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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Comparative Study
Does the choice of local anesthetic affect the catecholamine response to stress during epidural anesthesia?
Previous work has established that 2-chloroprocaine epidural anesthesia has no effect on circulating plasma epinephrine concentrations in young, healthy, resting volunteers, and results in a decrease in norepinephrine concentration only when a level of analgesia to pinprick of C-8 is reached. The current study was performed to evaluate the possibility that this finding is unique to 2-chloroprocaine. ⋯ Epidural anesthesia with all three local anesthetic agents tested resulted in an incomplete sympathectomy in the resting state in healthy young men, judged by plasma catecholamine concentrations and cardiovascular variables minimally changed from resting baseline. Lidocaine epidural anesthesia did not attenuate the catecholamine response to CPT, indicating decreased blockade of sympathetic efferent neural traffic compared with bupivacaine and chloroprocaine epidural anesthesia.
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Supraventricular dysrhythmias are common during anesthesia, but have been incompletely investigated. Mechanisms may involve altered automaticity of subsidiary pacemakers and participation of vagal reflexes. The following hypotheses were tested: (1) shifts from the sinoatrial (SA) node to subsidiary pacemakers require intact vagal reflexes and (2) halothane sensitizes the heart to epinephrine-induced atrial pacemaker shifts. ⋯ Pacemaker shifts account for atrial dysrhythmias in the conscious state and during 1.25 MAC halothane with epinephrine, and require vagal participation. Halothane sensitizes the heart to epinephrine-induced atrial dysrhythmias. Atropine and halothane facilitate His bundle beats during exposure to epinephrine.
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Large studies reporting anesthetic outcome for morbidly obese parturients are lacking. This study compares the anesthetic and obstetric outcome in morbidly obese parturients and matched control parturients. ⋯ The high incidences of antepartum medical disease and emergency cesarean section complicate anesthetic care in the morbidly obese parturients. Epidural anesthesia is feasible; however, the high initial failure rate necessitates early catheter placement, critical block assessment and catheter replacement when indicated, and provision for alternative airway management.