Journal of clinical monitoring
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Our objective was to determine if rebreathing would reduce the gradient between arterial and end-tidal CO2 tension during positive-pressure ventilation. ⋯ Rebreathing with a Mapleson D circuit and a VF equal to VA permitted normal CO2 elimination. Arterial PCO2 to PECO2 gradient decreased significantly during rebreathing, thus improving the reliability of capnography for estimating arterial PCO2. Consideration should be given to using the Mapleson D as a rebreathing circuit.
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Comparative Study
Simultaneous in vivo comparison of two-versus three-wavelength mixed venous (Svo2) oximetry catheters.
Venous oximetry catheters provide useful realtime information about mixed venous hemoglobin saturation (Svo2). Currently available systems utilize either two or three wavelengths of light to obtain these measurements. Previous animal and clinical studies have attempted to compare the accuracy of these two devices under similar circumstances. However, the relative accuracy of the two-wavelength versus three-wavelength systems has never been assessed under identical conditions. For this purpose, we designed an animal model for simultaneous measurement of Svo2, over a wide range of physiologic and pathologic states. ⋯ Both currently available in vivo spectrophotometric systems are capable of producing satisfactory results over wide ranges of Svo2. In contradistinction to older reports, we found that the two-wavelength Svo2 system produced results equivalent to those obtained from the three-wavelength device. In this regard, there is no detectable advantage in accuracy to measuring in vivo Svo2 with three rather than with two wavelengths.
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Our objective was to overcome the limitations of linear models of oscillometric blood pressure determination by using a nonlinear technique to model the relationship between the oscillometric envelope and systolic and diastolic blood pressures, and then to use that technique for near-continuous arterial pressure monitoring at the supraorbital artery. ⋯ The ANN produced a better model of the relationship between the oscillometric envelope and reference systolic and diastolic pressures than did the standard oscillometric algorithm. Noninvasive blood pressure measured from the supraorbital artery agreed with pressure measured by auscultation in the brachial artery, and may sometimes be more clinically useful than an arm cuff device.
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Our objective was to develop an audiovideo data acquisition system that facilitates studying the activities of anesthesia care providers in the clinical environment. ⋯ Videotapes of the process of anesthetizing and resuscitating trauma patients provided a record of the activities of anesthesia care providers. Video vignettes may be useful training tools. Excerpts from real scenarios can be incorporated into anesthesia stimulators. The soundtrack and timing of real events from such video acquisition may be useful in the development of multimedia simulations of trauma patient resuscitation. The data collection may be useful for research into human performance, ergonomics, training techniques, quality assurance, and certification of anesthesia care providers in trauma patient management. Potential additional applications of VASNET include remote monitoring of patients in the operating room, in the intensive care unit, during transportation, in hazardous environments, and in the field. Such VASNET telemetry may facilitate the availability of expert opinions during medical and other consultations.