What Does ROTEM Stand For?
ROTEM stands for Rotational Thromboelastometry, a point-of-care viscoelastic testing device that assesses whole blood coagulation from initial clot formation through clot propagation, stabilization, and final dissolution 1.
Technical Overview
ROTEM is one of two commercially available semi-automated viscoelastic machines that use similar technology, the other being TEG (thromboelastography) 1.
The device works by placing a whole blood sample (300 µl) in a stationary cup with an oscillating pin that senses changes in blood as it progresses through various stages of clot formation and breakdown 1, 2.
ROTEM transduces changes in the viscoelastic strength of clotting blood to which a constant rotational force is applied, generating both graphical and numerical output 3, 2.
Clinical Applications
ROTEM provides real-time assessment of hemostasis at the patient's bedside, measuring coagulation from initial clot formation through clot propagation and stabilization to final clot dissolution (fibrinolysis) 1.
The device has been shown to be effective in reducing bleeding, transfusion requirements, complication rates, and healthcare costs when used with evidence-based algorithms 4.
ROTEM-guided transfusion therapy has demonstrated improved patient safety and outcomes including perioperative morbidity and mortality in several randomized controlled trials and meta-analyses 4.
Specific Testing Modalities
INTEM evaluates the intrinsic coagulation pathway using ellagic acid activation 5.
EXTEM assesses the extrinsic pathway through tissue factor activation 5.
FIBTEM isolates fibrinogen's contribution to clot formation by inhibiting platelets with cytochalasin D 5.
APTEM specifically evaluates the fibrinolytic pathway using aprotinin (a fibrinolysis inhibitor) 5.
HEPTEM detects heparin effects on coagulation using heparinase 5.
Key Parameters Measured
Clotting Time (CT) reflects the time required for initial fibrin formation and corresponds to the intrinsic or extrinsic coagulation pathways 5.
Clot Formation Time (CFT) and alpha angle represent the speed at which the clot develops and strengthens 5.
Maximum Clot Firmness (MCF) reflects the combined contributions of platelets and fibrinogen to overall clot stability 5.
Clot lysis parameters (CL30, CL60, or maximum lysis) indicate the breakdown of the clot over time 5.
Important Limitations
ROTEM cannot assess the contribution of endothelium to coagulation, so it cannot detect von Willebrand disease or disorders affecting endothelial adherence 5.
The test is performed at 37°C and cannot assess the effects of hypothermia on coagulation 5.
Results show variability between devices and are not interchangeable between ROTEM and TEG systems 5.
There are concerns about standardization of both assays with poor quality control and assurance and wide variation in results between centers 1.
Limited interchangeability between TEG and ROTEM requires development and validation of separate treatment algorithms for the two devices 1.
Clinical Evidence
In patients with cirrhosis undergoing invasive procedures, ROTEM-guided transfusion policies have been shown to decrease prophylactic blood product transfusions, though studies have been unable to demonstrate association between viscoelastic test alterations and bleeding events due to paucity of bleeding events 1.
ROTEM may be used to guide transfusion therapy for postpartum hemorrhage, though only two randomized controlled trials on TEG/ROTEM use in obstetrics existed as of 2020 1.
In trauma patients, the integrated ROTEM model (INR >1.2 with EXTEM A5 ≤35 mm and/or EXTEM LI30 <97%) increased detection of acute traumatic coagulopathy by 15% and those requiring massive transfusion by 22% compared to INR alone 6.