Factors Affecting Magnitude and Time Course of Neuromuscular Block Produced by Suxamethonium

Abstract

This study was designed to identify factors that significantly alter the magnitude and duration of suxamethonium-induced neuromuscular block in patients with an apparently normal genotype for pseudocholinesterase. One hundred and fifty-six adults (ages 18-65 yr) were allocated to 13 subgroups. Patients in each subgroup received suxamethonium 50-2000 micrograms kg-1. The mechanographic response of the adductor pollicis brevis muscle to ulnar nerve stimulation was recorded. The ED50 was found to be 167 micrograms kg-1, ED90 was 316 micrograms kg-1 and ED95 was 392 micrograms kg-1. The duration of action (delta t) was in agreement with earlier published results. The magnitude of block was dose-related and decreased with increasing onset time (ton) and pseudocholinesterase activity (PChA). Neither age nor gender affected the degree of suxamethonium-induced block. Delta t was dose-related, decreased with increasing PChA, and was shorter for women. Age and ton had no effect on delta t.

Cholinesterase Its significance in anaesthetic practice

“…those with a normal phenotype for the plasma cholinesterase gene and their response to suxamethonium, a study was performed by Vanlinthout and colleagues in 1992 [33]. They found that the magnitude of the block was dose-related and decreased with increasing plasma cholinesterase activity.…”

“…There were patients who had been classified as normal homozygotes on the basis of their dibucaine numbers (in the range 71-80) who had an unexpected low fluoride number (in the range 50-55). There were also patients who had been designated heterozygotes on their dibucaine numbers (52-60) who had much lower fluoride numbers (26)(27)(28)(29)(30)(31)(32)(33)(34). Family studies confirmed that there was a third gene which was able to influence the character of the cholinesterase gene and the patients who did not fit the correlation described were in reality carriers of this fluoride-resistant gene; instead of U/U and U/A they become U/F and A/F, respectively.…”

Effect of normal and pre-eclamptic pregnancies on plasma cholinesterase in Nigerian women

“…In such patients there is a wide variability in the neuromuscular blocking effect, onset and duration of paralysis caused by succinylcholine (16,17). The mechanisms by which normal and eclamptic pregnancies cause a reduction in plasma cholinesterase activity are not fully known.…”

Einfluss des Geschlechts auf die Intubationsbedingungen nach Rocuronium

“…Da her wur den die In tu ba ti ons be din gungen von weib li chen und männ li chen Pa tien ten be stimmt und mit den je ni gen nach Gabe von 1,0 mg/kgKG Sux (Kon troll gruppen) ver gli chen. Suc ci nyl cho lin wur de als Re la x ans in den Kon troll grup pen ge wählt, weil die Tie fe des neu ro mus ku lä ren Blocks un ab hän gig vom Ge schlecht war [15]. Die vor lie gen de Un ter su chung war als ran domi sier te kon trol lier te Stu die durch ge führt wor den, um zu zei gen, dass der ge fun dene ge schlechts s pe zi fi sche Un ter schied tatsäch lich Roc-spe zi fisch war.…”