1
Q
How much of body weight is composed of water?
A
60%
- 20% extracellular fluid- 5% intravascular, 15% interstitial
- 40% intracellular fluid
2
Q
Why is edema formation likely during hypoalbuminemia?
A
-albumin is a determinant of colloid oncotic pressure
3
Q
What influences fluid movement
A
- osmosis- dependent on concentration gradients of ions
- plasma proteins and oncotic pressure
- hydrostatic pressure: exerted by fluids due to their weight, antagonizes osmosis during fluid shift and drives fluid outwards
- extracellular fluid movement
4
Q
Crystalloids
A
- contain water, electrolytes, non-electrolytes
- can enter all body fluid compartments
- replaces small blood losses at 3:1 volume ratio
- can be isotonic, hypotonic, hypertonic
- types: replacement (balanced) solutions, maintenance solutions
5
Q
replacement/balanced solutions (crystalloids)
A
- ringers, lactated ringers, plasma-lyte R (normasol R)
- used to replace body water and electrolytes (diarrhea, vomiting, PU, third space losses, dehydration)
- electrolyte composition similar to ECF
- causes no change in electrolytes
- excessive large volumes dilute proteins
- large volumes cause rapid re-expansion of ECF, but does not remain for long
- normally contains alkalizing agents :lactate, acetate, gluconate
6
Q
When are replacement/balanced solutions of crystalloids contraindicated?
A
-large volumes contraindicated in hypoalbuminemia
7
Q
Maintenance crystalloids
A
- Plasmalyte M (normasol M) in dextrose 5%
- use in patients stabilized by replacement fluids- or those not taking in adequate amounts to meet daily requirements
- replace daily fluid lose, not for peri-anesthetic
- contain less Na+, more K+- body excretes K+ relatively quicker than Na+
- administered over 24 hrs, avoid large volumes and high infusion rate
8
Q
Other crystalloids
A
- physiological saline
- hypertonic saline
- dextrose 5%
9
Q
When is physiological saline indicated?
A
- rapid ECF expansion if replacement solution unavailable
- high volumes dilute other electrolytes- careful in patients with electrolyte imbalances
10
Q
When is hypertonic saline indicated?
A
- fast onset, short duration, temporary cardiac function improvement (rapid intravascular fluid compartment expansion)
- used to treat cerebral edema if blood brain barrier intact
- limits accumulation of lung fluid
11
Q
When is Dextrose 5% indicated?
A
- not used very often
- glucose rapidly metabolized, water is byproduct so used to provide water
- may be used as a component of a maintenance solution
12
Q
Colloids
A
- have large molecular weight
- stay in vascular for long- expand and maintain vascular space volume
- replace low volume blood loss at 1:1 volume ratio
- molecular weight too large for capillary pores
- co-administer with 2-3x as much crystalloids to minimize interstitial fluid deficits
- symmetric- hydroxyl-ethyl starch, dextran, gelatin
- natural: whole blood, plasma, albumin
- hb based O2 carrying solutions- oxyglobin
13
Q
True/False colloids are a long term solution for fluid replacement
A
-false- don’t carry O2 can cause hypoxemia if not given hemoglobin carrying fluid
14
Q
HES: hetastarch
A
- most common
- may alter homeostasis: decrease factor VIII and von Willebrand factor concentrations
- metabolized by serum amylase, eliminated by kidneys
- try to delay use and minimize amounts administered per day
15
Q
When is HES contraindicated?
A
- metabolized by serum amylase, eliminated by kidneys
- associated with osmotic nephropathy
- avoid in septic patients
16
Q
Dextrans
A
- polymers of glucose
- similar weight to HES
- more hyper-osmotic than plasma
17
Q
Plasma
A
- oncotic pull, can increase IVF volume
- albumin= main contributor to oncotic pull
- while still fresh has clotting factors, can be used for treating coagulopathies
18
Q
Patient comes in with Warfarin toxicity, which fluid can be used to help treat this coagulopathy?
A
-fresh plasma- clotting factors
19
Q
You work at a low cost clinic, the doctor would like to perform his routine castrations without the use of fluids to keep the cost low for the client. Why do you advise that this is a shitty idea?
A
- if under anesthesia patients should be on fluid therapy especially if the procedure is long
- anesthesia can lead to fluid, electrolyte, and acid-base imbalances
- should have a catheter anyways in case of CPR
- correction of deficits due to fasting
- CV support
20
Q
When is an interosseus catheter indicated?
A
-small and young animals as well as birds, reptiles, and neonates, very dehydrated or difficult to catheterize
21
Q
Standard rate for replacement (balanced) crystalloids (e.g. ringers)
A
10 ml/kg/hr
22
Q
Cases that would need less fluid
A
- 3-5 ml/kg/hr
- young animals
- long procedures
- heart failure
- renal disease
23
Q
Shit! Your patient is hypotensive! What do you do now?
A
- decrease anesthetic depth
- extra fluid over and above standard rates- crystalloids, colloids (HES)
- if still non-responsive after 2 boluses of fluid- cardioactive drugs
24
Q
Your patient has started to bleed out (hemorrhage), thankfully it’s minimal (less than 10% blood volume)
A
- crystalloids (3x volume of blood lost)
- colloids- exact blood volume lost
25
Patient comes in HBC with >20% BV loss- what do you do?
