Albumin does not provides coagulation factors
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Blood therapy complications
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(Most common)
Bacterial contaminants Transfusion-related lung injury (TRALI) ABO mismatch (Least common – most feared) Infectious disease transmission Hepatitis, HIV Hemolytic transfusion reaction |
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Most Common Blood Therapy Complications
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Bacterial contaminants
Transfusion-related lung injury (TRALI) ABO mismatch |
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Least common Blood Therapy Complication
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most feared
Infectious disease transmission Hepatitis, HIV Hemolytic transfusion reaction |
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Why is Third space very important?
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Fluid shifts, evaporative loss (large wound exposed to OR environment--air exchanged 15 times/hr)
Loss of moisture:mechanical ventilation of lungs w/ dry gases |
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Replacing surgical loss -- Third Spacing
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AKA evaporative surgical loss
Based upon size of excision & exposure of tissue to air [Minimal 2-4 ml/kg/h4(hernia repair); Moderate 4-6 ml/kg(hysterectomy); Severe 6-8ml/kg(bowel resection)] |
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Crystalloid solutions are what?
What are the 3 catagories? |
Inorganic and organic molecules in water;
Isotonic, Hypotonic, Hypertonic |
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Which solutions have limited ability to remain intravascular?
What is the importance of this? |
Isotonic & hypotonic
Edema not uncommon when large fluid resuscitation is necessary |
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Which fluid is prefered intraoperatively?
What determines which fluid choice? |
Isotonic (LRs, NaCl, Plasma-Lyte)
Na, K, Cl concentrations |
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Infectious Disease
(statistics) |
Incidence is greatly decreased
1980 about 10% Today Hep C and HIV about 1:1,000,000 |
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TRALI
Respiratory distress syndrome |
Respiratory distress syndrome occurring within 6 hrs of transfusion of PRBC or FFP
Dyspnea Arterial hypoxemia Secondary to non-cardiogenic pulmonary edema Diagnosis confirmed when pulmonary edema occurs in absence of left atrial hypertension and pulmonary fluid is high in proteins |
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When does Respiratory distress syndrome occur?
What are the S&S? |
6 hrs of transfusion of PRBC or FFP
S&S Dyspnea Arterial hypoxemia Secondary to non-cardiogenic pulmonary edema |
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How is Respiratory Distress Syndrome diagnosed?
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When pulmonary edema occurs in absence of left atrial hypertension and pulmonary fluid is high in proteins
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What is the treatment for
TRALI Respiratory Distress Syndrome? |
-STOP transfusion
-Symptomatic treatment of vital signs -Sample pulmonary edema and analyze for protein -CBC and chest xray -Notify blood bank of situation to prevent associated units from being transfused |
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Why is LR & Plasma-Lyte not used w/ renal patients?
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Because of K+ concentration & their relative hyperkalemia.
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Why isn't LR used to infuse blood?
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Presence of Ca++ in LR & citrate in blood produces used as anticoagulant.
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Which solution contain large molecules dissolved in solute?
(usually isotonic saline) Why does it tend to stay in the vasculature? Drawnbacks? |
Homogeneous non-crystalline substances
It contains large molecules dissolved in solute & thus more efficient at expanding intravascular volume (Albumin, dextran, hespan, hetastarch) More expensive than crystalloid |
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What is Albumin?
What are pros & cons? Staying power (1/2 life)? |
Purified human plasma 5% or 25% solution
Pros -- No known risk of Hep B, C, or HIV transmission d/t homogonization Cons -- religious groups may refuse b/c it is derived from human blood ½ life = 16 hrs (90% of dose remaining 2 hrs in intravascular space) |
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What is Hespan?
Staying power (1/2 life)? |
Semi-synthetic made from amylopectin
Branching D-glucose polymer ½ life = 17 days |
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What is Dextran?
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Semi-synthetic made from biosynthesized sucrose which is produced by bacterium Leuconostoc mesenteroides
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What is the IMPORTANCE of molecular weight of Dextran 40 or Dextran 70?
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--Smaller particles rapidly cleared in urine & is preferred in vascular surgery to dilute blood viscosity
--Larger particles have ½ life several days & is preferred for volume expansion |
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What are some Adverse Reactions?
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--Anaphylaxis occurs but is rare (Albumin, hetastarch, & dextran)
--Anticoagulation (Hespan can reduce factor VIII & von Willebrand factors, impair platelet function, prolong thromboplastin time) If infusions limited to < 1 liter, not usually seen |
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Transfusion related Immunomodulation
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Patients more at risk for post-operative infection
due to Depression of immune system -Surgical trauma -suppression of cell-mediated immunity Some transfusions have received leukoreduction -Removing WBCs from blood and platelets |
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Why are patients who received transfusions more at risk for post op infection?
