Masui. The Japanese journal of anesthesiology
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The effect of nicorandil on the neuromuscular block induced by vecuronium was investigated in vitro with rat phrenic nerve-hemidiaphragm preparation. Both single twitch (ST) and train-of-four ratio (TOFR) elicited with indirect electrical stimulation were used. ⋯ High concentration of nicorandil (4 x 10(-6) M) produced more significant effect on ST compared with low concentration of nicorandil (10(-7) M). In this study, the nicorandil showed similar effect as calcium antagonists on neuromuscular blockade.
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We investigated the effects of increased arterial carbon dioxide (PaCO2 not equal to 60 mmHg) on myocardial tissue oxygen tension and metabolism in anesthetized dogs. Ten adult mongrel dogs weighing 15.3 +/- 4.1 kg were anesthetized with 0.5% isoflurane in 50% oxygen and ventilated mechanically to maintain normocapnia. After thoracotomy, regional myocardial tissue PO2 was measured using a monopolar polarographic needle electrode inserted in the myocardium. ⋯ As a result, the coronary blood flow and myocardial oxygen tension increased during hypercapnia. The myocardial lactate extraction and coronary venous lactate were unchanged and excess lactate was kept below zero, although coronary venous L/P ratio increased during hypercapnia. These results indicate that hypercapnia (PaCO2 not equal to 60 mmHg) increases coronary blood flow and myocardial oxygen tension, while myocardial aerobic metabolism is not impaired under hypercapnia.