-give him a goddamn blood transfusion before he dies
26
Whole blood
- called fresh whole blood up to 8 hrs after collection
- after, called old whole blood- stored at 1-6 C
- RBCs, WBCs, plts, plasma proteins, coagulation factors
- old blood lacks some unstable clotting factors
- can be used up to 21-30 days after collection depending on storage
- indications: active bleeding, hypovolemia, secondary acute hemorrhage
27
Packed RBC
- contain only RBCs
- PCV about 70%
- ideal for patients with allergic reactions to plasma proteins or with febrile non-hemolytic rxns to WBCs, not common in vet practice
28
Platelet rich plasma
- harvested from fresh whole blood less than 8 hrs old if not cooled below 20 degrees C
- indicated: severe bleeding in thrombocytopenic patients
- can be further processed to platelet concentrate and pure plasma by centrifugation
29
pure plasma: fresh or frozen
- plasma protein and all clotting factors except some platelets
- thawed several times only rich in clotting factor VIII, von Willebrand factor, and fibrinogen
- can be viable for more than 1 yr
30
oxyglobin
- stabilized bovine hemoglobin-based oxygen carrying solution
- treat anemia in dogs and cats
- minimum duration of effect= 24 hrs
- adverse effects: potential for circulatory overload, allergic reactions, temporary discolorations of mucous membranes
31
challenges of blood sources
-collection, storage, expiration, screening tests
32
indications of transfusion intra-operatively
-severe hemorrhage
33
indications of transfusion peri-operatively
- severe acute hemorrhage (usually trauma)
- hypoalbuminemia
- thrombocytopenia
- clotting factor deficiency
34
Blood transfusion triggers
- acute blood loss >20% volume
- more than 10-15% blood volume loss intraoperatively
- acute anemia: PCV less than 20%
- chronic anemia: PCV less than 15%
- anemia and anesthesia: PCV less than 20%
- consider patients clinical presentation as well: HR elevation, weak pulse, hypotension
35
Blood loss estimation
- intraoperative blood loss:
- surgical site
- soaked swabs (estimate volume)
- surface
36
how much blood to administer in acute hemorrhage
- same amount lost
- start slow, check for reactions
- target completion within 4 hrs
37
how much to administer in anemic hemorrhage
- target pcv
- dogs:25-30%
- cat: at least 20%
38
empirical doses of blood (mL/kg)
- dogs: 10-40
- cats:5-20
- horses:20-30
- cattle: 10-40
39
survival times of RBCs
- dogs: 110-120
- cats 75-80
- horses: 140-150
- cattle 140-160
40
Good practices for blood transfusion
- slowly rewarm blood to 37 C before transfusion
- don't refreeze
- use one set/unit of blood product
- IV sets should contain in-line filters or syringe filters if injecting from syringe (cats)
- use separate IV port for blood products (Ca+ in lactated ringers will cause blood to clot on contact)
- monitor vitals throughout
- blood typing
41
Which species is blood typing necessary, which is recommended, which isn't needed?
- necessary: cats
- recommended: horses and cattle
- not necessary IN FIRST TRANSFUSION for dogs
42
dog blood groups
- at least 9
- DEA
- 1.1= most common and universal donor, 1.2 is also universal donor
- usually no need for blood typing 1st transfusion- lack alloantibodies
43
cat blood groups
- 3 major blood groups: A (most), B, AB
- distribution geographically dependent
- have naturally occurring alloantibodies ALWAYS BLOOD TYPE
44
horse blood groups
- at least 9
- A,C,Q most common
- Aa, Qa most antigenic
- recently pregnant mares carry most antibodies
- geldings and nulliparous mares of same breed are best donors
45
Monitoring transusion patient
- obtain pre-transfusion baseline readings
| - monitor CS intermittently, every 5-10 mins during transfusion
46
C.S. acute transfusion reactions
-tachycardias, dysrhytmias, hypotension, tachypnea/dyspnea, pyrexia, wheals/uticaria, vomiting, seizures/tremors, CV collapse
47
adverse effects of transfusing
- allergic/immunological reactions
- circulatory overload
- hypothermia
- citrate-induced hypocalcemia
- bacterial contamination
- transmission of infectious agents
48
allergic reaction to transfusion
- signs: fever, uticaria, angiodema, pruruitis, tachypnea
| - therapy- stop transfusion, diphenhydramine +/- dexamethasone +/- epi, restart transfusion at slower rate
49
anaphylactic shock due to transfusion
- sudden tachycardia, hypotension, cardiac arrest, collapse
| - therapy: stop transfusion OR give epi and dexamethasone
50
acute hemolysis due to transfusion
- signs: tachypnea, fever, hemoglobinemia, hemoglobinuria, shock
- therapy: stop transfusion, dex, saline diuresis, maintain BP
51
febrile reaction- non-hemolytic
- signs: temp rise by over 1 C, bradycardia
| - therapy: stop transfusion, Dex and Ketoprofen, restart at slower rate in 15 mins
52
circulatory (volume) overload due to transfusion
- signs: tachypnea, pulmonary edema, polyuria
- therapy: stop transfusion, oxygen supplementation, furosamide, restart transfusion at slower rate, consider diff blood product
53
hypothermia due to transfusion
- low body temp
| - stop transfusion, warm blood, begin external warming
54
citrate overdose induced hypocalcemia
- signs: arrhythmias, tremors, seizures
| - therapy: calcium sals slowly over 20 mins under ECG monitoring
55
hyperkalemia due to transfusion
- ECG abnormalities
| - therapy: stop transfusion, normal saline, dextrose with regular insulin
56
Canine history needed before anesthesia
- duration of complaint
- current meds: heartworm, diuretics, ACE inhibitors, Ca+ channel blockers, Bets blocker, anti-epileptics
- signs of systemic disease- especially cardiac and pulmonary
- previous blood transfusions
- previous anesthesia (problems or not)
57
Canine signalment- what you should know about for anesthesia
- age- pediatric/geriatric
- gender- if preggo
- breed- sighthounds- don't give thiobarbituates, longer recoveries with propofol and alfaxalone, boxers may be sensitive to acepromazine
- brachycephalic airway syndrome- careful with sedatives, small tube, intubation may be difficult, rapid return to conciousness, extended time with O2, extubate late, may have to re-intubate
- small breed- tracheal collapse- avoid excitement, use sedatives, supplemental O2, have longer ETT available
58
Breed related anesthetic concerns
- cardiomyopathy: dobies, boxers
- sick sinus syndrome: Schnauzers
- Mitral Valve disease: small breeds
- increased vagal tone: brachycephalics, dauchshunds
- vWD- dobies
- hemophilia- GSD
59
Premedications-anesthetic (dogs)
- usually opiod and sedative IM before catheter
- if IVC present give premeds IV before induction
- choose opiod based on patient and procedures
60
Which mu agonists are least likely to cause vomiting?
