Anesthesiology - Midterm 3

drraythe's version from 2016-02-28 21:19

LAs ctd

Question Answer
Intrathecal anesthesia refers to where? & aka? What should you know about this?Spinal or SUBARACHNOID → can be intentional or not, usually happens at L4-5-6 in dogs & the drugs mix w/ the CSF which means they can get to the brain (prolly not good)
What kinda shaving/septic margins do you want for epidural? What should you know about the septic technique?Big BIG margins bc needs to be VERY clean. DONT USE ALCOHOL (or at least dont lather it on) bc alcohol is NEUROTOXIC & you can push it into the spinal canal
What are 3 different ways you can verify correct placement of the needle?Gold standard: fluoroscopy contrast rxn (xray that moves), or feel a loss of resistance, or a HANGING DROP (distinct pop/plop sensation)
Things that can go wrong from injecting LA too fast? Things you can try to do to see if you're doing it slow enough?Recc you have ECG & BP monitoring in place while performing epi, due to LA side effects. If you inject too fast, will spread too far cranial. Might cz "patchy" anesthetic bc you injected too fast & it all went into fat depots instead of reaching nerves
No matter the drug used for epidural, what should you know about the formulation?PRESERVATIVE FREE
What are some drugs used for epidural?(PRESERVATIVE FREE)
α-2 adrenoceptor agonists
***Which wears out 1st... Sensory or motor block?Motor block wears off 1st (makes sense, thats the deepest level of block so they'll come out of it faster but sensory is a ton of diff nerves)
Compare the dose, onset & duration for Morphine vs Bupivacaine for an epiduralMorphine - Takes long, lasts long, need like nothing (DOSE: 0.1mg/kg, onset 30-90min, LASTS 16-24)
Bupivacaine - Even tho slow other ways, MUCH faster than Morphine (0.5-1mg/kg, ONSET: 3-4min, LASTS: 4-6hr)
For all drugs w/o preservatives used for epidural, what do you want to dilute them to & whats the max administered amount?NEW VIALS! Dilute to 0.2ml/kg, NO MORE THAN 6ml for a dog
Indications for eda (epidural)Perineal Sx
Tail amputation
Hind limb Sx
Lower abdominal Sx
CONTRAINDICATIONS FOR EDA (epidural)Skin infxn & injxn site
Blood clotting probs
Fractured pelvis or spine (those supposed to be landmarks)
Pre-existing hypotension (no LA for this-LA would make more hypotensive)
CNS disorders
OBESITY (cant palpate landmarks)
Discospondylitis (lumbosacral space not accessible anymore)
How much of reg dose if performing spinal anesthesia?1/3 dose
What’s different about epidurals in cats?Spinal cord further caudal, 50% of time its spinal epi. Also duration of effect usually shorter
Brachial plexus blocks which spinal nerves? Which area on body is blocked? → Good for what probs?C6-T1. Distal from elbow. (Good for radio-ulnar fractures) → blocks radial, ulnar, musculocutaneous, median, axillary.
2 techniques for brachial plexus block?(1) BLIND - Needle medial to tip of shoulder. Advance toward costochondral junction. Inject as needle is withdrawn
(2) Nerve locator - Instrument that senses elec impulse of nerves is used to find the nerves
Drugs for brachial nerve block? (What are the doses for each technique?)LIDOCAINE and/or BUPIVIVAINE (elbie's arm needs work)
(1) BLIND - 1ml/kg max 15ml
(2) Nerve locator - 0.25ml/kg (blind needs more bc not sure how effective placement)


