A standardized technique for performing thromboelastography in rodents

Abstract

Thromboelastography (TEG), used in liver transplant and cardiac surgery for nearly 50 years, has recently been applied to the trauma setting. Rodents are used widely for shock research, but are known to have differences in their coagulation system compared with humans. Consequently, the appropriate technique for performing TEG requires modification of the standard clinical protocol. Thromboelastography was performed with blood collected from the femoral artery of rodents, and technical modifications were tested to optimize results. Analysis of citrated whole blood using TEG revealed a more rapid onset of coagulation in rats compared with humans. The reference ranges of TEG parameters for Sprague-Dawley rats are detailed. Citrated native whole blood is the optimal TEG method in the assessment of coagulation in rodents. Investigators using TEG for research purposes should establish their own reference ranges to determine normal values for their target population.

Figure 1. TEG diagram

Representative TEG tracing. The following TEG parameters were recorded from standard tracings: split point (SP), reaction time (R, minutes), coagulation time (K, minutes), angle (α, degrees), maximum amplitude (MA, mm), clot strength (G, dynes/scm), and percentage lysis (LY30, Lysis at 30 min %). The coagulation index (CI) is a linear combination of R, K, Angle, and MA that is believed to represent the overall coagulation status.