Had a csection patient under GETA yesterday with suspected pseudocholinesterase deficiency; can someone enlighten me?
Nov 29, '01
Here goes, plasma pseudocholenesterase is what metabolizes succinylcholine. Succinylcholine is a very short acting depolarizing muscular relaxant, that mimics the action of acetylcholine at the neuromuscular junction. It is not metabolized at the junction by acetylcholinesterase and there is no reversal agent as there is for non-depolarizing neuromuscular blockers. This has good points and bad, as you found out. The good is that it's action is very rapid and in almost all cases very short acting. Onset is 45 seconds or so and it is gone in 2-3 min. making it the agent of choice for rapid sequence intubations (something pregnant women are in need of in a stat c-section with a full stomach and the increased pressure on the abdomen ). However succinylcholenine must diffuse away from the NMJ and into the plasma where it is metabolized by plasma pseudcholinesterase. In a few percent of the population, that enzyme is missing or partially inactivated leading to a prolonged blockade. This usually results in an ICU ventilator dependant stay until the succs degrades. This takes from a few hours to a day. There is no test or predicting this effect that I know of and it is one of the potentials hazards of anesthesia. In the future, she should get rapid acting non-depolarizing agents if the need for RSI occurs again, abiet with a slight increased risk of aspiration during induction and intubation. Probably more a theoretical hazard than a real one.