Flashcards in Neuromuscular Blockers Deck (41)
What do neuromuscluar blocking drugs do?
Interrupt nerve impulses at the NMJ
What is the result of a neuromuscular block?
Complete paralysis of striated muscles with no analgesia and retained consciousness
What are some indications for NMBs?
- Positioning eye centrally
- Relaxation of respiratory muscles (ICU patients)
- Relax muscles for neurological or orthopedic surgeries
- Aid in intubation (humans)
What are the components of balanced anesthesia?
2. Stop reflexive movements/muscle relaxation
Is mechanical ventilation required when using NMBs?
Yes, due to paralysis of respiratory muscles, spontaneous ventilation ceases
What systems need to be monitored when using NMBs?
Cardio, respiratory, oxygenation
What are the only two indications of noxious stimulation when using NMBs?
Tachycardia and high blood pressure
When should NMBs not be used?
-No ability to ventilate or monitor
- Insufficient analgesia during surgery
- As a sole agent for procedures or euthanasia
What is the MOA of depolarizing NMBDs?
Nicotinic ACh receptor agonist causing membrane depolarization
What is the MOA of non-depolarizing NMBDs?
Competitive antagonist on nicotinic ACh receptors stabilizing muscle membranes
What is the order of muscle relaxation?
Ocular muscles > Everything else (larynx observed esp) > Diaphragm
What are some factors that influence the effect of NMBDs?
What are some drugs that potentiate NMBD effects?
- Inhalation anesthetics
- Aminoglycoside antibiotics
- Local anesthetics
- Cardiac antiarrhythmic drugs
What is succinylcholine mainly used for?
Historically used as euthanasia drug (inhumane)
What is seen in Phase-1 block with succinylcholine?
Muscle fasciculation then paralysis
What is seen in Phase-2 block with succinylcholine?
Non-depolarizing blockade after prolonged/high dosages
What are some adverse effects of succinylcholine?
- Cardiac arrhythmias
- Fasciculation, myalgia, myoglobinuria
- Elevated intra-ocular and intra-gastic pressures
- Malignant hyperthemia
Cumulative effects are less likely with what type of NMBDs?
Which type of NMBDs have less adverse effects?
Do non-depolarizing NMBDs have cardiovascular side effects?
Little to none
What is the major metabolite in atracurim and what does it do?
Laudanosine, decreases seizure threshold
What is atracurium eliminated by?
Plasma esterase enzymes- plasma pH and temp dependent
Can atracurium cause histamine release at high doses?
Cisatracurium represents what percentage of atracurium mixtures?
15% oft he 10 isomer mixture
How is cistracurium elimated?
80% Hofmann elimination- organ dependent
Which NMBD is the first choice in vet med?
What is rocuronium antagonized by?
Sugammadex- usually not needed
How is rocuronium eliminated?
Mostly liver, partially kidneys
What must be monitored closes when recovering patients with MNBDs on board?