Canadian Anaesthetists' Society journal
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To assess the effects of isoflurane on chemical regulation of ventilation, we studied the ventilatory responses to (1) hyperoxic hypercarbia, (2) isocapnic hypoxaemia, and (3) a single half vital capacity breath of carbon dioxide 20 per cent in oxygen in 12 human subjects, awake and sedated or anaesthetized with isoflurane, 0.1 or 1.1 MAC. Sedation did not alter ventilation nor the ventilatory response to hypercarbia but reduced the responses to hypoxaemia and to the half vital capacity breath of CO2. ⋯ The results indicate that isoflurane reduces ventilatory responses to several chemical drives and that it selectively impairs those responses mediated by peripheral chemoreceptors. In these respects, isoflurane is similar to halothane and enflurane.
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The effect of epidural morphine on the duration of action of epidural 2-chloroprocaine was studied in a double-blind fashion in 30 patients following elective Caesarean section. When compared to epidural saline controls (n = 15), patients (n = 15) who received epidural morphine (4.0-5.0 mg) did not experience a prolongation or reduction in the duration of the somatic or sympathetic nervous system blockades produced by epidural 2-chloroprocaine.
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Comparative Study
Neostigmine antagonism of succinylcholine phase II block: a comparison with pancuronium.
To assess the efficacy of neostigmine antagonism of succinylcholine phase II block, succinylcholine infusions were given to 17 patients for durations varying from 44 to 192 minutes. A control group (17 patients) received a pancuronium infusion for similar times. Ninety per cent neuromuscular block was maintained in these two groups by adjustment of the infusion rates and, in a third group, with intermittent doses of pancuronium. ⋯ Ten minutes after the infusion was stopped, atropine and neostigmine were given to all patients who received pancuronium and to 11 patients in the succinylcholine group whose train-of-four ratio (T4/T1) was less than 0.7. During the subsequent 15 minutes, recovery was more rapid in the succinylcholine group than in either the pancuronium-infusion or pancuronium-bolus groups. It is concluded that succinylcholine-induced phase II block can be safely and rapidly antagonized with neostigmine.