Effect of changes in electrolytes, hydration and pH upon the reactions to muscle relaxants

artificial ventilation was performed, it would always be possible to maintain life in a curarized animal, until ultimate reversal of the paralysis had occurred. This presupposed a very low toxicity for the drug and a complete reversibility of its action. Although this belief has been largely justi-fied by both clinical practice (Rizzi, 1955) and animal experiments (Bovet et al., 1947, 1951), occasional reports of unusual and dangerous com-plications following the use of these drugs have cast some doubt upon this basic concept. There have been over thirty recorded deaths from "neostigmine resistant curarization " (Hunter, 1956; Foster, 1956; Burchell, 1957), and abnor-mally prolonged paralysis not conforming to this description has been reported following gallamine and d-tubocurarine. It has been suggested that, in some of these patients, abnormalities of electrolytes, fluid balance or pH have contributed to the unusual response of the patient to the muscle relaxant drugs. A consideration of the pharmacological and physio-logical effects that such changes may have upon a patient paralyzed by these drugs is therefore desirable