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;
143 Cards in this Set
- Front
- Back
purpose of preanaesthetic preparation (3)
|
identify exiting abnormalities of major organ fxn
assess severity of above plan for appopriate anaesthetic protol that considers the patients physical status and procedure to be performed |
|
Christinas anagram for preanaesthetic prepartion
|
Subjective
Objective Assessment Plan |
|
how long to withhold food & water prior to anaesthetic
|
8-12 hours food
2-4 hours water |
|
minimum data for preanaesthetic examination of healthy young animal
|
body temperature
auscultation of heart and lumgs palpation of pulse mm colour and CRT PCV, TP, BUN +/- USG |
|
options if preanaesthetic check is not within normal parameters
|
delay anaesthetic and retest, tx, adjust protocol, supportive care (eg IVFT)
|
|
advantages of premedication
|
calm patient
facilitate handling decrease required dose of anaesthetic for induction and maintenance provide analgesia reduce vomiting redce vagally or stress mediated responses (autonomic reflexes) improve quality of recovery |
|
less desirable aspects of a premed
|
delay in time to effect
cost delayed recovery |
|
families of premedications
|
anticholinergics- atropine
tranqs, sedatives - phenothiazines - butryophenones -benzodiazepines - A2 agonists opioids |
|
Action/ indications for atropine
|
anticholinergic, decreased vagal tone
prevents vagally mediated arrythmias- bradycardia, bradyarrhythmias reduces salivation and respiratory secretions |
|
reasons for increased vagal tone
|
drugs- opioids, a2 agonists, anaesthetics (reduce symp tone)
vagal reflexes during visceral manipulation eye surgery hypothermia |
|
disadvantages of atropine
|
may cause tachy
reduces GIT motility contraction of urinary bladder at lower doses may cause brady, 2` heart block causes pupilary dilation, ciliary muscle paralysis and increased intraocular pressure |
|
contraindications of atropien
|
hypertrophic CM
tachy, arrythmias hyperT perforating eye injury glaucoma |
|
what are the effects of glycopyrrolate and what are its advantages
|
similar to atropine wiht longer duration (4 hours)
doesnt cross BBB or placental B less likely to cause tachy |
|
action and main properties of ACP as a premedicant
|
blocks dopamine and a-adrenergic receptors
1. dose dependant sedation 2, long duration sedation 3. antiarrythmic, antiemetic, antihistamine 4. potentiates opioids |
|
disadvantages of ACP
|
1. lower seizure threshold
2. no analgesia 3. may decrease SBP 4. exaccerbates hypothermia- vasodilates 5. dosages need to bE reduced in debilitated or geriatric animals, those eith csrdiac or hepstic dz |
|
at what level is an animal considered hypotensive
|
mean arterial pressure <60mmHG
|
|
contraindications of ACP
|
1. hypovolaemia
2. hx of seizure 3. boxers 4. advanced cardiovasular disease- might not tolerate changes to BP 5. advanced hepatic disease- low metabolism |
|
butyrophenones have similar action to ___ and are used in ___
|
phenothiazines
used in pigs |
|
actions of benzodiazepine and useful properties
|
enhance inhibitory action of GABA and glycine in the CNS
1. sedative 2. potentiates CNS and muscle relaxing effects of anaesthetic 3. anticonvulsive 4. muscle relaxant 5., no significant CV effects 6. may stimulate A in cats 7. reversible |
|
disadvantages diazepam
|
1. unreliable sedation
2, anxiety/aggression in cats? 3. IM injections painful 4. IM and SC absorption unreliable |
|
3 common a2 agonists used in animals
|
xylazine
medetomidine dexmedetomidine |
|
differences between xylazine and medetomidine
|
medetomidine more potent and more a2 specific
|
|
action and advantages of a2 agonists
|
stimulate pre and post synaptic a2 adrenoreceptors in CNS and peripheral tissue
1. profound dose dependant sedation 2. profound analgesia 3. reversible- with atipamezole |
