Ruggedized Self-Propelling Hemostatic Gauze Delivers Low Dose of Thrombin and Systemic Tranexamic Acid and Achieves High Survival in Swine With Junctional Hemorrhage

INTRODUCTION

Hemorrhage is responsible for 91% of preventable prehospital deaths in combat. Bleeding from anatomic junctions such as the groin, neck, and axillae make up 19% of these deaths, and reports estimate that effective control of junctional hemorrhage could have prevented 5% of fatalities in Afghanistan. Hemostatic dressings are effective but are time-consuming to apply and are limited when proper packing and manual pressure are not feasible, such as during care under fire. CounterFlow-Gauze is a hemostatic dressing that is effective without compression and delivers thrombin and tranexamic acid into wounds. Here, an advanced prototype of CounterFlow-Gauze, containing a range of low thrombin doses, was tested in a lethal swine model of junctional hemorrhage. Outcomes were compared with those of Combat Gauze, the current dressing recommended by Tactical Combat Casualty Care.

MATERIALS AND METHODS

CounterFlow-Gauze containing thrombin doses of 0, 20, 200, and 500 IU was prepared. Swine received femoral arteriotomies, and CounterFlow-Gauze was packed into wounds without additional manual compression. In a separate study using a similar model of junctional hemorrhage without additional compression, CounterFlow-Gauze containing 500 IU thrombin was tested and compared with Combat Gauze. In both studies, the primary outcomes were survival to 3 h and volume of blood loss.

RESULTS

CounterFlow-Gauze with 200 and 500 IU had the highest 3-h survival, achieving 70 and 75% survival, respectively. CounterFlow-Gauze resulted in mean peak plasma tranexamic acid concentrations of 9.6 ± 1.0 µg/mL (mean ± SEM) within 3 h. In a separate study with smaller injury, CounterFlow-Gauze with 500 IU achieved 100% survival to 3 h compared with 92% in Combat Gauze animals.

CONCLUSIONS

An advanced preclinical prototype of CounterFlow-Gauze formulated with a minimized thrombin dose is highly effective at managing junctional hemorrhage without compression. These results demonstrate that CounterFlow-Gauze could be developed into a feasible alternative to Combat Gauze for hemorrhage control on the battlefield.

Self-propelling thrombin powder enables hemostasis with no observable recurrent bleeding or thrombosis over 3 days in a porcine model of upper GI bleeding

BACKGROUND AND AIMS

Hemostatic powders used to manage upper GI bleeding continue to exhibit high recurrent bleeding rates. Previously, self-propelling thrombin powder (SPTP) sprayed endoscopically managed severe Forrest class 1A bleeding. Here, we evaluate SPTP in a 3-day recovery model of diffuse ulcerated bleeding.

METHODS

Five anesthetized pigs underwent an endoscopic mucosal snare resection to trigger diffuse ulcer bleeding and were treated with SPTP. The time to hemostasis and the amount of powder delivered were measured. Pigs were recovered and monitored.

RESULTS

Five pigs achieved hemostasis in 4.5 ± 1.2 minutes At 3 days after the procedure, the pigs were rescoped and showed no recurrent bleeding. Measured blood parameters were not significantly different from baseline. There were no signs of foreign bodies or thromboembolism during gross necropsy and histopathology of key organs.

CONCLUSIONS

SPTP is a promising novel material that stopped diffuse ulcer bleeding in 5 pigs without recurrent bleeding or adverse local or systemic events.

Hemostatic powders for gastrointestinal bleeding: a review of old, new, and emerging agents in a rapidly advancing field

Background and study aims  Hemostatic powders are increasingly used to address limitations in conventional endoscopic techniques for gastrointestinal bleeding. Various agents exist with different compositions, characteristics, efficacy, and adverse events (AEs). We sought to review existing hemostatic powders, from preclinical to established agents. Methods  A literature review on hemostatic powders for gastrointestinal bleeding was undertaken through a MEDLINE search from 2000-2021 and hand searching of articles. Relevant literature was critically appraised and reviewed for mechanism of action, hemostasis and rebleeding rate, factors associated with hemostatic failure, and AEs. Results  The most established agents are TC-325 (Hemospray), EndoClot, and Ankaferd Blood Stopper (ABS). These agents have been successfully applied to a variety of upper and lower gastrointestinal bleeding etiologies, in the form of primary, combination, salvage, and bridging therapy. Few AEs have been reported, including visceral perforation, venous embolism, and self-limited abdominal pain. Newer agents include CEGP-003 and UI-EWD, which have shown results similar to those for the older agents in initial clinical studies. All aforementioned powders have high immediate hemostasis rates, particularly in scenarios not amenable to conventional endoscopic methods, but are limited by significant rates of rebleeding. Other treatments include TDM-621 (PuraStat) consisting of a liquid hemostatic agent newly applied to endoscopy and self-propelling thrombin powder (CounterFlow Powder), a preclinical but promising agent. Conclusions  Rapid development of hemostatic powders and growing clinical expertise has established these agents as a valuable strategy in gastrointestinal bleeding. Further research will continue to refine the efficacy and applicability of these agents.

