Effect of Changes in Electrolytes, Hydration and Ph upon the Reactions to Muscle Relaxants.

Claud Bernard (1883) postulated that, provided 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 justified by both clinical practice (Rizzi, 1955) and animal experiments (Bovet et al., 1947, 1951), occasional reports of unusual and dangerous complications 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 abnormally 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 physiological effects that such changes may have upon a patient paralyzed by these drugs is therefore desirable.