Exam 3 Flashcards
concerns for rums under anesthesia
salivation
regurgitation/aspiration - fast, extubate w/ cuff inflated
bloat - decreases lung vol
hypoventilation, V/Q mismatch - ventilate
size - myo/neuropathies
temperament - more sotic, suited for standing procedures
how do you pad a ruminant under anesthesia?
larynx higher than oral cavity and rumen
What’s important for injections in rum
if IM - neck or shoulder (protect meat)
pilot hole through tough skin
Xylazine and ruminants
- recumbency concern for standing procedure
- sensitivity: goat>sheep>cattle>EQine
- 3rd trimester abortion - avoid in pregos
- avoid in sheep (resp issues)
- reverse w/ tolazoline or yohimbine
Benzos and ruminants
good for calves, small rum
alpha 2’s for adult cows preferred
minimal cv depression
Opioids and Induction agents used in rum
Morphine, butorphanol
Ketamine (+xylazine + diazepam), guaifenesin
propofol = apnea risk
Ket-stun
special drug combo for standing sedation ~45 min
Butorphanol, Xylazine, Ketamine
Rum characteristics under anesthesia
eyes - jelly bean sized pupils, rotated ventrally and medially
hypertensive
where do you place a catheter in an SAC?
high on neck - further from carotid but thicker skin requires pilot hole
concerns for SAC and anesthesia
salivation, regurge, aspiration - fast bloat intubation - laryngospasm position - nose to sky, larynx high recovery - obligate nasal breathers, soft palate displacement
Concerns for pigs and anesthesia
- size variation = dose variation
- venous access hard - ears, IM injection in neck
- short necks, diverticular = difficult intubation
- malignant hyperthermia
sedation vs. chemical restraint
sedation - calm, awake, but arousable
restraint - progress from sedation, tranquilization
Acepromazine
- calming in 30 min
- no analgesia
- hypotension, maybe worsens seizures, paraphimosis in stallions
Benzo’s (Midaz and Diza)
- midaz preferred (water soluble, absorbs via IM/SQ)
- reversed by flumazenil
- good adjunct b/c CV safe, amensic but alone causes excitement
Alpha 2 agonists (Xylazine, Dexmetdetomidine, Detomidine, Romifidine)
- analgesic, heavy sedation, m relaxation
- bradycardia, AV block - only give to healthy animals
- GI effects, sudden arousal
- reversible
Opioids
- not sedative in EQ, don’t use
- morphine most sedating, fentanyl least
- CV safe
- dysphoria, panting
Ketamine/Telazol
can enhance sedation, give light anesthesia
telazol for fractious pets
Propofol or alfaxalone
heavy sedation to general anesthesia
give supp oxygen
Concerns when anesthetizing a pregnant patient
maternal safety
effects on neonate, oxygen delivery to fetus
risk of abortion
CV changes during pregnancy
- Increased blood vol (plasma) based on fetus #
- Increased CO (both SV, HR) but decreased SVR to maintain BP
- delayed baroreceptor compensatory response
What is the concern w/ hypotension during pregnancy
- uteroplacental perfusion is pressure dependent
- hypotension = decreased perfusion to fetus
respiratory changes during pregnancy
- pregnancy displaces diaphragm = decreased TLC, FRC = increased risk of hypoxia (preoxygenate!)
- increased progesterone = increased sensitivity to PaCO2 = compensatory ventilation sooner = increased o2 consumption
Other physiologic changes during pregnancy
- decreased anesthetic requirement (d/t progesterone, GABA, hormones)
- increased sensitivity to drugs (overdose risk)
- higher regurge/aspiration risk
fetal phys during pregnancy
- affected by drugs that can cross bbb
- decreased hepatic enz = longer drug effect
- fetal blood supply has lower PaO2, higher hgb affinity
- blood goes to liver first - drugs partially metabolized
Recommendations for anesthetizing preggos
- correct blood vol deficits ahead
- maintain BP
- preoxygenate
- rapidly secure airway
- minimize drug doses & time under
Premed for preggos
SA - opioids, anticholinergics
LA - alpha 2 agonists
Rum/camelid - benzos (propofol) or not used
Induction for preggos
IV (over IA) w/ 15 mins for redistribution
SA - propofol, alfaxalone
LA - ketamine +/- propofol
Maintenance for preggos
low dose IA (minimized neonate depression)
mechanical ventilation
avoid nitrous oxide
Post-op pain for preggos
Line/incision block - esp. if C-section
Morphine epidural, systemic opioids, or NSAIDs - but time against nursing
How to resuscitate a neonate
- Ideally 1 person per baby
- Remove membranes, clear oropharynx secretions
- anatognistic drugs sublingual or umbilical v.
