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Missingness matters: a secondary analysis of thromboelastography measurements from a recent prehospital randomized tranexamic acid clinical trial
Donohue, J. K., Iyanna, N., Lorence, J. M., Brown, J. B., Guyette, F. X., Eastridge, B. J., Nirula, R., Vercruysse, G. A., O'Keeffe, T., Joseph, B., et al
Trauma surgery & acute care open. 2024;9(1):e001346
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Abstract
BACKGROUND Tranexamic acid (TXA) has been hypothesized to mitigate coagulopathy in patients after traumatic injury. Despite previous prehospital clinical trials demonstrating a TXA survival benefit, none have demonstrated correlated changes in thromboelastography (TEG) parameters. We sought to analyze if missing TEG data contributed to this paucity of findings. METHODS We performed a secondary analysis of the Study of Tranexamic Acid During Air Medical and Ground Prehospital Transport Trial. We compared patients that received TEG (YES-TEG) and patients unable to be sampled (NO-TEG) to analyze subgroups in which to investigate TEG differences. TEG parameter differences across TXA intervention arms were assessed within subgroups disproportionately present in the NO-TEG relative to the YES-TEG cohort. Generalized linear models controlling for potential confounders were applied to findings with p<0.10 on univariate analysis. RESULTS NO-TEG patients had lower prehospital systolic blood pressure (SBP) (100 (78, 140) vs 125 (88, 147), p<0.01), lower prehospital Glascow Coma Score (14 (3, 15) vs 15 (12, 15), p<0.01), greater rates of prehospital intubation (39.4% vs 24.4%, p<0.01) and greater mortality at 30 days (36.4% vs 6.8%, p<0.01). NO-TEG patients had a greater international normalized ratio relative to the YES-TEG subgroup (1.2 (1.1, 1.5) vs 1.1 (1.0, 1.2), p=0.04). Within a severe prehospital shock cohort (SBP<70), TXA was associated with a significant decrease in clot lysis at 30 min on multivariate analysis (β=-27.6, 95% CI (-51.3 to -3.9), p=0.02). CONCLUSIONS Missing data, due to the logistical challenges of sampling certain severely injured patients, may be associated with a lack of TEG parameter changes on TXA administration in the primary analysis. Previous demonstration of TXA's survival benefit in patients with severe prehospital shock in tandem with the current findings supports the notion that TXA acts at least partially by improving clot integrity. LEVEL OF EVIDENCE Level II.
PICO Summary
Population
Patients at risk for haemorrhage receiving tranexamic acid before hospitalization, enrolled in the Study of Tranexamic Acid During Air Medical and Ground Prehospital Transport (STAAMP) Trial (n= 903).
Intervention
Prehospital tranexamic acid (TXA) (n= 447).
Comparison
Placebo (n= 456).
Outcome
This study was a secondary analysis of the STAAMP trial, comparing patients that received thromboelastography (TEG) (YES-TEG, n= 837) and patients unable to be sampled (NO-TEG, n= 66) to analyze subgroups in which to investigate TEG differences. NO-TEG patients had lower prehospital systolic blood pressure (SBP) (100 (78, 140) vs. 125 (88, 147)), lower prehospital Glascow Coma Score (14 (3, 15) vs. 15 (12, 15)), greater rates of prehospital intubation (39.4% vs. 24.4%) and greater mortality at 30 days (36.4% vs. 6.8%). NO-TEG patients had a greater international normalized ratio relative to the YES-TEG subgroup (1.2 (1.1, 1.5) vs. 1.1 (1.0, 1.2)). Within a severe prehospital shock cohort (SBP< 70), TXA was associated with a significant decrease in clot lysis at 30 min on multivariate analysis (β= -27.6; 95% CI [-51.3, -3.9].
