Abstract

BACKGROUND Tactical Combat Casualty Care (TCCC) is the standard of care for stabilization and treatment of military trauma patients. The DoD has mandated that all Service members receive role-based TCCC training and certification. Simulation education can increase procedural skills by providing opportunities for deliberate practice in safe, controlled environments. We developed and evaluated the effectiveness of a simulation-based TCCC training intervention to improve participants' skill performance and self-confidence in tourniquet placement. METHODS This study was a single-blinded, randomized trial with waitlist controls. Army ROTC cadets from a single training battalion comprised the study population. After randomization and baseline assessment of all participants, Group A alone received focused, simulation-based TCCC tourniquet application training. Three months later, all participants underwent repeat testing, and after crossover, the waitlist Group B received the same intervention. Two months later, all cadets underwent a third/final assessment. The primary outcome was tourniquet placement proficiency assessed by total score achieved on a standardized 8-item skill checklist. A secondary outcome was self-confidence in tourniquet application skill as judged by participants' Likert scale ratings. RESULTS Forty-three Army ROTC cadets completed the study protocol. Participants in both Group A (n = 25) and Group B (n = 18) demonstrated significantly higher performance from baseline to final assessment at five months and two months, respectively, following the intervention. Mean total checklist score of the entire study cohort increased significantly from 5.53 (SD = 2.00) at baseline to 7.56 (SD = 1.08) at Time 3, a gain of 36.7% (p < 0.001). Both groups rated their self-confidence in tourniquet placement significantly higher following the training. CONCLUSIONS A simulation-based TCCC curriculum resulted in significant, consistent, and sustained improvement in participants' skill proficiency and self-confidence in tourniquet placement. Participants maintained these gains two to five months after initial training. LEVEL OF EVIDENCE Level II - RCT with significant difference and only one negative criterion (<80% follow-up).

Abstract

Balanced crystalloids may improve outcomes compared to saline for some critically ill adults. Lower tonicity of balanced crystalloids could worsen cerebral edema in patients with intracranial pathology. The effect of balanced crystalloids versus saline on clinical outcomes in patients with traumatic brain injury (TBI) requires further study. We planned an a priori subgroup analysis of TBI patients enrolled in the pragmatic, cluster-randomized, multiple-crossover Isotonic Solutions and Major Adverse Renal Events Trial (SMART) (ClinicalTrials.gov: NCT02444988, NCT02547779). Primary outcome was 30-day in-hospital mortality. Secondary outcomes included hospital discharge disposition (home, facility, death). Regression models adjusted for pre-specified baseline covariates compared outcomes. TBI patients assigned to balanced crystalloids (n=588) and saline (n=569) had similar baseline characteristics including Injury Severity Score 19 (10); mean maximum head/neck Abbreviated Injury Score, 3.4 (1.0). Isotonic crystalloid volume administered between ICU admission and first of hospital discharge or 30 days was 2037 (3470) mL and 1723 (2923) mL in the balanced crystalloids and saline groups, respectively (P=0.18). During the study period, 94 (16%) and 82 (14%) patients (16%) died in the balanced crystalloid and saline groups, respectively (aOR, 1.03; 95% confidence interval [CI], 0.60 to 1.75; P=0.913). Patients in the balanced crystalloid group were more likely to die or be discharged to another medical facility (aOR 1.38 [1.02-1.86]; P=0.04). Overall, balanced crystalloids were associated with worse discharge disposition in critically injured patients with TBI compared to saline. The confidence intervals cannot exclude a clinically relevant increase in mortality when balanced crystalloids are used for patients with TBI.