|
undesired effects and disadvantages of a2 agonists
|
1. bradycardia, 1` or 2` HB
2. reduced CO 3. catecholamine induced dysrhythmias 4. hypertension followed by hypotension 5. poor tissue perfusion 6. respiratory depression at higher dose 7. may cause vomiting (xylazine) 8. xylazine associated with higher mortality rate in dogs |
|
xylazine contraindications
|
old animal
sick animals CVD DOGS- use medetomidine instead |
|
what is the reversal of medetomidine
|
atipamezole
|
|
types of opioids
|
pure agonist- bind and activate one or more receptor types
partial agonist- bind to one or more receptor type but will activate some but not others agonist/antagonist- activate one receptor type, inhibit, reverse another antagonists- bind/block |
|
opiod receptors
|
mu- sedation, analgesia, resp depression, brady, hypothermia
kappa- analgesia, sedation sigma- disphoria |
|
pure mu agonists
|
methadone
morphine fentanyl |
|
receptor action of butorphanol
|
kappa agonist
mu antagonist |
|
partial mu agonist
|
buprenorphine-
can partially reverse pure mu agonist effects or prevent action ofother pure mu agonists that have lesser affinity |
|
useful qualities of opioids
|
1. analgesia
2. sedation 3. fewer CV effects 4. antitussive 5. reversible |
|
undesirable effects opioids
|
1. brady
2. emesis, GI hypermotility, initial defecation followed by constipation 3. panting 4. excitation, dysphoria 5. resp depression (high doses) 6. histamine release 7. transient hyperthermia (cats) |
|
contraindications of morphine
|
in patients in which vomiting may have adverse consequences- stomach tube, eosophagitis, laryngeal weakness
|
|
duration of morphone
|
2-6h
|
|
duration of buprenorphine
|
2-12
|
|
duration of butorphanol
|
0.5-2
|
|
pharmokinetic differences in cats compared to dogs
|
mayu be a different response- buprenorphine may provide better analgesia than morphine
more likely to be adverse effects to morphine buprenorphine suitable for sublingual administration |
|
undesirable physiological effects of ACP vs Medetomidine
|
HR: ACP>M
MAP: M>ACP Cl: ACP>M cardiac index- CO to body surface |
|
common premedicant combos
|
tranq+ opioid
- meth/acp - butorph/ acp - bup/ acp -meth/diaz- old ill and debilitated- less reliable sedation dissociative+ benzodiazepine - tiletamine/ zolazepam - ketamine/ diazepam |
|
advantages/ indications of tranq + opioid
|
improvd sedation at lower dose of tranq
analgesia + sedation improved recovery doses can be modified for increased sedation/ analgesia |
|
undesirable effects of tranq + opioid
|
compounding CV effects
emesis, Gi hypermotikity panting |
|
useful effects of dissociative + benzo
|
1. dose dependant sedation + muscle relaxant
2. analgesia 3. rapid onset 4. suitable for young, healthy fractious cats 5. suitable for agro dogs |
|
undesirable effects benzo + dissociative
contraindications? |
icnrease salivation
ketamine without benzo= mucle rigidity recovery may be rough 1. not suitable for dogs unless unmanageable 2. renal cats with renal insufficincy/ failure- requires renal elimination 3, hyperT cats |
|
Preprepared premed combos
|
BAA
butorphanol, ACP, atropine MAA Morphoine, atropine, ACP BAG butorphanol, ACP, glycopyrrolate |
|
which premeds have no analgesia
|
benzos, phenothiaziens
|
|
considerations for choice of premed
|
1. physical status
2. how much analgesia required 3,. how much sedation required 4. what route of drug administration is available |
|
beginnig mask induction
|
1. o2 only to let animal settle
2. graduallg increase conc of inhalant starting at low setting |
|
advantages of mask induction
|
No/little metabolism required for regaining of consciousness
• Oxygen enriched gas mixture • Suitable in severely ill patients • “Reversible” |
|
disadvantages of mask induction
|
