[11.12b] Overview of Anesthesia (Part 2) V2.pdf

acetylcholine

What is the neurotransmitter responsible for muscle contraction?

antagonizes acetylcholine

How do skeletal muscle relaxants prevent muscle contraction?

neuromuscular junction

Where do neuromuscular blocking agents specifically act?

paralysis

What is the clinical result of blocking acetylcholine in the muscle junction?

needed to relax muscles so the surgeon can visualize the field and work efficiently

What is a primary therapeutic use for muscle relaxants during surgery?

intubation and control of breathing

What is a reason to paralyze respiratory muscles besides helping the surgeon?

bowels

Which body part would continue moving without muscle relaxants during abdominal surgery?

retraction

Relaxed muscles during surgery make it easier to perform what physical action for exposure?

non-depolarizing and depolarizing

What are the two main types of neuromuscular blocking agents?

non-depolarizing

Which type of neuromuscular blocking agent is longer acting?

depolarizing

Which type of neuromuscular blocking agent is shorter acting?

completely inhibiting ACh receptors

What is the mechanism of action for non-depolarizing muscle relaxants?

last synapse between the motor neuron and the muscle fiber

Where do non-depolarizing agents work relative to the neuron?

competitively inhibit ACh at the postjunctional membrane receptor

What is the specific binding action of non-depolarizing muscle relaxants?

prevents depolarization and propagation of action potential

How do non-depolarizing blockers physically stop muscle movement?

Tubocurarine

What is an example of a non-depolarizing NMB drug?

Metocurine

What is another example of a non-depolarizing NMB drug?

Atracurium

What is another example of a non-depolarizing NMB drug?

Cisatracurium

What is another example of a non-depolarizing NMB drug?

Mivacurium

What is another example of a non-depolarizing NMB drug?

Doxacurium

What is another example of a non-depolarizing NMB drug?

Vecuronium

What is another example of a non-depolarizing NMB drug?

Rocuronium

What is another example of a non-depolarizing NMB drug?

Rocuronium

Which non-depolarizing agent is noted as most commonly used in the OR?

intense muscular contraction and fasciculations

What happens initially when a depolarizing muscle relaxant is administered?

succinylcholine

What is the only depolarizing muscle relaxant of clinical importance?

two ACh molecules joined together

What is the chemical structure of succinylcholine?

ganglion blockade

What type of blockade does succinylcholine produce besides the NMJ?

cholinesterase

What enzyme hydrolyzes succinylcholine?

malignant hyperthermia

Name a rare but fatal complication associated with succinylcholine.

postoperative muscle pain and hyperkalemia

Name two side effects of succinylcholine.

receptor agonist

Is succinylcholine a receptor agonist or antagonist at the motor end plate?

stimulation and depolarization

What does succinylcholine produce at the motor end plate?

fatigue

What process caused by initial stimulation leads to the ultimate relaxation from succinylcholine?

30-60 seconds

How long do initial muscle contractions or fasciculations last?

extrinsic muscles of the eye

Which muscle group is the first to undergo paralysis?

face and extremities

Which muscle groups are the second to undergo paralysis?

intercostal muscles

Which muscles are third in the order of paralysis?

diaphragm

Which muscle is the last to relax?

apnea

What does the relaxation of the diaphragm cause?

reverse order

In what order do muscles recover from relaxation?

diaphragm

Which muscle group is the first to recover?

extrinsic muscles of the eye

Which muscle group is the last to recover?

breathing then swallowing then opening eyes

What is the physical sequence of recovery?

open your eyes

What specific instruction do physicians give to check if a patient can breathe on their own?

Neostigmine or Sugammadex

What two drugs can reverse non-depolarizing NMBs?

Neostigmine

Which reversal agent is considered the conventional option?

pharmacologic antagonism

What principle does Neostigmine use to reverse residual blockade?

avoid inadvertent hypoxia or apnea

Why is reversal of muscle relaxation necessary before waking the patient?

acetylcholinesterase inhibitor

What is the specific mechanism of action for Neostigmine?

