Anesthesiology updates: hypothermia and transfusion guidelines. #anesthesiology #transfusion #medicine

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From time to time, I enjoy looking through the literature for updates in anesthesiology.  Not only is this important for CME, but it’s also crucial in keeping the clinician up-to-date on today’s practice guidelines.  Here are some basic articles I perused and the key points noted.

Bleeding and the New Anticoagulants: Strategies and Concerns

Perioperative Temperature Management: Time for a New Standard of Care?

Core temperature trajectories in 58,814 patients undergoing noncardiac surgery. From Sun et al.,2 figure 3

Keypoints:

  • PCCs are the principal therapeutic agent for non-vitamin K antagonist oral anticoagulants (NOAC) such as dabigatran (direct thrombin inhibitor) and rivaroxaban, apixaban, and edoxaban (anti-Xa agents).  Clinical studies are underway.
  • Preoperative and intraoperative forced air warming improves core body temperature.  Longer duration of intraoperative hypothermia is associated with higher transfusion requirement and increased length of hospital stay.    Better studies needed to define normothermia, develop tools to measure temperature, and improved clinical study methodology.
  • Guidelines for blood transfusion (2012 ASA Guidelines):
    • Review previous medical records and interview the patient or family to identify:
      • Previous blood transfusion
      • History of drug-induced coagulopathy (e.g., warfarin, clopidogrel, aspirin and other anticoagulants, as well as vitamins or herbal supplements that may affect coagulation [appendix 3])
      • Presence of congenital coagulopathy
      • History of thrombotic events (e.g., deep vein thrombosis, pulmonary embolism)
      • Risk factors for organ ischemia (e.g., cardiorespiratory disease) which may influence the ultimate transfusion trigger for red blood cells (e.g., hemoglobin level)
    • Inform patients of the potential risks versus benefits of blood transfusion and elicit their preferences.
    • Review available laboratory test results including hemoglobin, hematocrit, and coagulation profiles.
    • Order additional laboratory tests depending on a patient’s medical condition (e.g., coagulopathy, anemia).
    • Conduct a physical examination of the patient (e.g., ecchymosis, petechiae, pallor).

If possible, perform the preoperative evaluation well enough in advance (e.g., several days to weeks) to allow for proper patient preparation.

    • Recommendations for Preadmission Patient Preparation
  • Administer iron to patients with iron deficiency anemia if time permits.

  • In consultation with an appropriate specialist, discontinue anticoagulation therapy (e.g., warfarin, anti-Xa drugs, antithrombin agents) for elective surgery.

    • Transition to a shorter acting drug (e.g., heparin, low-molecular-weight heparin) may be appropriate in selected patients.

    • If clinically possible, discontinue nonaspirin antiplatelet agents (e.g., thienopyridines such as clopidogrel, ticagrelor, or prasugrel) for a sufficient time in advance of surgery, except for patients with a history of percutaneous coronary interventions.§§

    • Aspirin may be continued on a case-by-case basis.

    • The risk of thrombosis versus the risk of increased bleeding should be considered when altering anticoagulation status.

    • Assure that blood and blood components are available for patients when significant blood loss or transfusion is expected.

    • When autologous blood is preferred, the patient may be offered the opportunity to donate blood before admission only if there is adequate time for erythropoietic reconstitution.

    • Erythropoietin with or without iron may be administered when possible to reduce the need for allogeneic blood in selected patient populations (e.g., renal insufficiency, anemia of chronic disease, refusal of transfusion).

      Recommendations for Preprocedure Preparation Blood Management Protocols.
      • Multimodal protocols or algorithms may be employed as strategies to reduce the usage of blood products. However, no single algorithm or protocol can be recommended at this time.

      • A restrictive red blood cell transfusion strategy may be safely used to reduce transfusion administration.***

        • The determination of whether hemoglobin concentrations between 6 and 10 g/dl justify or require red blood cell transfusion should be based on potential or actual ongoing bleeding (rate and magnitude), intravascular volume status, signs of organ ischemia, and adequacy of cardiopulmonary reserve.

        • Red blood cells should be administered unit-by-unit, when possible, with interval reevaluation.

      • A protocol for avoidance of transfusion may be used as a strategy to reduce blood loss for patients in whom transfusion is refused or is not possible.

      • A massive (i.e., hemorrhagic) transfusion protocol may be used when available as a strategy to optimize the delivery of blood products to massively bleeding patients.

