Noninvasive Method and Metric for Monitoring Lung Condition.

For hospitalized patients with pulmonary conditions, the onset of respiratory decline can occur unnoticed, due to the absence of a way to continuously and noninvasively monitor lung condition. Based on the relationship between lung volume and pleural pressure, we hypothesized that the time delay (∆t) between the start of a respiratory cycle and the occurrence of lung sounds associated with inspiration would correlate with lung volume. Additionally, we developed a re-search tool, consisting of a respiration belt, digital stethoscope, data collection system and MATLAB algorithm, to measure this delay. We conducted a feasibility study with three healthy individuals that involved safely manipulating lung volume, through subject position and activity, and plotting ∆t against volume measurements obtained via spirometry. The results indicated that ∆t was measurable and changed with lung volume and, therefore, has the potential to serve as a lung condition monitoring tool.

Design and Applicability of a Mechanical Impedance Sensor for Vein Penetration Detection.

Intravenous needle insertion is typically conducted manually, with needles guided into vessels by feel while looking for a brief flash of blood. This process is imprecise and leads to mispositioned needles, multiple reinsertion attempts, increased procedure time and higher costs for the hospital. We present a method for indicating that the needle has reached the vein by measuring the change in mechanical impedance of the needle as it passes through different tissue layers. Testing in a phantom indicated that this has the potential to identify transitions through tissue boundaries.

Center of Gravity Tracker for Operator Fatigue Detection.

Driver fatigue is a cause of serious accidents for heavy machinery operators. Monitoring operator position, as indicated by their Center of Gravity (CoG), may be a means to non-invasively detect driver fatigue. We prototyped a research tool that tracks CoG from four sensors located within the legs of a seat, and validated its accuracy and precision. Our primary contributions are the development of a low-cost integrated CoG detector for seated drivers and the design of a flexure structure to protect load cells from shocks, tensile and shear forces. This system will enable research into CoG as an indicator of fatigue.