Journal of anesthesia
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Journal of anesthesia · Jun 1997
Comparison of circulatory and respiratory responses between supplementary epidural buprenorphine and eptazocine administration during and immediately after total intravenous anesthesia.
Opioid supplements are often required in total intravenous anesthesia (TIVA). Most ϰ-opiate receptors are found in the spinal cord, wherea μ-opiate receptors are widespread throughout the brain and spinal cord. Buprenorphine has a strong μ-action with a minute ϰ-action, while eptazocine stimulates ϰ-receptors only. ⋯ A significant analgesic effect (P<0.01) of epidural eptazocine without circulatory and respiratory depression was observed. With epidural buprenorphine, circulatory and respiratory depression during and immediately after anesthesia were significant (P<0.05). These results suggest that medullary μ-stimulation by an epidural opioid induces circulatory (hypervagotonicity and hypervagosensitivity) and respiratory depression, while ϰ-stimulation produces only minimal effects on circulatory and respiratory systems.
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Journal of anesthesia · Jun 1997
Correlation between the anesthetic potency of local anesthetics and their binding ability to a model membrane.
The interaction between various local anesthetics and the phospholipid membrane was examined by(1)H-NMR (nuclear magnetic resonance) spectroscopy. By examining the chemical shift value in order to measure the extent of proximity of various local anesthetics to the membrane, it was determined that tetracaine (10.7 Hz) was closest to the membrane, followed in descending order of proximity by dibucaine (8.8 Hz), bupivacaine (4.4 Hz), propitocaine (4.4 Hz), and lidocaine (3.5 Hz). ⋯ In addition, we studied the interaction of local anesthetics with the membrane by examining the broadening of the half-width, and determined that tetracaine (12.2 Hz) bound closest to the membrane, followed in descending order of proximity by dibucaine (11.0 Hz), bupivacaine (9.6 Hz), propitocaine (9.0 Hz), lidocaine (8.8 Hz), procaine (8.0 Hz) and cocaine (7.9 Hz). In the present study, the binding ability of local anesthetics to the phospholipid membrane was found to be directly in parallel with the potency and toxicity of the anesthetic.
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Journal of anesthesia · Jun 1997
Possible evaluation of hemodynamic effects of the potassium channel opener KRN2391 on induced hypotension in dogs.
KRN2391 is potassium channel opener with a nitrate moiety which possesses potent vasodilatory action. The hemodynamic profiles of KRN2391-induced hypotension are still not well understood. The aim of this study was to investigate the potential use of KRN2391 for induced hypotension. ⋯ Left ventricular maximum dP/dt increased significantly during and after induced hypotension. Right atrial and mean pulmonary artery pressures increased significantly, whereas pulmonary capillary wedge pressure remained unchanged. The results of the present study show that KRN2391 is effective in reducing afterload during induced hypotension, and suggest that the hemodynamic profiles of KRN2391-induced hypotension are a hyperdynamic state as expressed by twofold increases in CI concomitant with the increase in right ventricular filling pressures.
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Journal of anesthesia · Jun 1997
RETRACTED ARTICLE: Nicardipine inhibits amrinone-enhanced contractility in fatigued diaphragm.
The purpose of this study was to examine the effect of amrinone, a bipyridine derivative, with and without nicardipine, a calcium channel blocker, on the contractility of fatigued diaphragm in dogs. Twenty dogs were divided into two groups of ten each: amrinone group (group A) and combined amrinone and nicardipine group (group AN). Diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz applied for 30 min. ⋯ The Pdi at each stimulus were increased compared with the fatigued values (P<0.05) by administering amrinone, and returned to these values after this agent was discontinued. The Pdi values at any frequency of stimulation did not change when amrinone was administered with nicardipine. Our results suggest that amirinone may enhance contractility in fatigued diaphragm via its effect on transmembrane calcium movement.