Anesthesiology
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Cumulative d-tubocurarine dose-response curves were determined in 35 unpremedicated adult surgical patients. In five awake patients with and five awake patients without ulnar nerve block the median effective doses of d-tubocurarine necessary for 50 per cent depression of twitch tension (ED50) were 8.3 and 9.1 mg/m2, respectively. ⋯ The ED50's of d-tubocurarine were 4.8, 4.5, 2.5, 3.2, and 3.8 mg/m2 in patients anesthetized with 1.0 to 1.3 per cent alveolar concentrations of halothane for 10, 20, 40, 80, and 160 minutes, respectively. It is concluded that duration of anesthesia has no effect on neuromuscular blockade by d-tubocurarine.
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The efficacy of hydroxocobalamin (vitamin B12a) as a specific, nontoxic antidote in acute cyanide poisoning was tested. Guinea pigs receiving lethal intravenous NaCN injections were treated with either vitamin B12a or saline solution. There was a statistically significant antidotal effect of the vitamin. No toxic effect was observed with large doses of the vitamin.
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Hemodynamic response to ganglionic blockade with pentolinium during N2O-halothane anesthesia in man.
Hemodynamic and blood-gas variables were studied before and after pentolinium tartrate administration in six patients anesthetized with nitrous oxide-halothane and maintained at PaCO2 35-40 torr. Measurements were made prior to induction of anesthesia; before and 10, 20, and 60 minutes after administration of pentolinium (0.3 mg/kg); 15 minutes after return of arterial blood pressure to control values. Mean arterial blood pressure (MAP) was significantly decreased at 20 (P less than 0.02) and 60 (P less than 0.001) minutes, in association with significant decreases in systemic vascular resistance (SVR) (P less than 0.05 and P less than 0.005). ⋯ Fifteen minutes after return of MAP to control levels, SVR was 11.5 per cent lower, while CO was still significantly higher (P less than 0.02) than control values. Following ganglionic blockade with pentolinium during halothane-N2O anesthesia, HR is a valuable index of changes in CO, while the HR X ASP index may be utilized to evaluate changes in MVO2. Assessment of myocardial performance during controlled hypotension is possible by the use of routinely available measurements.