Etiology of muscular spasms during general anesthesia

Abstract

I N 1880, Humphrey first noted muscuIar activity of a trembIing yet rhythmic type occurring during the administration of ether by inhaIation. During the years of the WorId War this manifestation was reported by several observers.l~3~6~Q*37~‘8,‘Q The condition is known as “ether cIonus” or “ether rigor”; it usuaIIy occurs in the course of induction of anesthesia; the tremor frequently is limited to the Iower Iimbs and ceases as anesthesia deepens. In 1916, Mytinger reported his experiences in anesthetizing IOO patients suffering from idiopathic epiIepsy. Epileptiform convuIsions occurred frequentIy in the stage of induction of anesthesia. In rgzz, Patch reported 2 caSes in which epiIeptiform convuIsions occurred in the course of anesthesia, in onIy one of which was epiIepsy known to be a factor. Both patients recovered. It is in this group of individuals who do not have epiIepsy that we are particuIarIy interested at this time. In 1927 WiIson, anesthetist at Manchester Royai Infirmary, reported 4 cases in which “ether” convuIsions were fataI in 1926. Pinson, on the same date, reported 15 cases in which convulsions occurred in the course of genera1 anesthesia, in nine years experience, incIuding I 1,000 administrations. FoIIowing the appearance of these articles, 12 more cases appeared in the Iiterature in 1927, 13~21~23~24~28~34~38~45~48~53~70~84 g in