NMJ

Where does Neostigmine perform its action?

competes with the NMB agent

How does increased ACh from Neostigmine affect the NMB blockade?

Bridion

What is the brand name for Sugammadex?

metabolism and excretion

How does the concentration of NMB agent at the NMJ decrease during recovery?

plasma ACh concentration

Recovery from NMB involves an increase in the concentration of what?

Rocuronium

Sugammadex specifically reverses which common NMB?

cyclodextrins

What selective reversal binding agents are found in Sugammadex?

vecuronium and pancuronium

To what two other drugs might Sugammadex work to a lesser extent?

plasma

Where does Sugammadex perform its action?

encapsulate the NMB agents

What is the mechanical action of Sugammadex on drugs like Rocuronium?

rapid chemical encapsulation

What term describes the selective binding interaction between Sugammadex and the NMB drug?

traps the drug to allow ACh more time to take effect

How does Sugammadex encapsulation result in reversal?

potential space

What type of space is the epidural space?

subarachnoid space

Which space contains the cerebrospinal fluid?

epidural space

Where is local anesthetic injected for epidural anesthesia?

catheter

What is used in epidural anesthesia to allow for longer procedures like labor?

slower onset and longer duration

How does epidural anesthesia compare to spinal in terms of onset and duration?

subarachnoid space

Where is local anesthetic injected for spinal anesthesia?

lumbar subarachnoid puncture

What is the only way to reach the spinal space?

CSF coming out of the needle

What is the indicator that a needle has reached the subarachnoid space?

mix with the CSF and circulate

How do anesthetics move within the spinal space?

immediate block of sensory, motor, and sympathetic nervous system

What is the neurological effect of spinal anesthesia?

faster onset and shorter duration

How does spinal anesthesia compare to epidural?

2-3 hours

How long can spinal anesthesia last?

combination

What is the technique called that uses both a subarachnoid injection and an epidural catheter?

convert to general anesthesia

What must be done if an operation exceeds the duration of spinal anesthesia?

post-operative pain control

What is a common use for an epidural after surgery?

peripheral nerve block

What type of anesthesia is used for specific limbs or acute/chronic pain management?

near a specific nerve or bundle of nerves

Where is a peripheral nerve block injected?

paravertebral block

List one site for a peripheral nerve block.

femoral block

List another site for a peripheral nerve block.

lumbar plexus block

List a third site for a peripheral nerve block.

supraclavicular or infraclavicular

What two blocks involve the clavicle?

interscalene brachial plexus

What block involves the scales of the neck?

isolated

How are peripheral blocks described compared to waist-down regional blocks?

infection over injection site

What is the first absolute contraindication for regional anesthesia?

varicella

What infectious disease is given as an example that would preclude regional anesthesia?

coagulopathy

Name the absolute contraindication involving bleeding risks.

Aspirin or Clopidogrel

Which two blood-thinning medications might preclude a spinal puncture?

hematoma

What can form in the spinous process if a patient has poor coagulation during a puncture?

marked uncorrected hypovolemia

Name the absolute contraindication related to low blood volume.

decrease blood pressure

What is the effect of regional anesthesia on blood pressure?

blockage of the central portion of the spinal cord

Why does regional anesthesia decrease blood pressure?

allergy to local anesthetics

Name an absolute contraindication related to drug hypersensitivity.

increased intracranial pressure

Name the absolute contraindication related to brain pressure.

patient refusal or inability to cooperate

Name the absolute contraindication related to consent.

general anesthesia

What should be given if a patient refuses regional anesthesia?

pediatric, psychiatric, and cognitive disabilities

Name three patient groups that may be unable to cooperate for regional anesthesia.

preexisting neurologic disease

Name one relative contraindication for regional anesthesia.

back disorders

Name a second relative contraindication.