Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
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We describe a novel algorithm to estimate the pulse pressure variation index (PPV) from arterial blood pressure signals (ABP). PPV has been shown to be one of the best predictors of fluid responsiveness in mechanically ventilated subjects. Our PPV algorithm uses a non-linear technique for envelope estimation, eliminating the need for automatic beat detection. ⋯ The algorithm was validated against the continuous PPV output obtained from the commercially available PiCCOreg system and gold standard expert PPV manual annotations. The data consists of ABP taken from subjects who experienced rapid changes in hemodynamics. This data comprised over six hours of continuous ABP monitoring.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2006
ReviewIntegrating data, models, and reasoning in critical care.
Modern intensive care units (ICUs) employ an impressive array of technologically sophisticated instrumentation to provide detailed measurements of the pathophysiological state of each patient. Providing life support in the ICU is becoming an increasingly complex task, however, because of the growing volume of relevant data from clinical observations, bedside monitors, mechanical ventilators, and a wide variety of laboratory tests and imaging studies. ⋯ There is a critical need to integrate the disparate clinical information into a single, rational framework and to provide the clinician with hypothesis-driven displays that succinctly summarize a patient's trajectory over time. In this paper, we present our recent efforts towards the development of such an advanced patient monitoring system that aims to improve the efficiency, accuracy, and timeliness of clinical decision making in intensive care.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2006
High rate shear insult delivered to cortical neurons produces heterogeneous membrane permeability alterations.
Traumatic brain injury (TBI) occurs when brain tissue is subjected to stresses and strains at high rates and magnitudes, yet the mechanisms of injury and cellular thresholds are not well understood. The events that occur at the time of and immediately after an insult are hypothesized to initiate cell dysfunction or death following a critical cell strain and strain rate. We analyzed neuronal plasma membrane disruption in two in vitro injury models-fluid shear stress delivered to planar cultures and shear strain induction of 3-D neural cultures. ⋯ Furthermore, increased membrane permeability led to increases in electrophysiological disturbance. Specifically, cells that exhibited increased membrane permeability did not fire random action potentials, in contrast to neighboring cells that had intact plasma membranes. This approach provides an experimental framework to investigate injury tolerance criteria as well as mechanistically driven therapeutic strategies.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Development and implementation of a biomedical information network.
Once the requirement for a biomedical information network has been articulated, the process of development and implementation can then be approached. Although the general architecture of such a system may appear to be self evident, there are careful design considerations that will allow the network to be robust and achieve increased levels of functionality as additional systems come on-line and become integrated into the network. ⋯ We have chosen the Emergin Orchestrator product (Boca Raton, Fl) as the vehicle for integrating these systems. The major design and implementation tasks include defining the basic information architecture, assessing the performance of the existing IT infrastructure, and understanding the native capabilities and limitations of each system involved in the network.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2006
Using a generalized neural network to identify airway obstructions in anesthetized patients postoperatively based on photoplethysmography.
Photoplethysmography has been recently studied asa non-invasive indicator of circulatory and respiratory function. In this study, photoplethysmographic (PPG) data were recorded from patients under the influence of anesthesia, but not intubated. ⋯ This classifier considers inter-subject variability so that it generalizes well to a large population. This classifier provided 86.1%accuracy to classify segments as being times of 'obstructed' vs.'normal' airways status.