A novel method for creating custom shaped ballistic gelatin trainers using plaster molds

Measuring the Compression Force Required for Vascular Shortening in Ultrasonic Vascular Models

Background Vascular compression is important for deep vein thrombosis screening. However, pressure analysis of ultrasound vessel models has not been performed. Therefore, we compared the human popliteal vein and several ultrasound vessel models at 50% compression. Methodology Four major ultrasound vascular models used in Japan and the popliteal vein of one subject constituted our measurement targets. Using a pressure-sensitive measuring device, the compressive force required to shorten the vessel diameter by 50% was determined. Results The compression force that shortened the popliteal vein by 50% was measured to be 191 ± 65 g. The blue phantom, ultrasound CV Pad II, ultrasound training block, and UGP-GEL required compression force of 701 ± 8 g, 265 ± 12 g, 697 ± 20 g, and 745 ± 15 g, respectively. The compression force for the ultrasound training block was 2.6 times higher than that for the ultrasound CV Pad II. The gel material around the vessels was the same; however, different vascular tubes required 2.6 times higher compression force. Conclusions This study showed that the objective numerical values of the compressive force were required to compress an ultrasound vascular model. Reproduction of the compressibility of veins required either removing the vascular structure or using thin tubing material.

A Unique Approach to Building a Learner-Guided Ultrasound Simulator for Central Venous Access Training

Commercial central line vascular access trainers are available but have significant limitations including cost, size, and limited durability when used for the complete procedure. A unique central venous access trainer was constructed using silicone loaf pan, ballistic gel, copper pipe and aluminum rods as vessels conduits, with varying inserts including latex and silicone to simulate different vascular structures, and the use of camouflage. This trainer is inexpensive, portable, reusable, allows the complete procedure to be simulated, and may be customized to the specific needs of the learner. The assembled simulator demonstrated excellent ultrasound visualization, including varying size and vessel character, allowed modification to specific learner needs, while at the same time being light-weight, portable, inexpensive, and reusable. A moderate-fidelity central venous access simulator can be constructed in a cost-effective manner, which can be optimized to the learner skill level and allows the entire procedure to be completed on the simulator.

Ballistic research techniques: visualizing gunshot wounding patterns

There are difficulties associated with mapping gunshot wound (GSW) patterns within opaque models. Depending on the damage measurement parameters required, there are multiple techniques that can provide methods of "seeing" the GSW pattern within an opaque model. The aim of this paper was to test several of these techniques within a cadaveric animal limb model to determine the most effective. The techniques of interest were flash X-ray, ultrasound, physical dissection, and computed-tomography (CT). Fallow deer hind limbs were chosen for the model with four limbs used for each technique tested. Quarantined 7.62 × 39 mm ammunition was used for each shot, and each limb was only shot once, on an outdoor range with shots impacting at muzzle velocity. Flash X-ray provided evidence of yaw within the limb during the projectile's flight; ultrasound though able to visualise the GSW track, was too subjective and was abandoned; dissection proved too unreliable due to the tissue being cadaveric so also too subjective; and lastly, CT with contrast provided excellent imaging in multiple viewing planes and 3D image reconstruction; this allowed versatile measurement of the GSW pattern to collect dimensions of damage as required. Of the different techniques examined in this study, CT with contrast proved the most effective to allow precise GSW pattern analysis within a cadaveric animal limb model. These findings may be beneficial to others wishing to undertake further ballistic study both within clinical and forensic fields.