Anesthesiology
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Randomized Controlled Trial Clinical Trial
End-tidal sevoflurane concentrations for laryngeal mask airway insertion and for tracheal intubation in children.
Sevoflurane, a new inhalational anesthetic agent characterized by a low blood-gas partition coefficient and nonpungent odor, appears suitable as an induction agent for children. The laryngeal mask airway is a new device for maintaining airway patency during anesthesia. This study was conducted to determine the sevoflurane concentrations required for insertion of a laryngeal mask (MACLMI) and for tracheal intubation (MACTI) in children. ⋯ Laryngeal mask insertion can be performed at a lesser sevoflurane concentration than that required for tracheal intubation.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of halothane and isoflurane on ventilation and occlusion pressure.
Isoflurane has been said to be more ventilatory depressant than halothane. However, data for comparing the respiratory effects of halothane and isoflurane in humans are insufficient at this time. The aim of this study was to extend our understanding of the nature of the central, as opposed to peripheral, ventilatory effect of halothane and isoflurane by comparing them at two concentrations. ⋯ Our study confirms the stronger ventilatory depression induced by isoflurane compared with that induced by halothane and indicates that halothane at 1.2 MAC induces significantly less ventilatory depression than expected.
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Randomized Controlled Trial Comparative Study Clinical Trial
A single dose of morphine sulfate increases the incidence of vomiting after outpatient inguinal surgery in children.
In children, opioids are valuable both for their analgesic properties and for their salutary effect on emergence delirium. Although intraoperative administration of opioids is often cited as the cause of postoperative emesis, few data quantitating the magnitude of this effect exist. ⋯ For children undergoing inguinal surgery, the administration of a single dose of intravenous morphine after the induction of anesthesia smooths emergence from anesthesia as assessed by improved cooperation and sedation in the PACU, decreases the need for postoperative analgesics, but increases the incidence of vomiting in the first 24 h after surgery.
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Randomized Controlled Trial Clinical Trial
Deliberate mild intraoperative hypothermia for craniotomy.
Despite enthusiasm for the use of mild hypothermia during neurosurgical procedures, this therapy has not been evaluated systematically. This study examined the feasibility and safety of deliberate mild hypothermia and rewarming. ⋯ Although deliberate mild hypothermia is easily achieved intraoperatively, complete rewarming may be difficult to attain during craniotomy with current methods. In addition to the need for determining whether deliberate mild hypothermia confers cerebral protection in humans, the potential risks of the therapy need to be further characterized.
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Randomized Controlled Trial Clinical Trial
Epidural anesthesia increases apparent leg temperature and decreases the shivering threshold.
Lower core temperatures than usual are required to trigger shivering during epidural and spinal anesthesia, but the etiology of this impairment remains unknown. In this investigation, we propose and test a specific mechanism by which a peripheral action of regional anesthesia might alter centrally mediated thermoregulatory responses. Conduction anesthesia blocks all thermal sensations; however, cold signals are disproportionately affected because at typical leg temperatures mostly cold receptors fire tonically. It thus seems likely that epidural and spinal anesthesia increase the leg temperature perceived by the thermoregulatory system. Because skin temperature reportedly contributes 5-20% to thermoregulatory control, increased apparent (as distinguished from actual) leg temperature would produce a complimentary decrease in the core temperature triggering thermoregulatory shivering. Accordingly, we tested the hypothesis that abnormal tolerance for hypothermia during epidural anesthesia coincides with an increase in apparent leg temperature. We defined apparent temperature as the leg-skin temperature required to induce a reduction in the shivering threshold comparable to that produced by epidural anesthesia. ⋯ Because leg-skin contributed approximately 11% to the shivering threshold, it is unlikely that the entire skin surface contributes at much less than 20%. These data suggest that the shivering threshold during epidural anesthesia is reduced by a specific mechanism, namely that conduction block significantly increases apparent (as distinguished from actual) leg temperature.