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-Leukoreduction of blood and platelets
-Depression of immune system -Surgical trauma -suppression of cell-mediated immunity |
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Metabolic abnormalities
(related to blood products) |
Stored whole blood
-Greater concentration of H+ ions -Lowered 2,3-DPG concentrations -this causes an Increased affinity for O2 on hgb (less available to tissues) Blood preservative citrate -Calcium bound by citrate -Calcium supplemented when -Rapid transfusion > 50ml/min -Hypothermia or liver disease (interfering with metabolism of citrate) -neonate |
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Whole blood has
_____ Hydrogen Ions concentrations _____ 2,3-DPG concentrations this causes |
Greater
Lower Increased affinity for O2 on hgb (less available to tissues) |
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Calcium Citrate binds with Calcium
When is the calcium supplemented? |
Rapid transfusion > 50ml/min
Hypothermia or liver disease interfering with metabolism of citrate neonate |
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Hypothermia
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With decrease in body temp, cardiac irritability
-Decrease of 0.5-1 degree C may cause shivering Increases O2 consumption by 400% -Fluid warmers to decrease hypothermia -If overheat, blood can hemolyze during transfusion=K+ bolus |
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What occurs if blood is overheated in fluid warmer?
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blood can hemolyze during transfusion resulting in a K+ bolus
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What decrease in temperature causes shivering?
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0.5-1 degree C
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The heart becomes ______ when a patient is hypothermic.
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irritable
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Microvascular bleeding
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Determined by clinical judgment and lab tests
FFP given in extreme situations when PT is 1.5 X normal or INR is >2.0 Another indicator If one blood volume has been transfused (~70ml/kg) |
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Microvascular Bleeding is likely under what condition?
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If one blood volume has been transfused (~70ml/kg)
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FFP is given to treat Microvalscular bleeding only in extreme situations where
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PT is 1.5 X normal or INR is >2.0
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Transfusion Reactions
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Hyperthermia
Most common – 0.5-1% of transfusions Interaction b/w recipient antibodies & antigens on donor leukocytes or platelets Temperature rarely > 38oC Treatment -Slow infusion -Give antipyretics -May need to D/C transfusion |
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How is hyperthermia (Transfusion reaction) treated?
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Slow infusion
-Give antipyretics -May need to D/C transfusion |
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Hyperthermia (transfusion reaction) is caused by
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Interaction btw recipient antibodies and antigens on donor leukocytes or platelets
Temperature rarely > 38oC |
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Allergic Reaction (transfusion reaction)
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Allergic reactions
Increased body temperature Uriticaria Pruritus Treatment Antihistamines D/C transfusion if necessary |
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What are the signs of a
Allergic Reaction? (transfusion reaction) |
Increased body temperature
Uriticaria Pruritus Treatment |
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How are
Allergic Reaction (transfusion reaction) treated? |
Antihistamines
D/C transfusion if necessary |
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Hemolytic reactions
(a transfusion reaction) |
Hemolytic reactions
Occur when wrong blood type given Activation of complement system -Immediate signs often masked by general anesthesia Free hgb in plasma or urine evidence of this Acute renal failure -Presence of hemolyzed RBCs in distal renal tubules DIC |
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How can hemolytic reaction occur?
(transfusion reaction) |
when wrong blood type given
- this activates a compliment system |
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What are the signs of a Hemolytic reaction?
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the activation of a compliment system is evidenced by
free hgb in plasma or urine Acute Renal Failure presence of hemolyzed RBC in distal renal tubules |
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How is a Hemolytic reaction treated?
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Immediate D/C of transfusion
Maintain UOP via crystalloid, mannitol, lasix |
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Autologous blood
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(using your own blood)
Hgb must be > 11 g/dL Most patients can donate 10.5 ml/kg every 5-7 days (max 2-3 units) Last unit collected > 72 hrs before surgery -Oral iron supplements taken |
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Autologous blood
To be able to donate and use your own your Hgb must be? |
Hgb must be > 11 g/dL
you must take iron supplements |
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Autologous blood
How often can you donate and the max? (when must the last dose be collected prior to surgery? |
Most patients can donate 10.5 ml/kg every 5-7 days (max 2-3 units)
-Last unit collected > 72 hrs before surgery |
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Autologous blood (2nd slide)
(how is it used and risks) |
Cell saver, cell salvage
-Re-infused into the patient intraoperatively after RBCs -collected, washed, and delivered to a reservoir Contraindicated when infection or malignant tissue is within operative site Complications of cell saver and Autologous blood Dilutional coagulopathy Anticoagulation due to reinfusion of heparin Hemolysis Air embolism DIC |
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What are the Complications of using Autologous blood & a cell saver?
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Dilutional coagulopathy
Anticoagulation due to reinfusion of heparin Hemolysis Air embolism DIC |
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How does the cell saver and autolygous blood work?
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Re-infused into the patient intraoperatively after RBCs
-collected, washed, and delivered to a reservoir |
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What are the CONTRAINDICATON of using Autologous blood and the cell saver?
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when infection or
malignant tissue is within operative site |
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Normovolemic hemodilution
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Withdrawing a portion of patient’s blood early in operation
Re-expansion of blood volume with crystalloids to a Hct of 27-33% Then when blood loss occurs, less RBCs are lost per ml of blood Conclusion of surgery, patient’s previously drawn blood is reinfused -Practice is questionable |
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Why might Normovolemic hemodilution be beneficial?
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when blood loss occurs, less RBCs are lost per ml of blood
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How is Normovolemic hemodilution performed?
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-Withdrawing a portion of patient’s blood early in operation
-Re-expansion of blood volume with crystalloids to a Hct of 27-33% - returning this blood back to the patient after sugry (any blood loss during surgery, less RBC's are lost per ml of blood) |