Abstract

BACKGROUND Resistance breathing amplifies the respiratory pump during inspiration, so may be an effective intervention for treatment of hemorrhagic injuries. In animal studies of actual hemorrhage, and human studies of simulated hemorrhage, resistance breathing protects arterial pressure, and improves tolerance to this stress. Anecdotally, resistance breathing also increases the coupling between sympathetic nerve activity and arterial pressure. The impact of resistance breathing on overall sympathetic nerve activity, however, has not been examined. We tested the hypothesis that resistance breathing increases sympathetic nerve activity during simulated hemorrhage in healthy humans. METHODS Lower body negative pressure (LBNP) was used to simulate hemorrhage in five human subjects (3M, 2F; 29.2 ± 6.8 y). Two experiments were conducted (randomized order): 1) a control condition in which LBNP was applied at 3 mmHg/min until the onset of presyncope, and 2) a resistance breathing condition in which the same LBNP protocol was used, but subjects breathed through a resistance device (set at -7 cm.H2O) during the final stages of the protocol. Arterial pressure and muscle sympathetic nerve activity (MSNA) of the radial nerve were monitored continuously. Bursts frequency (bursts/min) and burst incidence (burst/ 100 heart beats) were used to quantify MSNA. Coupling between diastolic arterial pressure (DAP) and MSNA was assessed by transfer function analysis coherence within the low frequency range (0.04-0.15 Hz). Two-way repeated measures ANOVAs were conducted for assessment of responses in the control and resistance breathing conditions, between baseline and at matched time points late in the LBNP protocol. RESULTS While LBNP induced increases in both MSNA burst frequency (P=0.003) and burst incidence (P=0.06), there was no effect of resistance breathing on MSNA for either index during LBNP (control, 57.9 ± 25.9 bursts/min vs. resistance breathing, 50.6 ± 21.7 bursts/min, P=0.99; control, 55.6 ± 25.6 b/100 heart beats vs. resistance breathing, 42.3 ± 18.3 b/100 heart beats, P=0.42). Additionally, there was no effect of resistance breathing on DAP (control, 73.2 ± 9.9 mmHg vs. resistance breathing, 72.8 ± 4.4 mmHg; P=0.99), or coherence between MSNA and DAP during LBNP (control, 0.53 ± 0.21 vs. resistance breathing, 0.69 ± 0.17; P=0.46). CONCLUSION Contrary to our hypothesis, resistance breathing had no effect on sympathetic nerve activity during LBNP. A limitation of this study is the low sample size (N=5), and high variability of MSNA. Future investigations with a larger sample size are needed to determine if respiratory dynamics can influence the coupling between MSNA and arterial pressure.

Abstract

BACKGROUND Maxillofacial trauma accounts for ~10% of trauma presentations to most centres, with massive haemorrhage occurring in 1.2-4.5% of cases. Despite its infrequent presentation, there is significant associated morbidity and mortality. Transcatheter arterial embolization (TAE) is playing an increasingly prominent role in trauma presentations. The aim of this article was to compare outcomes of TAE with more traditional management methods for the treatment of massive facial haemorrhage following maxillofacial trauma. METHODS A database and Google Scholar search was performed, with articles discussing massive facial haemorrhage secondary to maxillofacial trauma and its management included. RESULTS Twenty-seven articles were found that met inclusion criteria, encompassing 384 patients. Statistical testing comparing mortality between TAE and non-TAE groups did not find a significant difference, with a mortality rate of 30.2% in the TAE group and 38.9% in the non-TAE group. Assessment of morbidity directly related to interventions was difficult, as many of the included participants had significant associated injuries which contributed an indeterminate degree to morbidity. There was a 10% rate of adverse events associated with TAE, most commonly puncture site haematomas and soft tissue swelling, with more significant adverse events including cerebrovascular accidents and blindness. CONCLUSION Embolization was correlated with increased rates of haemorrhage control when compared with other interventions. Overall, despite no significant impact on mortality, embolization is recommended in the management of massive haemorrhage following maxillofacial trauma due to improved success rates at haemorrhage control and a low rate of significant adverse events.

Abstract

BACKGROUND The antifibrinolytic drug tranexamic acid (TXA) improves survival in adults with traumatic hemorrhage; however, the drug has not been evaluated in a trial in injured children. We evaluated the feasibility of a large-scale trial evaluating the effects of TXA in children with severe hemorrhagic injuries. METHODS Severely injured children (0 up to 18(th) birthday) were randomized into a double-blind randomized trial of 1) TXA 15 mg/kg bolus dose, followed by 2 mg/kg/hr infusion over 8 hours, 2) TXA 30 mg/kg bolus dose, followed by 4 mg/kg/hr infusion over 8 hours, or 3) normal saline placebo bolus and infusion. The trial was conducted at 4 pediatric Level I trauma centers in the United States between June 2018 and March 2020. We enrolled patients under federal exception from informed consent (EFIC) procedures when parents were unable to provide informed consent. Feasibility outcomes included the rate of enrollment, adherence to intervention arms, and ability to measure the primary clinical outcome. Clinical outcomes included global functioning (primary), working memory, total amount of blood products transfused, intracranial hemorrhage progression, and adverse events. The target enrollment rate was at least 1.25 patients per site per month. RESULTS A total of 31 patients were randomized with a mean age of 10.7 years (standard deviation [SD] 5.0 years) and 22 (71%) patients were male. The mean time from injury to randomization was 2.4 hours (SD 0.6 hours). Sixteen (52%) patients had isolated brain injuries and 15 (48%) patients had isolated torso injuries. The enrollment rate using EFIC was 1.34 patients per site per month. All eligible enrolled patients received study intervention (9 patients TXA 15 mg/kg bolus dose, 10 patients TXA 30 mg/kg bolus dose, and 12 patients placebo) and had the primary outcome measured. No statistically significant differences in any of the clinical outcomes were identified. CONCLUSION Based on enrollment rate, protocol adherence, and measurement of the primary outcome in this pilot trial, we confirmed the feasibility of conducting a large-scale, randomized trial evaluating the efficacy of TXA in severely injured children with hemorrhagic brain and/or torso injuries using EFIC.

