Articles: nerve-block.
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Randomized Controlled Trial Clinical Trial
Effect of digital pressure on the neurovascular sheath during perivascular axillary block.
We have assessed prospectively the influence of digital pressure on the effectiveness of perivascular axillary block using a catheter technique in two groups of patients. Ninety-eight patients received axillary injections of 2% mepivacaine with adrenaline 20 ml mixed with contrast agent 20 ml. During injection firm digital pressure was applied either on the neurovascular sheath (group 1) or 6-8 cm below it (group 2). ⋯ There were no statistically significant differences in proximal flow of mepivacaine or in the success rate of the block between the groups. Signs of flow obstruction by the head of the humerus were seen in only eight patients. In the majority of patients local anaesthetic spread above the coracoid process, which increased the success rate of the block, but did not guarantee an effective block.
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Journal of anesthesia · Dec 1995
Effects of stellate ganglion block on cardiac coronary circulation.
Since the stellate ganglion contains cardiac sympathetic nerves, stellate ganglion block (SGB) may influence cardiac and coronary hemodynamics. We investigated this influence of SGB by measuring the heart rate (HR), the left circumflex coronary artery blood flow (CBF), the maximum rate of increase of the left ventricular pressure (LV max dP/dt), the cardiac output (CO), the myocardial oxygen consumption (MVO2), and the myocardial oxygen extraction ratio (MOER) in nine dogs before and after performing SGB by means of injection of 2 ml 1% mepivacaine. Left SGB resulted in a decrease of 10% in CBF and a decrease of 15% in LV max dP/dt, but HR, CO, and MVO2 remained unchanged. ⋯ Inhalation of 100% oxygen decreased MOER to the pre-SGB level in either side, thus improving the myocardial oxygen supply-demand relationship. This study suggests the possibility that SGB has deteriorative effects on the myocardial oxygen supply-demand relationship. Those effects were counteracted by the inhalation of 100% oxygen.
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Journal of anesthesia · Dec 1995
Difference of train-of-four fade induced by nondepolarizing neuromuscular blocking drugs: a theoretical consideration on the underlying mechanisms.
Nondepolarizing neuromuscular blocking drugs induce train-of-four (TOF) fade, i.e., the reduction of the fourth to the first twitch height in a train under TOF stimulation. It has been observed that the degree of TOF fade varies with the drug used and is inversely correlated with the potencies of the drug. ⋯ The model was based on the following assumptions: (1) Twitch response is evoked by the binding of acetylcholine (ACh) molecules to the postsynaptic nicotinic receptors in a neuromuscular junction, (2) time-dependent ACh mobilization in a motor nerve terminal results in less ACh output at the fourth stimulus in a train than at the first stimulus, (3) the drugs compete with ACh for the postsynaptic receptors and inhibit the receptor-binding of ACh, and (4) the drugs have various affinities for the receptors. This study suggested that the difference of affinities of the drugs for postsynaptic ACh receptors may cause the difference of TOF fade.
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Clinical Trial
[Quantification of variations in arm perfusion after plexus anesthesia with color doppler sonography].
The axillary brachial plexus block is a well-known technique for intra- and postoperative analgesia and sympathetic blockade in hand and microsurgery. The aim of this study was to show the influence of the axillary brachial plexus block on the blood flow as a side effect. METHODS. ⋯ CONCLUSIONS. The brachial plexus block combines two advantages: pain relief and pain management plus temporary sympathectomy. In conclusion, it prevents vasospasms and improves the circulation of the hand in patients undergoing reimplantation of limbs and those with nutritional disorders.