Relatively slow induction
• Struggling • Pungent odor = struggling (?) • Pollution, operator exposure • Unsuitable for most patients • Anaesthesia machine required |
|
advantages and disadvantages of chamber induction
|
Advantages/indications
• No patient restraint required • Suitable for intractable small patients Disadvantages/contraindications Rough induction • Pollution difficult to avoid • Contraindicated in any manageable patient |
|
characteristics of injectible induction anaesthetic- adv/ disadv
|
•Rapid loss of consciousness
• Muscle relaxation • Short duration of action • Minimal CV depression diadv venous access required doe calc and adjustment required |
|
how to manage cardiopulm effects of IV anaesthetics
|
Cardiopulmonary effects are
dose dependent Dose can be minimised by: 1. Adequate pre- medication 2. Slow injection |
|
how to choose a safe IV anaesthetic
|
a. mortality rate (thio lowest)
b, adverse effects c. therapeutic index d. recovery e. contraindication |
|
effects of induction anaesthetics on MAP in unpremedicated dogs
|
MAP idecreased with propofol, alfaxolone
increased with thio and ketamine |
|
effects of thiopental
|
HR +
MAP 0 or + CO 0 or + dysrhythmia ++ oxygenation - pulm ventilation -- |
|
effects of propofol
|
HR +
MAP 0 or - CO 0 or + dysrhythmia + oxygenation -- pulm ventilation -- |
|
effects of ketamine
|
HR ++
MAP 0 or + CO 0 or + dysrhythmia + oxygenation 0 or - pulm ventilation - rough recovery seizures |
|
effects of alfaxan
|
HR +
MAP 0 or - (dose dependant) CO 0 or + dysrhythmia ? oxygenation -- pulm ventilation -- |
|
relative therapeutic index of induction anaesthetics
|
thio (7)<propofol (8)< < ketamine (13) << alfax (30)
|
|
time and quality of recovery, IV anaesthetics
|
propofol best wuality- 10 mins action, 20 mins walking
alfax, 10, 20 ketamine 15, 20 thio 12, 80 |
|
half life of injectable anasthetics
|
Alfaxolone 25 min
Propofol 30-60 min Ketamine 2-3 hrs Thiopental 8 hrs |
|
What does half life tell us
|
Half life determines “slope” of metabolic curve Half life determines time to complete recovery (not to time of regaining consciousness) Half life determines amount of drug left in body at time of regaining consciousness |
|
main properties of induction anaesthesias
|
Half life determines “slope” of metabolic curve Half life determines time to complete recovery (not to time of regaining consciousness) Half life determines amount of drug left in body at time of regaining consciousness |
|
contraindications thio
|
Severe liver disease/dysfunction
• Pre-existing cardiac arrhythmias • ASA >3 • Advanced cardiac disease (poor contractility) • Cesarean section • Greyhound dogs • Emaciated patients |
|
propofol contraindications
|
• Hypovolaemia
•Advanced cardiac disease (poor contractility) • Bradycardia (sick sinus syndrome) • Consecutive days in cats • Disease condition where hypotension poorly tolerated NEEDS PROPER STORAGE |
|
contraindications of ketamine
|
Increased intraocular pressure*
• Increased intracranial pressure* • (Seizures) • Cats with renal disease/urinary obstruction • Caesarean section • Heart disease (increased contractility, myocardial failure) *Mostly significant if Ketamine used without benzodiazepines |
|
maximising safety of IV anaesthetic induction
|
no ketamine or thio for PS 3 or 4
1. Calculate dose! 2. IV catheter 3. Administer as directed! 4. Always check patient before induction (HR, PR, MM colour)! 5. Administer oxygen via mask for 5 min before induction |
|
adv and disadv IM induction
|
Advantages;
• No venous access required • Suitable for “difficult” animals • Suitable for very small animals Disadvantages/caution: • Relatively slow onset • Effect less predictable difficult to titrate to effect • Over -, under-dosing possible • Prolonged recovery |
|
advantages of iv induction
|
