Anesthesiology
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Randomized Controlled Trial Clinical Trial
Epidural clonidine treatment for refractory reflex sympathetic dystrophy.
Intraspinally administered alpha 2-adrenergic agonists may relieve pain in sympathetically maintained pain (SMP) syndromes, such as reflex sympathetically dystrophy (RSD), by spinal, peripheral, and central nervous system actions. This study examined analgesic efficacy and side effects of epidurally administered clonidine in patients with severe, refractory RSD. ⋯ Transdermal clonidine has been demonstrated to produce analgesia in the area surrounding its application site in patients with SMP. The current study indicates that extensive analgesia may be obtained by epidural administration. Sedation and hypotension may limit bolus epidural clonidine administration for RSD. The role for chronic epidural infusion of clonidine has not yet been established.
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Randomized Controlled Trial Clinical Trial
Determinants of catecholamine and cortisol responses to lower extremity revascularization. The PIRAT Study Group.
Surgical trauma elicits diffuse changes in hormonal secretion and autonomic nervous system activity. Despite studies demonstrating modulation of the stress response by different anesthetic/analgesic regimens, little is known regarding the determinants of catecholamine and cortisol responses to surgery. ⋯ These data indicate that patient factors, such as age and inherent sympathetic responsivity, are important determinants of the catecholamine response to surgery. Modulation of the norepinephrine response by regional anesthesia/analgesia appears to be related, in part, to superior analgesia. The lack of correlation between catecholamine and cortisol secretion indicates that the stress response may consist of discrete systems responding to different stimuli.
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The authors observed transient increases in the amplitude of respiratory variations in pulmonary artery blood temperature in many patients after cardiopulmonary bypass (CPB). This increased "thermal noise" may significantly influence measurements of thermodilution cardiac outputs (TDCO) performed during this time. ⋯ The authors concluded that respiratory variations in pulmonary artery blood temperature are transiently increased in many patients after CPB, and that this increased "thermal noise" may cause significant errors in TDCO measurements.
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The influence of general anesthetics on developing organs has been a source of concern for many years. The central nervous system, which is developing rapidly at the time of birth, is of special interest in this regard. In this study, the biochemical characteristics of developing neural tips (growth cones) were examined after exposure to anesthetics to elucidate the molecular mechanism by which long-lasting alterations in the nervous system, including neuroteratogenicity, as previously described, were evoked. ⋯ Considering the crucial role of growth cones in the establishment of the neuronal network, the interruption of signal transduction in the growth cone at a time that is critical in directing the neurite extension may evoke a long-lasting alteration in the neural network. Therefore, the effect of inhalational anesthetics on the growth cone enzyme observed in this study may have a major role in the mechanism that induces morphologic or behavioral neuroabnormalities in later life.