Calcium and other biochemical alterations induced by masseter spasm following suxamethonium.

: Calcium and other biochemical disturbances are reported from the plasma of a child which presented masseter spasm following the administration of suxamethonium during the induction of halothane anesthesia. After masseter spasm, the ionized calcium concentration decreased whereas the total calcium level remained unchanged despite the occurrence of metabolic and respiratory acidosis. Throughout the rest of anesthesia, the total and ionized calcium concentrations continued to decrease. These variations may indicate that complex metabolic and biochemical events influenced the calcium binding to albumin and the calcium transfer into the muscle cells.