able to titrate to effect
Immediate onset of action Peak effects rapid Short duration of action as relatively low dose required for desired effects |
|
advantages of endotracheal intubation
|
decreases workload of breathing
provides secure and patent airway minimises pollution during inhalation anaesthetic minimal equipment dead space compared to mask- reduced anatomical dead space artificial ventilation possible airway protection- less likely to aspirate |
|
When to extubate
|
dogs- swallowing reflex
cats- light plane of anaesthesia- leaving in too long can cause laryngospasm |
|
Managing anaesthetic waste gases
|
- use scavenger system
- check machines for leaks- close relief valve, bock breathing tube, press gas valve, check pressure guage - used cuffed ET tube - dont turn vaporiser on until ET cuff inflated - turn o2 and vaporiser off and empty rebreathing bag before disconnecting patietn - careful filling vapourisers |
|
o2 flow/ vaporiser settings for breathing and non rebreathing
|
rebreathing-
first 5-10 mins 1-2L/min (2-3%) second 5 min 30ml/kg/min (2-2.5) continue: 30ml/kg/ min (1.5-2%) WHen discontinuing- turn off vaporiser and turn o2 back up to 1-2l/min non-rebreathing 300ml/kg/min first 5 (1.25-1.5) second 5 (1-1.25%) continue (0.75-1.25) |
|
how is potency of inhalational anaesthetics measured
|
Minimum alveolar concentration- concentration requird to maintain 50% patients non-responsive to a painful stimulus
halothane<iso<sevo |
|
how are inhalational anaesthetics absorbed?
|
vapour are delivered to the blood stream, via the respiratory tract. From the alveolar space, they are taken up in the blood and then tissues in which they will dissolve depending on their solubility
|
|
haemodynamic effects of the three main inhalational anaesthetics
|
- simialr dose related decrease in MAP seen with all 3
- CI least affected by isofluorance- similat at lower doses with sevofluorane, but decreased at higher doses. Most affected by halothane |
|
respiratory depression caused by the three main inhalational anaesthetics
|
isofluorane causes more respiratory depression in dogs and horses than the other two, less so in cats
halothane causes greater respiratory depression in cats |
|
reasons for iso and sevo use over halothane
|
maintain tissue bloodflow better at low doses- less hepatotoxicity, nephrotoxicity
low arrhythmogenicity cardiac output better maintained by iso |
|
Factors affecting speed of onset of action of inhalant anaesthetics
|
1. anaethetist factors- vaporiser setting, o2 flow (rebreathing), choice/ volume of breathing circuit- only influence arterial partial pressure
2. Solubility of anaesthetic 3. patient factors- tidal volume, RR, CO, tissue bloodflow = S x CO (partial arterial pressurex partial venous pressure i.e blood flow) |
|
factors affecting speed/ quality of recovery
|
1. premedication- increases recovery time but significantly improves quality of recovery
2. induction agent used- shorter halflife with have faster metabolism and redistribution- result in more complete recovery, less hangover effect 3. if prolonged anaethesia- higher fat solubility of inhaled anaesthesia could prolong recovery |
|
factors affecting choice of anaesthetic
|
1. safety
- CO depression (halo>iso) - arrythmogenicity(halo>iso) - metabolism (halo>iso) 2. onset of ation/ speed of recovery- similar 3. cost |
|
causes of anaesthesia related mortality
|
- cardiovascular complications (30-70%)
- respiratory complications (30-50%) - unknown (5-25%) >3/4 due to human error- inappropriate anaesthetic depth |
|
Usual cause of death in anaesthetised patient
|
tissue hypoxia caused by hypoventilation, circulatory dysfunction and poor oxygenation
= Inappropriate anaesthetic depth, inadequate patient monitoring |
|
Assessing anaesthetic depth
|
