Reversing Succinylcholine Paralysis
Abstract Number: 9
Abstract Type: Original Research
Introduction : The consequences of a failed intubation in the parturient can be fatal because of : decreased FRC, increased oxygen consumption, delayed gastric emptying, and decreased levels of butyrylcholinesterase .Oxygen saturation can fall to critically low levels leading to cerebral and cardiac anoxia Faced with a CICV (cannot intubate ,cannot ventilate) situation, reversal of succinylcholine induced paralysis can be life saving .
Methods: We tested a series of macrocyles to measure their ability to bind succinylcholine and decamethonium.The affinity constant(Ka) was determined thermodynamically( ΔG= Δ H- RT ln Ka) using a Microcal VP calorimeter to perform isothermal titrations.
Results:Cucurbituril binds depolarizing and non depolarizing muscle relaxants in the order: decamethonium> pancuronium> succinylcholine> vecuronium> rocuronium.
Discussion: Sugammadex,a modified cyclodextrin, can bind rocuronium, a drug that is not routinely used for rapid sequence induction, with a Ka= 10^7 /M . Sugammadex in a dose of 16mg/kg can restore a T4/T1 ratio to 0.9 in 2.2min. Cyclodextrins have a high affinity for cholesterol based drugs such as commonly used non depolarizing muscle relaxants: rocuronium> vecuronium> pancuronium, but no affinity for the depolarizers. In contrast , cucurbituril has a high affinity for diquaternary depolarizers with a Ka= 10^6 /M and may serve as chelating agents to further speed the clearance of succinylcholine or decamethonium thereby reversing apnea following a failed rapid sequence induction.
References: Bom A, AgnewChem Int Ed Engl2002;41:266-70 Lee, Anesthesiology2009;110: 1020-5