Medical instrumentation
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Medical instrumentation · Aug 1988
Comparative StudyDesign and evaluation of a new reflectance pulse oximeter sensor.
The design and construction of a new optical reflectance sensor suitable for noninvasive monitoring of arterial hemoglobin oxygen saturation with a pulse oximeter is described. The reflectance sensor was interfaced to a Datascope ACCUSAT pulse oximeter that was specially adapted for this study to perform as a reflectance oximeter. We evaluated the reflectance sensor in a group of 10 healthy adult volunteers. ⋯ The regression analysis revealed a high degree of correlation (r = 0.98) and a relatively small standard error of the estimate (SEE = 1.82%). The mean and standard deviations for the difference between the reflectance SpO2 and IL 282 measurements was 1.38 and 1.85%, respectively. This study demonstrates the ability to acquire accurate SpO2 from the forehead using a reflectance sensor and a pulse oximeter.
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Monitoring the critically injured patient is imperative, to assure adequate resuscitation from shock. Unfortunately, the commonly monitored variables correlate poorly with ultimate survival. As a result, therapy is inappropriately focused. ⋯ The pertinent devices are easy to use, portable, and accurate. Knowledge of their technical and physiologic limitations is needed to assure reliability. Their potential role extends beyond the intensive care unit setting, such as with prolonged radiologic evaluation or difficult transportation.
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Airway management in resuscitation of the traumatized patient is a complex and challenging area for the health care provider and the medical engineer involved in the improvement of airway management instrumentation. Surgical and nonsurgical airway management is discussed, with emphasis placed on the instrumentation available and its appropriate uses and limitations. Suggestions for areas requiring new innovations are included.
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Medical instrumentation · Feb 1988
Ambulatory monitoring of the ST segment, using direct-recording Holter systems.
Direct-recording ambulatory electrocardiographic monitoring systems may produce serious errors not only because of their restricted bandwidth, but even more because of the "half-wavelength-to-head-contact effect." This article describes an easy measurement procedure and a mathematic model of the storage medium. The frequency response is calculated by way of five data from a single measurement. Some errors of typical recorders are discussed with the help of synthesized electrocardiographs. Measurements by six different recorders are listed.
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Medical instrumentation · Oct 1987
An instrument using variation of resistance to aid in needle tip insertion in epidural block in monkeys.
A new method is proposed to detect the entrance of a needle into the epidural space. Measuring the changes in electric resistance during the insertion of the needle through different tissues in the interspinal space can help anesthesiologists judge whether and when the needle has entered the epidural space. ⋯ The difference was statistically significant (p less than 0.001). This difference in the resistance can be used to verify placement of the tip of the needle in the epidural space and help anesthesiologists administer epidural anesthesia.