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Prehospital tranexamic acid is associated with a dose-dependent decrease in syndecan-1 after trauma: A secondary analysis of a prospective randomized trial
Gruen DS, Brown JB, Guyette FX, Johansson PI, Stensballe J, Li SR, Leeper CM, Eastridge BJ, Nirula R, Vercruysse GA, et al
The journal of trauma and acute care surgery. 2023
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Abstract
BACKGROUND In the Study of Tranexamic Acid During Air and Ground Prehospital Transport (STAAMP) Trial, prehospital tranexamic acid (TXA) was associated with lower mortality in specific patient subgroups. The underlying mechanisms responsible for a TXA benefit remain incompletely characterized. We hypothesized that TXA may mitigate endothelial injury and sought to assess whether TXA was associated with decreased endothelial or tissue damage markers among all patients enrolled in the STAAMP Trial. METHODS We collected blood samples from STAAMP Trial patients and measured markers of endothelial function and tissue damage including syndecan-1, soluble thrombomodulin (sTM), and platelet endothelial cell adhesion molecule-1 (PECAM-1) at hospital admission (0 hours) and 12, 24, and 72 hours after admission. We compared these marker values for patients in each treatment group during the first 72 hours, and modeled the relationship between TXA and marker concentration using regression analysis to control for potential confounding factors. RESULTS We analyzed samples from 766 patients: 383 placebo, 130 abbreviated dosing, 119 standard dosing, and 130 repeat dosing. Lower levels of syndecan-1, TM, and PECAM measured within the first 72 hours of hospital admission were associated with survival at 30 days (P < 0.001). At hospital admission, syndecan-1 was lower in the TXA group (28.30 [20.05, 42.75] vs. 33.50 [23.00, 54.00] P = 0.001) even after controlling for patient, injury, and prehospital factors (P = 0.001). For every 1 g increase in TXA administered over the first 8 hours of prehospital transport and hospital admission, there was a 4 ng/mL decrease in syndecan-1 at 12 hours controlling for patient, injury, and treatment factors (P = 0.03). CONCLUSIONS Prehospital TXA was associated with decreased syndecan-1 at hospital admission. Syndecan-1 measured 12 hours after admission was inversely related to the dose of TXA received. Early pre- and in-hospital TXA may decrease endothelial glycocalyx damage or upregulate vascular repair mechanisms in a dose-dependent fashion. LEVEL OF EVIDENCE Level II, Secondary analysis of a prospective randomized trial.
PICO Summary
Population
Injured patients who received prehospital tranexamic acid (TXA) and were at risk for haemorrhage enrolled in the STAAMP randomised controlled trial (n= 766).
Intervention
Abbreviated dose: 1g of TXA (n= 130). Standard dose: 2g of TXA (n= 119). Repeat dose: 3g of TXA (n= 130).
Comparison
Placebo (saline), (n= 383).
Outcome
Blood samples were collected to measure markers of endothelial function and tissue damage including syndecan-1, soluble thrombomodulin (sTM), and platelet endothelial cell adhesion molecule-1 (PECAM-1) at hospital admission and 12, 24, and 72 hours after admission. Lower levels of syndecan-1, TM, and PECAM measured within the first 72 hours of hospital admission were associated with survival at 30 days. At hospital admission (mean ng/mL [IQR]), syndecan-1 was lower in the TXA group than the placebo group (28.30 [20.05, 42.75] vs. 33.50 [23.00, 54.00]) even after controlling for patient, injury, and prehospital factors. For every 1g increase in TXA administered over the first 8 hours of prehospital transport and hospital admission, there was a 4 ng/mL decrease in syndecan-1 at 12 hours controlling for patient, injury, and treatment factors.
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Pre-hospital freeze-dried plasma for critical bleeding after trauma: A pilot randomized controlled trial
Mitra B, Meadley B, Bernard S, Maegele M, Gruen RL, Bradley O, Wood EM, McQuilten ZK, Fitzgerald M, St Clair T, et al
Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 2023
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Abstract
OBJECTIVES Transfusion of a high ratio of plasma to packed red blood cells (PRBC), to treat or prevent acute traumatic coagulopathy, has been associated with survival after major trauma. However, the effect of pre-hospital plasma on patient outcomes has been inconsistent. The aim of this pilot trial was to assess the feasibility of transfusing freeze-dried plasma with red blood cells (RBC) using a randomized controlled design in an Australian aeromedical pre-hospital setting. METHODS Patients attended by Helicopter Emergency Medical Service (HEMS) paramedics with suspected critical bleeding after trauma managed with pre-hospital RBC were randomized to receive two units of freeze-dried plasma (Lyoplas N-w) or standard care (no plasma). The primary outcome was the proportion of eligible patients enrolled and provided the intervention. Secondary outcomes included preliminary data on effectiveness, including mortality censored at 24 hours and at hospital discharge, and adverse events. RESULTS During the study period of 01 June to 31 October 2022, there were 25 eligible patients, of whom 20 (80%) were enrolled in the trial and 19 (76%) received the allocated intervention. Median time from randomization to hospital arrival was 92.5 mins (IQR 68-101.5). Mortality may have been lower in the freeze-dried plasma group at 24h (RR 0.24; 95%CI: 0.03 - 1.73) and at hospital discharge (RR 0.73; 95%CI: 0.24 - 2.27). No serious adverse events related to the trial interventions were reported. CONCLUSIONS This first reported experience of freeze-dried plasma use in Australia suggests pre-hospital administration is feasible. Given longer prehospital times typically associated with HEMS attendance, there is potential clinical benefit from this intervention and rationale for a definitive trial.
