In Situ Tremor in Vitreoretinal Surgery.

OBJECTIVE: Surgeon tremor was measured during vitreoretinal microscopic surgeries under different hand support conditions. BACKGROUND: While the ophthalmic surgeon's forearm is supported using a standard symmetric wrist rest when operating on the patient's same side as the dominant hand (SSD), the surgeon's hand is placed directly on the patient's forehead when operating on the contralateral side of the dominant hand (CSD). It was hypothesized that more tremor is associated with CSD surgeries than SSD surgeries and that, using an experimental asymmetric wrist rest where the contralateral wrist bar gradually rises and curves toward the patient's operative eye, there is no difference in tremor associated with CSD and SSD surgeries. METHODS: Seventy-six microscope videos, recorded from three surgeons performing macular membrane peeling operations, were analyzed using marker-less motion tracking, and movement data (instrument path length and acceleration) were recorded. Tremor acceleration frequency and magnitude were measured using spectral analysis. Following 47 surgeries using a conventional symmetric wrist support, surgeons incorporated the experimental asymmetric wrist rest into their surgical routine. RESULTS: There was 0.11 mm/s2 (22%) greater (p = .05) average tremor acceleration magnitude for CSD surgeries (0.62 mm/s2, SD = 0.08) than SSD surgeries (0.51 mm/s2, SD = 0.09) for the symmetric wrist rest, while no significant (p > .05) differences were observed (0.57 mm, SD = 0.13 for SSD and 0.58 mm, SD = 0.11 for CSD surgeries) for the experimental asymmetric wrist rest. CONCLUSION: The asymmetric wrist support reduced the difference in tremor acceleration between CSD and SSD surgeries.

Automated Device for Uncapping Multiple-Size Bioanalytical Sample Tubes Designed to Reduce Technician Strain and Increase Productivity.

Technicians in a commercial laboratory manually uncap up to 700 sample tubes daily in preparation for bioanalytical testing. Manually twisting off sample tube caps not only is a time-consuming task, but also poses increased risk for muscle fatigue and repetitive-motion injuries. An automated device capable of uncapping sample tubes at a rate faster than the current workflow would be valuable for minimizing strain on technicians' hands and saving time. Although several commercial sample tube-uncapping products exist, they are not always usable for a workload that uses a mix of tube sizes and specific workflow. A functioning uncapping device was developed that can semi-automatically uncap sample tubes with three different heights and diameters and was compatible with the workflow in a commercial laboratory setting. Under limited testing, the average success rate with uncapping each of the three sample tube sizes or a mix of them was 90% or more, more than three times faster than manual uncapping, and met standard acceptance criteria using mass spectrometry. Our device with its current performance is still a prototype, requiring further development. It showed promise for ergonomic benefit to the laboratory technicians, however, reducing the necessity to manually unscrew caps.

Review of pulmonary emboli and techniques for their mechanical removal to inform device design.

Pulmonary emboli present a significant burden of disease, with limited treatment options for some patients. Mechanical devices for pulmonary emboli removal are becoming increasingly prevalent though more work remains to be done. This paper briefly discusses the mechanical properties of pulmonary emboli, the disease state they cause, and the existing embolectomy devices. The goal of this paper is to aid the design of minimally invasive mechanical pulmonary emboli removal devices, by providing a review of this topic as well as some key design specifications.

Void sorcerer: an open source, open access framework for mouse uroflowmetry.

Observational and experimental studies of rodent voiding behaviors have greatly contributed to our understanding of lower urinary tract function including the complex social, environmental, and internal stimuli that affect voiding in health and models of disease. Void spot assays (VSA), cystometry (awake or anesthetized), and uroflowmetry are techniques commonly used in rodent models to assess voiding. Uroflowmetry is non-invasive and can be performed multiple times in the same freely moving animals and can be used to generate synchronized video corresponding to each void to characterize micturition patterns (e.g., droplets versus solid stream). However, approaches to evaluate uroflowmetry in rodent models vary widely across laboratories. Most importantly, an open access software to run these tests is not freely available (although complete systems are commercially available), limiting use of this important assay. We developed the Void Sorcerer, an uroflowmetry system for mice for reliable determination of frequency, voided volume, voiding duration, interval times between micturitions, and flow rate. This report provides a detailed description of how to build this system and includes open access software for developing uroflowmetry capability in their laboratories and improve upon it in a cost-effective manner. Our goals are to improve access, increase reproducibility among laboratories, and facilitate standardizing testing procedures.

