Neuromuscular blockers 2 Flashcards
Identify the statement that demonstrates the MOST accurate understanding of succinylcholine (select 2.):
a. hypertension is a normal side effect
b. it’s an absolute contraindication with an open globe injury
c. severe sepsis increases the risk of hyperkalemia
d. masseter spasm warrants cancellation of the planned procedure
a. hypertension is normal side effect
c. severe sepsis increases the risk of hyperkalemia
Succinylcholine can produce a wide variety of side effects including:
bradycardia
tachycardia
increased serum K+
increased intraocular pressure
increased intracranial pressure
increased intragastric pressure
malignant hyperthermia
__________ are more susceptible to bradycardia with succinylcholine because of
children; because of a higher baseline vagal tone
If a child requires a second dose of succinylcholine, you should administer _________ before administering the second dose of succinlycholine
atropine
Succinylcholine is safe in patients with
renal failure and a normal serum potassium level
Succinylcholine can cause
masseter spasm
If masseter spasm occurs with succinylcholine,
it does not warrant cancellation of the planned surgical procedure; this finding in the absence of other s/sx of MH is normal
How does succinylcholine cause bradycardia or asystole?
stimulating the M2 receptor in the SA node
How can succinylcholine cause tachycardia and hypertension?
by mimicking the action of Ach at the sympathetic ganglia
Succinylcholine transiently intraocular pressure by
5-15 mmHg for up to 10 minutes
How can a temporary increase in ICP be prevented when giving succinylcholine?
giving a defasciculating dose
Is the risk of aspiration increased with succinylcholine?
No because contraction of the abdominal muscle increase intragastric pressure but succinylcholine also raises lower esophageal sphincter tone and they cancel each other out
Which enzymes hydrolyze succinylcholine? Select 3
a. butyrylcholinesterase
b. type 1 cholinesterase
c. true cholinesterase
d. pseudocholinesterase
e. plasma cholinesterase
f. acetylcholinesterase
a. butyrylcholinesterase
d. pseudocholinesterase
e. plasma cholinesterase
Acetylcholinesterase is found in
the neuromuscular junction
Acetylcholinesterase metabolizes
acetylcholine
Pseudocholinesterase is found in the
plasma
Pseudocholinesterase metabolizes
succinylcholine
mivacurium
ester local anesthetics
Other names for acetylcholinesterase include
genuine cholinesterase
type 1 cholinesterase
true cholinesterase
specific cholinesterase
Other names for pseudocholinesterase include
butyrylcholinesterase
type 2 cholinesterase
false cholinesterase
plasma cholinesterase
Pseudocholinesterase is produced in the
liver and serves as an indicator of hepatic synthetic function
In the plasma, pseudocholinesterase has a reference concentration range of
2900-7100 units/L
Pseudocholinesterase is also located in
smooth muscles
intestines
white matter of the brain
heart
pancreas
NOT located in the CSF
With pseudocholinesterase, neuromuscular symptoms begin at __ of normal and become serious at ____ of normal
60%; 20%
Which factors prolong the duration of succinylcholine? (select 3).
a. metoclopramide
bb. edrophonium
c. obesity
d. late-stage pregnancy
e. myasthenia gravis
f. esmolol
a. metoclopramide
d. late-stage pregnancy
f. esmolol
Key drugs that reduce pseudocholinesterase activity include
metoclopramide
esmolol
neostigmine
Key conditions that reduce pseudocholinesterase activity include:
atypical PChe
severe liver disease
burns
neoplasm
pregnancy (late-stage)
All co-existing diseases that reduce pseudocholinesterase activity include
atypical PChe
severe liver disease
chronic renal disease
organophosphate poisoning
burns
neoplasm
advanced age
malnutrition
pregnancy (late stage)
All drugs that prolong the duration of succinylcholine include
metoclopramide
esmolol
neostigmine (not edrophonium)
echothiphate
oral contraceptives/estrogen
cyclophosphamide
monoamine oxidase inhibitors
nitrogen mustard
A patient with a dibucaine number of 20 received succinylcholine. This patient:
a. is heterozygous for pseudocholinesterase
b. fails to produce pseudocholinesterase in sufficient quantity
c. should receive fresh frozen plasma
d. will be paralyzed for eight hours
d. will be paralyzed for eight hours
______________ is an amide local anesthetic that is used to diagnose atypical PChE
Dibucaine
Dibucaine inhibits __________, but has no effect on ______________.
normal PChE, no effect on atypical PChe
_________________ determines the type of pseudocholinesterase she produces (typical or atypical)
A patient’s genetic makeup
What does a dibucaine number of 20-30 indicate
atypical homozygous
What does a dibucaine number of 70-80 indicate?
typical homozygous (normal)
What does a dibucaine number of 50-60 indicate?
heterozygous variant
The best treatment for a patient with atypical PChE who has received succinylcholine is
mechanical ventilation
sedation
tincture of time
Atypical PChE variants cannot _______________ so the duration of succinylcholine will be ________________
hydrolyze succinylcholine; prolonged
A normal dibucaine number is
80
A normal dibucaine number of 80 indicates that
dibucaine has inhibited 80% of the pseudocholinesterase in the sample
A tentative bedside diagnosis of pseduocholinesterase deficiency can be made if
the response to train-of-four stimulation is absent for longer than expected
With a dibucaine number of 50-60, succinylcholine duration is prolonged by
20-30 minutes
With a dibucaine number of 20-30, succinylcholine duration is prolonged by
4-8 hours
Atypical plasma cholinesterase is a
qualitative defect; pseudocholinesterase in produced in sufficient quantity however the enzyme that is produced is not functional
_______, _______, or ________________ will restore plasma pseudocholinesterase levels in a patient with an atypical variant but it is not necessarily the treatment of choice.
whole blood, FFP, or purified human cholinesterase
The routine administration of succinylcholine is contraindicated in young children because of the possibility of:
a. malignant hyperthermia
b. hyperkalemic rhabdomyolysis
c. trismus
d. bradycardia
b. hyperkalemic rhabdomyolysis
Succinylcholine sports a black box warning that details the risk of
cardiac arrest and sudden death secondary to hyperkalemia in children with undiagnosed skeletal muscle myopathy
The most common cause of skeletal muscle myopathy is
Duchenne muscular dystrophy
Succinylcholine-induced hyperkalemia typically presents with
peaked T waves and sudden cardiac arrest
Succinylcholine-induced hyperkalemia most commonly affects
males under 8 years old
Succinylcholine is generally avoided in
children under 8 years of age
If a health infant or small child develops cardiac arrest following succinylcholine, treatment should include
stabilizing the myocardium
shifting potassium into cells
enhancing potassium elimination
What should be given in a succinylcholine induced cardiac arrest to stabilize the myocardium?
IV calcium
What should be given in a succinylcholine induced cardiac arrest to shift potassium into cells
glucose+insulin
sodium bicarbonate
hyperventilation
albuterol
What should be given in a succinylcholine induced cardiac arrest to enhance potassium elimination?
furosemide
volume resuscitation
hemodialysis
hemofiltration
Other forms of skeletal muscle myopathy that can lead to succinylcholine induced cardiac arrest include
Becker
Emery-Dreifuss
facioscapuloumeral
limb-girdle muscular dystrophy
What is the dose of calcium chloride?
20 mg/kg
What is the dose of calcium gluconate?
60 mg/kg
What is the dose of sodium bicarbonate?
1-2 mmol/kg
What is the dose of furosemide?
1mg/kg
What is the dose of glucose + insulin?
0.3-0.5 g/kg as 10% glucose solution + 1 unit insulin per 4-5 g IV glucose
