[Phenotype of plasma cholinesterase in prolonged apnea and sensitivity to succinylcholine]

90% of the injected dose of succinylcholine is hydrolysed by serum cholinesterase (E.C.3.I.I.8) Abnormal variants of serum cholinesterase lead to prolonged apnea. This report presents the results of 62 serum cholinesterase phenotyping including 12 cases of prolonged apneas. One clinical case of prolonged apnea in a patient homozygous for the atypical cholinesterase gene is presented with a study of his genealogy. The phenotypes were established on the basis of dibucaïne, fluorure, chloride and propranolol differential inhibition. The frequency and significance of the various phenotypes is discussed.