Increased Use of Prehospital Tourniquet and Patient Survival: Los Angeles Countywide Study

Effectiveness and safety of tourniquet utilization for civilian vascular extremity trauma in the pre-hospital settings: a systematic review and meta-analysis

BACKGROUND

Tourniquets (TQ) have been increasingly adopted in pre-hospital settings recently. This study examined the effectiveness and safety of applying TQ in the pre-hospital settings for civilian patients with traumatic vascular injuries to the extremities.

MATERIALS AND METHODS

We systematically searched the Ovid Embase, PubMed, and Cochrane Central Register of Controlled Trials databases from their inception to June 2023. We compared pre-hospital TQ (PH-TQ) use to no PH-TQ, defined as a TQ applied after hospital arrival or no TQ use at all, for civilian vascular extremity trauma patients. The primary outcome was overall mortality rate, and the secondary outcomes were blood product use and hospital stay. We analyzed TQ-related complications as safety outcomes. We tried to include randomized controlled trials (RCTs) and non-randomized studies (including non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies, and case-control studies), if available. Pooled odds ratios (ORs) were calculated and the certainty of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology.

RESULTS

Seven studies involving 4,095 patients were included. In the primary outcome, pre-hospital TQ (PH-TQ) use significantly decrease mortality rate in patients with extremity trauma (odds ratio [OR], 0.48, 95% confidence interval [CI] 0.27-0.86, I2 = 47%). Moreover, the use of PH-TQ showed the decreasing trend of utilization of blood products, such as packed red blood cells (mean difference [MD]: -2.1 [unit], 95% CI: -5.0 to 0.8, I2 = 99%) or fresh frozen plasma (MD: -1.0 [unit], 95% CI: -4.0 to 2.0, I2 = 98%); however, both are not statistically significant. No significant differences were observed in the lengths of hospital and intensive care unit stays. For the safety outcomes, PH-TQ use did not significantly increase risk of amputation (OR: 0.85, 95% CI: 0.43 to 1.68, I2 = 60%) or compartment syndrome (OR: 0.94, 95% CI: 0.37 to 2.35, I2 = 0%). The certainty of the evidence was very low across all outcomes.

CONCLUSION

The current data suggest that, in the pre-hospital settings, PH-TQ use for civilian patients with vascular traumatic injury of the extremities decreased mortality and tended to decrease blood transfusions. This did not increase the risk of amputation or compartment syndrome significantly.

Vascular imaging immediately after tourniquet removal does not increase vasospasm risk

BACKGROUND

Prehospital tourniquet use is now standard in trauma patients with diagnosed or suspected extremity vascular injuries. Tourniquet-related vasospasm is an understudied phenomenon that may confound management by causing erroneous arterial pressure indices (APIs) and abnormalities on computed tomography angiography (CTA) that do not reflect true arterial injuries. We hypothesized that shorter intervals between tourniquet removal and CTA imaging and longer total tourniquet times would be correlated with a higher likelihood of false positive CTA.

MATERIALS AND METHODS

We performed a single-institution retrospective cohort study of patients presenting to a busy, urban Level 1 Trauma Center with prehospital tourniquets from 2019 to 2021. Patients who presented with a tourniquet disengaged upon arrival or who died prior to admission to the Trauma Unit were excluded. Tourniquet duration, time between tourniquet removal and CTA imaging (CTA interval), CTA findings, and management of extremity arterial injuries were extracted. The proportion of false positive injuries on CTA was assessed for correlation with increasing time interval from tourniquet removal to CTA imaging and correlation with increasing total tourniquet time using multivariable logistic regression.

RESULTS

251 patients were identified with prehospital tourniquets. 127 underwent CTA of the affected extremity, 96 patients had an abnormal CTA finding, and 57 (45% of total CTA patients) had false positive arterial injuries on imaging. Using multivariable logistic regression, neither the CTA interval nor the tourniquet duration was associated with false positive CTA injuries. Female sex was associated with false positive injuries on CTA (OR 2.91, 95% CI: 1.01 - 8.39). Vasospasm was cited as a possible explanation by radiologists in 40% of false positive CTA reports.

