Neuromuscular blocking Flashcards
Describe the production of Acetylcholine
Acetyl CoA + choline. Choline acetyl transferase. Ach + CoA
Write the structure of Ach
ch3 - coo-ch2-ch2-nh4+
Described the location and structure of Ach
Ach is on the bumps of the post synaptic membrane. It has 5 subunits (a alpha, beta, e and delta). The AchE is found int he clefts.
The ammonium ion binds to the alpha subunit. The binding of the first subunit increases affinity for the second.
Describe the location and function of AchE
ache is found in the clefts.
It has an anionic enzyme found and an ester group the best breaks down the ester and a bionic attacks the ammonium group. The production is Achetyl coA and choline.
Describe the structure, presentation and dose of succinylcholine
two each molecule attached at the terminal cH3 Group. Presented as a clear colourless solution of 50mg/mL. It is stored at 4 degrees in the fridge.
dose is 1-1.5mg/kg. it has a rapid onset of 30 seconds (determined by the cessation of fasciculation.
Described the mechanism of action of sux
Binds to the ach receptor, causing depolarisation and then remaining bound. The membrane remains depolarised rendering na channels within 2nm void. Further doses act on the pre-synaptic membrane and cause a phase 2 block
describe the kinetics and genetic variance of sux
broken down by plasma cholinesterase. 20% of the initial dose makes it to the nmj. Plasma cholinesterase is encoded on chromosome 3. there as 10 different alleles. 96% can break down sux normally and it lasts for a few minutes.
6% of the population are heterozygous and break down sux slowly with a block lasting for 10 minutes.
A small homozygous proportion of the population do not break down sux and take hours for it to wear off. they can be treated with FFP.
Described the specific stimulation in a TOF
0.1ms stimulation at an amplitude of 2hz x 4 times.
Described the interpretation of a TOF
Placed on the medial aspect of the arm over the ulnar nerve, causes opposition of thumb.
1 should = 4 in unblocked people. T4 begins to fade at 70% block. Once T4 is 1/4 of the size of T1, T1 will start to fade. At 95% block only T1 will remain.
Described the mechanism of a Tetany block
1ms stimulus at 50hz. Causes prolonged block because of permanent depolarisation. This begins to fade in blocked patients due to blocking of the presynaptic receptors.
Described types of non-depolarising NMB
Aminosteroids such as rocuronium and vercuronium.
Benzynolisoquinilium - actracurium