Question Answer
Nociception =/=Pain (sensory & emotional experience & inability to communicate doesnt mean no pain)
Whats transduction?Detection of innocuous (not harmful) & noxious info.
Which fibers arent myelinated? Thinly myelinated? What should you know about the effect of myelination?B & C arent myelinated. A-delta are thinly myelinated. **THIS MAKES THEM SLOWER
Which is the "1st pain" fibers?A-delta (A delta carwash should be your 1st choice)
Which is the "second pain" (burning, slow pain) fibers?C-fibers (C is's the roundabout pain)
Activation of what 2 nerve fibers is necessary for perception of acute pain?A-delta (delta is the A choice for fast cars-1st pain fibers) & C (roundabout pain-slow burning)
What are the silent/sleeping nociceptors & why are the called this?The A-delta & C-fibers (once responsible for acute pain)-they are sleeping bc NOT activated by tissue damaging events-activated by inflammation (particularly sensitive to mechanical stim) (ADC, SLEEEEPY)
Path of pain w/ fancy wordsStimulus → transduction (end of fiber) → xmission (to spinal nerve) → modulation (SC modifies signal) → projection (up spinal cord) → perception (brain)
Explain low intensity stimulus vs high intensity stimulus (which fibers)Low intensity stim: (A-beta fibers) transmit innocuous sensation.(A-B is so lazy it just transmits that something happened, not pain...lazy bc just said 1st 2 letters of alphabet & was done w/ it) HIGH intensity stimulus: (A-delta & C fibers) PAIN!
Allodynia is what & is czd by what fibers?NONPAINFUL stim feels like pain-so is A-Beta fibers. Makes sense bc they are the AB-lazy ones who usually do innocuous stim, but theyre overstim so are like "uhh what do? PAIN"
Hyperalgesia is what & czd by what fibers?Sensitized nerves cz more pain that what was actually reasonable. So czd by nerves which are already doing pain-A-delta & C fibers
What is 1° hyperalgesia?Aka peripheral sensitization. Inflammatory/sensitizing soup, results as hyperalgesia at site of injury
What is central sensitization?Results in 1° & 2° hyperalgesia (2°=pain sensitivity that occurs in surrounding undamaged tissues) & allodynia, responsible for pain memory
What is wind up?Temporal summation of sensory inputs in the spinal cord. (Perceived ↑ in pain intensity over time when a given non painful stimulus is delivered repeatedly above a critical rate. It is czd by repeated stimulation of group C peripheral nerve fibers, leading to progressively increasing electrical response in the corresponding spinal cord (posterior horn) neurons) SHE SAYS: czs ↑ sympathetic innervation/excitation or DORSAL ROOT GANGLION (sensory one). Also disinhibition of inhibitory inputs. Leads to abnormal patterns of spinal cord internuronal communication
Peripheral sensitization activates what fibers?Silent nociceptors (A-d & C)
Substances which work on pain signal inhibition in the brainInhalants
Injectable anesthetics
Substances which work on pain signal inhibition in the SCInhalants/injectable anesthetics
a-2 agonists
Substances which work on pain signal inhibition in the xmission of painLAs
Substances which work on pain signal inhibition in the TRANSDUCTION of painOpioids
α-2 agonists
UMPS-uni of Melbourne pain scale-explainObjective physiological data - HR, RR, pupil size, rectal temp. Also b/h responses-activity, response to palpation, posture, mental status, vocalization. Assign #s to each factor & end score will be btwn 0-27
Most vigorously validated scale for assessing acute post-operative pain in dogs? ExplainGCPS: Glasgow composite measure pain scale. Bh categories (posture, comfort, vocalization, attention to wound, demeanor & response to humans, mobility, response to touch),
Pray posture specific to what sp?Dogs
Low carriage of tail specific to what sp?Dogs
Hunched posture w/ lowered back spp?Cat
Eyelids half closed means what in who?Pain in cats
Not grooming could mean pain inCats
Pain scale at least hourly post op for how long?4-6hr
Preemptive analgesia why?Prevent wind-up/hypersensitivity
3 pillars of traditional analgesia?Opioids, NSAIDs, LAs
What’s cool about location & amount of opioid receptors?They can occur anywhere theyre needed ((grow more too)
Opioid notable for CRI?Fentanyl
How can you make Fentanyl absorption of patch faster?Warm that area of skin. Onset ~12hr. duration 72hr
Fentanyl transdermal-onset? Duration?2-4hrs onset, pain relief for 4 days
COX 1 vs COX 21-housekeeping (housekeeping is most important) COX 2-response to tissue damage
Traditional NSAIDS vs COXIBSTraditional: Inhibit cox 1 (housekeeping) & cox 2. more adverse effects. bc both inhibited. 2 types-non-specific ((aspirin) & preferential (meloxicam)
COXIBS: Only COX 2 :)
NSAID pregnancy effects?Premature closure of ductus arteriosus
Contraindications for NSAIDS?Impaired renal/hepatic fxn, dehydration/hypovolemia, coagulopathies, other nsaids or corticosteroids already being received, GI ulcers/lesions/diarrhea, preg/lactating animals
Which LA is Burney & what can you do to help?Bupivi-use in intraabdominal, add sodium bicarb to lessen sting
NEUROPATHIC PAIN DRUGSTrauma-doll, neuropathic pain? LI down, G(r) ABA NSAID (neuropathic pain is tramadol, Lidocaine, GABApentin, NSAIDS)
MLK is bad for cats...why?MLK = Corneal ulcers. MLK is Morphine, Lidocaine, Ketamine
BLK HORSESButorphanol, Lidocaine, Ketamine (& the BLK horses name is dEX/met)
Lidocaine CRI used for?Analgesia for neuropathic pain
Reduce hyperalgesia
Widely used in dogs horses cats
Ketamine reduces sensitization where?Dorsal horn
Ketamine reduces requirement for what anesthetic gas?Iso
How much Ketamine for pain Tx?Microdoses-WAY LESS than induction
Which alpa-2 agonists in sm ani? Lg?SMALL = Dex & me
LG = Xyla, Det, Romifidine, Me
Which drugs provide analgesia?Ketamine (NMDA ANTAGONISTS) & the α-2 agonists (also N2O goes, from inhalants)
Some stuff about tramadolOpioid like, synthetic analogue of Codeine, weak mu receptor agonist, plus inhibit uptake of serotonin & noradrenaline. Low potential for abuse, PO route (tablets), dogs+cats+horses
Which czs diuresis?α-2 agonists
MLK vs FLKFLK expensive but useful if need to do neuro tests
CV depressant in catsLidocaine (I dont LI DO, cats have no heart)
Prevents wind up & central sensitizationKetamine
MLK → in 1000ml LRS, add how much of each & infusion rate intraoperative & post20 morphine (two is addicted to Morphine)
300 Lidocaine (no additives...three like to feel numb)
60mg Ketamine (six will get you high w/ fear)
INTRA = 10ml/kg/hr. POST = 2-5ml/kg/hr

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