Surface Activation of Whole Blood: Clot Detection with a Thrombelastograph

Abstract

Various methods are used to decrease the length of time required to generate useful data from thrombelastography (TEG). The quicker this data can be produced and analyzed the sooner decisions can be made for hemostasis management. The present study was designed to determine the effects of glass compared to plastic with respect to their effect on the activation of the intrinsic pathway of coagulation. Thirty-seven samples of native whole blood (NWB) were drawn via radial artery catheter, internal jugular sheath or by direct venous puncture. Half of each sample was placed in a glass test tube and the other half in a plastic (polypropylene) container, and allowed to sit for periods of 1 minute (n = 4 ), 1.5 minutes (n = 5), 2 minutes (n = 9), 2.5 minutes (n = 9) and 3 minutes (n = 10). The glass activated samples were placed in plastic TEG cups that had been randomized to one of the two TEG channels, with the plastic activated samples being placed in metal TEG cups in the opposite channel. This resulted in a total of seventy-four TEG profiles. There were no significant correlations (p < 0.05) between any of the inter- or intra-related TEG parameters, reaction time (R time), kinetic time (K time), maximum amplitude (MA), or alpha angle (AA). However, the R time of the glass activated samples showed a linear decrease in time required to achieve this value. The plastic activated samples did not exhibit this linear decrease in R time. The thrombelastograph index (TI) showed an initial hypocoagulability at 1 min for glass (-1.84 ± 3.46) when compared to plastic ( + 1.58 ± 0.23). At 1.5 minutes, the TI for glass ( -0.12 ± 2.97) approached those for plastic ( +0.035 ± 1.68) and remained relatively close until3 min of activation when the glass samples TI (2.48 ± 3.16) proved to be hypercoagulable when compared to the plastic at 3 min, TI (1.97 ± 2.64). The MA, K time and alpha angle seemed to be largely unaffected by the different activation times. This study has shown that glass activation may be used effectively to decrease the time required to generate TEG data from NWB samples, and that the glass activation does not seem to affect the TEG parameters significantly other than the R time.