      • Use a maximal surgical blood order schedule, when available and in accordance with your institutional policy, as a strategy to improve the efficiency of blood ordering practices.

      Reversal of Anticoagulants.
      • For urgent reversal of warfarin, administer PCCs in consultation with the appropriate specialist, or administer FFP.

      • Administer vitamin K for selected patients for nonurgent reversal of warfarin, except when rapid restoration of anticoagulation after surgery is required.

      Antifibrinolytics for Prophylaxis of Excessive Blood Loss.
      • Use antifibrinolytic therapy for prophylaxis of the use of allogeneic blood transfusion in patients undergoing cardiopulmonary bypass.

        • Consider using antifibrinolytic therapy for prophylaxis in certain orthopedic procedures such as knee replacement surgery.

        • Consider using antifibrinolytic therapy for prophylaxis in liver surgery and other clinical circumstances at high risk for excessive bleeding.†††

      Acute Normovolemic Hemodilution (ANH).
      • Consider ANH to reduce allogeneic blood transfusion in patients at high risk for excessive bleeding (e.g., major cardiac, orthopedic, thoracic, or liver surgery), if possible.‡‡‡

      Recommendations for Intraoperative and Postoperative Management of Blood Loss Allogeneic Red Blood Cell Transfusion.
      • Administer blood without consideration of duration of storage.

      • Leukocyte-reduced blood may be used for transfusion for the purpose of reducing complications associated with allogeneic blood transfusion.

      Reinfusion of Recovered Red Blood Cells.
      • Reinfuse recovered red blood cells as a blood-sparing intervention in the intraoperative period, when appropriate.

      Intraoperative and Postoperative Patient Monitoring.
      • Periodically conduct a visual assessment of the surgical field jointly with the surgeon to assess the presence of excessive microvascular (i.e., coagulopathy) or surgical bleeding.

      • Use standard methods for quantitative measurement of blood loss, including checking suction canisters, surgical sponges, and surgical drains.

      • Monitor for perfusion of vital organs using standard ASA monitors (i.e., blood pressure, heart rate, oxygen saturation, electrocardiography) in addition to observing clinical symptoms and physical exam features.‖‖‖

        • Additional monitoring may include echocardiography, renal monitoring (urine output), cerebral monitoring (i.e., cerebral oximetry and NIRS), analysis of arterial blood gasses, and mixed venous oxygen saturation.

      • If anemia is suspected, monitor hemoglobin/hematocrit values based on estimated blood loss and clinical signs.

      • If coagulopathy is suspected, obtain standard coagulation tests (e.g., INR, aPTT, fibrinogen concentration) or viscoelastic assays (e.g., TEG and ROTEM), if available, as well as platelet count.

      • During and after transfusion, periodically check for signs of a transfusion reaction including hyperthermia, hemoglobinuria, microvascular bleeding, hypoxemia, respiratory distress, increased peak airway pressure, urticaria, hypotension, and signs of hypocalcemia.

        • If signs of a transfusion reaction are apparent, immediately stop the transfusion, give supportive therapy, and initiate supportive care.

        • Notify the blood bank of the transfusion reaction case.

      Treatment of Excessive Bleeding.
      • In patients with excessive bleeding, the following recommendations are made based upon the evidence for each of these interventions when studied singly or when compared with placebo. The impact of combinations of these interventions is not addressed in these Guidelines.

        • Obtain a platelet count before transfusion of platelets, if possible (see table 1 for suggested transfusion criteria for platelets).###  In addition, obtain a test of platelet function, if available, in patients with suspected or drug-induced (e.g., clopidogrel) platelet dysfunction.

        • Obtain coagulation tests (i.e., PT or INR and aPTT) before transfusion of FFP, if possible (see table 1 for suggested transfusion criteria for FFP).****

        • Assess fibrinogen levels before the administration of cryoprecipitate, if possible (see table 1 for suggested transfusion criteria for cryoprecipitate).

        • Desmopressin may be used in patients with excessive bleeding and platelet dysfunction.

        • Consider topical hemostatics such as fibrin glue or thrombin gel.

        • Consider the use of antifibrinolytics (i.e., ε-aminocaproic acid, tranexamic acid) if fibrinolysis is documented or suspected and if these agents are not already being used.

        • PCCs may be used in patients with excessive bleeding and increased INR.

        • Consider recombinant activated factor VII when traditional options for treating excessive bleeding due to coagulopathy have been exhausted.††††

        • Fibrinogen concentrate may be used.

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