Anesthesiology
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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 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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Comparative Study
Neuromuscular effects of rocuronium on the diaphragm and adductor pollicis muscles in anesthetized patients.
Rocuronium has properties that may make it suitable for rapid-sequence intubation. However, its neuromuscular effects have been studied only on the adductor pollicis. This study compares the neuromuscular effect of rocuronium on the diaphragm and adductor pollicis in humans. ⋯ The diaphragm is more resistant than the adductor pollicis to rocuronium, as shown by greater ED50 and ED95 and faster recovery of the twitch height. The intubating dose of 0.60 mg.kg-1 is close to the ED95 of 0.50 mg.kg-1 for the diaphragm.
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The antinociceptive effects of somatostatin (SST) after intrathecal administration in rats and dogs and analgesic effects after intrathecal or epidural administration in humans were described previously. In this study, we seek to determine the efficacy of SST in cancer pain management and its potential neurotoxicity. ⋯ SST administered intrathecally and epidurally was an effective analgesic in patients with terminal cancer. Because the described neuropathologic changes could also be cancer-related or result from chemotherapy or radiation therapy we suggest that further judicious use of SST is justified in this category of patients, if their pain remains unrelieved despite large doses of opioid analgesics.
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Comparative Study Clinical Trial Controlled Clinical Trial
Comparison of arterial tonometry with radial artery catheter measurements of blood pressure in anesthetized patients.
Arterial tonometry has been introduced for continuous noninvasive measurement of blood pressure. The accuracy of this method depends on the performance of two components: a piezoelectric crystal array and an oscillometric cuff. This study evaluates overall performance of arterial tonometry in terms of the performance of these two components by comparing it with simultaneous recording of blood pressure from an intraarterial catheter. ⋯ Discrepancies in blood pressure readings by arterial tonometry versus intraarterial measurement result from both the piezoelectric crystal array and the oscillometry used for calibration. Accuracy for individual measurement is inferior to oscillometry alone. The ability to detect significant changes of blood pressure more rapidly than with oscillometry alone is limited by the accuracy of the piezoelectric crystal component but is enhanced by the reduced interval between measurements.