Grant H. Kruger

An Injectable 64 nW ECG Mixed-Signal SoC in 65 nm for Arrhythmia Monitoring

A syringe-implantable electrocardiography (ECG) monitoring system is proposed. The noise optimization and circuit techniques in the analog front-end (AFE) enable 31 nA current consumption while a minimum energy computation approach in the digital back-end reduces digital energy consumption by 40%. The proposed SoC is fabricated in 65 nm CMOS and consumes 64 nW while successfully detecting atrial fibrillation arrhythmia and storing the irregular waveform in memory in experiments using an ECG simulator, a live sheep, and an isolated sheep heart.

Specificity improvement for network distributed physiologic alarms based on a simple deterministic reactive intelligent agent in the critical care environment.

Automated physiologic alarms are available in most commercial physiologic monitors. However, due to the variability of data coming from the physiologic sensors describing the state of patients, false positive alarms frequently occur. Each alarm requires review and documentation, which consumes clinicians’ time, may reduce patient safety through ‘alert fatigue’ and makes automated physician paging infeasible. To address these issues a computerized architecture based on simple reactive intelligent agent technology has been developed and implemented in a live critical care unit to facilitate the investigation of deterministic algorithms for the improvement of the sensitivity and specificity of physiologic alarms. The initial proposed algorithm uses a combination of median filters and production rules to make decisions about what alarms to generate. The alarms are used to classify the state of patients and alerts can be easily viewed and distributed using standard network, SQL database and Internet technologies. To evaluate the proposed algorithm, a 28 day study was conducted in the University of Michigan Medical Center’s 14 bed Cardiothoracic Intensive Care Unit. Alarms generated by patient monitors, the intelligent agent and alerts documented on patient flow sheets were compared. Significant improvements in the specificity of the physiologic alarms based on systolic and mean blood pressure was found on average to be 99% and 88% respectively. Even through significant improvements were noted based on this algorithm much work still needs to be done to ensure the sensitivity of alarms and methods to handle spurious sensor data due to patient or sensor movement and other influences.

The use of portable ultrasound devices in low- and middle-income countries: a systematic review of the literature.

To review the scientific literature pertaining to the use of hand‐carried and hand‐held ultrasound devices in low‐ and middle‐income countries (LMIC), with a focus on clinical applications, geographical areas of use, the impact on patient management and technical features of the devices used.

24.3 An implantable 64nW ECG-monitoring mixed-signal SoC for arrhythmia diagnosis

Electrocardiography (ECG) is a critical source of information for a number of heart disorders. In arrhythmia studies and treatment, long-term observation is critical to determine the nature of the abnormality and its severity. However, even small body-wearable systems can impact a patients everyday life and signals captured using such systems are prone to noise from sources such as 60Hz power and body movement. In contrast, implanted devices are less susceptible to these noise sources and, while having closer-spaced electrodes, can obtain similar quality ECG signals due to their proximity to the heart [1]. In addition, implanted devices enable continuous monitoring without affecting patient quality of life. As in other implantable systems, low power consumption is a critical factor; in this case to provide a sufficiently long operating time between wireless recharge events.

Advanced integrated real-time clinical displays.

Intelligent medical displays have the potential to improve patient outcomes by integrating multiple physiologic signals, exhibiting high sensitivity and specificity, and reducing information overload for physicians. Research findings have suggested that information overload and distractions caused by patient care activities and alarms generated by multiple monitors in acute care situations, such as the operating room and the intensive care unit, may produce situations that negatively impact the outcomes of patients under anesthesia. This can be attributed to shortcomings of human-in-the-loop monitoring and the poor specificity of existing physiologic alarms. Modern artificial intelligence techniques (ie, intelligent software agents) are demonstrating the potential to meet the challenges of next-generation patient monitoring and alerting.

Analysis of the FSW Force Footprint and its Relationship with Process Parameters to Optimise Weld Performance and Tool Design

Advanced process automation is essential to ensure consistent and reliable friction stir welds. This paper illustrates the potential for a better understanding of the influence of certain process parameters on weld properties, through their monitoring and feedback into process control during the welding process. To accomplish this, the force footprint and temperature profile need to be accurately monitored and controlled during welding. In particular, the reaction forces of the tool can be described through a “force footprint” and related to weld quality and dynamic performance. This requires the integration of reliable and accurate sensor output into a computerised control program. Such an instrumented friction stir welding (FSW) set-up has been created. These parameters include tool torque, tool temperature, vertical force of the tool shoulder on the material and the horizontal force profile around the tool during its revolution. Future work will include more complete determination of the temperature profile associated with the thermomechanically affected zone (TMAZ) weld region. The system monitors these parameters during welding and can modify tool speed, feed and forces in response to changing weld conditions.