- rub chest vigorously to stim respiration
- supp oxygen, heat
- maybe Doxapram to increase breathing, not start it initially
Concerns for neonates based on their phys
- fewer liver enz = decreased metabolic capacity
- reduced glycogen stores = hypoglycemia risk
- greater SA to bw ratio = heat loss risk
- immature symp NS = lower BP, lower contractility & CO
- weak muscles = decreased FRC, more thoraicic compliance
Concerns when anesthetizing neonates
- decreased ability to metabolize drugs
- hypoglycemia
- hypothermia
- bradycardia, hypotension
- hypoventilation
What kind of drugs do you use to anesthetize neonates
short acting, reversible - IA’s, propofol, opioids
Ephedrine if BP drops
What’s key about shock and trauma patients
Likely in or about to be in compensatory shock - will crash if anesthetize now - STABILIZE FIRST
Types of thoracic injuries seen w/ trauma
lung contusions
pneumothorax
myocardial contusion
diaphragmatic hernia
Lung contusions
- common
- take 12-24 hrs to appear
- prone to atelectasis (lung collapse), hypoxemia/hypoventilation
- give PPV, but increased risk of barotrauma
Pneumothorax
- common, can be open or closed form
- risk of atelectasis, hypoxemia, tension pneumothorax
What’s the concern w/ tension pneumothorax
some air leaks out w/ each breath –> builds up cavity P –> lung compression = decreased venous return, SV/CO, hypotension –> CV collapse
Signs of tension pneumothorax during anesthesia
- decreased lung compliance
- sudden decrease in BP (b/c decreased venous return)
- stop PPV, do emergency thoracocentesis
What’s the concern about myocardial contusions
- arrhythmias, which may be worsened under anesthesia
- ECG!
- avoid arrhythmogenic drugs - alpha 2’s, thiopental, halothane
What’s the concern about diaphragmatic hernia
abdomen in chest compression lungs
decreased FRC –> atelectasis, hypoxemia
Ruptured bladder
common
urine leaks into abdomen
azotemia, electrolytes - hyponatremia/chloremia, hyperkalemia
What’s the concern w/ ruptured bladder causing hyperkalemia?
- raises resting membrane potential - triggers systole more often
- can –> arrhythmias (V fib, asystole), bradycardia
How to treat hyperkalemia
- give CA to resolve conduction, not hyperkalemia
- drain urine (catheter)
- NaHCO3, insulin or dextrose to normalize K
What are the concerns w/ head trauma
Increased ICP
Anesthesia could alter blood flow to brain
Signs of increased ICP
decreased mentation
small pupils
Cushing’s response - hypertension, bradycardia
sometimes altered breathing
Head trauma and anesthesia
- intubation can spike ICP (b/c cough, give lidocaine)
- low dose drugs to minimize cerebral autoreg effects
- PPV to maintain PaCO2
- avoid ketamine, alpha 2’s b/c increase ICP
Lab values to keep track of in an anesthetized trauma patient
Hgb
Acid/base
electrolytes - K, Ca
Oxygenation/ventilation parameters
Common drug combos for trauma anesthesia induction
Fentanyl + midaz/diaz
Etomidate + midaz/diaz - most CV/resp sparing, use for cats
Avoid ketamine in head traumas b/c increase ICP
Propofol/alfaxalone - decrease ICP but hypotension, apnea are concerns
What breeds are actually sensitive to anesthesia?
- greyhounds and thiobarbiturates - delayed recover d/t liver metab
- collies and MDR1/p-glycoprotein - Ace, torb
- boxers and acepromazine (anecdotal collapse)
- brachycephalics
T/F: opioids always cause excitation/dysphoria in cats
False, only high dose, not clinical doses
but only use to treat for pain in cats, not to sedate
T/F: Butorphanol is an excellent analgesic
False: only treats mild pain, short acting (1-2 hrs)
T/F: Hydromorphone and Morphine are equally efficacious at providing analgesia
True, but potency varies
Hydro - lower dose needed than morphine to achieve same effects
Fentanyl more potent than hydro or morphine
T/F: alpha 2 agonists have severe CV effects
True, even for low doses
Dexmedetomidine can decrease CO up to 50%
T/F: Propofol is the safest induction drug
False, actually very similar to thiopental in CV and resp effects
T/F: Iso is better than Sevo
False - clinically very similar
Sevo has slightly faster induction/recovery b/c lower solubility
T/F: Pulse quality does not indicate BP and tissue perfusion
True - only indicates systole/diastole differen
T/F: hypotension is a concern for any anesthetized patient
True
What are the clinical signs of hypotension in an anesthetized patient
There are none - must measure!
