Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Jul 1987
Randomized Controlled Trial Comparative Study Clinical TrialGlycopyrrolate compared with atropine in association with ketamine anaesthesia.
Atropine and glycopyrrolate given intravenously before the induction of a ketamine anaesthesia to diminish salivary secretion were compared for their effect on psychotomimetic side-effects, awakening time and heart rate. Though atropine is a tertiary amine that crosses the blood-brain barrier, which glycopyrrolate as a quaternary ammonium compound does not, it did not increase the incidence of psychotomimetic side-effects nor did it significantly prolong the awakening time after ketamine anaesthesia. During intubation the increase in heart rate was significantly higher following atropine than following glycopyrrolate.
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Acta Anaesthesiol Scand · Jul 1987
Comparative StudyIn vitro diagnosis of susceptibility to malignant hyperthermia: comparison between dynamic and static halothane and caffeine tests.
In vitro tests for the diagnosis of malignant hyperthermia susceptibility were performed in 105 patients and 20 normal controls according to the protocol of the European MH Group. Results of dynamic halothane and caffeine tests (in which muscle bundle length is cyclically changed) were compared to those of static tests (constant muscle bundle length). ⋯ The magnitude of contractures was, however, significantly greater in the dynamic than in the static halothane test for halothane concentrations less than 3%, but this did not influence diagnosis. The results indicate that dynamic tests are not superior to static tests, but several tests should be performed to enhance diagnostic safety.
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Acta Anaesthesiol Scand · Jul 1987
In vitro diagnosis of susceptibility to malignant hyperthermia: evaluation of tests with halothane-caffeine, potassium chloride, suxamethonium and caffeine-suxamethonium.
Susceptibility to MH was determined in 77 patients according to the protocol of the European MH Group. Additional muscle bundles were used for diagnostic in vitro tests with caffeine in the presence of 1% halothane, potassium chloride, suxamethonium, and caffeine-suxamethonium. Significant differences between MH-susceptible (MHS) and MH-negative (MHN) patients were obtained with the halothane-caffeine test and the potassium chloride test, whereas no differences were found with the suxamethonium test. ⋯ In all tests there was an overlap in results between MHS and MHN groups, and the predictive values of the tests ranged between 63 and 95%. Prior small doses of caffeine followed by a 4 mmol/l dose of caffeine elicited significantly smaller contractures than 4 mmol/l given as the first dose of caffeine. This underlines the necessity of a common protocol for performance and interpretation of diagnostic tests for MH.
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Acta Anaesthesiol Scand · Jul 1987
Gas exchange in low-compression HFPPV is maintained at low distending pressures in the pig.
The fact that collateral ventilation normally occurs in the human lung has led to the suggestion that it might contribute to the successful clinical effects of low-compression high-frequency positive-pressure ventilation (HFPPV). As the pig has poor collateral ventilation, pulmonary vasoconstriction has to be part of the regulatory mechanisms matching ventilation-perfusion. A study was made on nine pigs anesthetized with ketamine hydrochloride intravenously to elucidate the maintenance of ventilation-perfusion balance during mechanical ventilation. ⋯ The tidal volume required for normoventilation differed significantly between the three ventilatory patterns, but there were no differences in circulatory and oxygen-transport variables. By measurements of airway pressure and intrapleural liquid surface pressure, it was demonstrated that the distending pressure (at end-inspiration) was significantly lower with a low-compression system (H-20 versus SV-20), especially at a high ventilatory frequency (H-60 versus H-20). Consequently, although the mean airway pressure was set at the same level for the three different ventilatory modalities, the distending pressures required for the same alveolar ventilation and arterial oxygenation differed significantly.(ABSTRACT TRUNCATED AT 250 WORDS)
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Acta Anaesthesiol Scand · Jul 1987
Effect of chronic bupivacaine infusion on seizure threshold to bupivacaine.
Thirty rats were pretreated with a continuous infusion of bupivacaine or placebo. On the fourth day the acute seizure threshold to bupivacaine was determined for both groups. The seizure dose, blood and brain concentration of bupivacaine showed no difference between the groups. The tachyphylaxis seen clinically when bupivacaine is used for a regional nerve blockade does not seem to evolve for the CNS-effects.