Intelligent machine agent architecture for adaptive control optimization of manufacturing processes

Intelligent agents have been earmarked as the key enabling technology to provide the flexibility required by modern, competitive, customer-orientated manufacturing environments. Rational agent behavior is of paramount importance when interacting with these environments to ensure significant losses are not incurred. To achieve rationality, intelligent agents must constantly balance technical (process) and economic (enterprise wide) trade-offs through co-operation, learning and autonomy. The research presented in this manuscript integrates methodological commonalities in intelligent manufacturing research and prognostics to design and evaluate a generic architecture for the core services of self-learning, rational, machining process regulation agents. The proposed architecture incorporates learning, flexibility and rational decision making through the integration of heterogeneous intelligent algorithms (i.e. neural networks and genetic algorithms) from fields such as machine learning, data mining and statistics. The architectures ability to perceive, learn and optimize is evaluated on a high-volume industrial gun drilling process.

Arterial elasticity imaging: Comparison of finite-element analysis models with high-resolution ultrasound speckle tracking

BackgroundThe nonlinear mechanical properties of internal organs and tissues may be measured with unparalleled precision using ultrasound imaging with phase-sensitive speckle tracking. The many potential applications of this important noninvasive diagnostic approach include measurement of arterial stiffness, which is associated with numerous major disease processes. The accuracy of previous ultrasound measurements of arterial stiffness and vascular elasticity has been limited by the relatively low strain of nonlinear structures under normal physiologic pressure and the measurement assumption that the effect of the surrounding tissue modulus might be ignored in both physiologic and pressure equalized conditions.MethodsThis study performed high-resolution ultrasound imaging of the brachial artery in a healthy adult subject under normal physiologic pressure and the use of external pressure (pressure equalization) to increase strain. These ultrasound results were compared to measurements of arterial strain as determined by finite-element analysis models with and without a surrounding tissue, which was represented by homogenous material with fixed elastic modulus.ResultsUse of the pressure equalization technique during imaging resulted in average strain values of 26% and 18% at the top and sides, respectively, compared to 5% and 2%, at the top and sides, respectively, under physiologic pressure. In the artery model that included surrounding tissue, strain was 19% and 16% under pressure equalization versus 9% and 13% at the top and sides, respectively, under physiologic pressure. The model without surrounding tissue had slightly higher levels of strain under physiologic pressure compared to the other model, but the resulting strain values under pressure equalization were > 60% and did not correspond to experimental values.ConclusionsSince pressure equalization may increase the dynamic range of strain imaging, the effect of the surrounding tissue on strain should be incorporated into models of arterial strain, particularly when the pressure equalization technique is used.

A 120nW 8b sub-ranging SAR ADC with signal-dependent charge recycling for biomedical applications

We present an 8-bit sub-ranging SAR ADC designed for bursty signals having long time periods with small code spread. A modified capacitive-DAC (CDAC) saves previous samples MSB voltage and reuses it throughout subsequent conversions. This prevents unnecessary switching of large MSB capacitors as well as conversion cycles, reducing energy consumed in the comparator and digital logic and yielding total energy savings of 2.6×. In 0.18μm CMOS, the ADC consumes 120nW at 0.6V and 100kS/s with 46.9dB SNDR.

Performance of Biopsy Needle With Therapeutic Injection System to Prevent Bleeding Complications

Renal disease is epidemic in the United States with approximately 8 × 106 people having chronic kidney disease. Renal biopsies are widely used to provide essential diagnostic information to physicians. However, the risk of bleeding complications possibly leading to life-threatening situations results in the contra-indication of biopsy in certain patient populations. Safer renal biopsies will allow more accurate diagnosis and better management of this epidemic health problem. We report the preclinical testing of a novel biopsy device called the therapeutic injection system (TIS). The device introduces a third stage to the standard two-stage side-cut percutaneous biopsy process. The third stage is designed to reduce bleeding complications by injecting a hemostatic plug at the time of biopsy. Laboratory evaluation and preliminary in vivo animal testing using an anticoagulated porcine model of the TIS and Bard Monopty® (Bard Medical, Covington, GA) control device were performed. The hemostatic material Gelfoam® (Pfizer, Brussels, Belgium) was selected as the active material comprising the hemostatic plugs. The performance of two composite plugs, one composed of polyvinyl alcohol (PVA) combined in 2:1 and 12:1 ratios with the hemostatic material, and one plug composed of 100[Formula: see text] hemostatic material were tested. Stroke sequence and hemostatic plug deployment were verified by sequential firing of the TIS biopsy needle into clear gelatin and ex vivo bovine kidney specimens. In vivo trials with porcine specimens revealed a significant reduction in blood loss (8.1 [Formula: see text] 3.9 ml, control versus 1.9 [Formula: see text] 1.6 ml, 12:1 PVA/hemostatic, TIS, [Formula: see text] = 0.01, [Formula: see text] = 6). The 100[Formula: see text] hemostatic plug showed a substantial and immediate reduction in blood loss (9.2 ml, control versus 0.0 ml, TIS, [Formula: see text] = 1). The prototype device was shown to work repeatedly and reliably in laboratory trials. Initial results show promise in this approach to control post biopsy bleeding. This solution maintains the simplicity and directness of the percutaneous approach, while not significantly changing the standard percutaneous biopsy procedure.