Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2006
Comparative StudyTechnologies and solutions for data display in the operating room.
Recent advances in technology have led to the introduction of a variety of innovative devices, each with their own platform for data display, into the operating room (OR). While these innovative applications are expanding the traditional boundaries of the surgical space and enhancing treatment capabilities, the introduction of additional screens and displays is placing an ever-increasing load on the OR team. ⋯ No single display configuration provides an ultimate solution for presenting patient data in the OR. A multi-sensory data display including visual, acoustic and haptic manipulation is suggested as a promising configuration for data display in the OR.
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J Clin Monit Comput · Jun 2006
Real-time computation of a patient's respiratory effort during ventilation.
In this paper, a new algorithm is proposed to compute the spontaneously generated respiratory effort during ventilation. ⋯ The respiratory effort increases over time until the patient is disconnected from the ventilator. We hope the maximum amplitude can be used as an indicator of the pressure the muscles of the patient are able to produce. This amplitude of the (mus)-signal in combination with the standard deviation (SD) may eventually lead to a new indicator to determine the moment that the patient can be weaned from the ventilator. This will have to be examined in the future.
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For years researchers have been attempting to understand the relationship between central hemodynamics and the resulting peripheral waveforms. This study is designed to further understanding of the relationship between ear pulse oximeter waveforms, finger pulse oximeter waveforms and cardiac output (CO). It is hoped that with appropriate analysis of the peripheral waveforms, clues can be gained to help to optimize cardiac performance. ⋯ The ear is relatively immune to vasoconstrictive challenges which make ear plethysmographic waveforms a suitable monitor for central hemodynamic changes. The ear plethysmographic width has a good correlation with CO.
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J Clin Monit Comput · Jun 2006
Comparative Study Controlled Clinical TrialThe effect of addition of nitrous oxide to a sevoflurane anesthetic on BIS, PSI, and entropy.
N(2)O is a commonly used anesthetic that has amnestic and analgesic properties. Recently, devices that estimate depth of consciousness have been introduced in an attempt to better titrate anesthesia, however the effect of N(2)O on these monitors is unclear. ⋯ Supplementing sevoflurane with > 65% N(2)O did not result in a significant change in either BIS or PSI when sevoflurane concentration was kept constant. Entropy, however, significantly decreased as anesthetic depth increased. When sevoflurane concentration was reduced during N(2)O administration, both BIS and Entropy rose despite maintenance of anesthetic depth, indicating a variable concentration effect between volatiles and N(2)O.
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J Clin Monit Comput · Jun 2006
Using the morphology of photoplethysmogram peaks to detect changes in posture.
The morphology of the pulsatile component of the photoplethysmogram (PPG) has been shown to vary with physiology, but changes in the morphology caused by the baroreflex response to orthostatic stress have not been investigated. Using two FDA approved Nonin pulse oximeters placed on the finger and ear, we monitored 11 subjects, for three trials each, as they stood from a supine position. Each cardiac cycle was automatically extracted from the PPG waveform and characterized using statistics corresponding to normalized peak width, instantaneous heart rate, and amplitude of the pulsatile component of the ear PPG. ⋯ During standing, the pulse rate always increases, and then amplitude of the ear PPG constricts by a factor of two or more. We hypothesis that the baroreflex first reduces the percentage of time blood flow is stagnant during the cardiac cycle, then increases the hear rate, and finally vasoconstricts the peripheral tissue in order to reestablishing a nominal blood pressure. These three features therefore can be used as a detector of the baroreflex response to changes in posture or other forms of blood volume sequestration.