-fentanyl, methadone
61
When giving H1 antihistamine is indicated for premeds
- diphenhydramine
- when removing mast cell tumor (release histamine when disturbed)
- histamine causes vasodilation and leaky vessels
62
What drug can be given 30 minutes before opiod to reduce risk of vomiting?
-maropitant- cerenia- NK1 receptor antagonist
63
This sedative is commonly used as a premed in systemically healthy patients in low doses.
acepromazine
- causes hypotension- especially when followed by inhalant anesthetic
- causes mild to moderate sedation
64
This premedication should only be used in systemically healthy patients as it cause hypertension, reflex bradycardia, and DECREASED CO
-dexdomitor- causes marked sedation
65
This sedative is not usually used in healthy dogs, however it may cause sedation in young, old or sick patients as it is CV and respiratory sparing
-benzodiazepines
66
sedation for aggressive dogs
IM- ketamine, telazol, or alfaxolone should be combined with alpha 2 agonist and opiod
- alpha 2 combos without anesthetic drug may be dangerous
- owner should give informed consent as you prob won't be able to do pre-anesthetic eval on them
67
When anticholinergics (antimuscarinics) are indicated
- patients with pre-existing high vagal tone (brachycephalics, opthalamic disease)
- puppies
- specific procedures that may cause vagal stimulation- opthalamic, laryngeal, GI, urogenital
- don't administer with alpha 2 agonist unless low BP- consider partial reversal of alpha 2 agonist instead
68
Induction (dogs)- propofol, alfaxalone, etomidate
- titrate to effect
| - give slowly- 1/2 calculated dose over 10-15 seconds and evaluate effect
69
induction (dogs)- ketamine
- high therapeutic index
- may titrate or administer calculated dose over 10-15 seconds in healthy dog
- always give with benzo
- longer onset of action than other induction drugs
70
intubation of dogs
- relatively easy to intubate- large trachea vs patient size
- use murphy tube
- brachycephalics may be difficult- long soft palate
- advance tube into thoracic inlet only
71
maintenance- inhalants for dogs
-iso, sevo
72
maintenance- CRI injectable for dogs
-propofol, alfaxalone, NOT ETOMIDATE
73
adjunct CRIs for dogs
- opiods (fentanyl most common)
- lidocaine
- ketamine
- benzos
74
Cardiovascular support for dogs
- IV fluids- blood volume about 90 mL/kg
- balanced, isotonic crystalloids (LRS, plasmalyte- A, Norm-R)
- common rate= 10 mL/kg/hr
75
How to treat hypotension in dogs
- dopamine, dobutamine, ephedrine
| - norepinephrine and vasopression for very sick patients- profound vasoconstriction so titrate carefully
76
T/F regurgitation is more common in cats
- false- dogs
| - large dogs in ortho procedures
77
Why do we want to prevent regurg in dogs? (other than aspiration)
-esophageal damage
-esophageal stricture is difficult to treat- you may have to euthanize and then LAWSUIT CUZ U SUCK
-
78
Well shit, your dog just aspirated-what's next, what do you do to prevent Mrs. Krabs from suing your ass for killing Fluffy Lumpkins
- if regurg occurs:
- - postural drainage while still anesthetized (nose down)
- -swab or suction caudal oropharynx before extubation
- -keep cuff inflated or partially inflated for extubation
- -place in sternal ASAP
79
How could you have prevented Fluffy Lumpkins from aspirating in the first place?
- proper ETT cuff and lubrication
| - if high risk: proton pump inhibitors (omeprazole or esomeprazole), prokinetic drugs (metaclopramide or cispride)
80
What are certain challenges when it comes to anesthetizing cats?
- more difficult to anesthetize, higher mortality
- smaller body size, more difficult to intubate
- more likely to be hypotensive under anesthesia
- differences in drug metabolism- can be more sensitive
81
relevant anesthetic history: cats
- owners may be less attentive
- cats hide disease well
- cats generally don't cough except with asthma- difficult to tell heart disease, also difficult because exercise intolerance not appreciable
- outdoor vs indoor important in relation to infectious disease and trauma risk
82
cat breed considerations for anesthesia
- Maine Coon= HCM- assess for murmur refer to cardiologist if you detect it
83
Preferred mu agonist opiods for cats
- oxymorphone, methadone- less likely to cause exceitement
- fentanyl
- buprenorphine- good for visceral analgesia at home
84
What can all opiods cause in cats?
-post-operative hyperthermia
85
Premeds- sedatives in cats
- acepromazine, dexmedetomidine- higher dose requirements then dogs, use in healthy patients
- dex causes vasoconstriciton- difficult IVC placement
- benzodiazepines don't cause good sedation, may cause excitement
86
IM anesthesia- fractious cats
-alfaxalone or ketamine IM combinations will provide immobilization for fractious cats- intubate as soon as laryngeal reflexes lost
87
"kitty magic"
-ketamine +alpha 2 +opiod
88
Induction-cats
- chamber or mask not recommended
- propofol (not propofol 28), alfaxalone, etomidate
- Heinz body anemia can result from repeated propofol administration
89
intubation in cats
- more difficult, cats are special and fragile
- laryngospasm- use lidocaine
- ensure proper anestetic depth before
- can have tracheal damage/tears- SQ emphysema, pneumomediastinum
- don't overfill cuff
- disconnect from breathing tubes when moving/flipping
90
Maintenance- cats
- inhalant anesthetics- MAC is higher in cats (iso 1.4-1.6) than dogs and horses
- injectables: propofol, alfaxalone, NOT ETOMIDATE
- adjunct drugs (CRIs)- opiods (fentanyl), ketamine, benzos, NOT LIDOCAINE
91
Kitty cat complications
- hypotension- common in cats, be careful with IV fluid rate and excessive fluid boluses (can cause fluid overload)-give dopamine
- post-anesthetic cortical blindness-decreased O2 delivery to brain- mouth gags
- blood transfusions- can die always crossmatch
- NSAIDs- renal effects, cats susceptible
92
Common horse surgeries
-colic
-arthroscopy
-castration
0upper airway
93
Where to catheterize horse
-usually jugular vein
94
preanesthetic prep horse
- fast 4-6 hrs, no water at least 2 hrs before
- pull off shoes (or bandage)
- rinse mouth
95
premeds- alpha 2 for horses
- xylazine- abortion in third trimester of pregnancy
- detomidine
- romifidine
- acepromazine-mild sedative may cause penile prolapse
96
which drug is the most common opiod analgesic for horses?
butorphanol
| -can also use methadone or morphine, more reserved for severe pain
97
Pre-med analgesia for horses
- alpha 2 agonist
- flunixine meglumine
- meloxicam
- butorphanol
- methadone/morphine
98
Induction of anesthesia in horse
- muscle relaxant before induction- GGE/gaufinesin
- benzodiazepine: diazepam or midazolam
- ketamine
- thiopentone
99
Intubation horses
- usually 26 mm diameter
- use mouth gag
- neck extended
100
What are important positioning considerations in equine sx?
