Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 1999
Autoregulation in a simulator-based educational model of intracranial physiology.
To implement a realistic autoregulation mechanism to enhance an existing educational brain model that displays in real-time the cerebral metabolic rate (CMRO2), cerebral blood flow (CBF), cerebral blood volume (CBV), intracranial pressure (ICP), and cerebral perfusion pressure (CPP). ⋯ The autoregulated brain model, with incorporated CO2 responsivity and a variable oxygen extraction, automatically produces changes in CVR, CBF, CBV, and ICP consistent with literature reports, when run concurrently with a METI full-scale patient simulator (Medical Education Technologies, Inc., Sarasota, Florida). Once the model is enhanced to include herniation, vasospasm, and drug effects, its utility will be expanded beyond demonstrating only basic neuroanesthesia concepts.
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The Verbal Numerical Scale (VNS) for rating pain is bounded between 0 (= no pain) and 10 (= worst pain imaginable). We hypothesized that the limitations inherent to this boundary when rating extremely painful stimuli may be identified by integrating the VNS with an unbounded score such as magnitude estimation of relative change. ⋯ The combined use of VNS and magnitude estimation confirmed that the ceiling of the bounded pain scale may significantly limit a patient's ability to describe a new pain stimulus. VNSext may provide a means of overcoming this limitation.
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J Clin Monit Comput · Dec 1999
Ergonomic evaluation of an ecological interface and a profilogram display for hemodynamic monitoring.
Comprehensive monitoring of the patient state and subsequent decision making is an essential part of the task of an anaesthetist. The physicians' decision making process is based upon a concept of partly abstract physiologic parameters such as depth of anaesthesia or contractility. This concept is derived from the measured parameters given on todays' trend displays in addition to context information available for the anaesthetist. We investigated two alternative approaches of display design for hemodynamic monitoring: 1) integrated displays based on ecological interface design, and 2) profilogram displays based on intelligent alarms. ⋯ Our results have shown that subjects came to more effective solutions with the traditional trend display. The main reason for this result may be their years of experience with this kind of display type. Regarding safe and goal-intended decision finding, the results are encouraging for further experiments with redesigned ecological displays. But these displays ought to have smoother changes with respect to the traditional trend displays. Furthermore, new experiments have to be performed under real or fairly real (e.g. together with an anaesthesia simulator) conditions to underline the positive results for ecological interfaces.
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J Clin Monit Comput · Dec 1999
Response time of the Opti-Q continuous cardiac output pulmonary artery catheter in the urgent mode to a step change in cardiac output.
This study was conducted to determine the response time of the Opti-Q continuous cardiac output (CCO) device to a step change in cardiac. ⋯ Continuous cardiac output measurement was as accurate as those made by standard bolus thermodilution. The average response time to acute changes in cardiac output was approximately 1.5 minutes or ten times faster than previously reported systems. Response time is independent of animal mass, shunt volume and the direction of cardiac output perturbations.