What are the targeted interventions for patients with significant coagulopathy based on Thromboelastography (TEG) interpretation?

Targeted Interventions for Coagulopathy Based on Thromboelastography (TEG) Interpretation

Thromboelastography (TEG) should guide specific blood component therapy and pharmacologic interventions based on the identified coagulation abnormality, with targeted treatments for each parameter abnormality to optimize outcomes in patients with significant coagulopathy. 1, 2

Understanding TEG Parameters and Their Clinical Significance

• R time (Reaction time) measures time to initial fibrin formation, with prolonged R time suggesting coagulation factor deficiency or anticoagulant effect, while shortened R time indicates hypercoagulability 2
• K time (Kinetics) represents the time from clot initiation to reach 20mm clot width, with prolonged K time indicating delayed clot formation 2
• Alpha angle indicates the rate of clot formation, with increased angle suggesting faster clot formation and decreased angle indicating slower clot formation 2
• Maximum Amplitude (MA) represents maximum strength of the clot, with decreased MA suggesting thrombocytopenia or platelet dysfunction 2
• LY30 measures the percentage of clot lysis 30 minutes after MA is reached, with increased LY30 (>7.5%) indicating hyperfibrinolysis 2

Targeted Interventions Based on TEG Parameters

For Prolonged R Time (Delayed Clot Initiation)

• Administer fresh frozen plasma (FFP) or prothrombin complex concentrate (PCC) to correct factor deficiencies 3, 2
• Target 4 units FFP when R time is prolonged (rTEG MA > 65 mm plus rTEG ACT > 120 s or EXTEM CA5 > 40 mm plus EXTEM CT > 80 s) 1
• For patients on anticoagulants, consider specific reversal agents based on the anticoagulant used 3

For Decreased Maximum Amplitude (Weak Clot Strength)

Fibrinogen Deficiency

• If functional fibrinogen TEG MA < 20 mm (FF TEG MA) or FIBTEM CA5 < 10 mm, administer 2 pools of cryoprecipitate (equivalent to 4g fibrinogen replacement) 1, 4
• Target fibrinogen levels of at least 1.5-2.0 g/L in bleeding patients 1, 4
• Fibrinogen concentrate (first choice) or cryoprecipitate should be used to restore fibrinogen levels, as fibrinogen is often the first coagulation factor to reach critically low levels during major bleeding 3, 4

Platelet Dysfunction/Deficiency

• If rTEG MA – FF TEG MA < 45 mm or EXTEM CA5 – FIBTEM CA5 < 30 mm, administer 1 pool of platelets 1
• Maintain platelet count >50,000/mm³ for patients with life-threatening hemorrhage, and consider higher platelet counts for patients requiring neurosurgery or with traumatic brain injury 3

For Hyperfibrinolysis

• If rTEG LY30 > 10% or EXTEM LI30 < 85%, administer additional 1g tranexamic acid 1, 5
• Note that TEG may be poorly sensitive to fibrinolysis in some cases, so integrate clinical assessment with laboratory findings 3

Goal-Directed Resuscitation Strategy

• Resuscitation measures should be continued using a goal-directed strategy, guided by standard laboratory coagulation values and/or viscoelastic monitoring (VEM) 1
• Goal-directed therapy using TEG parameters has been shown to improve survival and reduce blood product waste compared to conventional coagulation test-guided therapy 4, 6
• For initial coagulation support while awaiting viscoelastic tests, consider administering 2g fibrinogen based on clinical criteria at admission (systolic blood pressure < 100 mmHg, lactate ≥5 mmol/L, base excess ≤ -6 or hemoglobin ≤ 9 g/dL) 1

Special Considerations

Trauma Patients

• TEG-guided resuscitation in trauma patients has demonstrated lower mortality at 24 hours and 30 days compared to conventional testing 4, 7
• In the initial phase following trauma without brain injury, use a restricted volume replacement strategy with a target systolic blood pressure of 80-90 mmHg until major bleeding has been stopped 1
• For patients with severe traumatic brain injury (GCS ≤ 8), maintain a mean arterial pressure ≥ 80 mmHg 1

Obstetric Patients

• TEG correlates significantly with standard laboratory measures of coagulopathy in postpartum hemorrhage, including in patients with hypofibrinogenemia 8
• Pregnancy naturally induces a hypercoagulable state with increased MA values, which may not require correction unless extremely elevated 2

Pitfalls to Avoid

• Do not rely solely on conventional coagulation tests (PT, aPTT) as they may not correlate well with clinical bleeding or TEG parameters 3, 6
• Do not delay treatment while waiting for laboratory results in cases of severe bleeding 3
• Standard TEG is insensitive to antiplatelet agents and cannot reliably detect platelet dysfunction 2
• Results vary between devices and are not interchangeable between TEG and ROTEM systems 2, 9
• TEG is performed at 37°C and cannot assess effects of hypothermia on coagulation 2

Monitoring Response to Interventions

• Repeat TEG 15-30 minutes after intervention to assess response to treatment 3, 4
• Continue to monitor TEG parameters to guide ongoing treatment and optimize resuscitation 3