CONCLUSIONS

Arterial vasospasm is a frequent finding on CTA after tourniquet use for extremity trauma, but concerns regarding tourniquet-related vasospasm should not alter trauma patient management. Neither the duration of tourniquet application nor the time interval since removal is associated with decreased CTA accuracy, and any delay in imaging does not appear to reduce the likelihood of vasospasm. These findings are important for supporting expedited care of trauma patients with severe extremity injuries.

Prehospital tourniquet application in extremity vascular trauma: Improved functional outcomes

BACKGROUND

Support for prehospital tourniquet use has increased, with recent data suggesting that tourniquet usage decreases shock without increasing limb complications. We hypothesized that prehospital tourniquet application in extremity vascular trauma, compared with no prehospital tourniquet application, is associated with lower rates of delayed amputation and better functional mobility.

METHODS

We retrospectively studied adult patients with extremity vascular trauma at an urban civilian Level 1 trauma center (June 2016-May 2021). Outcomes of interest included delayed amputation and mobility at hospital discharge, measured by the Activity Measure for Post-Acute Care "6 Clicks" Basic Mobility Score. The "6 Clicks" Basic Mobility Score was documented by physical therapy; higher scores indicate more independent mobility. Injury mechanism, initial lactate, 24-hour transfusions, mortality, and acute kidney injury were also collected. Comparisons were performed using χ2 analysis and Fisher Exact and Wilcoxon rank-sum tests.

RESULTS

Of 232 patients, prehospital tourniquet application was not associated with mortality or lactate level (both P > .05). The prehospital tourniquet application group had more transfusions, lower rates of acute kidney injury, and fewer delayed amputations (all P < .05). Ninety-one patients (45 prehospital tourniquet application and 46 without prehospital tourniquet application) were evaluated for "Moving between Bed and Chair" in the "6 Clicks" Basic Mobility Score, with patients in the prehospital tourniquet application group demonstrating higher levels of independence (P = .034).

CONCLUSION

Prehospital tourniquet application was associated with favorable outcomes, including higher functional mobility and decreased delayed amputation. This suggests that tourniquet use should be encouraged in the civilian setting to improve outcomes and reduce the risk of limb loss.

[Prehospital treatment of polytrauma : Ongoing challenge in prehospital emergency services]

Tscherne was the first to define the term polytrauma in 1966 as "multiple injuries to different regions of the body sustained simultaneously, with at least one injury or the combination of these injuries being life-threatening". This definition highlights the essential pathophysiological paradigm of polytrauma, with the life-threating characteristics resulting from injuries to multiple organ systems. The treatment of polytrauma patients begins at the scene of the accident. Important life-saving initial interventions can already be carried out on site through targeted measures and expertise of the emergency medical service team, thus improving patient survival. The advanced trauma life support/prehospital trauma life support (ATLS/PHTLS) concept is the worldwide gold standard. As prehospital treatment of severely injured patients is not routine for most emergency teams, concepts and emergency interventions must be regularly trained. This is the prerequisite for safe and effective emergency treatment in this time-critical situation.

[The chapters "Stop the bleed-prehospital" and "Coagulation management and volume therapy (emergency departement)" in the new S3 guideline "Polytrauma/severe injury treatment"]

The S3 guideline on the treatment of patients with severe/multiple injuries by the German Association of the Scientific Medical Societies was updated between 2020 and 2022. This article describes the essence of the new chapter "Stop the bleed-prehospital" and the revised chapter "Coagulation management and volume therapy".

The Impact of the Addition of a Virtual Reality Trainer on Skill Retention of Tourniquet Application for Hemorrhage Control Among Emergency Medical Technician Students: A Pilot Study

INTRODUCTION

Trauma is a leading cause of preventable death in the United States. Emergency Medical Technicians (EMTs) often arrive first at the scene of traumatic injuries to perform life-saving skills such as tourniquet placement. While current EMT courses teach and test tourniquet application, studies have shown efficacy and retention of EMT skills such as tourniquet placement decay over time, with educational interventions needed to improve retention of skills.

