Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
26 Cards in this Set
- Front
- Back
|
List 6 absolute contraindications to neuraxial blockade
|
Infection at site of injection
Pt refusal coagulopathy/bleeding diathesis severe hypovolemia Increased ICP Severe aortic or mitral valve stenosis from M&M p299 |
|
|
List 6 relative contraindications to neuraxial blockade
|
Sepsis
uncooperative patient preexisting neurological deficits demyelinating lesions stenotic valvular heart lesions (not severe) severe spinal deformity from M&M p299 |
|
|
What is the resting potential of neural membranes? The inside is more _______ (positive, negative) than the outside of the cell?
|
-60 to -90 mV; the inside is more negative than the outside of the cell
|
|
|
Local anesthetics bind to ____ channels in the ____ or ________ state.
|
Na+; open, inactivated-closed
|
|
|
Local anesthetics are weak _________ (acids, bases) prepared in a/an _________ (acidic, basic) solution
|
bases; acidic
|
|
|
What does the Henderson-Hasselbach equation represent? What is the simplified equation?
|
The equilibrium between charged cations (AH+) and neutral free-base molecules (A), which is determined by pH
The simplified equation is pK = pH – log (base/cation) |
|
|
The pH of most local anesthetics is between ___ and ___, therefore ________ (cations, bases) outnumber _______ (cations, bases) in normal tissue pH (7.4)
|
7.5, 9.0; cations, bases
|
|
|
Which form of local anesthetic diffuses more easily through the bilipid nerve membrane? Which form binds to the receptor sites, blocking the Na+ channel and suppressing the action potential?
|
free base (nonionized) diffuses more easily through the bilipid nerve membrane
the cation (ionized) form of LA binds to the receptor sites, blocking the Na+ channel and suppressing the action potential |
|
|
pKA (amount of n onionized form) directly effects the _____ characteristics of a local anesthetic
|
onset
|
|
|
lipid solubility is a primary determinant of _________
|
potency
|
|
|
Protein binding is a primary determinant of _______ of local anesthetic action
|
duration
|
|
|
What does the term “short latency pain” refer to?
|
Pain that warns the organism that it is in danger so that it will alter the situation (e.g., take flight, withdraw limb)
|
|
|
What does the term “long latency pain” refer to?
|
Pain that immobilizes the organism so that recovery from injury can occur
|
|
|
Nociception is a _________ process, while pain is an _____ process
|
physical; emotional
|
|
|
_________ is when a normally painful stimulus is more painful than expected
|
Hyperalgesia
|
|
|
_________ is when a normally non-painful stimulus is painful
|
allodynia
|
|
|
What structures comprise the ascending pain pathways?
|
Nociceptors
primary afferents (A-delta and C fibers) dorsal horn spinothalamic tract thalamus cortex |
|
|
What do first-order neurons do? What are they and where are they located?
|
Nociceptors sense substances that indicate tissue damage;
Sensitivity may be increased by inflammatory mediators (notably prostaglandins) First-order neurons in pain pathways are nerve endings in the skin (A-delta or C fibers) |
|
|
What do second-order neurons do?
|
Second-order neurons process nociceptive information
They also communicate with various reflex networks and sensory pathways in the spinal cord and travel directly to the thalamus |
|
|
What do third-order neurons do?
|
Third-order neurons project pain information to the cortex, where it is perceived
|
|
|
Name the three categories of nociceptive pain
|
Superficial somatic pain
Deep somatic pain Visceral pain |
|
|
Name 3 general types of pain mediators
|
Mechanical
Thermal Chemical |
|
|
Name 9 examples of endogenous chemical mediators of pain
|
Cations (esp H+ and K+)
Cytokines (esp IL-1 and IL-6) Free radicals (e.g., NO and OH-) Histamine from mast cells Kinins (bradykinin, kallidin) Prostanoids (esp PGE2 and leukotrienes) Purines (eg, adenosine) Serotonin (5-HT) from neurons in the CNS Tachykinins (eg, Substance P and Neurokinin A released from presynaptic nerve endings at the synapse in the spinal cord dorsal horn) |
|
|
A-beta fibers have a conduction velocity that is relatively _______ (fast/slow) and an activation threshold that is relatively _______ (high/low)
|
fast; low
|
|
|
C fibers have a conduction velocity that is relatively ____ (fast/slow) and an activation threshold that is relatively _____ (high/low)
|
slow; high
|
|
|
Name some structures in the descending modulatory pain pathway
|
Somatosensory cortex
hypothalamus Periaqueductal gray (midbrain) Locus ceruleus/subceruleus A5 cell group Nucleus Raphe Magnus (medulla) Lateral reticular nucleus Dorsolateral funiculus Spinal dorsal horn |