PICO Summary
Population
Patients attended by Helicopter Emergency Medical Service (HEMS) paramedics with suspected critical bleeding after trauma (n= 20).
Intervention
Two units of freeze-dried plasma (Lyoplas N-w), (n= 9).
Comparison
Standard care (no plasma), (n= 11).
Outcome
The primary outcome was the proportion of eligible patients enrolled and provided the intervention. Secondary outcomes included preliminary data on effectiveness, including mortality censored at 24 hours and at hospital discharge, and adverse events. Nineteen patients (76%) received the allocated intervention. Median time from randomization to hospital arrival was 92.5 mins (IQR 68-101.5). Mortality may have been lower in the freeze-dried plasma group at 24h (RR 0.24; 95% CI [0.03, 1.73]) and at hospital discharge (RR 0.73; 95% CI [0.24, 2.27]. No serious adverse events related to the trial interventions were reported.
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The Restrictive Red Blood Cell Transfusion Strategy for Critically Injured Patients (RESTRIC) trial: a cluster-randomized, crossover, non-inferiority multicenter trial of restrictive transfusion in trauma
Hayakawa, M., Tagami, T., Kudo, D., Ono, K., Aoki, M., Endo, A., Yumoto, T., Matsumura, Y., Irino, S., Sekine, K., et al
Journal of intensive care. 2023;11(1):34
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Abstract
BACKGROUND The efficacies of fresh frozen plasma and coagulation factor transfusion have been widely evaluated in trauma-induced coagulopathy management during the acute post-injury phase. However, the efficacy of red blood cell transfusion has not been adequately investigated in patients with severe trauma, and the optimal hemoglobin target level during the acute post-injury and resuscitation phases remains unclear. Therefore, this study aimed to examine whether a restrictive transfusion strategy was clinically non-inferior to a liberal transfusion strategy during the acute post-injury phase. METHODS This cluster-randomized, crossover, non-inferiority multicenter trial was conducted at 22 tertiary emergency medical institutions in Japan and included adult patients with severe trauma at risk of major bleeding. The institutions were allocated a restrictive or liberal transfusion strategy (target hemoglobin levels: 7-9 or 10-12 g/dL, respectively). The strategies were applied to patients immediately after arrival at the emergency department. The primary outcome was 28-day survival after arrival at the emergency department. Secondary outcomes included transfusion volume, complication rates, and event-free days. The non-inferiority margin was set at 3%. RESULTS The 28-day survival rates of patients in the restrictive (n = 216) and liberal (n = 195) strategy groups were 92.1% and 91.3%, respectively. The adjusted odds ratio for 28-day survival in the restrictive versus liberal strategy group was 1.02 (95% confidence interval: 0.49-2.13). Significant non-inferiority was not observed. Transfusion volumes and hemoglobin levels were lower in the restrictive strategy group than in the liberal strategy group. No between-group differences were noted in complication rates or event-free days. CONCLUSIONS Although non-inferiority of the restrictive versus liberal transfusion strategy for 28-day survival was not statistically significant, the mortality and complication rates were similar between the groups. The restrictive transfusion strategy results in a lower transfusion volume. TRIAL REGISTRATION NUMBER umin.ac.jp/ctr: UMIN000034405, registration date: 8 October 2018.
