Bupivacaine hydrochloride 0.25% and 0.50% solutions, were administered 115 times by the i.v. regional route to 64 surgical patients and in 38 subjects suffering from pain syndromes. The clinical effects were limb numbness up to 20 h following cuff release, while analgesia and weakness of the limb muscles were evident 5 h after the tourniquet. Clinical and electrophysiological findings revealed a dose relationship of the effects. Toxic signs were noted in three patients in whom the cuff was released in a one-step fashion. In 11 patients, mean arterial plasma concentrations of bupivacaine reached 3.7 micrograms ml-1 after administration of 0.5% bupivacaine 40 ml, 5 min after final cuff release, and decreased gradually thereafter. In selected conditions which do not require a bloodless field and in certain intractable pain states, i.v. regional anaesthesia with high-dose bupivacaine (200 mg of 0.5% solution) may be a simple and effective technique.
Motor nerve conduction (MNC) from proximal and distal points of the median and ulnar nerve was examined in 14 patients receiving a total of 29 i.v. regional anaesthetics (IRA) with bupivacaine hydrochloride in doses ranging from 100 to 300 mg. Conduction was tested during and following vascular obstruction, until MNC returned to pre-IRA value. After 20 min of obstruction, MNC was unobtainable in most patients, an effect which was dose-related. The action of bupivacaine on MNC persisted for up to 3 h after cuff release, depending on the dose, and paralleled voluntary movements. MNC block began at the proximal point of both nerves, the median nerve being affected earlier. Based on the clinical and electrical findings, bupivacaine 200 mg proved to be optimum dose for producing safe and prolonged IRA.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.