A model-based control methodology was developed for automated regulation of mean arterial pressure and cardiac output in critical care subjects using inotropic and vasoactive drugs. The control algorithm used a multiple-model adaptive approach in a model predictive control framework to account for variability and explicitly handle drug rate constraints. The controller was experimentally evaluated on canines that were pharmacologically altered to exhibit symptoms of hypertension and depressed cardiac output. The controller performed better as compared to experiments on manual regulation of the hemodynamic variables. After the model bank was determined, mean arterial pressure was held within /spl plusmn/5 mm Hg 88.9% of the time with a standard deviation of 3.9 mmHg. The cardiac output was held within /spl plusmn/1 l/min 96.1% of the time with a standard deviation of 0.5 l/min. The manual runs maintain mean arterial pressure only 82.3% of the time with a standard deviation of 5 mmHg, and cardiac output 92.2% of the time with a standard deviation of 0.6 l/min.

Electrical impedance spectroscopy (EIS) is an electrokinetic method that allows for the characterization of intrinsic dielectric properties of cells. EIS has emerged in the last decade as a promising method for the characterization of cancerous cells, providing information on inductance, capacitance, and impedance of cells. The individual cell behavior can be quantified using its characteristic phase angle, amplitude, and frequency measurements obtained by fitting the input frequency-dependent cellular response to a resistor–capacitor circuit model. These electrical properties will provide important information about unique biomarkers related to the behavior of these cancerous cells, especially monitoring their chemoresistivity and sensitivity to chemotherapeutics. There are currently few methods to assess drug resistant cancer cells, and therefore it is difficult to identify and eliminate drug-resistant cancer cells found in static and metastatic tumors. Establishing techniques for the real-time monitoring of changes in cancer cell phenotypes is, therefore, important for understanding cancer cell dynamics and their plastic properties. EIS can be used to monitor these changes. In this review, we will cover the theory behind EIS, other impedance techniques, and how EIS can be used to monitor cell behavior and phenotype changes within cancerous cells.

The artificial pancreas (AP) is a closed-loop (CL) device with the potential to reduce the complications associated with type 1 diabetes mellitus (T1DM) by maintaining euglycemia in patients. The AP encompasses an algorithm that determines the amount of insulin (and other hormones) to be administered to the patient via a continuous subcutaneous insulin infusion (CSII) pump using information provided by a continuous glucose monitor (CGM) and other sensors. As the AP approaches commercialization special attention must be given to safety within all the individual components, including physiological changes in the patient, as well as, safety issues that can arise when these components are combined into a single system. Therefore, we analyzed the specific hazards applicable to the AP with the aim of exposing areas of safety that have yet to be addressed.

Experimental studies of two control methodologies for regulating multiple variables in critical care patients are described. The control strategies for the regulation of mean arterial pressure and cardiac output use vasoactive and inotropic drugs. Corresponding experimental results from the evaluation of the controllers with canines are presented.