Anesthesia and analgesia
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Anesthesia and analgesia · Jan 1988
Potentiation of neuromuscular blocking agents by calcium channel blockers in rats.
The effect of calcium channel blockers (Ca-antagonists) on the potency and reversibility of muscle relaxants (MR) was investigated in the in vitro phrenic nerve-hemidiaphragm and in vivo sciatic nerve-tibialis anterior preparation of rats. To increase the relevance of the experimental findings to the clinical situation, the [Ca++] and [Mg++] in vitro were the same as in the plasma of rats and humans and the stimulation parameters used in vitro and in vivo were similar to those that elicit voluntary movements of the muscles used. Both verapamil and nifedipine significantly decreased the I50 and I90 of d-tubocurarine (d-Tc), pancuronium, vecuronium, and atracurium in vitro and those of the first three MR in vivo (P less than 0.001). ⋯ Under these circumstances the decrease of P caused by all Ca-antagonist-MR combinations recovered spontaneously close to control levels. This study indicates that acute administration of verapamil during anesthesia may increase MR potency, but it is unlikely that spontaneous recovery or reversibility of the residual neuromuscular (NM) block at the end of anesthesia will be significantly affected. However, long-term administration of Ca-antagonists may make difficult the reversal of the residual NM block.
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Anesthesia and analgesia · Dec 1987
Comparative Study Clinical Trial Controlled Clinical TrialClinical pharmacokinetics of carbonated local anesthetics. II: Interscalene brachial block model.
A double-blind comparison of 1.1% lidocaine carbonate and 1.0% lidocaine hydrochloride was carried out in 30 healthy adult patients undergoing upper-extremity surgery under interscalene brachial plexus block. Epinephrine (1:200,000) was added to both solutions just before injection. As compared to lidocaine hydrochloride, lidocaine carbonate produced, in addition to a 38% reduction in onset time, a remarkable increase in the extent of anesthesia: lidocaine carbonate produced surgical anesthesia of the entire upper extremity including the hand in 87% of the patients, whereas lidocaine hydrochloride produced similar anesthesia in only 53% of the patients. Thus, supplemental blocks were required in 66% of the patients who received lidocaine hydrochloride, whereas they were required in only 25% of those who received lidocaine carbonate.
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Anesthesia and analgesia · Dec 1987
Central nervous system complications after 6000 retrobulbar blocks.
Six thousand consecutive patients in whom retrobulbar anesthesia was performed by an anesthesiologist before ophthalmic surgery were studied. Sixteen patients (1 in 375) developed signs and symptoms presumed to be caused by the direct spread of the local anesthetic agents to the central nervous system. These signs and symptoms ranged from drowsiness, blindness of the contralateral eye, abnormal shivering, or vomiting, through to respiratory depression, apnea, hemiplegia, aphasia, convulsions, unconsciousness, and cardiopulmonary arrest. ⋯ The time of the onset of symptoms after the retrobulbar injection was variable (average 8 min, range 2 to 40 min). The possibility of a life-threatening complication occurring was rare (1 in 750) but unpredictable. The need for closely monitored anesthesia care of all patients having surgery under retrobulbar anesthesia is stressed.
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Anesthesia and analgesia · Dec 1987
Comparative StudyA new parascalene approach to the brachial plexus in children: comparison with the supraclavicular approach.
A technique for blocking the brachial plexus was designed after reevaluation of the gross anatomy of the neck in children. It consists of penetrating the perineural sheath at the level of the omohyoid muscle using a strictly anterior-posterior direction for insertion of the needle. ⋯ Insulated needles and a nerve stimulator were used with both techniques. Although both techniques produced a high degree of sensory blockade in almost all infraclavicular branches of the brachial plexus, the parascalene approach proved to be easier and more reliable while also being almost free of complications.