Easy calibration of the Light Plate Apparatus for optogenetic experiments.

Optogenetic systems use genetically-encoded light-sensitive proteins to control and study cellular processes. As the number and quality of these systems grows, there is an increasing need for user-friendly and flexible hardware to provide programmed illumination to cultures of cells. One platform which satisfies this need for a variety of optogenetic systems and organisms is the Light Plate Apparatus (LPA), which delivers a controlled light dose to each well of a 24-well plate. Experimental reproducibility requires appropriate calibration to produce accurate light doses within individual wells of the LPA and between LPAs. In this study, we present an easy and accurate method for calibrating the LPA. In particular, we: •developed a 3D printed adaptor and MATLAB code to allow rapid measurement of irradiance produced by the LPA and subsequent calibration•provide appropriate code and methodology for generating a standard curve for each LPA•demonstrate the utility and accuracy of this method between users and LPAs.

Surgical sponge blood salvage spinning device design and testing.

One method to clear intraoperative blood from the surgical field is to remove blood with surgical sponges. Currently, absorbed blood cannot be retrieved effectively and is lost. A spinning device was created to salvage red blood cells from the sponges. With this device the sponges are gently washed with saline and the resultant bloody fluid can be delivered to a cell saver to prepare it for autologous blood transfusion. In this article, we demonstrate how a novel sponge extractor can be used to extract blood from sponges. Several tests were conducted with porcine blood to optimise viable blood salvage by varying spin speed, and spin time of the device. At spin speeds greater than 1000 RPM, the blood salvaged from the device was similar to blood volumes obtained by hand wringing sponges. Cell viability testing yielded no significant differences in haemolysis for device trials compared to gently hand wringing. Spin time testing showed no significant differences in the blood salvaged at times greater than one minute. Optimal parameters for the device were determined to be a one-minute spin time at 1500 RPM.

Reducing thumb extensor risk in laboratory rat gavage.

Gavage is a common technique for orally administering compounds to small laboratory animals using a syringe. It involves highly repetitive thumb extensor exertions for filling the syringe, a risk factor for DeQuervain's tenosynovitis. As an intervention, a series of bench tests were performed varying fluid viscosity, syringe size and needle size to determine the forces required for drawing fluid. Forces up to 28 N were observed for a viscosity of 0.29 Pa s. A guide is presented to minimize thumb forces for a particular combination of syringe (3 mL, 5 mL and 10 mL), fluid viscosity (0.001 Pa s, 0.065 Pa s, 0.21 and 0.29 Pa s), and needle length (52 mm, 78 mm and 100 mm) based on maximum acceptable exertion levels. In general, a small syringe and large needle size had a greater number of acceptable rat gavages per day due to the lower forces experienced as compared to all other syringe and needle combinations.

TaserX26 current increases with dart depth.

The TaserX26 output current waveform consists of an arc phase and a stimulation phase, which is responsible for electromuscular stimulation. We modeled the current discharge during the stimulation phase using a simplified overdamped series R-L-C circuit. The model provides a reasonable approximation to the TaserX26 current waveform and explains the changes in the peak current and rise and fall time constants due to load variations. We simulated a physiological load using a 0.2% saline solution in a 75 × 30 × 17.2 cm fish tank to represent a supine human torso with resistivity similar to skeletal muscles. The peak current and load resistance varied more with the depth of the Taser darts in saline than with their distance of separation. Experiments performed on three pigs confirmed the decrease in resistance and increase in current with the depth of the Taser dart in the body. An R-C circuit with a time constant of about 2 ms was used to measure the variation of the Taser in stimulating cardiac cells. The Taser is 2.05 times more likely to stimulate the cardiac cell when the darts penetrate 9 mm into the load as compared to when they were just touching the load.

Hands-on curriculum teaches biomedical engineering concepts to home-schooled students.

University level outreach has increased over the last decade to stimulate K-12 student interest in engineering related fields. Home schooling students are one of the groups that are valued for engineering admissions due to diligent study habits and high achievement scores. However, home schooled students have inadequate access to science, math, and engineering related resources, which precludes the development of interdisciplinary teaching methods. To address this problem, we have developed a hands-on, STEM based curriculum as a safe and comprehensive supplement to current home schooling curricula. The ultimate goal is to stimulate university-student relations and subsequently increase engineering recruitment opportunities. Our pre and post workshop survey comparisons demonstrate that integrating disciplines, via the manner presented in this study, provides a K-12 student-friendly engineering learning method.

Medical devices for developing countries: design constraints and approaches.