T/F: Bradycardia means patient is too deep
False
Common causes: hypothermia, vagal stimulation, opioids, alpha 2’s
What spp doesn’t have an epiglottis
birds, reptiles
Spp w/ an apical bronchus to R cranial lung lobe
rum, pigs
Spp where ocular signs have little significance as an indicator of depth of anesthesia
llamas
EQ - nystagmus and palpebral
rum - ventral/medially rotates eyes
Spp w/ complete tracheal rings
birds, some reptiles
Spp w/ a ventral laryngeal diverticulum impacting intubation
pigs
Spp w/ dive reflex
marine mammals, sea turtles/reptiles, diving birds
Spp w/ sensitivity/lack of sensitivity to xylazine
rum most sensitive (low dose), pigs unsensitive (high dose)
Spp in which a respiratory sinus arrhythmia is normal
dogs
Spp that may be hypertensive during anesthesia
cattle, maybe wild ruminants
Spp susceptible to malignant hyperthermia
pigs
Spp that could vocalize w/ an ET tube in place
birds
What drug do you avoid in a cat w/ hyperthyroid and concurrent hypertrophic cardiomyopathy?
Ketamine
What drug class treats tachyarrhythmias assoc’d w/ hyperthyroidism in cats/
beta blockers
Key pre-op management for anesthetizing an Addison doggo
glucocorticoid supp
Hyperkalemia can manifest in what ECG change?
absence of P waves
What drug has potential to increase blood glu?
Dexmedetomidine
FS dog w/ diabetes, mod mitral valve murmur getting a dental w/ possible extractions. drug plan?
Torb, atropine, etomidate, midazolam, iso
What is the goal of neuroanesthesia
prevent increasing ICP
how do you not increase ICP during anesthesia?
- Decrease cerebral metabolic rate by maintaining approp anesthetic depth
- maintain low to normal paCO2, prevent hypoxemia
- maintain MAP to prevent ischemia
- maintain acid/base status
maintain mild hypothermia - avoid hyperthermia, low metabolic rate
What can you do if there is an increase in ICP during anesthesia?
- decrease ECF via mannitol or furosemide
- glucocorticoids contraindicated for traumatic brain injury
Clin signs of head trauma
papilledema, anisocoria, strabismus changed mentation abnormal resp opisthotonus Cushing's reflex to ICP: bradycardia and hypertension
What is the one drug that doesn’t decrease CMR (cerebral metabolic rate) and CBF (cerebral blood flow)?
Ketamine
increases CMR, slightly decreases CBF
What is the concern w/ IA’s and neuroanesthesia?
CNS vasodilation as higher doses - avoid by using low dose, balanced anesthesia
Concerns for spinal cord neuro procedures
long
concern for hypothermia, drug accum
Spinal imaging and horses
weakness, ataxia
minimize alpha 2’s - use ketamine, benzo, propofol
What’s important about post-op care for neuro patients?
neuro status may worsen after surgery d/t increased anxiety, pain
Want calm recovery! Sedate - phenothiazine, low dose alpha 2
Between kidneys and liver, which once can regenerate?
Hepatocytes are regenerative to a point
kidney can’t regenerate nephrons
Additional concerns for animals w/ renal dz
anemia
hypertension
electrolyte abnormalities
stage of renal dz
Prepping a renal dz patient
- prevent hypovolemia (anesthetics reduce GFR)
- recheck electrolytes
- correct anemia
Anesthesia drugs to avoid for a renal patient
- avoid Ace, alpha 2’s b/c decrease CO
- maybe avoid ketamine - metabolized in kidneys in cats
- maybe avoid sevo - make nephrotoxic compound
- maybe avoid NSAID’s for post-op pain - alter PG synth which alters renal blood flow
What’s the concern w/ lidocaine in renal or heptic dz patients?
cleared slowly in general, risk of buildup in dz’d patients - use low doses
Concern for cats w/ urethral blockage & post-renal azotemia
hyperkalemia, acidemia
Give Ca, bicarb, insulin/dextrose before anesthesia
expect post-op diuresis - don’t let them dehydrate
Prepping a hepatic dz patient
- prevent hypovolemia
- treat hepatic sequelae
- treat coagulopathies
- avoid hypoxemia
what’s a good pre-med choice for liver dz patients?
Opioids - minimally metabolized, reversible, little CV effects
Avoid alpha 2’s, ace b/c CV effects and metabolized by liver
What IA is contraindicated for liver dz?
Halothane
