chapter 49. quiz 3- Blood Component Therapy: Indications for Transfusion
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Questions and Answers

What is the basic philosophy behind blood component therapy?

  • Treating patients with a mixture of plasma and components
  • Providing patients with the specific fraction of blood they lack (correct)
  • Administering whole blood to patients for maximum effect
  • Using crystalloid solutions exclusively for transfusions

    • Why is lactated Ringer solution not recommended as a diluent or carrier for PRBCs?

  • Because it lacks essential nutrients for RBCs
  • Because it causes RBCs to swell and lyse
  • Because it makes the RBCs shrink
  • Because it contains Ca2+ which can cause clotting (correct)

    • What is the approximate Hct value of PRBCs?

  • 40%
  • 50%
  • 60% (correct)
  • 30%

    • How does using hypotonic solutions as diluents affect RBCs?

    <p>RBCs will swell and eventually burst</p> Signup and view all the answers

    Which component of blood is conserved by using PRBCs rather than whole blood?

    <p>Plasma</p> Signup and view all the answers

    What is the purpose of utilizing crystalloid or colloid as a carrier for PRBCs?

    <p>To facilitate the administration of PRBCs</p> Signup and view all the answers

    What is the recommended solution compatible with packed erythrocytes that has a pH of 7.4?

    <p>Normosol-R with</p> Signup and view all the answers

    What is the primary reason for administering RBC transfusions?

    <p>To increase O2-carrying capacity</p> Signup and view all the answers

    Why is increasing intravascular volume alone not an indication for blood transfusion?

    <p>It can be achieved through crystalloid administration</p> Signup and view all the answers

    What should prompt transfusion therapy besides the patient's Hb value?

    <p>Overall patient status</p> Signup and view all the answers

    What does the Hb value primarily serve as in defining transfusion strategies?

    <p>Primary criterion</p> Signup and view all the answers

    What can be created by using crystalloids or colloids to treat hypovolemia?

    <p><strong>Normovolemic dilutional anemia</strong></p> Signup and view all the answers

    At what Hb level did inadequate splanchnic and preportal oxygen delivery and consumption occur in a study by Mathru and colleagues?

    <p>$5.9$ g/dL</p> Signup and view all the answers

    In which patients did a 1988 NIH Consensus Conference conclude that perioperative blood transfusions are rarely needed?

    <p><strong>Patients with Hb value over $10$ g/dL</strong></p> Signup and view all the answers

    What is a key consideration for determining when a patient should benefit from a blood transfusion?

    <p>**No specific measure **</p> Signup and view all the answers

    What does the O2 extraction ratio require for prediction of benefits from blood transfusions?

    <p>Invasive monitoring</p> Signup and view all the answers

    patients with chronic anemia (as in renal failure) might tolerate an Hb concentration of

    <p>less than 6 to 7 g/dL</p> Signup and view all the answers

    What is the recommended solution compatible with packed erythrocytes ?

    <p>5% dextrose in 0.45% saline</p> Signup and view all the answers

    What is the recommended solution compatible with packed erythrocytes ?

    <p>5% dextrose in 0.9% saline</p> Signup and view all the answers

    why 5% Dextrose in 0.2% saline is not recommended solution compatible with packed erythrocytes ?

    <p>cause hemolysis at 37 temperature</p> Signup and view all the answers

    which solution cause the most hemolysis at 37 temperature

    <p>5% Dextrose in water</p> Signup and view all the answers

    American College of Surgeons Classes of Acute Hemorrhage- class I defined by

    <p>Blood loss-750mL,</p> Signup and view all the answers

    Metabolic Characteristics of Packed Red Blood Cells, what is the pH value ?

    <p>6.79</p> Signup and view all the answers

    Metabolic Characteristics of Packed Red Blood Cells, what is the pCO2 value ?

    <p>79</p> Signup and view all the answers

    What approach is typically used to measure blood loss when assessing the need for blood transfusions?

    <p>Combination of visualization and gravimetric measurements</p> Signup and view all the answers

    In what way did anesthesiologists tend to misjudge blood loss according to a study in patients undergoing spine surgery?

