A Deployable Viscoelastic Coagulation Monitor Enables Point-of-Care Assessment of Coagulopathy in Swine With Polytrauma

Abstract

ABSTRACT Introduction Absence of pre-hospital coagulation tests challenges prompt management of hemostasis after trauma. The Viscoelastic Coagulation Monitor (VCM, Entegrion, Durham, NC) is a hand-held coagulation test for point-of-care. We evaluated VCM in a translational swine polytrauma model, hypothesizing that VCM correlates with a laboratory reference method, the TEG 5000 (Haemonetics, Boston, MA), and can identify coagulopathic phenotypes relevant to trauma. Our secondary hypothesis was that pre-warming of VCM disposable test cartridges using a heating plate versus pre-warming of cartridges by carrying the cartridge in the user’s pocket does not significantly alter results. Materials and Methods This study was conducted in tandem with a parent study involving anesthetized, mechanically ventilated swine (n = 20; 54 ± 5 kg) that encountered traumatic brain injury, pulmonary contusion and hemorrhage, or combination/polytrauma injury. Blood was collected at baseline, post-injury, post-shock, post-transfusion, and 6-, 24-, and 48 h post-injury to perform VCM at point-of-care. Within-group effect of time was assessed. Spearman correlation examined linear relations between VCM and standard laboratory-based coagulation tests; as well as lactate, ionized calcium, and body temperature. Logistic regression examined predictiveness of VCM to identify coagulopathic phenotypes, with receiver operator characteristic curves generated to assess diagnostic capability. At a subset of timepoints, necessity of pre-warming the VCM test cartridge using a heating plate versus pre-warming the cartridge by placement in the user’s pocket was assessed by conducting simultaneous tests on two separate instruments, with results analyzed by paired t-test with crossover design. Results VCM revealed time-dependent changes in clotting time, clot formation time (CFT), alpha, maximum clot firmness (MCF), and lysis index (LI30). All VCM metrics correlated with the respective TEG 5000 metrics, with strongest correlation for VCM MCF with TEG MA (rhos = 0.77, P < .0001) and VCM LI30 with TEG LY30 (rhos = −0.76, P < .0001). VCM demonstrated good (area under the curve >0.70) to excellent (area under the curve >0.90) diagnostic accuracy in detection of low platelet count (MCF), low hematocrit (clotting time, clot formation time, alpha, and MCF), low fibrinogen (MCF), and high fibrinogen (alpha, MCF). There was no statistically or clinically relevant effect of cartridge warming method on results. Conclusions In a trauma model, VCM detected significant changes in coagulation at point-of-care in a simplified portable form factor. VCM could enable informed hemostasis management in pre-hospital settings where coagulations tests are unavailable, pending further validation in clinical trials.