TEG 6s blood management in cardiac surgery requires more than transferring familiar thresholds from an older analyzer. A 2025 systematic literature review and expert opinion paper proposes a framework for treating intraoperative and immediate postoperative bleeding, while emphasizing that the specific algorithm still requires clinical validation.
Why a TEG 6s Blood Management Algorithm?
Bleeding after cardiopulmonary bypass can reflect several overlapping problems: residual heparin, reduced coagulation factor activity, inadequate fibrin contribution, platelet abnormalities, and fibrinolysis. Viscoelastic testing helps distinguish these patterns, providing a basis for targeted assessment rather than treating every abnormality with the same blood component.
Maxey-Jones and colleagues reviewed published TEG algorithms and combined the findings with structured expert discussion. Their goal was to develop a starting framework for adult cardiac surgical patients with significant intraoperative or immediately postoperative bleeding. The paper does not report a new randomized comparison testing the proposed algorithm.
What Evidence Supported the Proposal?
The literature search covered January 2009 through June 2024 in PubMed and EMBASE. Fourteen of 304 identified manuscripts met the inclusion criteria, with two additional articles suggested by the authors. The included publications covered differing designs, populations, testing schedules, and intervention thresholds.
Evidence specific to TEG 6s was limited. The review identified only one publication describing a dedicated TEG 6s algorithm, in a French study protocol, and two additional publications assessing TEG 6s assays. Most of the available experience involved TEG 5000. Consequently, the proposed framework draws on a mixture of published algorithms, assay reference ranges, and expert judgment.
Understanding the Assays
| Assay or measurement | Educational interpretation |
|---|---|
| Citrated kaolin reaction time | Characterizes clot initiation; prolongation must be interpreted with possible heparin effect and factor abnormalities. |
| Kaolin with heparinase | Helps distinguish the contribution of heparin when compared with the non-heparinase assay. |
| Citrated RapidTEG maximum amplitude | Reflects overall clot strength, including platelet and fibrin contributions. |
| Citrated functional fibrinogen maximum amplitude | Assesses the fibrin contribution to clot strength with the platelet contribution inhibited. |
| LY30 | Describes clot lysis 30 minutes after maximum amplitude; interpretation depends on the assay and clinical setting. |
How the Proposed Framework Organizes Bleeding Assessment
The authors organize their algorithm around residual heparin, coagulation factor deficiency, reduced platelet contribution, inadequate fibrin contribution, and hyperfibrinolysis. This approach encourages teams to interpret related measurements together. For example, low overall clot strength accompanied by preserved fibrin contribution suggests a different problem from low overall strength with impaired fibrin contribution.
One example illustrates the uncertainty around thresholds. The authors propose a functional fibrinogen maximum amplitude below 15 mm as a trigger within their framework, prioritizing specificity. They also discuss research suggesting a threshold nearer 20 mm, which favors sensitivity. These values are not interchangeable definitions of the same treatment decision, and the paper does not establish one universal threshold for every institution.
The review also discusses lower proposed cutoffs for recognizing fibrinolysis than those historically used in many TEG 5000 algorithms. Those proposals incorporate extrapolation and expert opinion. Readers should consult the unchanged original PDF for the complete algorithm, its doses, supporting references, and qualifying details.
Why TEG 5000 and TEG 6s Values Need Careful Comparison
Correlation between platforms does not establish that every intervention threshold can be carried across unchanged. The review describes studies showing good agreement in some settings, alongside evidence of greater discordance at abnormal values. One paired-sample cardiac surgery study suggested that using the older algorithm with TEG 6s could change treatment recommendations in at least 10% of patients.
This matters when a department adopts a new analyzer or cartridge. Local protocols need to account for the actual assay, specimen requirements, timing of collection, and the way results are interpreted. A familiar number on a different platform may not have precisely the same clinical meaning.
Cartridge Choice and Heparin Exposure
The paper distinguishes the standard citrated multichannel cartridge from a heparin-neutralization cartridge. In the standard cartridge discussed, the RapidTEG and functional fibrinogen channels do not neutralize heparin. The newer cartridge adds heparinase to those assays, expanding assessment during heparin exposure.
However, technical validation and established reference ranges are separate from proof that a treatment algorithm improves patient outcomes. The authors describe limited outcome evidence for the newer cartridge at the time of publication. Their discussion should be read in its 2025 context rather than as a statement about every subsequent product development.
Relevance for Perfusion Teams
For perfusionists, the review highlights communication across bypass separation, heparin reversal, sampling, and hemostatic assessment. Its practical educational value is the structured distinction between possible causes of bleeding and the importance of matching interpretation to the assay being used.
The proposed framework applies to bleeding adult cardiac surgical patients. It does not establish a screening transfusion protocol for patients without bleeding or validate the same thresholds for pediatric surgery or ECMO. PlateletMapping was outside the algorithm’s scope, and standard viscoelastic results do not capture every platelet, von Willebrand, or surgical bleeding problem.
For related IPA discussion of blood management, see femoral cannulation and transfusion in redo cardiac surgery.
Evidence Quality and Disclosures
The paper offers a useful synthesis and a framework for research alignment, but prospective validation of the complete proposed TEG 6s algorithm remains necessary. Mixed study designs, reliance on older technology, extrapolated intervention thresholds, and expert-derived recommendations limit certainty about patient outcomes.
Several authors were affiliated with Haemonetics, and the publication reports manufacturer-related financial support and competing interests. Those disclosures are relevant when assessing a device-specific proposal. IPA’s editorial evidence rating is 3 out of 5: clinically relevant educational synthesis with substantial uncertainty around the proposed protocol.
Original Article
Maxey-Jones C, Seelhammer TG, Arabia FA, et al. TEG® 6s–Guided Algorithm for Optimizing Patient Blood Management in Cardiovascular Surgery: Systematic Literature Review and Expert Opinion. Journal of Cardiothoracic and Vascular Anesthesia. 2025;39:1162–1172. doi:10.1053/j.jvca.2025.02.011.
This independently written IPA educational review summarizes the uploaded publication. The source is open access under a CC BY-NC-ND 4.0 license; the linked original PDF is unchanged. The cover is an AI-generated editorial illustration, not a product photograph.