    <p>Overestimated by as much as 40%</p> Signup and view all the answers

    Why did optical scanners tend to underestimate blood loss compared to standard gravimetric calculations?

    <p>Due to variations in measurement accuracy</p> Signup and view all the answers

    What is a key consideration needed to determine whether subsequent units of blood are necessary after the initial transfusion?

    <p>Measurement of vital signs and blood loss</p> Signup and view all the answers

    Why is there no universally accepted standard for quantifying blood loss?

    <p>Variability in measurement accuracy</p> Signup and view all the answers

    What is an important component related to intraoperative transfusion medicine?

    <p>Predicting surgical blood loss</p> Signup and view all the answers

    What is a limitation of intermittent measurements of Hb levels during blood loss?

    <p>Fluid shifts and intravenous volume infusions</p> Signup and view all the answers

    How does the accuracy of SpHb (spectrophotometric finger technology) relate to patients with moderately to severely low Hb levels?

    <p>It decreases</p> Signup and view all the answers

    Which factor can help assess the accuracy of the SpHb value provided by the monitor?

    <p>Perfusion index (PI) greater than 4% to 5%</p> Signup and view all the answers

    How does a bupivacaine digital nerve block impact the accuracy of SpHb values?

    <p>Decreases inaccurate values</p> Signup and view all the answers

    What is an important feature that can improve the accuracy of SpHb measurements?

    <p>Perfusion index (PI) greater than 4% to 5%</p> Signup and view all the answers

    In what situation would SpHb monitoring perform worse according to the text?

    <p>Patients with moderately to severely low Hb levels</p> Signup and view all the answers

    What is the recommended method for clinicians to detect a changing Hb level ?

    <p>Observation of the trend</p> Signup and view all the answers

    According to Giraud and colleagues, what was the main advantage of SpHb monitoring?

    <p>Less invasiveness but continuous data provision</p> Signup and view all the answers

    What factor should prompt clinicians to explore the reasons behind sudden changes in SpHb value, even if the absolute value is satisfactory?

    <p>Decrease in SpHb reading from 11 g/dL to 9.5 g/dL</p> Signup and view all the answers

    Which point-of-care Hb test is mentioned as providing quick and efficient bedside Hb level determination in less than 5 minutes?

    <p>HemoCue</p> Signup and view all the answers

    What is the primary advantage of using warming of the finger in terms of SpHb monitoring accuracy?

    <p>Improve PI and thereby SpHb accuracy</p> Signup and view all the answers

    Preoperative anemia (i.e., low Hb value in women <12 g/ dL; in men <13 g/dL) is a common comorbidity among patients undergoing major surgery with an incidence of

    <p>40%</p> Signup and view all the answers

    Preoperative anemia is an independent risk factor that can increase

    <p>postoperative acute kidney injury</p> Signup and view all the answers

    when the Hb value should be obtained In patients with a moderate to high risk of significant blood loss (defined as >500 mL)

    <p>3 to 8 weeks prior to surgery</p> Signup and view all the answers

    what is the goal of treating anemia preoperatively

    <p>decrease the need for intraoperative transfusions</p> Signup and view all the answers

    Erythropoiesis-stimulating agents (ESAs)

    <p>Stimulate BM</p> Signup and view all the answers

    What Hb value range is considered for a restrictive transfusion strategy?

    <p>7-8 g/dL</p> Signup and view all the answers

    In a liberal transfusion strategy, at what Hb value is blood transfusion typically administered?

    <p>9-10 g/dL</p> Signup and view all the answers

    What did Ely and Bernard confirm regarding transfusion triggers?

    <p>better outcomes have not consistently occurred</p> Signup and view all the answers

    What is a potential advantage of using a restrictive transfusion strategy?

    <p>Fewer transfusion reactions</p> Signup and view all the answers

    What conclusion arises from studies comparing liberal and restrictive transfusion strategies?

    <p>No consistent benefit to liberal strategy</p> Signup and view all the answers

    What is the primary concern highlighted with a one-value transfusion strategy?