PICO Summary
Population
Adult patients with severe trauma at risk of major bleeding, enrolled in the RESTRIC cluster-randomized, crossover trial at 22 tertiary emergency medical institutions in Japan (n= 422).
Intervention
Restrictive transfusion strategy (n= 222).
Comparison
Liberal transfusion strategy (n= 200).
Outcome
The restrictive and liberal red blood cell strategy groups included 216 and 195 patients in the intention-to-treat analysis, respectively. The primary outcome was 28-day survival after arrival at the emergency department. Secondary outcomes included transfusion volume, complication rates, and event-free days. The non-inferiority margin was set at 3%. The 28-day survival rates of patients in the restrictive (n= 216) and liberal (n= 195) strategy groups were 92.1% and 91.3%, respectively. The adjusted odds ratio for 28-day survival in the restrictive versus liberal strategy group was 1.02; 95% confidence interval [0.49, 2.13]. Significant non-inferiority was not observed. Transfusion volumes and haemoglobin levels were lower in the restrictive strategy group than in the liberal strategy group. No between-group differences were noted in complication rates or event-free days.
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Prehospital plasma is associated with survival principally in patients transferred from the scene of injury: A secondary analysis of the PAMPer trial
Lewis RE, Muluk SL, Reitz KM, Guyette FX, Brown JB, Miller RS, Harbrecht BG, Claridge JA, Phelan HA, Yazer MH, et al
Surgery. 2022
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BACKGROUND We sought to characterize if prehospital transfer origin from the scene of injury (SCENE) or from a referral emergency department (REF) alters the survival benefit attributable to prehospital plasma resuscitation in patients at risk of hemorrhagic shock. METHODS We performed a secondary analysis of data from a recently completed prehospital plasma clinical trial. All of the enrolled patients from either the SCENE or REF groups were included. The demographics, injury characteristics, shock severity and resuscitation needs were compared. The primary outcome was a 30-day mortality. Kaplan-Meier analysis and Cox-hazard regression were used to characterize the independent survival benefits of prehospital plasma for transport origin groups. RESULTS Of the 501 enrolled patients, the REF group patients (n = 111) accounted for 22% with the remaining (n = 390) originating from the scene. The SCENE group patients had higher injury severity and were more likely intubated prehospital. The REF group patients had longer prehospital times and received greater prehospital crystalloid and blood products. Kaplan-Meier analysis revealed a significant 30-day survival benefit associated with prehospital plasma in the SCENE group (P < .01) with no difference found in the REF group patients (P = .36). The Cox-regression verified after controlling for relevant confounders that prehospital plasma was independently associated with a 30-day survival in the SCENE group patients (hazard ratio 0.59; 95% confidence interval 0.39-0.89; P = .01) with no significant relationship found in the REF group patients (hazard ratio 1.03, 95% confidence interval 0.4-3.0). CONCLUSION Important differences across the SCENE and REF cohorts exist that are essential to understand when planning prehospital studies. Prehospital plasma is associated with a survival benefit primarily in SCENE group patients. The results are exploratory but suggest transfer origin may be an important determinant of prehospital plasma benefit.
PICO Summary
Population
Severely injured trauma patients enrolled in the PAMPer trial (n= 501).
Intervention
Thawed plasma (n= 230).
Comparison
Standard pre-hospital air medical care (n= 271).
Outcome
For this secondary analysis of the PAMPer trial, the study population was composed of 390 (78%) patients with an air medical transfer origin from the scene of injury (SCENE) and 111 (22%) patients transferred from an outside referral emergency department (REF). Randomization to plasma or standard of care was equally distributed across each transfer origin group. The SCENE group had higher injury severity and were more likely intubated pre-hospital. The REF group had longer pre-hospital times and received greater pre-hospital crystalloid and blood products. Kaplan-Meier analysis revealed a significant 30-day survival benefit associated with pre-hospital plasma in the SCENE group with no difference found in the REF group. The Cox-regression verified after controlling for relevant confounders that pre-hospital plasma was independently associated with a 30-day survival in the SCENE group with no significant relationship found in the REF group.