Abstract

BACKGROUND Complement activation after trauma promotes hemostasis but is associated with increased morbidity and mortality. However, the specific pathways and downstream mediators remain unclear. Recently the anaphylatoxin C4a has been shown to bind to thrombin receptors. While plasma-based resuscitation has been shown to modify the endotheliopathy of trauma, it may provide complement zymogens that fuel ongoing inflammatory cascades. We sought to characterize the activation of complement after injury and the effect of fresh frozen plasma (FFP) on this inflammatory response. We hypothesized that trauma induces C4 activation, which is associated with worse outcomes and influenced by FFP resuscitation. METHODS Blood was collected from injured patients at a single Level I Trauma Center enrolled in the COMBAT randomized clinical trial. Proteomic analyses were performed through targeted liquid chromatography coupled with mass spectrometry. For the present observational study, concentrations of complement proteins were analyzed at multiple time points, compared between treatment groups, and correlated with outcomes. RESULTS C4 activation occurred over the first six hours post-injury with peak activation 6-24 hours. Tissue hypoperfusion, defined as base deficit >10 mEq/L, and requirement for massive transfusion were associated with greater C4 activation. C4 activation was associated with mortality, multiple organ failure, and longer ventilator requirement. Additionally, temporal trends of C1q, factor B, and C3 by outcome groups support the prevailing theory of primary classical pathway activation with alternative pathway amplification. Resuscitation with FFP over the first six hours was associated with increased C4 activation at 12 and 24 hours. CONCLUSIONS C4 activation has an important inflammatory role post-injury, and FFP has the potential to augment this complement activation during resuscitation. EVIDENCE Level III, Prognostic/Epidemiological.

Abstract

IMPORTANCE Tranexamic acid is widely available and used off-label in patients with bleeding traumatic injury, although the literature does not consistently agree on its efficacy and safety. OBJECTIVE To examine the association of tranexamic acid administration with mortality and thromboembolic events compared with no treatment or with placebo in patients with traumatic injury in the literature. DATA SOURCES On March 23, 2021, PubMed, Embase, and the Cochrane Library were searched for eligible studies published between 1986 and 2021. STUDY SELECTION Randomized clinical trials and observational studies investigating tranexamic acid administration compared with no treatment or placebo among patients with traumatic injury and traumatic brain injury who were 15 years or older were included. Included studies were published in English or German. The electronic search yielded 1546 records, of which 71 were considered for full-text screening. The selection process was performed independently by 2 reviewers. DATA EXTRACTION AND SYNTHESIS The study followed the Cochrane Handbook for Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data were extracted by 2 independent reviewers and pooled using the inverse-variance random-effects model. MAIN OUTCOMES AND MEASURES Outcomes were formulated before data collection and included mortality at 24 hours and 28 and 30 days (1 month) as well as the incidence of thromboembolic events and the amount of blood products administered. Owing to missing data, overall mortality was added and the amount of blood products administered was discarded. RESULTS Thirty-one studies with a total of 43 473 patients were included in the systematic review. The meta-analysis demonstrated that administration of tranexamic acid was associated with a significant decrease in 1-month mortality compared with the control cohort (risk ratio, 0.83 [95% CI, 0.71-0.97]; I2 = 35%). The results of meta-analyses for 24-hour and overall mortality and thromboembolic events were heterogeneous and could not be pooled. Further investigations on clinical heterogeneity showed that populations with trauma and trial conditions differed markedly. CONCLUSIONS AND RELEVANCE These findings suggest that tranexamic acid may be beneficial in various patient populations with trauma. However, reasonable concerns about potential thromboembolic events with tranexamic acid remain.

