What is the recommended treatment to correct high K time on Thromboelastography (TEG)?

Correcting High K Time on Thromboelastography (TEG)

The most effective treatment to correct high K time on TEG is fibrinogen replacement, either with fibrinogen concentrate or cryoprecipitate, as this directly addresses the delayed clot formation kinetics indicated by prolonged K time. 1

Understanding K Time on TEG

• K time measures the time from clot initiation to reach a clot width of 20mm, representing clot kinetics or the speed of clot formation 2, 3
• Prolonged K time indicates delayed clot formation, which is often associated with fibrinogen deficiency or dysfunction 3
• K time correlates strongly with fibrinogen levels, with a significant inverse relationship (r = -0.84, P = .0001) demonstrated in clinical studies 2

First-Line Treatment: Fibrinogen Replacement

Fibrinogen Concentrate

• Administer fibrinogen concentrate as first choice at 4g for adults or 70 mg/kg for children under 12 years 1, 4
• Target a fibrinogen level of at least 1.5-2.0 g/L in bleeding patients, with higher targets (>2.0 g/L) recommended in obstetric hemorrhage 2, 1
• In vitro studies have shown that fibrinogen in a dose equivalent to 4 gm/70 kg adult improved clot strength at 50% hemodilution 5

Cryoprecipitate

• If fibrinogen concentrate is unavailable, administer cryoprecipitate (typically 2 pools) when functional fibrinogen TEG MA is <20 mm or FIBTEM CA5 is <10 mm 2
• Cryoprecipitate contains concentrated fibrinogen and can effectively correct high K time 1

Second-Line Treatment: Fresh Frozen Plasma (FFP)

• Consider FFP (10-15 mL/kg) if fibrinogen concentrate or cryoprecipitate is unavailable 1, 3
• For massive transfusion scenarios, maintain a 1:1:1 ratio of packed RBCs, FFP, and platelets 1
• FFP contains approximately 70% of normal levels of clotting factors, so larger volumes may be required 1

Platelet Contribution

• While fibrinogen is critical, platelets also contribute significantly to clot strength 6
• Consider platelet transfusion if TEG shows that platelet contribution to clot strength is reduced (rTEG MA – FF TEG MA <45 mm or EXTEM CA5 – FIBTEM CA5 <30 mm) 2
• Maintain platelet count >50,000/mm³ for patients with significant bleeding 1

Monitoring Response

• Repeat TEG 15-30 minutes after intervention to assess response 3
• Target normalization of K time and improvement in alpha angle 7
• Continue monitoring fibrinogen levels, as fibrinogen is often the first coagulation factor to reach critically low levels during major bleeding 1

Special Considerations

• In traumatic brain injury, prolonged K time and narrower alpha angle are associated with progressive hemorrhagic injury, suggesting that early correction may be particularly important in these patients 7
• In pregnancy, baseline TEG parameters reflect a hypercoagulable state with shorter K times; therefore, a "normal" K time may actually represent coagulopathy in this population 2, 3
• In liver disease, TEG may provide more valuable information than standard coagulation tests 2, 1

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 1
• Remember that TEG functional fibrinogen levels (FLEV) may overestimate fibrinogen compared to the Clauss method, potentially leading to undertreatment 2
• Do not delay treatment while waiting for laboratory results in cases of severe bleeding 1
• Recognize that anemia can paradoxically show hypercoagulable TEG results due to decreased blood viscosity, potentially masking coagulopathy 3