METHODS

A prospective randomized pilot study was conducted to determine differences in retention of tourniquet placement among 40 EMT students after initial training. Participants were randomly assigned to either a virtual reality (VR) intervention or a control group. The VR group received instruction from a refresher VR program 35 days after initial training as a supplement to their EMT course. Both the VR and control participants' tourniquet skills were assessed 70 days after initial training by blinded instructors.  Results: There was no significant difference in correct tourniquet placement between both groups (Control, 63% vs Intervention, 57%, p = 0.57). It was found that 9/21 participants (43%) in the VR intervention group failed to correctly apply the tourniquet while 7/19 of the control participants (37%) failed in tourniquet application. Additionally, the VR group was more likely to fail the tourniquet application due to improper tightening than the control group during the final assessment (p = 0.04).  Conclusion: In this pilot study, using a VR headset in conjunction with in-person training did not improve the efficacy and retention of tourniquet placement skills. Participants who received the VR intervention were more likely to have errors relating to haptics, rather than procedure-related errors.

Precise Limb Tourniquet Arterial Occlusion Pressure Determination using Real-Time Ultrasonography and a Capacitive-Based Force Sensor

BACKGROUND

Hemorrhage control prior to shock onset is increasingly recognized as a time-critical intervention. Although tourniquets (TQs) have been demonstrated to save lives, less is known about the physiologic parameters underlying successful TQ application beyond palpation of distal pulses. The current study directly visualized distal arterial occlusion via ultrasonography and measured associated pressure and contact force.

METHODS

Fifteen tactical officers participated as live models for the study. Arterial occlusion was performed using a standard adult blood pressure (BP) cuff and a Combat Application Tourniquet Generation 7 (CAT7) TQ, applied sequentially to the left mid-bicep. Arterial flow cessation was determined by radial artery palpation and brachial artery pulsed wave doppler ultrasound (US) evaluation. Steady state maximal generated force was measured using a thin-film force sensor.

RESULTS

The mean (95% CI) systolic blood pressure (SBP) required to occlude palpable distal pulse was 112.9mmHg (109-117); contact force was 23.8N [Newton] (22.0-25.6). Arterial flow was visible via US in 100% of subjects despite lack of palpable pulse. The mean (95% CI) SBP and contact force to eliminate US flow were 132mmHg (127-137) and 27.7N (25.1-30.3). The mean (95% CI) number of windlass turns to eliminate a palpable pulse was 1.3 (1.0-1.6) while 1.6 (1.2-1.9) turns were required to eliminate US flow.

CONCLUSIONS

Loss of distal radial pulse does not indicate lack of arterial flow distal to upper extremity TQ. On average, an additional one-quarter windlass turn was required to eliminate distal flow. Blood pressure and force measurements derived in this study may provide data to guide future TQ designs and inexpensive, physiologically accurate TQ training models.

Advances in the Management of Coagulopathy in Trauma: The Role of Viscoelastic Hemostatic Assays across All Phases of Trauma Care

Uncontrolled bleeding is the leading cause of preventable death following injury. Trauma-induced coagulopathy can manifest as diverse phenotypes ranging from hypocoagulability to hypercoagulability, which can change quickly during the acute phase of trauma care. The major advances in understanding coagulation over the past 25 years have resulted from the cell-based concept, emphasizing the key role of platelets and their interaction with the damaged endothelium. Consequently, conventional plasma-based coagulation testing is not accurate in predicting bleeding and does not provide an assessment of which blood products are indicated. Viscoelastic hemostatic assays (VHA), conducted in whole blood, have emerged as a superior method to guide goal-directed transfusion. The major change in resuscitation has been the shift from unbridled crystalloid loading to judicious balanced blood product administration. Furthermore, the recognition of the rapid changes from hypocoagulability to hypercoagulability has underscored the importance of ongoing surveillance beyond emergent surgery. While the benefits of VHA testing are maximized when used as early as possible, current technology limits use in the pre-hospital setting and the time to results compromises its utility in the emergency department. Thus, most of the reported experience with VHA in trauma is in the operating room and intensive care unit, where there is compelling data to support its value. This overview will address the current and potential role of VHA in the seriously injured patient, throughout the continuum of trauma management.