balance between effect of anaesthetic drugs and magnitude of painful stimulus- subjective measure
1. physical signs 2. cardiopulmonary responses to painful stimuli |
|
Indicators of anaesthetic depth
|
Reliable- spontaneous movemet (light)
refelx movement cardiopulmonary response- light to med less reliable muscle/jaw tone palpebral reflex eyeball position PLR- absent deep +/- med |
|
Principles of patient monitoring
|
1. regularly assess depth
2. Circulation 3. oxygenation 4. ventilation - anaesthetic record - personnel |
|
monitoring circulation in the anaesthetised animal
|
1. HR manual- HR, PR- early problem detection difficult
electronic- oesophageal stethoscope 2. BP- SAP (force), DAP (filling), MAP (perfusion pressure) doppler or oscillometric 3. BP- palpate lingual, femoral, dorsal pedal artery for pulse quality |
|
importance of monioring BP
|
most easily measured indicator of adequacy of circulation
- fucntion of CO and systemic vascular resistance blood pressure + mm gives indication of blood flow |
|
interpretation of pale mm in anaesthetised patient
|
pale with high BP- vasocontriction due to light plain of anaesthesia, hypothermia
pale with low BP- vasoconstriction and poor CO- blood loss, hypothermia |
|
how does doppler BP monitor work
|
1. occlusion of blood flow in appendage by pressurising cuff (ciff width 30-40% apendage circumference
2. returning flow once SBP is equivalent to cuff pressure as cuff deflated slowly by sphygmomanometer' return of sound= SAP 3. flow detector placed over artery- distal to duff |
|
how does oscillometric BP analyser work
|
1. cuff inflated to supra systolic P
2. cuff slowly deflated- oscillation amplitudes measued and averaged at each step SAP- pressure when ampliture rapidly increases DAP- rapid decrease MAP- lowest prssure with greatest av oscillation |
|
oscillometric BO analyser- application sites
|
1. forelimb- prox to carpus
2. hindlimb just above/below hock (better) 3. tail base positon cuff at heart level |
|
disadvages oscillometric
|
under reads SAP
over or under estimates MAP and DAP- not as much as SAP- less if on hindlimb |
|
Doppler measurements in dog
|
normal, conscious- 152
anaesthetised- 120 hypotension- 85 severe hypotension <75 hypertension >180 |
|
Doppler measurements cat
|
normal, awake 136
anaesthetised- 94 hypotensive 70 severe hypotension <60 hypertension >190 |
|
tissue oxen delivery algorythm
|
cardiac output + blood oxygen content (mostly PO2xSaO2xPCV)
|
|
Relationship between PO2 and SO2
|
oxygen- haemoglobin dissociated curve
at low PO2, small change to PO2 causes drastic change in SO2- never want animal under 85-90SO2 Anaemic animals- SO2 will be normal even if PO2 low |
|
measuring oxygenation
|
1. BGA
2. haemoxymetry 3. pulse oxymetry |
|
advantages of pulse oxymetry
|
clinical practical and useful for assessing ocygenaton
pulse monitor- will alarm if no detectable pulse non invasive continuous simple to apply allow for early detection of problems |
|
disadvantages pulseoxymeter
|
accuracy affected by:
- poor perfusion - vasoconstriction - hypoterhmia - anaemia - changes in background absorption |
|
Main principles of monitoring ventilation
|
adequate pulmonary ventilation is dependent on RRxTV
Alveolar ventilation is the amount of air per time unit that reaches the alveoli and takes place in gas exchange- most important way that body can excrete CO2 THerefore CO2 elimination can be used as a way to assess alveolar ventilation 1. Arterial CO2 (PaCO2) is inversely proportional to alveolar ventilation 2. alveolar CO2 and arterial CO2 are close to equal 3. PCO2 in the end tidal air (ETCO2) can be used as a measure of PaCO2 |
|
measuring pulmonary ventilation
|
1. rate, depth of breathing- observe rebreathing bag
2. PaCO2- BGA- invasive 3. Capnometry- ETCO2 |
|
normal ETCO2
|
35-45
