Chris Rylander

Abstract RealCooL is a platform technology that can rapidly heat or cool liquids. Currently, RealCooL is being redesigned for blood warming in austere environments. This new device will utilize a sodium acetate heater that can reach temperatures of 54 °C and a plastic heat exchanger composed of multiple polymer bags. Preliminary experiments were done to determine the type of material and number of bags needed to heat 500 mL in 60 s or less. Three materials were evaluated: EVA, metalized bags, and LDPE. Each type of bag was filled with 50 mL, 125 mL, 250 mL, and 500 mL of water and placed in a 54 °C water bath. The temperature was recorded after vigorously shaking the bag every minute. We found that four bags containing 125 mL of water are needed in order to heat 500 mL in 60 seconds or less. All three materials had similar thermal performance when filled with 125 mL, with an average temperature of 41±2.7 °C for all three bag types at 1 minute. Given that the thermal performance is so similar, future work will evaluate the durability of these three materials, as well as examine the effect of critical blood components while in contact with these materials by looking at things such as hemolysis and coagulation factors.

Abstract Premature infants often require respiratory support, vital signs monitoring, and gastric feeding during intensive care, but current monitoring systems rely on external devices that can damage fragile neonatal skin. This paper presents an engineering evaluation of the airway pressure sensing feature as part of a multifunctional feeding catheter designed to integrate vital signs monitoring and airway pressure monitoring with existing feeding capabilities. Two sensing modalities—direct sensing using embedded microtransducers and remote sensing via air-filled lumens—were experimentally compared under 24-h cyclic and static pressure conditions. Results show that while embedded sensors face challenges such as drift and miniaturization constraints, a remote architecture using an external amplified sensor offers superior signal stability and ease of integration. In addition, the study characterizes how lumen length and internal diameter affect pressure transmission. Narrow or excessively long lumens introduce signal delays as long as 15 s and signal dampening, while larger, shorter lumens preserve signal fidelity. These findings provide design guidance for future development of a multifunctional neonatal feeding and monitoring catheter and define critical engineering parameters for final performance optimization and manufacturability.

Abstract RealCooL is a device that can rapidly modify the temperature of many liquids to a desired target value. Extensive interviews revealed that there is a need for a device that can rapidly cool or heat liquids, specifically for the use of rewarming or chilling human milk for babies. Commercially available devices such as freezers or baby bottle warmers provide slow rates of chilling and lack the ability for temperature control of the milk. The heating and cooling rates of RealCooL were compared to two commercially available devices: a standard LG freezer for cooling and a Thermo Fisher water bath for heating. Bovine milk was used to simulate human milk in these experiments. Results indicate that RealCooL results in a 6-fold higher cooling rate and a 45-fold higher warming rate compared to commercial devices. Next steps include examination of whether RealCooL affects nutritive and biologically active components in human milk and determination of optimal cooling and heating rates for HM.

Abstract Convection-enhanced delivery is an experimental method for glioblastoma treatment. This work evaluates the Convection-Enhanced Therapy Catheter System (CETCS) by subjecting it to several cadaveric fetal bovine and porcine brain tests that replicate the anticipated future clinical use of the device. CETCS includes a cannula containing six microneedles. First, the CETCS cannula and microneedle visibility were evaluated with CT imaging in cadaveric tissue. Second, the cannula and microneedles were subjected to a cadaveric tissue insertion test and evaluated for tissue accumulation postinsertion. This test was also performed with a silicone elastomer material similar to a predicate device. A third test evaluated the microneedle's ability to undergo a syringe drop test with 3, 10, and 20 mL water-filled syringes. The results of this study prove that the CETCS cannula and microneedles are visible with CT imaging. CETCS and the predicate device material for the tissue insertion tests behave similarly, with an average tissue accumulation mass of 16.4 ± 3.6 mg and 21.4 ± 4.0 mg, respectively. The microneedles did not experience function-limiting damage with any attached syringes in the syringe drop test. The passing of all tests suggests that CETCS will satisfactorily meet regulatory testing milestones required for future clinical use.

Abstract Our lab is developing a novel device, the convection-enhanced thermo-chemotherapy catheter system (CETCS), to improve drug dispersal around a glioblastoma. To help prepare the device for clinical trials, we were advised to first prepare and receive 510(k)-clearance. The 510(k)-clearance process includes proving the novel device is substantially equivalent to a previously cleared predicate device. For the CETCS device, we have identified the Cleveland Multiport Catheter (CMC) as our predicate device. In this work, we test infusion pump flow rate, high-pressure flow rate, and microneedle tip deflection; each with respect to infusion and aspiration. The CMC’s 510(k) summary sheet provided guidelines for the test protocols to follow. If the CMC’s 510(k) summary did not state a metric, we set the metric based on the CETCS device specifications. Replicating or exceeding the threshold passing criteria set by the CMC device or the CETCS specifications demonstrates that CETCS is substantially equivalent to the predicate device for those specific metrics.