Abstract

BACKGROUND Early hemorrhage control after interpersonal violence is the most urgent requirement to preserve life and is now recognized as a responsibility of law enforcement. Although earlier entry of first responders is advocated, many shooting scenes remain unsafe for humans, necessitating first responses conducted by robots. Thus, robotic hemorrhage control warrants study as a care-under-fire treatment option. METHODS Two bomb disposal robots (Wolverine and Dragon Runner) were retrofitted with hemostatic wound clamps. The robots' ability to apply a wound clamp to a simulated extremity exsanguination while controlled by 4 experienced operators was tested. The operators were randomly assigned to perform 10 trials using 1 robot each. A third surveillance robot (Stair Climber) provided further visualization for the operators. We assessed the success rate of the application of the wound clamp to the simulated wound, the time to application of the wound clamp and the amount of fluid loss. We also assessed the operators' efforts to apply the wound clamp after an initial attempt was unsuccessful or after the wound clamp was dropped. RESULTS Remote robotic application of a wound clamp was demonstrated to be feasible, with complete cessation of simulated bleeding in 60% of applications. This finding was consistent across all operators and both robots. There was no difference in the success rates with the 2 robots (p = 1.00). However, there were differences in fluid loss (p = 0.004) and application time (p < 0.001), with the larger (Wolverine) robot being faster and losing less fluid. CONCLUSION Law enforcement tactical robots were consistently able to provide partial to complete hemorrhage control in a simulated extremity exsanguination. Consideration should be given to using this approach in care-under-fire and care-behind-the-barricade scenarios as well as further developing the technology and doctrine for robotic hemorrhage control.

Abstract

INTRODUCTION Exsanguination is the most preventable cause of death. Paradigms such as STOP THE BLEED recognize increased responsibility among the less experienced with Wound Packing (WP) being a critical skill. As even trained providers may perform poorly, we compared Video-modelling (VM), a form of behavioural modelling involving video demonstration prior to intervention against remote telementoring (RTM) involving remote real-time expert-guidance. METHODS Search and Rescue (SAR-Techs), trained in WP were asked to pack a wound on a standardized simulator randomized to RMT, VM, or control. RESULTS 24 SAR-Techs (median age 37, median 16.5 years experience) participated. Controls were consistently faster than RTM (p = 0.005) and VM (p = 0.000), with no difference between RTM and VM. However, 50% (n = 4) Controls failed to pack properly, compared to 100% success in both VM and RTM, despite all SAR-Techs feeling the task was "easy". DISCUSSION Performance of a life-saving technique was improved through either VM or RTM, suggesting that both techniques are beneficial and complementary to each other. Further work should be extended to law enforcement/lay public to examine logistical challenges.

Abstract

BACKGROUND A 2-gram bolus of tranexamic acid (TXA) has been shown to reduce 28-day mortality in a RCT. This study investigates whether out-of-hospital TXA use is associated with adverse events or unfavorable outcomes in suspected TBI when intracranial hemorrhage (ICH) is absent on initial CT. METHODS This study utilized data from a 2015-2017, multicenter, randomized trial studying the effect of the following TXA doses on moderate to severe TBI: 2-gram bolus, 1-gram bolus plus 1-gram infusion over 8 hours, and a placebo bolus with placebo infusion. Of the 966 participants enrolled, 395 with an initial CT negative for ICH were included in this analysis. Fifteen adverse events (28-day incidence) were studied: MI, DVT, seizure, pulmonary embolism, ARDS, cardiac failure, liver failure, renal failure, CVA, cardiac arrest, cerebral vasospasm, "any thromboembolism", hypernatremia, AKI, and infection. Other unfavorable outcomes analyzed include mortality at 28 days & 6 months, GOSE ≤4 at discharge & 6 months, ICU-free days, ventilator-free days, hospital-free days, and combined unfavorable outcomes. In both study drug groups the incidence of dichotomous outcomes and quantity of ordinal outcomes were compared to placebo. RESULTS No statistically significant increase in adverse events or unfavorable outcomes was found between either TXA dosing regimen and placebo. Demographics and injury scores were not statistically different other than two methods of injury which were overrepresented in the 1-gram TXA bolus +1-gram TXA infusion. CONCLUSIONS Administration of either a 2-gram TXA bolus or a 1-gram TXA bolus plus 1-gram TXA 8-hour infusion in suspected-TBIs without ICH is not associated with increased adverse events or unfavorable outcomes. Because the out-of-hospital 2-gram bolus is associated with a mortality benefit it should be administered in suspected-TBI. LEVELS OF EVIDENCE Level II, Therapeutic.