elevated plateau >45 indicated hypoventilation >55 requires intervention low plateau <35 hyperventilation- light plane small patient with small tidal vol/ hypotension |
|
sudden decrease in ETCO2
|
1. Apnoea
2. inadequate pulm blood flow- severe hypotension, cardiac arrest, air embolism 3. side stream sampling system occluded |
|
ddx elevated baseline ETCO2
|
exhausted soda lime
defunct one way valve - rebreathing inadequate gas flow- rebreathing |
|
6 most common anaesthesia complications
|
1. hypothermia
2. hypoventilation 3. bradycardia 4. hypoxaemia 5. hypotension 6. inappropriate depth |
|
recognising hypotension
|
1. poor pulse quality
2. poor BP 3. pale MM 4. Pulseox failing to read |
|
tx perianaesthetic hypotension
|
1. asess patient/depth
2. adjust vapouriser 3. analgesia 4. IV bolus 5. sympathomimetics- dopamine, ephedrine |
|
recognising hypoventilation
|
1. reduced RR <4
2. poor tidal vol 3. difficulties maintaining anaesthesia 4. elecated ETCO2 |
|
treatment hypoventilation
|
1. assess depth
INDUCTION APNEA if light- give 1 poitve pressure breath every 30s if deep- turn off vapourer, empty bag, fill with 02, breath until spontaneous breathing returns HYPOVENTILATION 1. assess depth 2. check positioning 3. reduce by 1/3 4. artificail breath |
|
causes of bradycardia
|
inappropriate depth
pain anaesthetic drugs, opioids, a2 agonists hypothermia |
|
tx bradycardia during anaesthetic
|
1. check patient
2. check pulse 3. additional analgesia if due to pain 4. atropine 0.02mg/kg repeated 2-3 times in 30-60 sec intervals then .02mg s/c once effective |
|
treatment of tachycardia during surg
|
check patient
analgesia mm colour, pulse ox, ETCO2- ensure ventilation, o2 delivery adjust vaporiser |
|
recognition of perianaesthetic hypoxaemia
|
cyanotic mm
tachy increased pulm ventilation |
|
treatment anaesthetic hypoxaemia
|
1IMprove pulm blood flow
- decrease anaesthetic depth to improve CO - fluid bolus - sympathomimetics to improve tissue delivery 2. improve alveolar ventilation in order to improve o2 uptake - decr vaporiser - PPV- but may decr CO |
|
actions of opioids
|
1 activation of descending inhibitory pain pathways
2 inhibit pain transmission in the dorsal horn 3. inhibit excitation of peripheral sensory nerve endings 4. inhibit relesse of substance p and other neuropeptides at the dorsal horn gsnglia and sensory nerve endings |
|
side effects of opioids
|
dose dependant...
respiratory depression brsdycardia morphine in higher doses can cause histamine release-hypotensiom, hupovolaemic shock morphine, apomorphine vomiting defectaiom then constipation high doses cats csn csuse cns excitement sedation cns tolerance |
|
which opioid mostly used for epidural and why
|
morphine. less lipophilic. slower diffusion into meninges, longer duration of action
|
|
nsaid analgesia vs opioid analgesia
|
1 analgesia w,o sedation
good for inflammatory pain less effective analgesia than opioids generally poor visceral analgesia- except in horse w flunixin |
|
benefits and disadvantsges of using a2 agomists for pain management
|
effective analgesia
potentiate opioid analgesia- synergistic sedation profound sedation cardio effects- hypertension then hypotension, bradycsrdia, decreased CO |
|
useof a2 agonists for analgesia
|
reserved for young healthy animals, used most commonky as part of sedation protocol for short minor procedures in clmbimation with opioid (eg medetomidine and torbugesic)
contraindicated in old ill pstients csrdiac patients low doses in adjunct anaesthesia |
|
lethal La doses
|
bupivicaine 3mg.kg
lignocaine 10mg.kg (4mg.kg cat) |
|
hoe dose LA toxicity occur
|
resuly of inhibitory effects on excitable cells other thsn peripheral cells. eg brain and myocardium
cns tox occurs at lower plasma conc than myocardial tox first cns depressiom, then as inhibitort pathways affected, cns excitemrnt, then coma |