Videoconferencing for Large Animal Trauma Experiments During COVID-19: A Cross-Continent Experience

INTRODUCTION

COVID-19 shutdowns in many research facilities across North America impacted preclinical trauma-related research and development. Shutdown limited the speed and resources available for large animal experiments necessary for advancing medical devices and technologies. However, the pandemic led to the rapid adoption and expansion of videoconferencing in social circles, workplaces, and primary care health settings. Here, we describe the use of simple videoconferencing equipment to plan and carry out 3 total weeks of large animal experiments with a large, cross-continent, interdisciplinary team testing a novel technology in swine models of noncompressible intraabdominal hemorrhage and junctional hemorrhage.

MATERIALS AND METHODS

Animal experiments using swine were scheduled over 3 weeks in February and March 2021 to take place in Toronto, Canada. All relevant animal protocols and COVID-19 site-specific risk assessments were completed and approved by the responsible institutional committees. Experiments were conducted by connecting 12 total research personnel from 3 sites by a simple video conferencing setup which included low-cost, high-definition webcams and standard smartphones streaming to Zoom.

RESULTS

Video conferencing allowed for 3 weeks of trauma experiments to take place at the height of Toronto's third peak of COVID-19 cases. Up to 3 experiments were completed for models requiring 6 hours of monitoring, and up to 5 experiments were completed for models requiring 3 hours of monitoring. The large amount of digital data collected during these experiments was rapidly shared with our network of collaborators, who analyzed results and interpreted findings in real time.

CONCLUSIONS

The system described in this paper has the potential to reduce costs of trauma animal model development and allow for rapid testing and implementation of life-saving devices in settings with limited onsite personnel as experienced during the COVID-19 pandemic.

Severe upper gastrointestinal bleeding is halted by endoscopically delivered self-propelling thrombin powder: A porcine pilot study

Background and study aims  Hemostatic powders have emerged recently to treat upper gastrointestinal bleeding (UGIB). Previously, we developed a novel self-propelling thrombin powder (SPTP) that effectively manages external pulsatile arterial bleed without compression, by effervescing and carrying thrombin into the wound. Here, we tested if SPTP, sprayed endoscopically, can manage severe UGIB in a live porcine model. Materials and methods  Anesthetized pigs underwent laparotomy to insert the gastroepiploic vascular bundles into the stomach lumen via a gastrotomy. Bleeding was initiated endoscopically in the stomach by needle knife. SPTP was delivered to the site of bleeding from a CO ₂ -powered spray device using a 7 FR catheter. Successful primary hemostasis, time to hemostasis, and the mass of SPTP delivered were measured. Results  Hemostasis was achieved at all bleeding sites using SPTP. Mean time to hemostasis was 4.2 ± 0.9 minutes (mean ± standard error of the mean, n = 12). The average mass of SPTP delivered was 2.4 ± 0.6 g. Conclusions  In this pilot study, SPTP successfully stopped 12 cases of severe UGIB, demonstrating early promise asa novel hemostatic powder.

High rate of re-bleeding after application of Hemospray for upper and lower gastrointestinal bleeds

BACKGROUND & AIMS

Hemospray (TC-325, Cook Medical) has recently been approved for use in GI bleeding. Specific clinical indications and predictors of success or failure have not been well delineated.

METHODS

We conducted a retrospective cohort study of Hemospray use at a tertiary center. We assessed demographics and characteristics of Hemospray use. We analyzed outcomes of hemostasis, rebleeding, need for embolization or surgery, and death.

RESULTS

86 applications of Hemospray were identified. The most common etiology of upper GI bleeds were ulcers (67.1%) whilst the etiology of lower GI bleeds varied. Hemospray was applied as monotherapy in 28 procedures (32.6%). Immediate hemostasis rate was 88.4%, but there was a high rate of re-bleeding (33.7%). Most re-bleeds occurred within 7 days (86.2%). Syncope was an independent predictive factor re-bleeding at 7 days for EGD (OR = 12.16, 95% CI = 1.51-97.75, P = 0.019). Bleeding refractory to endoscopic treatment with hemospray required radiological embolization in 9 instances, and surgery in 9 instances. Hemospray therapy was protective against need for embolization (p < 0.05). 2 patients underwent liver transplantation and there was a total of 5 deaths. Hepatic disease was an independent predictor of death (OR = 47.15, 95% CI = 2.42-916.89, P = 0.011).

CONCLUSION

Hemospray is effective in achieving immediate hemostasis but is plagued by high rates of rebleeding. Syncope is a predictor of rebleeding, and hepatic disease is a predictor of death in patients undergoing Hemospray therapy. Despite high rates of embolization and surgery, Hemospray may reduce need for embolization. Hemospray use during endoscopy should prompt physicians to consider early re-look endoscopy and more aggressive therapy.