Alterations in tissue oxygen saturation measured by near-infrared spectroscopy in trauma patients after initial resuscitation are associated with occult shock.

PURPOSE: Persistent occult hypoperfusion after initial resuscitation is strongly associated with increased morbidity and mortality after severe trauma. The objective of this study was to analyze regional tissue oxygenation, along with other global markers, as potential detectors of occult shock in otherwise hemodynamically stable trauma patients. METHODS: Trauma patients undergoing active resuscitation were evaluated 8 h after hospital admission with the measurement of several global and local hemodynamic/metabolic parameters. Apparently hemodynamically stable (AHD) patients, defined as having SBP ≥ 90 mmHg, HR < 100 bpm and no vasopressor support, were followed for 48 h, and finally classified according to the need for further treatment for persistent bleeding (defined as requiring additional red blood cell transfusion), initiation of vasopressors and/or bleeding control with surgery and/or angioembolization. Patients were labeled as "Occult shock" (OS) if they required any intervention or "Truly hemodynamically stable" (THD) if they did not. Regional tissue oxygenation (rSO2) was measured non-invasively by near-infrared spectroscopy (NIRS) on the forearm. A vascular occlusion test was performed, allowing a 3-min deoxygenation period and a reoxygenation period following occlusion release. Minimal rSO2 (rSO2min), Delta-down (rSO2-rSO2min), maximal rSO2 following cuff-release (rSO2max), and Delta-up (rSO2max-rSO2min) were computed. The NIRS response to the occlusion test was also measured in a control group of healthy volunteers. RESULTS: Sixty-six consecutive trauma patients were included. After 8 h, 17 patients were classified as AHD, of whom five were finally considered to have OS and 12 THD. No hemodynamic, metabolic or coagulopathic differences were observed between the two groups, while NIRS-derived parameters showed statistically significant differences in Delta-down, rSO2min, and Delta-up. CONCLUSIONS: After 8 h of care, NIRS evaluation with an occlusion test is helpful for identifying occult shock in apparently hemodynamically stable patients. LEVEL OF EVIDENCE: IV, descriptive observational study. TRIAL REGISTRATION: ClinicalTrials.gov Registration Number: NCT02772653.

Dynamic use of fibrinogen under viscoelastic assessment results in reduced need for plasma and diminished overall transfusion requirements in severe trauma.

BACKGROUND: Despite advances in trauma management, half of trauma deaths occur secondary to bleeding. Currently, hemostatic resuscitation strategies consist of empirical transfusion of blood products in a predefined fixed ratio (1:1:1) to both treat hemorrhagic shock and correct trauma-induced coagulopathy. At our hospital, the implementation of a resuscitation protocol guided by viscoelastic hemostatic assays (VHAs) with rotational thromboelastometry has resulted in a goal-directed approach. The objective of the study is twofold, first to analyze changes in transfusion practices overtime and second to identify the impact of these changes on coagulation parameters and clinical outcomes. We hypothesized that progressive VHA implementation results in a higher administration of fibrinogen concentrate (FC) and lower use of blood products transfusion, especially plasma. METHODS: A total of 135 severe trauma patients (January 2008 to July 2019), all requiring and initial assessment for high risk of trauma-induced coagulopathy based on high-energy injury mechanism, severity of bleeding and hemodynamic instability were included. After 2011 when we first modified the transfusion protocol, a progressive change in transfusional management occurred over time. Three treatment groups were established, reflecting different stages in the evolution of our strategy: plasma (P, n = 28), plasma and FC (PF, n = 64) and only FC (F, n = 42). RESULTS: There were no significant differences in baseline characteristics among groups. Progressive implementation of rotational thromboelastometry resulted in increased use of FC over time ( p < 0.001). Regression analysis showed that group F had a significant reduction in transfusion of packed red blood cells ( p = 0.005), plasma ( p < 0.001), and platelets ( p = 0.011). Regarding outcomes, F patients had less pneumonia ( p = 0.019) and multiorgan failure ( p < 0.001), without significant differences for other outcomes. Likewise, overall mortality was not significantly different. However, further analysis comparing specific mortality due only to massive hemorrhage in the F group versus all patients receiving plasma, it was significantly lower ( p = 0.037). CONCLUSION: Implementing a VHA-based algorithm resulted in a plasma-free strategy with higher use of FC and a significant reduction of packed red blood cells transfused. In addition, we observed an improvement in outcomes without an increase in thrombotic complications. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.