The tight rope act: A multicenter regional experience of tourniquets in acute trauma resuscitation

BACKGROUND

As tourniquets have become more prevalent, device use has been questioned. This study sought to characterize the incidence, indication, and efficacy of tourniquet placement in acute trauma resuscitation.

METHODS

Nine regional level 1 trauma centers prospectively enrolled for 12 months adult patients (18 years or older) who had a tourniquet placed. Age, sex, mechanism, tourniquet type, indication, applying personnel, location placed, level of occlusion, and degree of hemostasis were collected. Major vascular injury, imaging and operations performed, and outcomes were assessed. Analyses were performed with significance at p < 0.05.

RESULTS

A total of 216 tourniquet applications were reported on 209 patients. There were significantly more male patients (183 [88%]) and penetrating injuries (186 [89%]) with gunshots being most common (127 [61%]). Commercial tourniquets were most often used (205 [95%]). Ninety-two percent were placed in the prehospital setting (by fire/paramedics, 56%; police, 33%; bystanders, 2%). The most common indications were pooling (47%) and pulsatile (32%) hemorrhage. Only 2% were for amputation. The most frequent location was high proximal extremity (70%). Four percent were placed over the wound, and 0.5% were distal to the wound. Only 61% of applications were arterial occlusive. Median application time was 30 minutes (interquartile range, 20-40 minutes). Imaging was performed in 54% of patients. Overall, 36% had a named arterial injury. Tourniquet application failed to achieve hemostasis in 22% of patients with a named vascular injury. There was no difference in hemostasis between those with and without vascular injury (p = 0.12) or between who placed the tourniquet (p = 0.07). Seventy patients (34%) required vascular operations. Thirty-four percent of patients were discharged home without admission.

CONCLUSION

Discerning which injuries require tourniquets over pressure dressings remains elusive. Trained responders had high rates of superfluous and inadequate deployments. As tourniquets continue to be disseminated, emphasis should be placed on improving education, device development, and quality control.

LEVEL OF EVIDENCE

Prognostic/Epidemiologic, Level III.

Prehospital Tourniquets Placed on Limbs Without Major Vascular Injuries, has the Pendulum Swung Too far?

BACKGROUND

Combat applications of tourniquets for extremity trauma have led to increased civilian prehospital tourniquet use. Studies have demonstrated that appropriate prehospital tourniquet application can decrease the incidence of arrival in shock without increasing limb complications. The aim of this study was to examine outcomes of prehospital tourniquet placement without definitive vascular injury.

METHODS

Retrospective review was performed of a prospectively maintained database by the American Association for the Surgery of Trauma from 29 trauma centers. Patients in this subset analysis did not have a significant vascular injury as determined by imaging or intra-operatively. Patients who received prehospital tourniquets (PHTQ) were compared to patients without prehospital tourniquets (No-PHTQ). Outcomes were amputation rates, nerve palsy, compartment syndrome, and in-hospital mortality.

RESULTS

A total of 622 patients had no major vascular injury. The incidence of patients without major vascular injury was higher in the PHTQ group (n = 585/962, 60.8 vs n = 37/88, 42.0%, P < .001). Cohorts were similar in age, gender, penetrating mechanism, injury severity scores (ISS), abbreviated injury score (AIS), and mortality (P > .05). Amputation rates were 8.3% (n = 49/585) in the PHTQ group compared to 0% (n = 0/37) in the No-PHTQ group. Amputation rates were higher in PHTQ than No-PHTQ with similar ISS and AIS (P = .96, P = .59). The incidence of nerve palsy and compartment syndrome was not different (P > .05).

CONCLUSIONS

This study showed a significant amount of prehospital tourniquets are being placed on patients without vascular injuries. Further studies are needed to elucidate the appropriateness of prehospital tourniquets, including targeted education of tourniquet placement.

