title: Prolonged apnoea after suxamethonium: an analysis of the first 225 cases reported to the Danish Cholinesterase Research Unit.
abstract: During the last 4 years, 225 patients have been referred to the Danish Cholinesterase Research Unit following an episode of prolonged apnoea after suxamethonium. Fourteen patients (6.2%) were found to have a low serum cholinesterase activity due to an acquired deficiency (for instance, liver disease, chronic debilitating disease or carcinoma). One hundred and forty-eight patients (65.8%) had an inherited abnormal serum cholinesterase, and 105 of these patients (46.7%) were homozygous for the atypical enzyme (E1 Ea1). The mean period of apnoea in this latter group was 92 min (range: 25--240). Seventeen patients (7.6%) were heterozygous for the normal and the atypical enzyme (Eu1 Ea1), with a mean apnoea period of 25 min (range: 7--60 min). Twelve patients were found to be heterozygous for the atypical and the silent gene (E(a)1 E(s)1). The mean period of apnoea was 126 min (range: 45--210 min). Fourteen patients had other rare genotypes. The longest mean period of apnoea (170 min, range: 70--330) was found in patients homozygous for the silent gene (Es1 Es1). The silent gene and the fluoride-resistant gene were found in 8.9% and 2.7% of the patients, respectively. In 63 patients (28.1%) both the type and quantity of serum cholinesterase were normal. In 34 of these patients (15.2%), the prolonged apnoea was due to other causes; for example, suxamethonium overdose, hyperventilation and central as well as peripheral respiratory depression. However, in the other 29 patients (12.9%), the reason for the prolonged apnoea could not be established. The possibility therefore exists that these cases represent unknown genotypes.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001049:Apnea / Q000139:chemically induced* / Q000201:enzymology / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D002802:Cholinesterases / Q000097:blood / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D013390:Succinylcholine / Q000009:adverse effects*; D013997:Time Factors
chemical_list: D002802:Cholinesterases; D013390:Succinylcholine