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Traumatic injury clinical trial evaluating tranexamic acid in children (TIC-TOC): a pilot randomized trial
Nishijima DK, VanBuren JM, Linakis SW, Hewes HA, Myers SR, Bobinski M, Tran NK, Ghetti S, Adelson PD, Roberts I, et al
Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 2022
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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.
PICO Summary
Population
Severely injured children enrolled in the TIC-TOC trial across four centers in US (n= 31).
Intervention
15 mg/kg of tranexamic acid (TXA) dose, followed by 2 mg/kg/hr infusion (n= 9).
Comparison
30 mg/kg of TXA dose, followed by 4 mg/kg/hr infusion (n= 10). Saline placebo and infusion (n= 12).
Outcome
All patients had their primary outcome measured. 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 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. No statistically significant differences in any of the clinical outcomes were identified.
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Resuscitation with blood products in patients with trauma-related haemorrhagic shock receiving prehospital care (RePHILL): a multicentre, open-label, randomised, controlled, phase 3 trial
Crombie N, Doughty HA, Bishop JRB, Desai A, Dixon EF, Hancox JM, Herbert MJ, Leech C, Lewis SJ, Nash MR, et al
The Lancet. Haematology. 2022
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Abstract
BACKGROUND Time to treatment matters in traumatic haemorrhage but the optimal prehospital use of blood in major trauma remains uncertain. We investigated whether use of packed red blood cells (PRBC) and lyophilised plasma (LyoPlas) was superior to use of 0·9% sodium chloride for improving tissue perfusion and reducing mortality in trauma-related haemorrhagic shock. METHODS Resuscitation with pre-hospital blood products (RePHILL) is a multicentre, allocation concealed, open-label, parallel group, randomised, controlled, phase 3 trial done in four civilian prehospital critical care services in the UK. Adults (age ≥16 years) with trauma-related haemorrhagic shock and hypotension (defined as systolic blood pressure <90 mm Hg or absence of palpable radial pulse) were assessed for eligibility by prehospital critial care teams. Eligible participants were randomly assigned to receive either up to two units each of PRBC and LyoPlas or up to 1 L of 0·9% sodium chloride administered through the intravenous or intraosseous route. Sealed treatment packs which were identical in external appearance, containing PRBC-LyoPlas or 0·9% sodium chloride were prepared by blood banks and issued to participating sites according to a randomisation schedule prepared by the co-ordinating centre (1:1 ratio, stratified by site). The primary outcome was a composite of episode mortality or impaired lactate clearance, or both, measured in the intention-to-treat population. This study is completed and registered with ISRCTN.com, ISRCTN62326938. FINDINGS From Nov 29, 2016 to Jan 2, 2021, prehospital critical care teams randomly assigned 432 participants to PRBC-LyoPlas (n=209) or to 0·9% sodium chloride (n=223). Trial recruitment was stopped before it achieved the intended sample size of 490 participants due to disruption caused by the COVID-19 pandemic. The median follow-up was 9 days (IQR 1 to 34) for participants in the PRBC-LyoPlas group and 7 days (0 to 31) for people in the 0·9% sodium chloride group. Participants were mostly white (62%) and male (82%), had a median age of 38 years (IQR 26 to 58), and were mostly involved in a road traffic collision (62%) with severe injuries (median injury severity score 36, IQR 25 to 50). Before randomisation, participants had received on average 430 mL crystalloid fluids and tranexamic acid (90%). The composite primary outcome occurred in 128 (64%) of 199 participants randomly assigned to PRBC-LyoPlas and 136 (65%) of 210 randomly assigned to 0·9% sodium chloride (adjusted risk difference -0·025% [95% CI -9·0 to 9·0], p=0·996). The rates of transfusion-related complications in the first 24 h after ED arrival were similar across treatment groups (PRBC-LyoPlas 11 [7%] of 148 compared with 0·9% sodium chloride nine [7%] of 137, adjusted relative risk 1·05 [95% CI 0·46-2·42]). Serious adverse events included acute respiratory distress syndrome in nine (6%) of 142 patients in the PRBC-LyoPlas group and three (2%) of 130 in 0·9% sodium chloride group, and two other unexpected serious adverse events, one in the PRBC-LyoPlas (cerebral infarct) and one in the 0·9% sodium chloride group (abnormal liver function test). There were no treatment-related deaths. INTERPRETATION The trial did not show that prehospital PRBC-LyoPlas resuscitation was superior to 0·9% sodium chloride for adult patients with trauma related haemorrhagic shock. Further research is required to identify the characteristics of patients who might benefit from prehospital transfusion and to identify the optimal outcomes for transfusion trials in major trauma. The decision to commit to routine prehospital transfusion will require careful consideration by all stakeholders. FUNDING National Institute for Health Research Efficacy and Mechanism Evaluation.
