Viscoelastic hemostatic assay (VHA) provides a graphical representation of a clot\'s lifespan and reflects the real time of coagulation. It has been used to guide trauma resuscitation; however, evidence of the effectiveness of VHAs is still limited. This systematic review aims to summarize the published evidence to evaluate the VHA-guided strategy in resuscitating trauma patients.
The PubMed, Embase, and Web of Science databases were searched from their inception to December 13, 2021. Randomized controlled trials (RCTs) or observational studies comparing VHA-guided transfusion to controls in resuscitating trauma patients were included in this systematic review.
Of the 7743 records screened, ten studies, including two RCTs and eight observational studies, met the inclusion criteria. There was great heterogeneity concerning study design, enrollment criterion, VHA device, VHA-guided strategy, and control strategy. Thrombelastography (TEG) was used as a guiding tool for transfusion in eight studies, and rotational thromboelastometry (ROTEM), and TEG or ROTEM were used in the other two studies. The overall risk of bias assessment was severe or mild in RCTs and was severe or moderate in observational studies. The main outcomes reported from the included studies were blood transfusion (n = 10), mortality (n = 10), hospital length of stay (LOS) (n = 7), intensive care unit LOS (n = 7), and cost (n = 4). The effect of the VHA-guided strategy was not always superior to the control. Most of the studies did not find significant differences in the transfusion amount of red blood cells (n = 7), plasma (n = 5), platelet (n = 7), cryoprecipitate/fibrinogen (n = 7), and mortality (n = 8) between the VHA-guided group and control group. Notable, two RCTs showed that the VHA-guided strategy was superior or equal to the conventional coagulation test-guided strategy in reducing mortality, respectively.
Although some studies demonstrated VHA-guided strategy probable benefit in reducing the need for blood transfusion and mortality when resuscitating trauma patients, the evidence is still not robust. The quality of evidence was primarily downgraded by the limited number of included studies and great heterogeneity and severe risk of bias in these. Further studies are strongly recommended.

BACKGROUND: Hyperosmolar therapy, using either hypertonic saline (HTS) or mannitol (MT), is considered the treatment of choice for intracranial hypertension, a disorder characterized by high intracranial pressure (ICP). However, hyperosmolar agents have been postulated to impair coagulation and platelet function. The aim of this study was to identify whether HTS and MT could affect coagulation in moderate traumatic brain injury (TBI) patients.
METHODS: In this prospective and randomized double-blind study, we included adult patients with moderate TBI. Patients were divided into two groups according to the type of hypertonic solution administered. Group A patients received 20% MT and group B patients received 3% HTS. Rotational thromboelastometry (ROTEM) parameters were used to assess coagulation and platelet function.
RESULTS: ROTEM parameters included CT (clotting time), CFT (clot formation time), maximum clot firmness (MCF) measured by MCF (EXTEM and INTEM), MCF (FIBTEM) and standard coagulation tests (p>0.05). No significant differences were found between the two groups. Moreover, ROTEM parameters did not show significant changes at different time points after administration of the hyperosmolar solutions (p>0.05). Conclusions Overall, use of 3% HTS and 20% MT for the control of ICP did not significantly affect patients\' coagulation function. Therefore, hyperosmotic solution is safe and does not increase the risk of intracranial rebleeding.