    <p>The lack of consideration for patient comorbidities</p> Signup and view all the answers

    Why might a one-size-fits-all approach to transfusion decision-making be insufficient?

    <p>It lacks specific indications for subsequent blood units</p> Signup and view all the answers

    What does the American College of Surgeons propose as a basis for transfusion decisions?

    <p>overall condition of the patient</p> Signup and view all the answers

    What is the main limitation highlighted in the liberal versus restrictive strategy associated with Patient Blood Management (PBM)?

    <p>Failure to address indications for repeat transfusions</p> Signup and view all the answers

    What is one of the important conclusions made about Hb levels and transfusion decisions?

    <p>Variability exists in the need for increased O2-carrying capacity</p> Signup and view all the answers

    What is a caution highlighted regarding using Hb levels for transfusion decisions?

    <p>Patients may have different requirements for O2 delivery</p> Signup and view all the answers

    ASA’s 2015 updated practice guidelines recommendations?

    <p>Transfusion is almost always indicated when it is less than 6 g/dL</p> Signup and view all the answers

    Study Notes

    Blood Transfusions

    • Recommended solutions compatible with packed erythrocytes: 5% dextrose in 0.45% saline, 5% dextrose in 0.9% saline, 0.9% saline, and Normosol-R with a pH of 7.4.
    • RBC transfusions are given to increase O2-carrying capacity, not to increase intravascular volume.

    Indications for Transfusion

    • A sole Hb value should not be the only basis for a transfusion decision.
    • Consider the overall status of the patient, including hemodynamics, organ perfusion, and oxygen delivery.
    • Goals for transfusion in hemorrhaging patients: restore and maintain intravascular volume, cardiac output, and organ perfusion.

    Hemoglobin Values

    • 1988 National Institutes of Health (NIH) Consensus Conference: healthy patients with Hb > 10 g/dL rarely require perioperative blood transfusions, while patients with acute anemia with Hb < 7 g/dL frequently require blood transfusions.
    • Patients with chronic anemia (e.g., renal failure) may tolerate Hb < 6 to 7 g/dL.

    Blood Component Therapy

    • PRBCs contain the same amount of Hb as whole blood but with less plasma.
    • Hct value of PRBCs is approximately 60%.
    • Most indications for RBCs can be effectively treated with PRBCs, conserving plasma and components for other patients.

    Determination of Hemoglobin Concentration

    • Continuous blood Hb monitoring is available using spectrophotometric finger technology (Masimo SpHb).
    • SpHb measurements are relatively accurate, but may be inaccurate in patients with moderately to severely low Hb levels or during active resuscitation.
    • Accuracy can be improved with a perfusion index (PI) > 4% to 5%.

    Additional Blood Transfusions

    • To determine whether subsequent units of blood are indicated, reassess the overall condition of the patient and the clinical situation.
    • Consider vital signs, blood loss, intravenous fluids, Hb concentration, and surgical concerns.

    Measurement of Blood Loss

    • A standard approach includes visualization and gravimetric measurements based on weight differences between dry and blood-soaked gauze pads.
    • Accuracy of measurements is not uniformly consistent, and no "gold standard" for blood loss quantification exists.

    Liberal Versus Restrictive Transfusion Strategy

    • Terminology refers to the Hb value when a transfusion decision is made.
    • Restrictive policy: administer blood transfusion when Hb value is 7-8 g/dL or less.
    • Liberal policy: administer blood transfusion when Hb value is 9-10 g/dL or greater.
    • Recent studies show no benefit to a liberal strategy compared to a restrictive strategy.

    General Conclusions

    • Emphasis on Hb levels for transfusion decisions needs caution.
    • Individual patient's Hb level may vary perioperatively independent of and in addition to transfusions of RBCs.
    • Development of more sensitive indicators of tissue oxygenation (e.g., intramucosal pH) may provide indicators for transfusion in the future.

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    Description

    Explore the concept of blood component therapy and the indications for transfusion in medical treatments. Understand the philosophy of administering specific blood fractions for optimal patient care. Learn about the challenges faced by surgical teams in balancing the need for whole blood with the benefits of blood component therapy.

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