- cushion pressure points: head, shoulders, pelvis, limbs
- stretch and spread apart limbs
- protect eyes from trauma and pressure
- advance limb down to protect radial n
- keep in only one lateral recumbency throughout
101
Maintenance in horses
- iso, sevo
- large animal circle anesthesia
- mechanical ventilation preferable if over 45 minutes
- use local anesthetic drugs
102
Maintenance of horse: PIVA
- reduce the use of inhalants
- balanced anesthesia
- reduce CVS adverse effects
- ketamine, medetomidine, lidocaine
103
maintenance of horse TIVA
- less CV depression
- good analgesia
- less likelihood of movement in response to sx stimlus
- decreased surgical stress
- lower morbidity and mortality
- better recovery
104
Triple drip
-ketamine, GGE, xylazine
OR (alternative- ketamine, GGE, romifidine)
-top up with intermittent boluses of ketamine or diazepam/midazolam
105
What should be especially monitored in equine anesthesia
- hypoventilation- IPPV
- hypotension- monitor with ECG lead 1 (base-apex)
- do regular arterial blood gas measurements
106
special recovery consideration--> horse
- keep in same lateral recumbency as they were during sx
| - assisted vs unassisted recovery
107
equine hypotension
- MAP <70 mmHg, SAP <90 mmHG
| - reduce anesthetics, volume rescuscitation, cardioactive drugs (dobutamine, phenylephrine)
108
equine hypoventilation
- target 35-45 mmHg PetCO2
| - mechanical ventilation
109
Myopathy! important- clinical changes
- myoglobinuria and hyperglobulinemia
- muscle enzymes elevated
- electrolytes
- elevated BUN and CREA
- CBC: inflammatory leukogram
110
predisposing factors of compartmental myopathy in horse
- muscle and nerve tissue ischemia associated with inadequate perfusion
- heavily muscled horse
- fit/nervous horse
- persistently low MAP (<70 mmHg)
- improper positioning peri-operatively
- prolonged anesthesia
- halothane
111
signs of compartmental myopathy in horse
- failure to stand on specific muscle group
- muscle feels hard and is severely painful
- myoglobinuria, subsequent renal failure
112
tx of compartmental myopathy in horse
- symptomatic- fluids, pain management, oxygen radical scavengers, physiotherapy, TLC
- fasciotomy- decompression
113
Malignant hyperthermia
- genetic
| - horses and pigs- mutations in ryanodine gene- excessive calcium release into sarcoplasm
114
what conditions can promote malignant hyperthermia?
- halothane
- stress
- depolarizing muscle relaxants (succinyl choline)
- improper positioning perioperatively
115
signs and symptoms of malignant hyperthermia
-hyper metabolic state: hyperthermia, hypercapnea, lactic acidosis
-
116
A large white pig is given halothane for a castration sx, he is now profusely sweating, breathing rapidly, his ECG is showing arythmias, he has prolapsed third eyelids, flared nostrils, contracted masseters as well as muscle rigidity, oh and when he pees his blood is red (myoglobinuria)- what do you suspect? how do you treat? what could have been done to prevent?
- malignant hyperthermia
- prevention: correct positioning and padding, pre-anesthetic dantrolene, maintain normal bp, do not give inhalant anesthetics or depolarizing muscle relaxants such as succinyl choline
- treatment: dantrolene, water/alcohol baths, acepromazine for vasodilation, sodium bicarb for lactic acidosis
117
What breeds are susceptible to Hyperkalemic periodic paralysis, what is the pathology, what can be due to prevent, how to treat?
- QH and appaloosas
- failure in sodium channels to deactivate- excessive sodium influx and potassium outward flux in muscle cells
- triggered by: transport, stress, sedation, anesthesia
- treatment: increase potassium excretion by: acetazolamide, dextrose, calcium gluconate
118
What nerves are most susceptible to neuropathy in horses, how to prevent
- facial nerve, radial nerve, spinal malacia
- prevention: correct positioning and padding, remove halter during anesthesia, maintain normal bp, nerve may revitalize once swelling subsides, treat symptomatically
119
Complications of anesthesia- equine
- nasal edema- place nasal tube until horse stands
| - excitement during recovery- more prone to damage to horse and handler- sedate with romifidine/detomidine
120
What is a very effective sedative in foals?
-benzodiazepine
121
major differences in donkey anesthesia
- more resistant to sedatives, anesthetics, analgesics- increase dose by 30%
- half life of ketamine shorter
- more sensitive to GGE
122
Which small animal should be extubated slightly earlier to avoid laryngospasm?
-cats
123
What to do if regurgitation occurs in small animal patient
- postural drainage- nose low, sternal recumbency
- suction
- swab posterior pharynx with gauze before awakening
- remove ETT with cuff inflated
124
When is pulse oximeter especially important in small animal patients?
-brachycephalics, upper or lower airway disease, pulmonary pathology
125
When is blood pressure monitoring especially important in small animal patients?
-hemorrhage, sepsis, hypovolemia
126
What are considered the most painful surgeries?
