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The Role of Point of Care Testing in Optimal Patient Blood Management

The Role of Point of Care Testing in Optimal Patient Blood Management. Paula J. Santrach MD Associate Professor of Laboratory Medicine & Pathology Mayo Clinic Rochester, MN SABM Annual Meeting September 21, 2012. Disclosures.

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The Role of Point of Care Testing in Optimal Patient Blood Management

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  1. The Role of Point of Care Testing in Optimal Patient Blood Management Paula J. Santrach MD Associate Professor of Laboratory Medicine & Pathology Mayo Clinic Rochester, MN SABM Annual Meeting September 21, 2012

  2. Disclosures • Employee of Mayo Clinic and member of the Department of Laboratory Medicine & Pathology • Mayo Medical Laboratories is a business of the Mayo Clinic • Off label uses: none

  3. Point of Care Testing • The analysis of clinical specimens as close as possible to the patient (TheFreeDictionary) • Medical testing at or near the site of patient care (Wikipedia) • Testing performed outside of a traditional centralized laboratory (National Center for Competency Testing) • There is a wide spectrum of application in a variety of clinical settings

  4. Point of Care Testing • The Good • Rapid turnaround time • Easy to use in general • Accessible • The Not So Good • Comparability to laboratory methods • Cost • Oversight issues • True clinical utility depends on • Facilitation of clinical workflow • Facilitation of clinical decision-making • Improved patient outcomes • It is not something you should do just because you can

  5. Key Preoperative Questions That May Utilize Point of Care Laboratory Data • Is this patient at a higher risk of bleeding? • Patient history is the most important • History of bleeding: spontaneous, procedure-related, birth-related • Type, need for transfusion • Concomitant medical illnesses • Concomitant medications • Anticoagulation, anti-platelet therapy, others • Procedural issues • Extracorporeal circulation, reoperation, others • Evaluation of patients with a history suggestive of a bleeding disorder will need further laboratory workup

  6. Key Preoperative Questions That May Utilize Point of Care Laboratory Data • What about the patient on anti-platelet therapy? • Balancing act • Need for surgery • 10-15% of patients presenting with acute coronary syndromes have to undergo CABG and 5-25% have to undergo non-cardiac surgery during the first five years after percutaneous coronary intervention • Risk of bleeding during surgery • Pretty clear for cardiac surgery • Literature more mixed for non-cardiac surgery Gruber et al. ThrombHaemost 106:248, 2011

  7. Key Preoperative Questions That May Utilize Point of Care Laboratory Data • Balancing act (cont) • Risk of interruption of anti-platelet therapy • Very important issue for patients with stents • Preoperative discontinuation is associated with ~20% incidence of ischemic events • Preoperative continuation is associated with ~35% incidence of bleeding • Would preoperative platelet function testing be useful? • Anecdotal reports of using <50% platelet inhibition as decision point Gruber et al. ThrombHaemost 106:248, 2011

  8. POC Platelet Function Tests for Anti-Platelet Therapy

  9. Comparison of 6 Platelet Function Tests to Determine Prevalence of Aspirin Resistance in Patients with Stable Coronary Artery Disease 201 patients on daily ASA European Heart J 28:1702, 2007

  10. Comparison of 4 Tests to Assess Inhibition of Platelet Function by Clopidogrel in Stable Coronary Artery Disease Patients 116 patients in clopidogrel dosing trial > 50% resistance found by all assays except WBA (47%) poor correlation between tests European Heart J 29:2877, 2008

  11. TARGET-CABG Study • Timing Based on Platelet Function Strategy to Reduce Clopidogrel-Associated Bleeding Related to CABG • Single center, nonrandomized, unblinded observational study • 180 patients, elective first-time isolated on-pump CABG, on aspirin with or without clopidogrel • Waiting time for surgery based on platelet function tests (MAADP from TEG Platelet Mapping System) • Primary endpoint: 24 hr chest tube drainage Mahla et al. CircCardiovascInterv 5:261, 2012