PICO Summary
Population
Patients aged 16 years old or older with trauma-related haemorrhagic shock enrolled in the resuscitation with pre-hospital blood products (RePHILL) trial, based across four UK prehospital critical care services (n= 432).
Intervention
Packed red blood cells and lyophilised plasma (PRBC-LyoPlas, n= 209).
Comparison
Sodium chloride (n= 223).
Outcome
The primary outcome was a composite of episode mortality or impaired lactate clearance, or both, measured in the intention-to-treat population. The composite primary outcome occurred in 128 (64%) of 199 patients receiving PRBC-LyoPlas and 136 (65%) of 210 receiving sodium chloride. The rates of transfusion-related complications in the first 24 hours after emergency department arrival were similar (PRBC-LyoPlas eleven (7%) of 148 compared with sodium chloride nine (7%) of 137). Serious adverse events included acute respiratory distress syndrome in nine (6%) of 142 patients in the PRBC-LyoPlas group and three (2%) of 130 in the sodium chloride group, and two other unexpected serious adverse events, one in the PRBC-LyoPlas (cerebral infarct) and one in the sodium chloride group (abnormal liver function test). There were no treatment-related deaths.
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Robotically applied hemostatic clamping for care-under-fire: harnessing bomb robots for hemorrhage control
Kirkpatrick AW, McKee IA, Knudsen B, Shelton R, LaPorta AJ, Wachs J, McKee JL
Canadian journal of surgery. Journal canadien de chirurgie. 2022;65(2):E242-e249
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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.
PICO Summary
Population
Public safety bomb technicians (n= 4).
Intervention
Application of wound clamps with the heavy-duty bomb disposal Wolverine robot (n= 2).
Comparison
Application of wound clamps with the lightweight bomb disposal Dragon Runner robot (n= 2).
Outcome
There was complete cessation of simulated bleeding in 60% of applications consistently across all technicians and both robots. There was no difference in success rates with the two robots. However, there were differences in fluid loss and application time, with the Wolverine robot being faster and losing less fluid.
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Effect of tranexamic acid on intracranial haemorrhage and infarction in patients with traumatic brain injury: a pre-planned substudy in a sample of CRASH-3 trial patients
Mahmood A, Needham K, Shakur-Still H, Harris T, Jamaluddin SF, Davies D, Belli A, Mohamed FL, Leech C, Lotfi HM, et al
Emergency medicine journal : EMJ. 2021;38(4):270-278
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BACKGROUND Early tranexamic acid (TXA) treatment reduces head injury deaths after traumatic brain injury (TBI). We used brain scans that were acquired as part of the routine clinical practice during the CRASH-3 trial (before unblinding) to examine the mechanism of action of TXA in TBI. Specifically, we explored the potential effects of TXA on intracranial haemorrhage and infarction. METHODS This is a prospective substudy nested within the CRASH-3 trial, a randomised placebo-controlled trial of TXA (loading dose 1 g over 10 min, then 1 g infusion over 8 hours) in patients with isolated head injury. CRASH-3 trial patients were recruited between July 2012 and January 2019. Participants in the current substudy were a subset of trial patients enrolled at 10 hospitals in the UK and 4 in Malaysia, who had at least one CT head scan performed as part of the routine clinical practice within 28 days of randomisation. The primary outcome was the volume of intraparenchymal haemorrhage (ie, contusion) measured on a CT scan done after randomisation. Secondary outcomes were progressive intracranial haemorrhage (post-randomisation CT shows >25% of volume seen on pre-randomisation CT), new intracranial haemorrhage (any haemorrhage seen on post-randomisation CT but not on pre-randomisation CT), cerebral infarction (any infarction seen on any type of brain scan done post-randomisation, excluding infarction seen pre-randomisation) and intracranial haemorrhage volume (intraparenchymal + intraventricular + subdural + epidural) in those who underwent neurosurgical haemorrhage evacuation. We planned to conduct sensitivity analyses excluding patients who were severely injured at baseline. Dichotomous outcomes were analysed using relative risks (RR) or hazard ratios (HR), and continuous outcomes using a linear mixed model. RESULTS 1767 patients were included in this substudy. One-third of the patients had a baseline GCS (Glasgow Coma Score) of 3 (n=579) and 24% had unilateral or bilateral unreactive pupils. 46% of patients were scanned pre-randomisation and post-randomisation (n=812/1767), 19% were scanned only pre-randomisation (n=341/1767) and 35% were scanned only post-randomisation (n=614/1767). In all patients, there was no evidence that TXA prevents intraparenchymal haemorrhage expansion (estimate=1.09, 95% CI 0.81 to 1.45) or intracranial haemorrhage expansion in patients who underwent neurosurgical haemorrhage evacuation (n=363) (estimate=0.79, 95% CI 0.57 to 1.11). In patients scanned pre-randomisation and post-randomisation (n=812), there was no evidence that TXA reduces progressive haemorrhage (adjusted RR=0.91, 95% CI 0.74 to 1.13) and new haemorrhage (adjusted RR=0.85, 95% CI 0.72 to 1.01). When patients with unreactive pupils at baseline were excluded, there was evidence that TXA prevents new haemorrhage (adjusted RR=0.80, 95% CI 0.66 to 0.98). In patients scanned post-randomisation (n=1431), there was no evidence of an increase in infarction with TXA (adjusted HR=1.28, 95% CI 0.93 to 1.76). A larger proportion of patients without (vs with) a post-randomisation scan died from head injury (38% vs 19%: RR=1.97, 95% CI 1.66 to 2.34, p<0.0001). CONCLUSION TXA may prevent new haemorrhage in patients with reactive pupils at baseline. This is consistent with the results of the CRASH-3 trial which found that TXA reduced head injury death in patients with at least one reactive pupil at baseline. However, the large number of patients without post-randomisation scans and the possibility that the availability of scan data depends on whether a patient received TXA, challenges the validity of inferences made using routinely collected scan data. This study highlights the limitations of using routinely collected scan data to examine the effects of TBI treatments. TRIAL REGISTRATION NUMBER ISRCTN15088122.
PICO Summary
Population
Patients with traumatic brain injury from 10 hospitals in the UK and 4 in Malaysia, enrolled in the CRASH-3 trial (n= 1,767).
Intervention
Tranexamic acid (TXA).
Comparison
Placebo.
Outcome
One-third of the patients had a baseline Glasgow Coma Score of 3 (n= 579) and 24% had unilateral or bilateral unreactive pupils. 46% of patients were scanned pre-randomisation and post-randomisation (n= 812/1767), 19% were scanned only pre-randomisation (n= 341/1767) and 35% were scanned only post-randomisation (n= 614/1767). In all patients, there was no evidence that TXA prevents intraparenchymal haemorrhage expansion (estimate= 1.09) or intracranial haemorrhage expansion in patients who underwent neurosurgical haemorrhage evacuation (n= 363), (estimate= 0.79). In patients scanned pre-randomisation and post-randomisation (n= 812), there was no evidence that TXA reduces progressive haemorrhage and new haemorrhage. When patients with unreactive pupils at baseline were excluded, there was evidence that TXA prevents new haemorrhage. In patients scanned post-randomisation (n= 1431), there was no evidence of an increase in infarction with TXA. A larger proportion of patients without (vs. with) a post-randomisation scan died from head injury (38% vs 19%).