-thoracotomy, amputation,e ar resection, pelvic repair, cervical disk repair
127
What category of pain would an ovariohysterctomy (spay) fall under?
moderate
128
how to tell pain from opioid dysphoria
- painful patient will quiet with additional opioids
- dysphoric patient will become more distressed with additional opioids
- test: administer short acting opiods e.g. fentanyl and observe effects
129
alpha 2 agonists used to treat dysphoria and pain
- acepromazine
- benzodiazepine
- butorphanol- maintain some analgesic (opioid antagonist)
130
short term effects of hypothermia
- increased oxygen demand
- prolonged recovery
- discomfort
131
long term effect of hypothermia
- delayed healing
| - infection
132
Which of the following should you not use for active warming on your patient?
A. bair hugger
B. heating pad
c. warm water blanket
d. heated cage
bair hugger is one of the most effective methods, HEATING PAD IS DANGEROUS- THERMAL BURNS
133
Hyperthermia is rare in small animal anesthesia, but when should you be careful about it
-opioid treated cats, MRI in obese furry dogs
134
most common causes of hypoxemia (cause you know Ambrisko lives for this)
-airway obstruction, hypoventilation, pulmonary pathology (V/Q mismatch)
135
Why should you avoid mouth gags in cats?
-cortical blindness due to cerebral hypoxia
136
Why should you extubate equines earlier than most patients
- because they are dinguses and freak out- regurg is uncommon in them anyways cause their long ass necks
- obligate nasal breathers, keep nasaltracheal (idk if this is the right word but whatever goes in the nose) on hand
137
Free recovery in horses
- healthy horses without orthopedic disease
- short anesthetic event (1-2 hrs) without complication
- dangerous horses
138
assisted recovery in horses
- old, weak, systemically ill
- orthopedic disease
- airway obstruction concern- sinus/dental sx
- optho sx
139
What medication is most commonly used for long term pain management in horses?
NSAIDs
140
Which medication is used for visceral (colic pain) in horses?
-alpha 2 agonists, butorphanol
141
Why wouldn't you want to use a strong opiod in equines?
-concern for ileus
142
Common anesthetic complications in horses
- hypothermia- large body mass, difficult to warm
- hypoxemia- give nasal O2 once extubated
- airway obstruction- check for nasal edema before recovery- apply intranasal phenylephrine, nasopharyngeal lube
- weakness- check blood work for proper electrolyte balance
- rhabdomyolysis- myopathy
- neuropathy- try to prevent
143
ruminant recovery
-regurgitation and bloat are common
144
What are challenges in intubating pigs?
- ETT visualization is difficult
- laryngospasm- spray lidocaine, intubate at surgical anesthetic depth, laryngeal junction curved
- malignant hypothermia
145
What type of restraint is best for pigs?
chemical restraint- they are strong and can hurt you
146
Common pig premeds
- AZAPERONE-popular pig anxiolytic
- most sedatives are not usually effective
- other options- midazolam, xylazine, medetomidine, acepromazine
147
Where are pigs most commonly catheterized?
-auricular vein
148
induction drugs used for pigs
- ketamine
- ketamine/xylazine combos
- telazol
- thiopentone
- inhalants are last resort
149
True/false- lab animals have fast metabolic rates, are prone to hyperglycemia
False- do have fast metabolic rates but prone to hypoglycemia so mostly dont need to fast
150
commonly used induction drugs for lab animals
- inhalational: iso or sevo
| - inectable: ketamine with alpha 2 adrenergic agonists or midazolam
151
commonly used sedatives for lab animals
- alpha 2 adrenergic agonists (dex)-medetomidine, xylazine
| - benzodiazepines: midazolam
152
In ectotherms is recovery usually quicker or prolonged?
- prolonged because ambient temp affects body temp and metabolic rate, low metabolic rate
- can hold breath for long periods
153
Special considerations in ecotherm cardiopulmonary system
- 3 chambered heart
| - renal portal system- avoid IM injections into caudal body parts
154
Special considerations in ectotherm respiratory system
- no muscular diaphragm
| - trachea is complete cartilagenous ring
155
Croc anesthesia things that are weird: CRIKEY! (RIP Steve Irwin)
- don't dart- danger of drowning
- succinyl choline can be used- causes depolarization of muscle fibers
- Gallamine is competitive non-depolarizing nueromuscular blocker, animal is conscious even though immobilized AND STILL FEELS PAIN- can reverse with neostigmine
156
Fish anesthesia tings
- risk of regurg so fast 12-24 hrs
- anesthesia options: MS-222 immersion, inhalation anesthetic flow by
- special way of monitoring: righting reflex
157
Range of different wildlife equiptment
- pole syringe: 3-4 meters
- blow pipes: 10-15 m
- dart projectors: up to 50 meters (pistol: 1-25 m) (rifle 5-60 m)
158
Dart projector-physics
-powered by compressed gas or explosive charge
| -
159
How could darts injure animals?