Recommendations for Improving Stop the Bleed: A Systematic Review

INTRODUCTION

In response to mass casualty events, The Hartford Consensus brought together subject matter experts across multiple disciplines in health care and public safety to create guidelines and publications intended to improve survivability in active shooter events. Among the recommendations was the earlier recognition and treatment application of life-threatening hemorrhage control. These recommendations culminated in efforts to create the Stop the Bleed Campaign, which aims to empower the layperson to render aid in a life-threatening bleeding emergency. As of February 2020, the program has held over 86,000 courses, trained over 1.4 million attendees, and over 77,000 instructors since its inception. In addition to spreading within the United States, American College of Surgeons (ACS) Stop the Bleed (StB) classes have been held in 118 different countries. This systematic narrative review aims to answer the following research question: What does the ACS StB Initiative do well, and where can it improve?

MATERIALS AND METHODS

The following search terms were utilized: "Stop the Bleed," "American College of Surgeons," "bleeding control," "first-aid," tourniquet, "wound pack," "direct pressure" hemorrhage, and bystander. The inclusion criteria were that the article needed to speak to the program or some aspect of bystander first aid, the article needed to be in a civilian setting, the article needed to be more than a case study or overview, and the first aid tools needed to be in the StB curriculum. 4 databases were searched, which produced 138 articles for screening. One hundred four full-text articles were able to be retrieved, and 56 articles were determined to meet the inclusion criteria once the full text was reviewed.

RESULTS

Fifty-six articles were included in the final review and were placed into the following categories: Needs Within the Community, Confidence and Knowledge, Training Modalities, Barriers and Gaps in Training, Instructor Selection, Skill Retention, and Patient Outcomes. The articles were then organized into each outcome for synthesis and reporting of the results. The program overwhelmingly improves short-term confidence, but gaps in skill retention, data collection on patient outcomes, and settings that would benefit were identified.

CONCLUSION

StB is an effective tool in building confidence in laypersons, which is its biggest strength. A review of the literature shows several areas where the curriculum and materials could be better developed. Research can also be further refined to better quantify the program's impact.

Blood component use and injury characteristics of acute trauma patients arriving from the scene of injury or as transfers to a large, mature US Level 1 trauma center serving a large, geographically diverse region

BACKGROUND

Advanced trauma care demands the timely availability of hemostatic blood products, posing special challenges for regional systems in geographically diverse areas. We describe acute trauma blood use by transfer status and injury characteristics at a large regional Level 1 trauma center.

STUDY DESIGN AND METHODS

We reviewed Harborview Medical Center (HMC) Trauma Registry, Transfusion Service, and electronic medical records on acute trauma patients for demographics, injury patterns, blood use, and in-hospital mortality, 2011-2019.

RESULTS

Among 47,471 patients (mean age 45.2 ± 23.0 years; 68.3% male; Injury Severity Score 12.6 ± 11.1), 4.7% died and 8547 (18%) received at least one blood component through HMC. Firearms injuries were the most often transfused (690/2596, 26.6%) and the most urgently (39.9% ≥3 units in <1 h; 40.6% ≥5 units in <4 h), and had the highest mortality (case-fatality, 12.2%) (all p < .001). From-scene patients were younger than transfers (42.9 ± 21.0 vs. 47.2 ± 24.4), predominated among firearms injuries (68.2% from-scene vs. 31.8% transfers), were more likely to receive blood (18.5% vs. 17.6%) more urgently (≥3 units first hour, 24.4% vs. 7.7%; ≥5 units first 4 h: 25.6% vs. 8.2%), were more likely to die of hemorrhage (15.5% vs. 4.3%) and from firearms injuries (310/1360, 22.8%) (all p < .001).

DISCUSSION

Early blood use, firearms injuries, and mortality were all greater among from-scene patients, and firearms injuries had worse outcomes despite greater and more urgent blood use, but the role of survivor bias for transfer patients must be clarified. Future research must identify strategies for providing local hemostatic transfusion support, particularly for firearms injuries.