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Tranexamic acid to reduce head injury death in people with traumatic brain injury: the CRASH-3 international RCT
Roberts I, Shakur-Still H, Aeron-Thomas A, Beaumont D, Belli A, Brenner A, Cargill M, Chaudhri R, Douglas N, Frimley L, et al
Health technology assessment (Winchester, England). 2021;25(26):1-76
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Editor's Choice
Abstract
BACKGROUND Tranexamic acid safely reduces mortality in traumatic extracranial bleeding. Intracranial bleeding is common after traumatic brain injury and can cause brain herniation and death. We assessed the effects of tranexamic acid in traumatic brain injury patients. OBJECTIVE To assess the effects of tranexamic acid on death, disability and vascular occlusive events in traumatic brain injury patients. We also assessed cost-effectiveness. DESIGN Randomised trial and economic evaluation. Patients were assigned by selecting a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients, caregivers and those assessing outcomes were masked to allocation. All analyses were by intention to treat. We assessed the cost-effectiveness of tranexamic acid versus no treatment from a UK NHS perspective using the trial results and a Markov model. SETTING 175 hospitals in 29 countries. PARTICIPANTS Adults with traumatic brain injury within 3 hours of injury with a Glasgow Coma Scale score of ≤ 12 or any intracranial bleeding on computerised tomography scan, and no major extracranial bleeding, were eligible. INTERVENTION Tranexamic acid (loading dose 1 g over 10 minutes then infusion of 1 g over 8 hours) or matching placebo. MAIN OUTCOME MEASURES Head injury death in hospital within 28 days of injury in patients treated within 3 hours of injury. Secondary outcomes were early head injury deaths, all-cause and cause-specific mortality, disability, vascular occlusive events, seizures, complications and adverse events. RESULTS Among patients treated within 3 hours of injury (n = 9127), the risk of head injury death was 18.5% in the tranexamic acid group versus 19.8% in the placebo group (855/4613 vs. 892/4514; risk ratio 0.94, 95% confidence interval 0.86 to 1.02). In a prespecified analysis excluding patients with a Glasgow Coma Scale score of 3 or bilateral unreactive pupils at baseline, the results were 12.5% in the tranexamic acid group versus 14.0% in the placebo group (485/3880 vs. 525/3757; risk ratio 0.89, 95% confidence interval 0.80 to 1.00). There was a reduction in the risk of head injury death with tranexamic acid in those with mild to moderate head injury (166/2846 vs. 207/2769; risk ratio 0.78, 95% confidence interval 0.64 to 0.95), but in those with severe head injury (689/1739 vs. 685/1710; risk ratio 0.99, 95% confidence interval 0.91 to 1.07) there was no apparent reduction (p-value for heterogeneity = 0.030). Early treatment was more effective in mild and moderate head injury (p = 0.005), but there was no obvious impact of time to treatment in cases of severe head injury (p = 0.73). The risk of disability, vascular occlusive events and seizures was similar in both groups. Tranexamic acid is highly cost-effective for mild and moderate traumatic brain injury (base case of £4288 per quality-adjusted life-year gained). CONCLUSION Early tranexamic acid treatment reduces head injury deaths. Treatment is cost-effective for patients with mild or moderate traumatic brain injury, or those with both pupils reactive. FUTURE WORK Further trials should examine early tranexamic acid treatment in mild head injury. Research on alternative routes of administration is needed. LIMITATIONS Time to treatment may have been underestimated. TRIAL REGISTRATION Current Controlled Trials ISRCTN15088122, ClinicalTrials.gov NCT01402882, EudraCT 2011-003669-14, Pan African Clinical Trial Registry PACTR20121000441277. FUNDING The project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 26. See the NIHR Journals Library website for further project information. In addition, funding was provided by JP Moulton Charitable Trust, Joint Global Health Trials (Medical Research Council, Department for International Development and the Wellcome Trust). This project was funded by the NIHR Global Health Trials programme.
PICO Summary
Population
Adults with traumatic brain injury enrolled in the CRASH-3 trial (n=9127).
Intervention
Tranexamic acid (TXA), (n= 4613).
Comparison
Matching placebo (n= 4514).
Outcome
The risk of head injury death was 18.5% in the TXA group versus 19.8% in the placebo group. In a pre-specified analysis excluding patients with a Glasgow Coma Scale score of 3 or bilateral unreactive pupils at baseline, the results were 12.5% in the TXA group versus 14.0% in the placebo group. There was a reduction in the risk of head injury death with tranexamic acid in those with mild to moderate head injury, but in those with severe head injury there was no apparent reduction. Early treatment was more effective in mild and moderate head injury, but there was no obvious impact of time to treatment in cases of severe head injury. The risk of disability, vascular occlusive events and seizures was similar in both groups.