neuromuscular blockade justin roberts

neuromuscular blockade justin roberts

Transcript

1. Justin Roberts, MD Chief Resident – CA-3 ITE Review Session 1/22/2020
2. Common Uses  Facilitate endotracheal intubation  Reducing incidence of post-intubation hoarseness and airway injury  Facilitation of surgery  Improvement of surgical conditions  Lower insufflation pressures
3. Nondepolarizing NMBA  MOA – competing with Ach to bind the alpha subunits of the nicotinic receptor -> inhibition  Evidence to also show blocking of the ion channel and inhibiting Na influx  Assessed via train of four  T4:T1 <0.7 for adequate relaxation
4.  Paralyzation occurs central -> peripheral  Ie: laryngeal adductors -> adductor pollicus  Speed of onset inversely proportional to potency
5. Nondepolarization NMB (cont’d)  Enhancement with administration of inhalational anesthetics, local anesthetics, diuretics, aminoglycosides and magnesium
6.  Atracurium: hoffman elimination AND ester hydrolysis; production of laudanosine (neuroexcitatory). Also causes dose dependant histamine release -> avoid in asthma  Cisatracurium: does NOT cause histamine release; hoffman elimination  Pancuronium: excreted unchanged in urine; renal failure increased duration of action  Rocuronium: can be used for RSI when administered at three times the ED95.  Mivicurium: histamine induced bronchospasm
7. Depolarizing NMB: Succinylcholine  Two Ach molecules bonded (Diacetylcholine)  Myalgias: pretreatment with defasciculating dose does NOT help  Hyperkalemia risk (increase 0.5-1.0 mEq/L)  UMN lesions  Stroke  Third degree burns  Immobility  Malignant hyperthermia: known trigger  Associated with : Noonan syndrome, osteogenesis imperfecta, king denenborough, CPT II (carnitine palmitolytransferase deficiency), McArdle’s disease
8.  Pediatric arrhythmias: Stimulating muscarinic receptors of sinus node in adults, however, in children it stimulates nicotinic and muscarinic receptors in ganglia -> bradycardia in sympathotonic children (adults are vagotonic)  Phase II block: Re-dosing of succinylcholine or large dose of succinylcholine over a prolonged period of time. Mirrors non-depolarizing NMB and may hinder successful post op extubation  Intraocular pressure: modest transient increase in IOP  Hopefully ABA will stay away from this  Will also cause ICP increase
9. Butylcholinesterase deficiency
10. Reversal of NMB  AChE inhibitors: neostigmine, pyridostigmine, physostigmine and edrophonium.  Metabolization of Ach into choline and acetic acid  Neostigmine, pyridostigmine and edrophonium do NOT cross BBB