Anesthesia/Pain Management Flashcards
What is the contraindication for interpleural analgesia?
When pericardium is disrupted
How to perform an interpleural analgesia?
1) Prepare bupivacaine 1.5 mg/kg
2) 1 to 4 dilution with normal saline
3) Slowly infuse the solution into the chest tube and allow it to sit for 30 minutes. Keep the incision side down
4) Same procedure can be repeated q4-6h, with the max dose of 9mg/kg/d
How many percentage of PCV can decrease during anesthesia?
3-5%
Which induction agent can cause adrenal suppression?
Etomidate
How is remifentanil metabolized?
Non-specific esterases in the blood
How is atracurium metabolized?
Partially by ester hydrolysis
Partially by Hofmann elimination (spontaneous degradation in normal temperature & pH)
- Hofmann elimination is sowed down by acidosis and hypothermia
What are potential side effects for atracurium administration?
1) laudanosine release (product from Hoffman elimination) → CNS excitement
2) Histamine release
What is the reversal for neuromuscular blockage?
edrophonium, neostigmine (anticholinesterase)
What is the dose, onset and duration of neostigmine?
Onset 7-10 min
Duration 60-70 min
Dose 0.04 mg/kg IV
*Can combine with glycopyrrolate 0.01 mg/kg to combat bradycardia
Which electrolytes are GABAA receptor coupled with?
Chloride
GABAa receptor is a ligand-gated chloride channel
- GABAA (fast response) receptors are anion channels whereas the GABAB (slow response) receptors are G‐protein‐coupled receptors
How does GABAa receptor work when it’s activated?
It allows chloride to enter the cell → hyperpolarization of the cell → inhibit the cell to subsequent depolarization → CNS depression
What are the agonists for AMDA and NMDA receptor?
Glutamate
*Aspartate is also an endogenous agonist for NMDA receptor
* glycine is a co‐agonist required to open the NMDA channel efficiently
How does NMDA receptor work when it’s activated?
NMDA receptor It allows Na and Ca to enter the cell & K to leave the cell → cell is more likely to depolarize → excitatory effect
Where are NMDA receptor most commonly found in the neuron.
Post-synaptic membrane
True or False: ATP is the main source of energy for G-protein coupled receptor.
False
Guanosine triphosphate (GTP) is the energy
Explain how does G-protein coupled receptor work.
There are two types of G proteins, Gs (stimulation) and Gi (inhibitory). When the receptor binds to an agonist, both the receptors and G protein change their conformations → the GDP attached on the G protein (𝜶 unit) is replaced by GTP → stimulate/inhibit the adenylyl cyclase or other membrane enzymes → AC uses ATP to produce cAMP → activate/inhibit protein kinase A → downstream enzyme production & cell signaling
Define potency.
The concentration of the drug needed to achieve a pharmacological effect equal to 50% of Emax.
Which cholinergic receptors do atropine and glycopyrrolate mainly inhibit? muscarinic or nicotinic?
Muscarinic
Which of the anticholinergics can cross BBB? Atropine or glycopyrrolate?
Atropine
When you give low dose atropine, why sometimes you will see transient bradycardia and 2nd degree AV block prior to tachycardia?
The presynaptic M1 receptors are blocked first, which inhibit the negative feedback inhibitory effect → more acetylcholine release
*usually after a while once the postsynaptic M2 receptors are blocked, bradycardia will resolve.
What are the MOA for 𝜶1 and 𝜶2 adrenergic receptors?
𝜶1: excitatory G protein-coupled receptor linked to phospholipase C → increases intracellular inositol triphosphate → increase in intracellular [Ca2+]
𝜶2: inhibitory G protein-cpupled receptor linked to adenyly cyclase → decrease cAMP
True or False: 𝜶2 adrenergic receptor activation can lead to platelet aggregation
True
What is the MOA for 𝜷1 and 𝜷2 adrenergic receptors?
𝜷1 and 𝜷2: excitatory G protein-coupled receptor linked to adenylyl cyclase → increase cAMP
- 𝜷2: increased cAMP activates protein kinase A → increase activity of Na/K ATPase → hyperpolarization → smooth muscle relaxation
What are the MOA for dopamine1 and dopamine2 receptors?
D1: excitatory G protein-coupled receptor linked to adenylyl cyclase → increase cAMP
D2: inhibitory G protein-cpupled receptor linked to adenyly cyclase → decrease cAMP
How does epinephrine cause hyperglycemia?
1) inhibition of insulin secretion (α2‐ and β2‐adrenergic effect)
2) glycogenolysis in liver and muscle (α1‐ and β2‐adrenergic effect)
3) lipolysis (β2‐ and β3‐adrenergic effect)
4) gluconeogenesis (α1‐ and β2‐adrenergic effect)
What are the predominant receptors dopamine work on at different CRI rate?
1-2 mcg/kg/min: D1 & D2 receptors
2-10 mcg/kg/min: 𝜷1 adrenergic receptors
> 10 mcg/kg/min: 𝜶1 adrenergic receptors
Is propanolol a 𝜷1 or 𝜷2 antagonist?
It is a non-selective 𝜷 receptor antagonost
What is MOA for acepromazine?
dopamine receptor antagonist → sedation
𝜶1 adrenergic receptor antagonist → vasodilation
histamine 1 receptor antagnoist
How does 𝜶2 agonist cause bradycardia?
Vasoconstriction → baroreceptor-mediated reflexes → bradycardia
What is the MOA for opioid receptor?
Gi protein-coupled receptor → inhibition of adenylyl cyclase → decrease cAMP production → inhibition of Ca2+ channels in presynaptic neurons → decreased release of excitatory neurotransmitters (e.g., glutamate and substance P)
decrease cAMP production → enhancement of cellular K+ outflow in postsynaptic neurons → hyperpolarization of nociceptive neurons and nociceptors → increased activation thresholds
- In supraspinal area, opioid binds to receptors within the periaqueductal gray (PAG) region → release dopamine and glutamate → supraspinal antinociception effect
What are the two neural fibers mediated pain?
C fibers: slow‐conducting, unmyelinated nerves associated with dull aching pain
A 𝛅 fibers: fast‐conducting, myelinated nerves associated with sharp, discrete pain