  12. TARGET-CABG Study Mahla et al. CircCardiovascInterv 5:261, 2012

  13. TARGET-CABG Study Mahla et al. CircCardiovascInterv 5:261, 2012

  14. TARGET-CABG Study – Outcomes Mahla et al. CircCardiovascInterv 5:261, 2012

  15. TARGET-CABG Study - Outcomes Mahla et al. CircCardiovascInterv 5:261, 2012

  16. TARGET-CABG Study - Outcomes • Mean total amount of RBCs transfused: no difference • Median length of hospital stay: clopidogrel significantly longer, due to inpatient clopidogrel withdrawal • Duration of intubation: no difference • Length of ICU stay: no difference • Re-thoracotomy rates: no difference • 30 day mortality & 30 day readmissions: no difference • 46% reduction in waiting time to surgery without increasing bleeding Mahla et al. CircCardiovascInterv 5:261, 2012

  17. Key Preoperative Questions That May Utilize Point of Care Laboratory Data • Is this patient anemic? • Point of care testing can have a role in screening • Testing method makes a difference • Electrical conductivity for hematocrit • Significant hemodilution leads to inaccurate results • Spectrophotometry for hemoglobin • Particle counting for hematocrit • Cell packing/centrifugation for hematocrit • Methods vary so be consistent • Diagnosis of the underlying problem requires more advanced data not available through POCT

  18. Key Intraoperative Processes That May Utilize Point of Care Laboratory Data • Acute normovolemichemodilution • Hemoglobin or hematocrit testing can guide the collection of the appropriate number of whole blood units • Procedural anticoagulation with heparin • Activated clotting time or heparin concentration • Use of these approaches in various subpopulations may make a difference in the likelihood of bleeding and need for transfusion • Procedural anticoagulation with other agents • Monitoring strategy is unclear

  19. Perioperative Transfusion DecisionsWhere the Money is (Literally & Figuratively) • Point of care or other rapid form of testing can significantly influence transfusion decisions • Liver transplantation • Cardiac surgery • Trauma • Building the transfusion algorithms • What abnormalities need to be detected? • What devices will be used for detection? • What are the decision points for transfusion? • What products should be transfused? How many?

  20. Transfusion AlgorithmsCardiac Surgery as an Example • Microvascular bleeding after cardiopulmonary bypass • Coagulation factor deficiency • Hypofibrinogenemia among others • Thrombocytopenia • Platelet dysfunction • Fibrinolysis • Persistent heparinization

  21. Point of Care Tests for Post-CPB Bleeding

  22. Thromboelastography

  23. Thromboelastography

  24. Transfusion Triggers for POCT • Options • Reference range • Multiples of the upper limit of the reference range • Decision points provided by device manufacturer • Decision points from published studies • Do your own study • Context: patient population of practice

  25. Transfusion Triggers for POCT Nuttall, et al. J Cardiothorac Vasc Anesth 9:355, 1995

  26. Transfusion Triggers for POCT Nuttall, et al. J Cardiothorac Vasc Anesth 9:355, 1995

  27. POCT Algorithm Outcome Studies

  28. Operating Room Transfusion Algorithm Excessive microvascular bleeding in surgical field Order coagulationand platelet tests PT >16.6(1.6)sec aPPT >57 sec and/or and/or PLT <102K/mm3 TEG MA<48 mm Fibrinogen<140 mg/dL ACT >Baseline Allnormal Platelettransfusion Fresh frozen plasmatransfusion Cryoprecipitatetransfusion Protamine Surgicalre-explorationof chest Nuttall, Oliver & Ereth: Anesthesiology 94: 773, 2001

  29. Clinical Use of Transfusion Algorithm Nuttall, et al. Anesthesiology 94:773, 2001

  30. ICU Transfusion Algorithm Chest tube output <150cc/hr (<2cc/kg/hr) Excessive microvascular bleeding in surgical field AddPEEP OR Do nothing – observe Coagulation and platelet tests ordered PT >12.6(1.2)sec aPPT >45 sec and/or and/or PLT <140K/mm3 TEG MA<55 mm Fibrinogen<200 mg/dL ACT >Baseline Allnormal Platelettransfusion Fresh frozen plasmatransfusion Cryoprecipitatetransfusion Protamine Surgicalre-explorationof chest Nuttall, Ereth, & Oliver, Transfusion, Oct 2010

