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Pharm Test 2
Pharm Test 2 Ch. 12 Local Anesthetics
the goal of local anesthetics (LAs)? | block afferent neural transmission along the peripheral nerve |
where do LAs work? | peripheral nerve |
If given in a specific spot in the spine can the LA travel throughout the body? | yes |
What has a faster recovery time and less residual effects, LAs or GAs? | LAs |
T/F LAs mess w/ cardio, respiratory &/or renal functions? | false |
Do they take effect quickly? | no |
Can LAs be used to treat analgesia? | yes |
How can PTs use LAs? | iontophoresis and phonophoresis |
What is phonophoresis? | using ultrasound to enhance the topical drug |
What is iontophoresis? | using electrical current to penetrate drugs into the body through skin |
Do Las contain lipophilic and hydrophilic groups connected by an intermediate chain? | yes |
How are LAs chosen? | -operative site -nature of the procedure -type of regional anesthesia desired -Pt's size and general health -duration needed |
What is the common ending of LAs? | -caine |
Pharmokinetics of LAs | injections |
Are vasoconstrictors used with some of these drugs? If so why? If not why? | yes and to prevent washouts |
How are these drugs eliminated? | by hydrolyzing or breaking apart the molecule - catalyzed by hepatic enzymes or enzymes in circulation of the plasma - KINDEYS EXCRETE |
What are the types of LAs? | Topical, transdermal, infiltration |
Infiltration is? | injecting directly into the tissue |
What are the types of infiltration anesthesia? | peripheral nerve block central nerve block Sympathetic blockade IV |
Peripheral Nerve Block (PNB) is done where? | mostly done close to the nerve trunk but can be done near nerve plexus - dental procedures |
How many types of PNBs are there? | 2; minor and major |
Minor nerve block is when? | 1 nerve is blocked |
Major nerve block is when? | more than 1 nerve is blocked |
Can PNBs be given after surgery? | yes by a small catheter |
Prolonged use of PNB can lead to? | necrosis and pain |
Central Nerve Block (CNB) are given where? | spaces surrounding the spinal cord -epidural |
Where is the epidural? | between the bony vertebral column and the dura mater |
T/F CNB can be given in the sacral hiatus | true |
Intrathecal anesthesia is also known as | spinal nerve block within the subarachnoid space |
Intrathecal anesthesia is given when? | when larger regions need analgesia |
intrathecal anesthesia is normally given between what vertebrae? | L3-4 or L4-5 |
Where does the spinal cord in? | L2 |
Which is easier to perform, epidural or intrathecal? | epidural |
Which is more rapid epidural or spinal? | spinal |
Which has the higher risk, spinal or epidural? | spinal |
T/F Local anesthetics are neurotoxic when given in large amounts. | True |
Sympathetic Blockades are given to do what? | disrupt sympathetic discharges |
Reflex sympathetic dystrophy syndrome (RSDS) is also known as... | central regional pain syndrome (CRPS) or causalgia |
CRPS involves sympathetic or parasympathetic discharge? | sympathetic; often causing increased pain and dysfunction of distal part of extremity |
How is sympathetic blockade administered? | injected into the area surrounding the sympathetic chain ganglion that innervates the affected limb |
Where is sympathetic blockades mainly given? | Stellate ganglion for upper L2 for lower extremity |
How often is this treatment given to a Pt? | 10 days of 5 injections on every other day |
T/F Sympathetic blockades can be given IV or subcutaneously | true |
IV regional anesthesia is also known as.. | Beir Blocker |
Where are IV regional anesthesia administered? | peripheral vein located in arm or leg |
Must a tourniquet be used for the IV regional anesthetic? | yes |
Where should the tourniquet be placed for IV? | proximal to prevent it from leaving the area |
Mechanisms of Action | LOOK AT NOTES! |
Differential Nerve Blocks are used for what? | to block specific nerve fiber groups depending on the size of the fiber (diameter) |
Which nerve fibers are more sensitive, large or small? | small |
What type of fiber transmits pain? | type C |
Type A fibers are large or small? | large |
WHat do type A fibers do? | skeletal motor |
which fiber is 1st to be affected and which is last? | C then A; temp., touch, proprioception is 2nd |
the main importance for a differential nerve block is sensory or motor? | sensory |
Local anesthetic systemic toxicity (LAST) is when? | the LA is given & sometimes being absorbed into the general circulation |
LAs can effect organs when get into general circulation? | yes |
Virtually all LAs stimulate what initially, brain or body? | brain |
T/F central excitation is followed by CNS depression | true |
does heart rate and force of contraction go up or down when on LAs? | down |
Early signs of LA toxicty | ringing of the ears, agitation, restlessness, decreased sensation of the tongue, bradycardia, cardiac depression |
What can be given to treat LAST? | lipid rescue or lipid resuscitation |
Lipid rescue or lipid resuscitation is given how? | injection |
What is injected in lipid rescue? | emulsified lipid compounds that soak up the lipophilic LA molecules |