Medical devices intended for use in developing countries have certain differences compared to those used in developed countries. Thus, many of the medical devices built for developed countries may not be compatible with the environment in developing countries. In this specific case study we consider the respiratory problems in India and elucidate design constraints and approaches for the development of medical devices to diagnose them.

Battery power comparison to charge medical devices in developing countries.

Many people in developing countries cannot afford or rely on certain modes of electricity. We establish the reasonability of relying on lead-acid batteries, 9 V alkaline batteries, and lithium-ion batteries for charging low-voltage medical equipment. Based on the research and tests we conducted, we determined that using these battery types to charge medical devices truly is a reasonable solution.

Electronic medical record systems for developing countries: review.

The majority of the focus related to the modernization of medical records is placed on developed countries. However, developing countries are also progressing from paper-based records to electronic records. The requirements of their systems can be dramatically different from those of the developed world. This paper describes briefly the benefits of EMRs in developing countries. It focuses on the basic EMR information, including types of EMRs, components of EMRs, and already existing case studies, in order to establish which EMR systems would be feasible and effective for specific situations.

Global engineering education initiative through student organization.

Engineering is becoming a more globally aware discipline that is revolutionizing the way individuals interact internationally. Engineering World Health (EWH) - Madison Chapter is a student-initiated organization that has developed opportunities to facilitate both local and global engineering education. Through EWH - Madison Chapter student-initiated activities, this organization has developed an interface between Traditional, Technical, and Translational education mediums. This study attests to the development of global engineering programs in the context of biomedical applications.

Safety of pulsed electric devices.

The strength-duration curve for tissue excitation can be modeled by a parallel resistor-capacitor circuit that has a time constant. We tested several short-duration electric generators: five electric fence energizers, the Taser X26 and a high-frequency generator to determine their current-versus-time waveforms. We estimated their safety characteristics using existing IEC and UL standards for electric fence energizers. The current standards are difficult to follow, with cumbersome calculations, and do not explicitly explain the physiological relevance of the calculated parameters. Hence we propose a new standard. The proposed new standard would consist of a physical RC circuit with a certain time constant. The investigator would discharge the device into a passive resistor-capacitor circuit and measure the resulting maximum voltage. If the maximum voltage does not exceed a limit, the device passes the test.

Ventricular fibrillation time constant for swine.

The strength-duration curve for cardiac excitation can be modeled by a parallel resistor-capacitor circuit that has a time constant. Experiments on six pigs were performed by delivering current from the X26 Taser dart at a distance from the heart to cause ventricular fibrillation (VF). The X26 Taser is an electromuscular incapacitation device (EMD), which generates about 50 kV and delivers a pulse train of about 15-19 pulses s(-1) with a pulse duration of about 150 micros and peak current about 2 A. Similarly a continuous 60 Hz alternating current of the amplitude required to cause VF was delivered from the same distance. The average current and duration of the current pulse were estimated in both sets of experiments. The strength-duration equation was solved to yield an average time constant of 2.87 ms +/- 1.90 (SD). Results obtained may help in the development of safety standards for future electromuscular incapacitation devices (EMDs) without requiring additional animal tests.

R-peak detection and signal averaging for simulated stress ECG using EMD.

This study used empirical mode decomposition (EMD) for R-peak detection in electrocardiogram signals in the presence of electromyogram-like noise. The EMG was modeled as random white Gaussian noise with a signal-to-noise ratio (SNR) in the range of around -10 dB to -20 dB. The EMD-based R-peak detection technique gives results comparable to those obtained with the Pan-Tompkins algorithm. The EMD technique is implemented for filtering of noisy ECG signals and is further compared with a traditional low-pass filtering approach. Finally signal averaging is performed using the EMD-based R-peak detection and filtering approach and compared with the standard signal averaging technique. We conclude that the EMD based technique for R-peak detection and filtering shows promise for enhancement of the stress ECG.

EMD-based 60-Hz noise filtering of the ECG.

This study used empirical mode decomposition (EMD) for filtering power line noise in electrocardiogram signals. When the signal-to-noise (SNR) is low, the power line noise is separated out as the first intrinsic mode function (IMF), but when the SNR is high, a part of the signal along with the noise is decomposed as the first IMF. To overcome this problem, we add a pseudo noise at a frequency higher than the highest frequency of the signal to filter out just the power line noise in the first IMF. The results are compared with traditional IIR-based bandstop filtering. This technique is also implemented for filtering power line noise during enhancement of stress ECG signals.