Masui. The Japanese journal of anesthesiology
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The change of analgesic levels, plasma concentrations and the radiographical changes of epidural space due to continuous epidural block were studied in 54 patients receiving pain relief. All the patients received 2 ml per hour of 2% lidocaine or 0.5% bupivacaine via the catheter over two weeks. The effect of epidural block was determined on 1, 2, 4, 7, 10 and 14 days, the epidurogram was performed on 1, 7, 14 days, and plasma concentration of lidocaine or bupivacaine was measured on 1, 3, 7, 14 days. ⋯ The effects and plasma concentrations of epidural block decreased significantly after a week, and the mean segmental number of radiographic spread decreased significantly after two weeks. The decreasing effect or duration of epidural block was due to decrease in spread of anesthetics because of adhesion around the catheter in the epidural space. We conclude that the safety period of continuous epidural block is within 2 weeks.
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During surgery, the anesthesiologists adjust the concentration of inhaled anesthetics according to the change in blood pressure in order to achieve good control of anesthesia. Usually the thinking patterns of individual anesthesiologists differ from one to another. ⋯ The results showed that anesthesiologists' regulation rules were formed independently of the 3 drugs and were specific to individuals. Some trends depending on institution were observed, but no statistically significant difference was found.
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The cytokines such as tumor necrosis factor and interleukin-1 secreted from macrophages/monocytes proved to play important roles in the pathogenesis of endotoxemia, severe pancreatitis and other surgical injuries. However, it is still unclear how inhalational anesthetic agents influence the secretion of these cytokines from macrophages/monocytes. ⋯ The inhibitory action of isoflurane disappeared between 1 and 3 hours after stopping isoflurane inhalation. We concluded that isoflurane could inhibit TNF-alpha and IL-1 beta secretions from peripheral blood monocytes stimulated by LPS in a dose-dependent fashion and that the inhibitory action of isoflurane was reversible.
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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.