Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2007
ReviewThe ability of diagnostic spinal injections to predict surgical outcomes.
Since their first description more than 80 yr ago, the use of diagnostic spinal injections to predict surgical outcomes has been the subject of intense controversy. Because there are no standardized guidelines or substantive reviews on this topic, their use has remained inconsistent. ⋯ The ability to evaluate the effect of diagnostic blocks on surgical outcomes is limited by a lack of randomized studies, methodological flaws, and wide-ranging discrepancies with regard to injection variables, surgical technique, and outcome measures. More research is needed to optimize injection techniques and determine which, if any, diagnostic screening blocks can improve surgical outcomes.
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Anesthesia and analgesia · Dec 2007
Randomized Controlled Trial Comparative StudyA randomized controlled trial of femoral nerve blockade administered preclinically for pain relief in femoral trauma.
Analgesia at the location of the accident and on transport for femoral trauma is often delayed or insufficient. In this prospective, randomized, controlled study, we evaluated the preclinical use of femoral nerve blockade for reducing pain and anxiety compared with IV analgesia using metamizol. ⋯ Preclinically administered femoral nerve blockade effectively decreases pain, anxiety, and heart rate after femoral trauma. Regional blockade is an option for out-of-hospital analgesia administered by a trained physician.
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Anesthesia and analgesia · Dec 2007
ReviewMaximizing the laboratory setting for testing devices and understanding statistical output in pulse oximetry.
Maximizing the laboratory setting for testing baseline pulse oximetry accuracy in an arterial desaturation study requires a study design that considers management of several aspects in the physiology of the test subject, special attention to the device under test, and great care in the preanalytical (sample handling) and analytical (Co-oximeter) phases. Statistics used to describe the resulting SpO2 performance include Precision (size of the data cloud), Bias (offset of the data cloud), and A(rms) (accuracy root mean square), which combines the size and offset of the data cloud in one number. The A(rms) is the primary statistic required by regulatory organizations to describe general performance over the entire saturation range. ⋯ The A(rms) statistic does not have the capacity to represent all pulse oximeter behavior. Saturation pop-ups, drop-downs, frozen readings, and periods of no reading are not portrayed by the A(rms). The next steps in the advancement of regulatory validation testing would be to develop standards that include an expanded analysis of pulse oximeter performance by assessment of pop-ups, dropouts, frozen readings, and periods of no reading through assessment of sensitivity/specificity and possibly a "Performance Index" similar to the approach taken by Barker.
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The underlying science of pulse oximetry is based on a simple manipulation of the Lambert-Beer law, which describes the attenuation of light traveling through a mixture of absorbers. Signals from detected red and infrared light that has traveled through blood-perfused tissues are used to estimate the underlying arterial hemoglobin oxygen saturation. However, light scatters in tissue and influences some of the simplifications made in determining this relationship. ⋯ Certain deviations from the nominal conditions, whether clinical in nature or misuse of the product, can affect system performance. Consequently, users should be cautious in modifying sensors and/or using them on tissue sites not intended by the manufacturer (off-label use). While perhaps helpful for obtaining pulsatile signals or extending the lifetime of a sensor, some practices can disrupt the optical integrity of the measurement and negatively impact the oxygen saturation reading accuracy.
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Anesthesia and analgesia · Dec 2007
Randomized Controlled Trial Comparative StudyThe paramedian technique: a superior initial approach to continuous spinal anesthesia in the elderly.
Spinal anesthesia in elderly patients is frequently associated with significant technical difficulties. Thus, we compared the classical midline approach to the paramedian approach to perform continuous spinal anesthesia (CSA). ⋯ In summary, after the initial attempt, the paramedian approach is associated with an increased success rate, compared with the midline approach, during the performance of CSA in elderly patients.