  31. TEG-Based Transfusion Algorithm Royston et al: Br J Anaesth 86:575, 2001

  32. TEG-Based Transfusion AlgorithmEffectiveness Royston et al: Br J Anaesth 86:575, 2001

  33. Capraro Transfusion Algorithm Hemoglobin <9.0 g/dL 1 U RBC Platelets <100 x 109 1U platelets/10 kg – round up to nearest 4 U WB APTT or PT 1.5 x normal value 10 mL/kg FFP – in whole units ACT >10 sec longer than preop ACT Protamine 0.5 mg/kg Bleeding time >12 min DDAVP 0.3 ug/kg Normal values in all previous tests Tranexamic acid 10 mg/kg IV Acta Anaesthesiol Scand 45:200, 2001

  34. Capraro Transfusion AlgorithmEffectiveness ActaAnaesthesiolScand 45:200, 2001

  35. Capraro Transfusion AlgorithmEffectiveness • Caveats • Imbalance in groups • More combined operations in algorithm group • Already very conservative in transfusion decisions • Re-exploration rate >20% in both groups • Testing done in first hour postoperatively • What about immediate post-pump time frame? Acta Anaesthesiol Scand 45:200, 2001

  36. Point of Care vs Conventional Lab Testing in Coagulopathic Cardiac Surgery Patients • Randomized controlled trial of 100 patients • Elective complex cardiothoracic surgery with cardiopulmonary bypass (high risk patients) • Enrolled after heparin reversal if at least one of these criteria met: • Diffuse bleeding from capillary beds at wound surfaces • Blood loss exceeding 250 mL/hr or 50 mL/10 min intraoperatively or in first 24 hours postoperatively • Conventional coagulation tests • Point of care tests • ROTEM (viscoelastography) • Multiplate (platelet aggregometry) Weber et al. Anesthesiology 117:531, 2012

  37. Point of Care vs Conventional Lab Testing in Coagulopathic Cardiac Surgery Patients Weber et al. Anesthesiology 117:531, 2012

  38. Weber et al. Anesthesiology 117:531, 2012

  39. Postoperative algorithm nearly identical Excessive bleeding: >250 mL/hr or >50 mL/10 min Weber et al. Anesthesiology 117:531, 2012

  40. Point of Care vs Conventional Lab Testing in Coagulopathic Cardiac Surgery Patients • Results • Trial stopped at interim analysis • Patient enrollment • Conventional: 45 in OR, 5 in ICU • Point of care: 43 in OR, 7 ICU • Conventional test results did not significantly differ between 2 groups at preop and at 24 hours after ICU admission • At ICU admission, POC group at significantly lower fibrinogen and lactate results Weber et al. Anesthesiology 117:531, 2012

  41. Point of Care vs Conventional Lab Testing in Coagulopathic Cardiac Surgery Patients Median (25th : 75th percentile) Weber et al. Anesthesiology 117:531, 2012

  42. Point of Care vs Conventional Lab Testing in Coagulopathic Cardiac Surgery Patients Median (25th : 75th percentile) Weber et al. Anesthesiology 117:531, 2012

  43. POC vs Conventional Lab TestingOutcomes Weber et al. Anesthesiology 117:531, 2012

  44. POC vs Conventional Lab TestingOutcomes Weber et al. Anesthesiology 117:531, 2012

  45. Weber et al. Anesthesiology 117:531, 2012

  46. Transfusion Algorithms in Other Clinical Situations • Liver transplantation • Trauma • Massive transfusion

  47. Rapid Thromboelastography & Massive Transfusion in Post-Injury Coagulopathy • Retrospective study before and after rapid thromboelastography (rTEG) implementation • 68 consecutive trauma patients, 34 before & 34 after, who received 6 or more units of blood in the fist 6 hours • rTEG ordered by anesthesiologist or surgeon • Algorithm in place, but decisions based primarily on response to treatment rather than strict adherence to algorithm Kashuk et al. Transfusion 52:23, 2012

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