Neuromuscular Reversal Flashcards

1
Q

Reversal of Nondepolarizing drugs

ANTICHOLINESTERASES: ?
__ ammonium compounds
Allow __ at NMJ
Neostigmine & pyridostigmine- ? Bind to esteric site of ____
Endrophonium- electrostatic attachment to ___ site of the enzyme-reversible H+ binding

A

ANTICHOLINESTERASES: Neostigmine, pyridostigmine, endrophonium
Quaternary ammonium compounds
Allow ↑Ach at NMJ
Neostigmine & pyridostigmine- covalent binding of carbamyl group. Bind to esteric site of acetylcholinesterase.
Endrophonium- electrostatic attachment to anionic site of the enzyme-reversible H+ binding

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2
Q

Goal of reversal

what are the two goals?

These goals are accomplished by ___ the competitive effect of the NMB & ____ the concentration of Ach at the NM junction

A

Re-establish spontaneous ventilation
Protect the airway from aspiration

These goals are accomplished by ↓ the competitive effect of the NMB & ↑ the concentration of Ach at the NM junction

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3
Q

Time to Recovery

Composite of : 
1. Antagonism & 2. Spontaneous recovery
Factors influencing: 1. Degree of \_\_; 
2. ?; 
3. blood levels of \_\_; 
4. infusion vs. \_\_ ; 
5. specific \_\_\_ used & dose;
 6. underlying \_\_\_\_; 
7. drug interactions (enflurane> isoflurane> halothane); 
8. ?; 
9. ?; 
10. age - Elderly: The lower the muscle mass, the greater the intensity of the block.
A

Composite of : 1. Antagonism & 2. Spontaneous recovery
Factors influencing: 1. Degree of paralysis; 2. pharmakokinetics/dynamics; 3. blood levels of relaxant; 4. infusion vs. bolus; 5. specific antagonist used & dose; 6. underlying NM dysfunction; 7. drug interactions (enflurane> isoflurane> halothane); 8. organ dysfunction; 9. acid-base disturbances; 10. age

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4
Q

Neostigmine:

____ used & is most reliable in ___ block >90%.
Not reliable in ____ block (100%)
Increasing dose over ____ DOES NOT increase effectiveness (ceiling effect)
Onset __min
Peak ___ min

Glycopyrrolate - onset and duration similar (peaks 3-5 min vs. 1-2 atropine)
Mixture ____ Neo + _____ glycopyrrolate
Metabolized by cholinesterases in _____
Principle route of excretion is the ____

A

Most commonly used & is most reliable in deep block >90%. Not reliable in profound block (100%)
Increasing dose over 0.07-0.08mg/kg DOES NOT increase effectiveness (ceiling effect)
Onset 3 min
Peak 7-10 min
Glycopyrrolate - onset and duration similar (peaks 3-5 min vs. 1-2 atropine)
Mixture 0.05-0.07 mg/Kg Neo + 0.01-0.02 mg/ kg glycopyrrolate
Metabolized by cholinesterases in NMJ and liver
Principle route of excretion is the kidney

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5
Q

hOW DO YOU CALCULATE NEOSTIGMINE DOSE?

A

3-4 CC PER 70-80 KG and then draw up the same amount of glyco. administer in same syringe.

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6
Q

ACh at NMJ has nicotinic effects as well as where else?

A

peripheral nervous system. driven by muscarinic receptors.

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7
Q
Pyridostigmine
\_\_ as potent as neostigmine
\_\_\_ onset
40% \_\_\_
Peak effect \_\_ min (can be as long as 15-20 min)
Mix w/ \_\_\_
\_\_\_\_ dose
Oral for \_\_\_\_
Most dependent on \_\_\_ clearance 75%
A
20% (1/5th) as potent as neostigmine
slower onset
40% longer duration
Peak effect 12 min (can be as long as 15-20 min)
Mix w/ glycopyrrolate 
0.14-0.25 mg/kg dose
Oral for myasthenia gravis
Most dependent on renal clearance 75%
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8
Q

Endrophonium

adequate reversal if all \_\_\_
\_\_ potent (\_\_\_ of neostigmine)
\_\_\_ onset
peak \_\_\_ min
↑ Ach release \_\_\_synaptic
less severe \_\_\_ effects
Typically administered w/ \_\_\_\_  (.01 mg/kg)  =onset times
\_\_\_\_ dose
A
adequate reversal if all 4 twitches present
least potent (1/10th of neostigmine)
fast onset
peak 1-2 min
↑ Ach release presynaptic
less severe muscarinic effects
Typically administered w/ atropine  (.01 mg/kg)  =onset times
0.5-1.0 mg/kg dose
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9
Q

Clinical Effects of increased Ach

Effects occur fastest for ?
Cardiovascular
Muscarinic effect –?
Pulmonary:
Muscarinic effect - ?
GI:
?
Cerebral
\_\_\_ crosses BBB
A
Effects occur fastest for endrophonium->neostigmine
->pyridostigmine
Cardiovascular
Muscarinic effect – bradycardia/ vagal stimulation 
Pulmonary
Muscarinic effect - bronchospasm
GI
Increased peristalsis and secretions
N/V
Fecal incontinence
Cerebral
Physostigmine crosses BBB
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10
Q

Use extreme caution with (endrophonium, neostgmine, pyridostigmine) in people who have what diseases?