-bone fracture, hemorrhage, intrathoracic injection
160
renarcotization
-recurrence of signs of opioid induction and sedation in varied time after administration of opioid antagonism
161
Wild life opiods
- etorphine (M99)- reversal= diprenoprhine (M5050)
- mixed agonist- antagonist: butorphanol
- fentanyl- reversal=naloxone
- carfentanil- reversal= naltrexone
- thiafentanil- reversal= nalmefene
162
Dissociative anesthetics- cyclohexamines
- ketamine, teletamine (telazol)
- telazole higher potency than ketamine, and causes excitement during recovery
- feral carnivore induction
163
Wildlife tranquilizers- butyrophenones and phenothiazines
- use with opiods for megaherbivoires to minimize stress
- butyrophenones: AZAPERONE (also used in piggies), haloperidol
- phenothiazines- acepromazine, propionylpromazine
- long acting phenothiazines (can last for days): zuclopenthixol acetate, perphenazine enanthate
164
zoo and wildlife sedatives-benzodiazepines
- midazolam
- diazepam:carnivoires, herbivoires
- zolazepam: carnivoire immobilization
165
zoo and wildlife sedatives: alpha 2 adrenergic agonists
- xylazine- reversal= yohimbine, atipamezole
- medetomidine- carnivoires
- detomidine- herbivoires
- romifidine- herbivoires
166
White rhino drug combinations (RIP)
- sensitive to opiods- muscle tremors, rigidity, hypoxemia, hyperthermia
- immobilization: etorphine and azaperone
- partial antagonism with butorphanol IV
167
black rhino drug combo
- less opiod effects than white rhinos, typically more excitable
- immobilization: etorphine+ azaperione, etorphine+detomidine, carfentanil
168
elephant drug combo
- massive GIT
- trunk: obligate nasal breathers
- immobilization- etorphine and azeperone
169
red deer
- xylazine and ketamine and telazol
| - medetomidine and ketamine
170
coyote
- ketamine with alpha 2
| - telazole, xylazine
171
wild dogs
- fentanyl xylazine combo
| - reversible with yohimbine and naloxone or naltrexone
172
bears
-hyaluronidase enhances absorption
173
capture myopathy- wild animals
- acute death syndrome= 3-4 hrs
- delayed peracute death syndrome- death one day after due to v.fib
- ataxic-myoglobinuric syndrome- renal failure and death within 4-5 days
- prevent by reducing stress on animal: less time for capture and restraint, sedatives, fluids, keep temp cool
174
special considerations for avian anesthesia (more anatomy stuff in further flash cards)
- high BMR
| - renal portal system
175
respiratory anatomy relevant to avian anesthesia
- two distinct functional components for ventilation and gas exchange
- counter current flow- air/blood
- highly efficient (counter current gas exchange)
- no diaphragm
- complete tracheal ring, glottis easily visualized so intubation easy USE UNCUFFED TUBE
- air sacs
- 2 inspiratory/expiratory cycles necessary for complete gaseous exchange
- can intubate thoracic or abdominal air sacs
- pneumatic bones: humerus, femur
176
cardiovascular system relevant to avian anesthesia
- highly efficient blood flow and delivery
- 4 chambered heart
- higher susceptibility to adverse effects from anesthetic drugs, stress, pain- ventricles and atria highly innervated
- renal portal system
- sensitive to bradycardia- treat quickly with anticholinergics
177
avian thermoregulation
- don't have sweat glands
- cool themselves by panting and gular flutter
- heat by: shivering, pylo-erection, eating, basking
- overhead radiant heat source during anesthesia- prone to hypothermia
178
bird restraint considerations
-small birds can die easily from improper restraint
179
fasting in birds
- become hypoglycemic quickly
| - before anesthesia allow crop to empty or in an emergency empty crop soon after anesthetic induction
180
injection sites for birds
- IM- pectoral (flying birds), thigh (non-flying birds)
- sub-q- poor absorption
- medial metatarsus, brachial vein, right jugular vein
- interosseus- proximal ulna or tibiotarsus
181
what is the most common route of anesthesia in birds
- inhalational- easier to administer, rapid recovery
- sevoflurane has faster induction and recovery, isoflurane can also be used
- in water birds can have dive response, ability to hold breath (problem for inhalants)- bradycardia and apnea
- MAC doesn't apply to birds- no alveoli
- need to have assisted ventilation
182
injectable anesthetics for birds (not as common)
- sedation/analgesia- weak opiods and benzodiazepines or alpha-2s
- immobilization- ketamine and sedatives/analgesics
- induction and maintenance- propofol, alfaxalone IV
- potent opiods- morphine, fentanyl
- LOCAL ANESTHETICS ARE HIGH RISK
- NSAIDs- carprofen, meloxicam
183
What type of heart do birds have (other than no heart cuz they're mean)
-apex to base- large negative deflection of S-wave on ECG
184
Why may pulse oximetry not always be accurate in birds?
- have nucleated RBCs
| - use arterial blood gas because more accurate
185
Neuromuscular blockade
- reversible occupation of nicotinic cholinergic receptors by drugs that prevent neuromuscular transmission (muscle movement) by restricting Ach access to receptor sites
- causes create relaxation of striated muscle
186
muscle relaxants-centrally acting
-benzodiazepines, guafinesin, alpha-2 adrenergic agonists
187
So we're back with the dumb doctor that doesn't want to give fluids with anesthesia (how hasn't he lost his license yet lmk)- he's doing an ortho sx and wants to give the patient succinyl choline to relax the muscles- he has the anesthesia machine hooked up without a ventilator because that's common for most procedures right? he also still wants to save money with his cheap ass so he's going to induce the patient with propofol and then keep him on iso- he'll be knocked out so who cares! What's wrong with this?
- NMBDs DON'T PROVIDE ANALGESIA- GIVE OPIOID OR OTHER POTENT ANALGESIC
- PUT THE PATIENT ON A VENTILATOR, NMBD TAKE AWAY THE ABILITY FOR PATIENT TO VENTILATE THEMSELVES
188
Indications for NMBDs
- opthalamic
- thoracic surgery and diaphragmatic hernia repair
- ortho sx
189
advantages of neuromuscular blockade
- may be antagonized
- predictable absolute muscle relaxation
- anesthetic sparing
- less muscle trauma
- facilitates IPPV
- facilitates ETT intubation
190
disadvantages of neuromuscular blockade
- need mechanical ventilation
- difficult to monitor anesthetic depth- reflexes lost
- risk of transecting nerves- no muscle response
- hard to monitor blockade
- post op weakness
- recurarization- NMB additive-effect drugs administered post op may cause full m paralysis again
- histamine release- rare but with succinylcholine or atracurium
191
Mechanism of action of neuromuscular blocking drugs
- reversibly occupy postsynaptic NICOTINIC cholinoceptors, prevent transmission by restricting Ach access to these sites
- depolarizing (non-competitive NMBDs)- structurally similar to Ach- depolarize post-synaptic membrane until fatigued which causes muscle paralysis- old drugs- succinyl choline
- non-depolarizing (competitive NMBDs)- block interaction of Ach with receptors- atracurium, and other curiums
192
order of muscle blockade
1. facial muscles of expression
2. neck muscles
3. diaphragm- first to regain contractions after effects wane
4. distal limbs
5. proximal limbs
6. abdominals
7. intercostal mm.
