Anesthesiology
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Biography Historical Article
John Snow's practice of obstetric anesthesia.
The influence of Queen Victoria on the acceptance of obstetric anesthesia has been overstated, and the role of John Snow has been somewhat overlooked. It was his meticulous, careful approach and his clinical skills that influenced many of his colleagues, Tyler-Smith and Ramsbotham and the Queen's own physicians. The fact that the Queen received anesthesia was a manifestation that the conversion of Snow's colleagues had already taken place. ⋯ Medical theory may have changed, but practice did not, and the actual number of women anesthetized for childbirth remained quite low. This, however, was a reflection of economic and logistical problems, too few women were delivered of newborn infants during the care of physicians or in hospitals. Conversely, it is important to recognize that John Snow succeeded in lifting theoretical restrictions on the use of anesthesia.
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Randomized Controlled Trial Clinical Trial
Concentration-effect relationship of intravenous lidocaine on the allodynia of complex regional pain syndrome types I and II.
Several lines of evidence suggest that neuropathic pain (including Complex Regional Pain Syndrome [CRPS] I and CRPS II) is mediated in part by an increase in the density of voltage-sensitive sodium channels in injured axons and the dorsal root ganglion of injured axons. This study sought to characterize the effects of intravenous lidocaine (a sodium channel blocker) on acute sensory thresholds within the painful area and the size of the painful area in patients suffering from CRPS I and II. ⋯ This study demonstrates that intravenous lidocaine affects pain in response to cool stimuli more than mechanical pain in subjects with neuropathic pain. There is a lesser effect on spontaneous pain and pain induced by stroking stimuli and no effect on the pain induced by punctate stimuli.
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Randomized Controlled Trial Comparative Study Clinical Trial
Cerebral hemodynamic effects of morphine and fentanyl in patients with severe head injury: absence of correlation to cerebral autoregulation.
The current study investigates the effects of morphine and fentanyl upon intracranial pressure and cerebral blood flow estimated by cerebral arteriovenous oxygen content difference and transcranial Doppler sonography in 30 consecutive patients with severe head injury in whom cerebrovascular autoregulation previously had been assessed. ⋯ The authors conclude that both morphine and fentanyl moderately increase intracranial pressure and decrease mean arterial blood pressure and cerebral perfusion pressure but have no significant effect on arteriovenous oxygen content difference and middle cerebral artery mean flow velocity in patients with severe brain injury. No differences on intracranial pressure changes were found between patients with preserved and impaired autoregulation. Our results suggest that other mechanisms, besides the activation of the vasodilatory cascade, also could be implicated in the intracranial pressure increases seen after opioid administration.
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Clinical Trial Controlled Clinical Trial
Neuromuscular effects of mivacurium in 2- to 12-yr-old children with burn injury.
Burned patients are usually resistant to the neuromuscular effects of nondepolarizing relaxants, mostly because of receptor changes. The magnitude of the resistance is related to burn size and time after burn. Mivacurium is a muscle relaxant, degraded by plasma cholinesterase, whose enzyme activity is decreased in burns. The present study tested the hypothesis that burn-induced depressed plasma cholinesterase activity counteracts the receptor-mediated resistance, resulting in a lack of resistance to mivacurium. ⋯ A normal mivacurium dosage (0.2 mg/kg) effects good relaxation conditions in burned patients, with an onset time similar to that in controls. This finding contrasts with the response seen with other nondepolarizing drugs, higher doses of which are required to effect paralysis. The decreased metabolism of mivacurium, resulting from depressed plasma cholinesterase activity, probably counteracts the receptor-mediated potential for resistance. Because succinylcholine is contraindicated in burned patients, larger doses of nondepolarizing agents are advocated to effect rapid onset of paralysis. This generalization does not hold for mivacurium. diatrics; plasma cholinesterase; relaxant resistance; succinylcholine, alternative to.)
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Comparative Study Clinical Trial Controlled Clinical Trial
Temperature-dependent pharmacokinetics and pharmacodynamics of vecuronium.
The authors evaluated the influence of temperature on the pharmacokinetics and pharmacodynamics of vecuronium because mild core hypothermia doubles its duration of action. ⋯ Our results show that reduced clearance and rate of effect site equilibration explain the increased duration of action of vecuronium with reducing core temperature. Tissue sensitivity to vecuronium is not influenced by core temperature.