|
clinical signs of la tox
|
sedation
restlessness confusiom progressing to excitation, nystsgmus, opsthotonus, muscle tremor, seizures, followed by cns depression and coma Cv tox- affects myocardium and vascular sm decreased contractility decreased conduction decreased excitability |
|
properties affectimg action of an la
|
1. lipid solubility- more soluble, less needed
2. protein binding- increased duration of actiom 3. dissociative constant- availavility of nonionised active form and trapping of ionised LA within excitable cell |
|
action and uses of tramadol
|
centrally acting synthetic anslogue of codeine
parent compound and M1 metabolite act at mu opioid receptors amd serotonin and adrenergic receptors. analgesic potency 1/10th that of morphine used mostly for chromnic psin or pain late in postop period csreful in cats |
|
tranqs for analgesia
|
potentiate opioid analgesia but (exc for medetomidine) provide no analgesia on their own
eg AcP meth, diaz mrth, midaz meth |
|
cornea LA
|
proparacine, proxymetacaine 0.5%
|
|
innervation around the horses eye
|
supraorbital n
lacrimal n infratrochlear n zygomatic n |
|
desensitising horse eye
|
suprsorbital medial 2/3rds
medial (infratrochlear) amd lsteral (lacrimal) canthus- infiltrate respective eyelid cornea- proxtmetacsine or proparacine lower eyelid (zygomatic)- lowest point of orbit globe- 2-3cm lateral to laterL csnthis then ventromedial |
|
desentising goat horn
|
cornual branch 1. cornusl br of zygomaticotemporal n- midway between lateral canthus of eye and lateral margin of horn
cb2. cornusl br of infratrochlear n |
|
nerves from the brachial plexus
|
axillary, rwdial, median, ulnar, musculocutaneous
|
|
procedures performed under epidural and sedatiom in lsrge animals and where?
|
procedures involving tail, perineum, anus, rectum, vulva vag, prepuce, bladder, skin scrotum
sacrococcygeal junction or between first 2 caudal vertebrae (caudal epidural) |
|
differemce between csudal and lumbosacral epidural
|
LS will result in motor ans sensory loss in pelvic limb and depending on dose, the abdo wall
Sacrococcygesl, if recommended dose used, wont affect motor and sensory innervation to limb so pstient csn remain standing |
|
duration of effect of epidural ligno vs bupiv
|
ligno 1 to 4
bupiv 3 to 6 |
|
what opioid is commonly used for epidural analgesia and why ?
|
Morphine
low lipid solubility = slow onset but long duration |
|
side effects of epidural opioids
|
Potential urinary retention
potential pruritis Sedation |
|
what effect does epidural a2 agonists have agonists have ?
|
Selectively mediate pain
Regional anaesthesia → Xylazine + detomidine (horse only) Xylazine has some additional LA effects Systemic side effects (Brady cardio, hypotension, sedation) → only det in horses, xyla in cattle lignocain + xylazine in horse → anaesthesia + some analgesia of rapid Onset and lasting longer than each on its own |
|
Onset of action & duration epidural ligneous bupiv
|
ligno fast 10-15
bupiv 20-30 ligno l-2hr bupiv 4-6hr |
|
Duration of epidural Morphine
|
depends on severit y of pain, site of pain, extensiveness ) pain tolerance
generally 24-48 hours |
|
Technique for dog epidural
|
sterna l or lateral
clip (scrub thumb / middle finger on highest points of iliac crest, Index finger just Caudal to spinal process of L7 on midline Insert needle 90° just in front of finger feel 9'pop'as needle passes through ligamentum flavumand enters spinal cord remove stylus → if CSF (subarachnoid puncture ) decrease dose b y 30'I. inject 1MI air or saline w/o resistance inject slowly over 10-15 seconds dont exceed 6mL |
|
3 Commandments of epidural
|
l. be clean
-scrub (clip -new vials including diluent 2. be meticulous ~ always Calculate correct dose dont exceed 6mi always aspirate first |