Research: Testing of a Novel Portable Body Temperature Conditioner Using a Thermal Manikin.

A battery-operated active cooling/heating device was developed to maintain thermoregulation of trauma victims in austere environments while awaiting evacuation to a hospital for further treatment. The use of a thermal manikin was adopted for this study in order to simulate load testing and evaluate the performance of this novel portable active cooling/heating device for both continuous (external power source) and battery power. The performance of the portable body temperature conditioner (PBTC) was evaluated through cooling/heating fraction tests to analyze the heat transfer between a thermal manikin and circulating water blanket to show consistent performance while operating under battery power. For the cooling/heating fraction tests, the ambient temperature was set to 15°C ± 1°C (heating) and 30°C ± 1°C (cooling). The PBTC water temperature was set to 37°C for the heating mode tests and 15°C for the cooling mode tests. The results showed consistent performance of the PBTC in terms of cooling/heating capacity while operating under both continuous and battery power. The PBTC functioned as intended and shows promise as a portable warming/cooling device for operation in the field.

Imaging assessment of a portable hemodialysis device: detection of possible failure modes and monitoring of functional performance.

BACKGROUND: The purpose of this study was to investigate the utility and limitations of various imaging modalities in the noninvasive assessment of a novel compact hemodialyzer under development for renal replacement therapy, with specific aim towards monitoring its functional performance. METHODS: The prototype is a 4×3×6 cm aluminum cartridge housing "blood" and "dialysate" flow paths arranged in parallel. A sheet of semipermeable silicon nanopore membranes forms the blood-dialysate interface, allowing passage of small molecules. Blood flow was simulated using a peristaltic pump to instill iodinated contrast through the blood compartment, while de-ionized water was instilled through the dialysate compartment at a matched rate in the countercurrent direction. Images were acquired under these flow conditions using multi-detector computed tomography (MDCT), fluoroscopy, high-resolution quantitative computed tomography (HR-QCT), and magnetic resonance imaging (MRI). MDCT was used to monitor contrast diffusion efficiency by plotting contrast density as a function of position along the path of flow through the cartridge during steady state infusion at 1 and 20 mL/min. Both linear and exponential regressions were used to model contrast decay along the flow path. RESULTS: Both linear and exponential models of contrast decay appeared to be reasonable approximations, yielding similar results for contrast diffusion during a single pass through the cartridge. There was no measurable difference in contrast diffusion when comparing 1 mL/min and 20 mL/min flow rates. Fluoroscopy allowed a gross qualitative assessment of flow within the device, and revealed flow inhomogeneity within the corner of the cartridge opposite the blood inlet port. MRI and HR-QCT were both severely limited due to the paramagnetic properties and high atomic number of the target material, respectively. During testing, we encountered several causes of device malfunction, including leak formation, trapped gas, and contrast-mediated nanopore clogging. We illustrate the imaging manifestations of each. CONCLUSIONS: Despite the inherent challenges in imaging a predominantly metallic device, some modalities show potential in the non-invasive assessment of a novel compact hemodialyzer. The approaches described here could potentially be translated to device evaluation in the implanted setting.

Development of a broadband telehealth system for critical care: process and lessons learned.

A broadband telehealth system has been developed for supporting critical care services between a major referral hospital and a rural hospital by transmitting very high-quality, realtime multimedia information, including images, audio and real-time video, over an Internet Protocol (IP)-based network. The technical design team took an iterative and user-centred approach toward the system design. Usability tests with scenario analysis were incorporated into the development process to produce a system that operates seamlessly in the critical care environment. Careful analysis of the reliability of the system was incorporated into the clinical protocols for integration into existing work practices. The use of high-quality multimedia data, consideration of human factors early in the design process, and incorporation of proper development approaches were critical for the success of the system design.