A

rate dependent cardiac disease (worried about the pt dropping their HR too much)
asthma
bronchospastic disease

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11
Q

___ are NOT given alone, use in combo with antimuscarinic

A

anticholinesterases

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12
Q

Anticholinergics/antimuscarinics

___ competitively bind to muscarinic Ach receptors
Prevents ____ mediated effects
Atropine & scopolamine are ___ amines- cross the Blood Brain Barrier (BBB)
Glycopyrrolate is a ____ amine- ionic charge ____ passage across BBB

A

aromatic esters competitively bind to muscarinic Ach receptors
Prevents cGMP or cAMP mediated effects
Atropine & scopolamine are tertiary amines- cross the Blood Brain Barrier (BBB)
Glycopyrrolate is a quarternary amine- ionic charge minimizes passage across BBB

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13
Q

Anticholinergics (Antimuscarinics)

Atropine- Onset __ / Duration ___
Glycopyrrolate- Onset ___/ Duration ___
With edrophonium – give several minutes prior to prevent ____

Scopolamine:
Not used in ?
Good for ___ and as an ____

A

Atropine- Onset 1 min/ Duration 30-60 min
Glycopyrrolate- Onset 2-3 min/ Duration 2-4 hours
With edrophonium – give several minutes prior to prevent bradycardia
Scopolamine
Not used in reversal of NDMR’s
Good for sedation
Good as an antisialagogue

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14
Q

Easy calculation:

for every cc of ___ draw a cc of __ in same syringe

A

neostigmine, glycopurrolate
mixture: 0.05 mg/Kg Neo + 0.01 -0.02 mg/kg glycopyrrolate

70kg x 0.05 neostigmine = 3.5 mg (draw 4 cc=4mg) + 4cc glycopyrrolate (4x 0.02 =0.08 mg)

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15
Q

When do we reverse?

A

MUST have at least one twitch present on PNS (peri nerve stimulator)
When was last dose of NDMR given???
Will the patient be intubated post-op?

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16
Q

Recovery:

Short acting MR have__ recovery with same dose of reversal than ___ MR
More rapid recovery in ____ than adults

___ are actively secreted into the ___ so clearance is delayed in___ failure

A

Short acting MR have faster recovery with same dose of reversal than long acting MR
More rapid recovery in infants & children than adults

Anticholinesterases are actively secreted into the tubular lumen so clearance is delayed in renal failure

17
Q

Clinical signs of adequate reversal

Sustained \_\_\_\_\_-indicates ability to adequately ventilate & protect the a/w
\_\_\_ ventilation
Opening the \_\_\_
Protrude the \_\_\_
\_\_\_\_\_-more sensitive but less useful
Leg raising- \_\_\_\_/as sensitive as head lift in adult
Coughing
Swallowing
Reaching toward endotracheal tube
A
Sustained 5 second head lift-indicates ability to adequately ventilate & protect the a/w
Spontaneous ventilation
Opening the eyes
Protrude the tongue
Hand grip-more sensitive but less useful
Leg raising- infants & neonates/as sensitive as head lift in adult
Coughing
Swallowing
Reaching toward endotracheal tube
18
Q

PNS responses

Pain- ____-> response to PNS appropriate then
When TOF __ Most neuromuscular function has returned to normal (some require >0.9)
Detection of _____ is difficult if the patient is not awake & cooperative
There should be ____.

A

Pain- may not be able to lift head-> response to PNS appropriate then
When TOF >0.7 Most neuromuscular function has returned to normal (some require >0.9)
Detection of residual block is difficult if the patient is not awake & cooperative
There should be NO detectable fade

19
Q

other anticholinesterases drugs

?

A

Physostigine
Echothiopate
- tx for glaucoma should use succs for echothiopate, the DOA will increase and there is no reversal for that
Nerve gases - Saran, Soman
- also act as anticholinesterases (bradycardia, bronchospasms, death)

20
Q
Physostigmine
is an \_\_\_
cross the \_\_
used for reversal of \_\_ following \_\_\_ and \_\_\_ (central anticholinergic syndrome)
reverses somnolence with \_\_\_\_\_
dose is \_\_\_\_
A

Anticholinesterase
Crosses the Blood Brain Barrier (BBB)
Used for reversal of confusion/disorientation following atropine&scopolamine (central anticholinergic syndrome)
Reverses somnolence with opoids/valium/versed/IA/ketamine
15-60 ug/kg

21
Q
Echothiopate
oNLY \_\_ \_\_ Drug used clinically 
long acting miotic that lowers \_\_
useful in treatment (Rx) OF \_\_
may prolong the duration of \_\_ after 1 month of treatment as \_\_ \_\_\_ activity may decrease to less than 5% of normal
A

Only organophosphate anticholinesterase drug used clinically
Long acting miotic that lowers IOP
Useful in Rx glaucoma
May prolong the duration of succinylcholine after 1 month of Rx as plasma pseudocholinesterase activity may decrease to less than 5% of normal