193
Drugs that potentiate effects of NMBD
- inhalational anesthetics
- injectable drugs
- local anesthetics
- antiarrhythmics
- diuretics
- magnesium
194
physiological influences on NMBDs
- hypothermia
- electrolyte abnormalites
- age
195
advantages of succinyl choline
-rapid onset, short duration
196
disadvantages of succinyl choline
- muscle fasiculations and contraction
- cardiac arrhythmias
- increased intraocular, intraabdominal, intracranial pressures
- may cause histamine release
197
non-depolarizing NMBDs- benzylisoquinolinums
- atracurium, cis-atracurium
- atracurium: rapid metabolism, inexpensive, can cause histamine release at high doses, may cause seizures
- cis-atracurium is more purified, more potent, and has less adverse effects but is more expensive
198
non-depolarizing aminosteroids
- vecuronium-no CV effects, eliminated by liver and partly kidneys
- rocuronium- similar to vecuronium- faster onset, longer duration, activity can be terminated by sugammadex
199
monitoring NMBDs
- stimulate peripheral nerve and record number and strength of evoked potential in innervated muscle group
- single twitch- simplest
- train of 4- more accurate
200
NMBD antagonism
- antagonized by anti-cholinesterase- edrophonium, neostigmine
- can give anticholinergics (atropine or glyco) to counteract Ach levels raised in body and PSNS effect
201
Indications of NSAIDs
- mild chronic pain
- anesthesia and surgery
- well hydrated, normotensive, young to middle aged animals (not cats) with normal renal functions
- compared to opioids- not as strong, higher efficacy for inflammation, take home and inexpensive
202
clinical effects of opiods
- analgesics
- anti-inflammatory
- anti-pyretic
203
COX-1
- liver, kidneys, platelets, gastric mucosa
| - good kinda cox- don't want to inhibit-adverse effects
204
COX-2
- inducible
- damaged or inflamed tissue
- inhibiting this prevents pain and fever and causes analgesia
205
Non-selective COX inhibitors
- aspirin
- ketoprofen, phenylbutazone
- flunixin meglumine
206
preferential COX-2 inhibitors (weak COX-1 inhibitors)
- meloxicam
- carprofen
- etodolac
207
selective COX-2 inhibitors
- robenacoxib
- firocoxib
- deracoxib
- coxibs
208
adverse effects of NSAIDs
- gastrointestinal- vomiting, diarrhea, gastric ulceration/perf
- platelet aggregation, may cause prothombotic state
- renal effects
- impaired hepatic blood flow
209
Ulcer prophylaxis and treatmetn
- sucralfate: aluminum salt that binds to mucosal defects
- misoprostal: synthetic PGE1 anolouge, inhances mucosal defense
- rantidine- H2 receptor antagonist, reduces gastric secretions
- omeprazole- proton pump inhibitor, reduces gastric secretions
210
Who not to use NSAIDs in (other than the ones that are contraindicated in due to adverse effects)
- pregnant
- pediatric- avoid NSAIDs before 4 weeks for proper nephrogenic development
- healing fractures
- felines- slow clearance, also predisposed to: fever, methemoglobinemia, hemorrhagic gastritis, kidney, and liver injury, Heinz body anemia with acetaminephin
211
Robenacoxib
- injectable (S/Q) or oral
- cats and dogs
- use up to 3 days
- minimal adverse effects
212
Carprofen
- injectable and oral
| - dogs
213
Meloxicam
- injectable and oral
- cats and dogs
- few adverse effects, mostly GI
214
phenylbutazone
- injectable and oral
| - horses and cattle no more than 20 months old (avoid residue in milk)
215
Ketoprofen
- ruminants and horses (dogs and cats)
| - can cause hemorrhage and GI effects
216
Flunixine Megulumine
-colic pain in horses
217
Acetylsalcyclic acid (aspirin)
- not approved by FDA for vet use
- bleeding, GIT effects common
- toxicity
218
Acetaminophen (Tylenol)
-very toxic to cats- hemolytic anemia
219
Galliprant
-anti-inflammatory for canine osteoarthritis
220
Anticholinergics
- competitive antagonists at muscarinic ACh receptors
- decrease parasympathetic tone
- increase firing rate of SA node (chrontrophy) and conduction speed through AV node (dronotrophy)
- indicated for bradycardia secondary to increased vagal tone
- side effects: GI- increased viscosity of saliva, causes ileus and colic, sedation, bronchodilation, mydriasis (atropine)-contraindicated in glaucoma
221
Atropine
- fast onset, short duration
- may cause marked tachycardia
- crosses BBB and placenta
222
Glycopyrrolate
- slower onset and longer duration than atropine
- causes mild-moderate tachycardia
- does not cross placenta or BBB, no mydriasis
- not for emergency use- slow onset
223
Class IB antiarrhythmic
- lidocaine
- sodium channel blocker
- tx ventricular arrhythmias
- short acting- give bolus and then CRI
- criteria for treating: hypotension/inadequate perfusion, R on T phenomenon, multiform VPCs, HR >180
224
Class II antiarrhythmic- Beta blockers
- severe sinus ur supraventricular tachycardia
- not common in aneshtesia- tachycardia associated with pheochromocytoma is only indication
- esmolol most common
225
Dopamine
- dose dependent receptor agonism
- low dose= dopamine receptor agonism
- medium dose- beta agonism (increased inotropy, chronotropy)
- high dose- beta and alpha agonism- beta effects + vasoconstriction
- common for hypotension in cats
226
Ephedrine
- mixed agonist- primarily alpha
- may see reflex bradycardia due to vasoconstrictive effects
- may cause CNS stimulation (increased MAC)
227
Norepinephrine
- mixed agonist- primarily alpha (causes vasoconstriction)
| - indicated for refractory shock or non-responsive hypotension
228
Epinephrine
- non-selective agonist
- CPR or anaphylaxis
- arrhythmogenic- V. Fib
229
phenylephrine
- alpha 1 agonist only- vasoconstriction, increased bp
- may decrease cardiac output and perfusion
- causes splenic contraction- nephrosplenic ligament entrapment in horses
- nasal edema in horses
230
dobutamine
- beta agonist
- primarily B1-increased inotropy
- mild B2- vasodilation
- equine anesthesia
231
isoproterenol
- beta 1 and beta 1 agonist
| - treat third degree AV block and bronchodilation
232
Vasopressin
- vasoconstriction- can be profound
| - indication- refractory shock, non-responsive hypotension
233
What is the underlying cause of cardiac arrest
-inadequate oxygenation to heart
234
Is the prognosis of CPR better under or not under anesthesia
-better under anesthesia
235
Chest compressions
- use 2 min uninterrupted cycles
- 100-120/min
- only achieve about 25-30% normal CO or less
- cardiac pump theory- small animals
- thoracic pump theory- large patients
236
Cardiac pump theory
- cats and small dogs- one handed compressions, fingers wrap around sternum
- narrow deep chested dogs- compress directly over heart
- medium, large, giant breed dogs with rounded chests- compress over widest part of chest
237
Ventilation of CPR patient
- continue chest compressions
- 10 breaths per minute
- ambu bag or anesthesia machine (100% O2)
238
What important value does End Tidal CO2 provide in CPR patients
- adequacy of cardiac compressions
| - sudden increase in EtCO2 indicates return of spontaneous circulation
239
impedence threshold device
- creates negative intrathoracic pressure to increase venous return (preload)
- animals over 10 kg
240
You're doing chest compressions on Shorty- a 10 yr old Chihuahua who came in in asystole, when should you evaluate ECG? What other therapies should you use?
