Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2007
Biography Historical ArticleTakuo Aoyagi: discovery of pulse oximetry.
In the 1930s and 1940s, photo cells permitted German, English, and American physiologists to construct ear oximeters with red and infrared light, requiring calibration. In 1940 Squire recognized that changes of red and infrared light transmission caused by pneumatic tissue compression permitted saturation to be computed. In 1949 Wood used this idea to compute absolute saturation continuously from the ratios of optical density changes with pressure in an ear oximeter. ⋯ His ideas, equations and instrument were adapted, improved and successfully marketed by Minolta about 1978, stimulating other firms to further improve and market pulse oximeters worldwide in the mid 1980s. Dr. Aoyagi and associates provided a detailed history for this paper.
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Anesthesia and analgesia · Dec 2007
Case ReportsThe use of brain positron emission tomography to identify sites of postoperative pain processing with and without epidural analgesia.
It is not known how different analgesic regimes affect the brain when reducing postoperative pain. We performed positron emission tomography (PET) scans on a 69-yr-old woman in the presence of moderate postoperative pain and then with epidural analgesia producing complete analgesia, during the first 2 days after total knee arthroplasty. ⋯ Other brain regions showing increased postsurgical activity were the contralateral parietal cortex, bilateral pulvinar and ipsilateral medial dorsal nucleus of the thalamus, contralateral putamen, contralateral superior temporal gyrus, ipsilateral fusiform gyrus, ipsilateral posterior lobe, and contralateral anterior cerebellar lobe. This study demonstrates the feasibility of evaluating the central processing of acute postoperative pain using PET.
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Anesthesia and analgesia · Dec 2007
Comparative StudyNeedlestick distal nerve injury in rats models symptoms of complex regional pain syndrome.
Complex Regional Pain Syndrome (CRPS)-I consists of chronic limb pain and dysautonomia triggered by traumas that sometime seem too trivial to be causative. Several pathological studies have identified minor distal nerve injuries (DNIs) in CRPS-I patients, but retrospective studies cannot establish causality. Therefore, we, prospectively investigated whether DNIs are sufficient to cause CRPS-like abnormalities in animals. We used needlestick, a cause of human CRPS, to evaluate lesion-size effects. ⋯ Needlestick DNI models several clinical and pathological features of human CRPS and provides direct prospective evidence that even minor DNI can cause CRPS-like abnormalities in rats.
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Anesthesia and analgesia · Dec 2007
Case ReportsA differential diagnosis of hyperalgesia, toxicity, and withdrawal from intrathecal morphine infusion.
Opioid-induced hyperalgesia, toxicity, and withdrawal are phenomena that may occur with intrathecal opioid infusion. We present a case in which a patient received intrathecal morphine infusion, and then experienced a clinical course that may have involved hyperalgesia, toxicity, and/or withdrawal. The possible differential diagnosis of opioid-induced hyperalgesia, toxicity, and withdrawal, and its implications in clinical pain management, are discussed. This report demonstrates the complexity of treating patients with long-term continuous intrathecal opioids when modest adjustment of the intrathecal cocktail results in a paradoxical clinical course.
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Anesthesia and analgesia · Dec 2007
Comparative StudyIn vitro, lidocaine-induced axonal injury is prevented by peripheral inhibition of the p38 mitogen-activated protein kinase, but not by inhibiting caspase activity.
All local anesthetics (LAs) are, to some extent, neurotoxic. Toxicity studies have been performed in dissociated neuron cultures, immersing both axon and soma in LA. This approach, however, does not accurately reflect the in vivo situation for peripheral nerve blockade, where LA is applied to the axon alone. ⋯ Whereas inhibition of either p38 mitogen-activated protein kinase or caspase activity promote neuronal survival after LA treatment of dissociated neuronal cultures, axonal degeneration induced by lidocain (40 mM) is prevented by p38 MAP kinase but not by caspase inhibition. We conclude that processes leading to LA-induced neurotoxicity in dissociated neuronal culture may be different from those observed after purely axonal application.