- do not evaluate ECG until 2 mins of uninterrupted compressions, chest compressions cause motion artifacts so evaluate and then quickly resume compressions
- vasopressor therapy- every other cycle (q 3-5 mins)-epinephrine or vasopressin
- use atropine every other cycle- esp in cases of high vagal tone
241
"shockable rhythms"
- pulseless v. tach/ v. fib
- defibrillate immediately after dx- "resets heart"-refractory period, allows pacemaker cells in SA node to take over
- vasopressor therapy also indicated
- DON'T HAVE ALCOHOL ON PATIENT BEING DIFIBRILLATED YOU WILL SET THEM ON FIRE
242
Reversal agents
- all reversible anesthetic drugs that have been administered should be reversed during CPR
- opiods- naloxone
- alpha-2- atipamezole
- benzodiazepines- flumazenil
243
electrolytes- CPR
- Calcium- hypocalcemia
| - potassium- hyper/hypokalemia
244
Post cardiac arrest patients
- unstable need to figure out and treat underlying cause
| - refer to 24 hr facility
245
Local anesthetics- structure and MoA
- lipophilic and hydrophilic portions joined by hydrocarbon chains
- binds to sodium channels in nerve membranes to slow rate of depolarization
- weak bases- acidic tissue (infection) will increase ionized inactive portion
- ionized form cannot pass through cell membrane
- non-ionized base is lipid soluble and can pass through cell membrane
246
Amide LA
- lidocaine
- bupivicaine
- mepivicaine
- prlicaine
247
lidocaine
- only local anesthetic that can be given IV or used for intravenous regional anesthesia
- fast onset, short duration
- available in patch form
- systemic effects: anti-arrhythmic, MAC sparing, analgesic, free-radical scavenger, improve GI motility
248
bupivicaine
- immediate onset
- highest CV toxicity
- long duration
- post-op CCL analgesia in dogs
249
Mepivicaine
- nerve block, intra-auricular in large animal
- fast onset
- duration 1.5-3 hrs
250
Commonly used esters
- procaine
- tetracaine and proparacaine (optho procedures)
- benzocaine
251
Metabolism of esters
- hydrolysis by plasma cholinesterase
| - metabolite (PABA) may cause allergic reaction
252
Metabolism of amides
- -metabolized by microsomal liver enzymes
| - more likely to accumulate
253
Additives to local anesthetics
- epinephrine- prolong duration of block, vasoconstriction which slows the systemic absorption
- bicarbonate- faster onset, prolonged duration, less sting
- combining LAs- may shorten onset and lengthen DOA, toxicity is additive
254
Why should you use preservative free LA in epidurals?
-neurotoxicity
255
most and least chondrotoxic local anesthetics
- bupivicane most damaging- don't use intraauricular
| - mepivacaine least damage
256
systemic toxicities of local anesthetics
- lidocaine: depression/sedation, twitching, seizures, then CV signs
- bupivicaine- CV collapse and then death, most cardiotoxic
- if you include epinephrine you will see increased heart rate as first sign of IV injection
257
treatment of arrest secondary to LA
- GIVE 20% LIPID EMULSION
- start CPR
- low dose epi
- avoid lidocaine, Ca channel blockers, beta blockers, vasopressin
258
Which local anesthetics are allergic reactions most common in?
- procaine- procaine penicillin G- metabolized to PABA which is an allergen
- much less commonly occurs with amide anesthesia
259
Order of nerve blockade
1. Beta fibers (preganglionic sympathetic)
2. alpha-delta and c fibers- pain
3. alpha- gamma- proprioception
4. alpha-beta- touch/pressure
5. alpha alpha- motor
260
Where does the spinal cord end
- dogs: L6-L7
- cats: L7--S3
- horses, ruminants, pigs- mid sacrum
- subarachnoid injection more likely at lumbosacral space in non-canines
- if you encounter CSF in epidural, decrease the dose by 50%
261
Epidural contraindications (CHINAS)
- coagulopathy
- hypovolemia
- infection at injection site
- neoplasia at injection site
- anatomy- can't palpate landmarks (fatties)
- sepsis
262
adverse effects of epidural
- depends on drug used
- hypotension- block sympathetic trunks which decreases vascular tone
- motor block/paralysis- bigger deal in horses than SA
- hematoma, infection, neurotoxicity
263
Topical anesthesia
- lidoderm patches- along incision after closure
- EMLA cream- lidocaine and prilocaine- IVC placement in sensitive patients- takes about 60 mins before full onset
- opthalamic- tetracaine or proparacaine most common
- laryngeal- lidocaine for intubation- which animals indicated? in PIGGIES AND CATS- ANIMALS PRONE TO LARYNGOSPASM
264
Wound Soaker Catheter
- closed tip catheter with multiple fenestrations
- placed during sx
- for: TOTAL EAR CANAL ABLATION, amputation, oncological sx, large wound closer
- catheter can become dislodged, cause disconnection, can cause local anesthetic tox (don't use bupivicaine- most cardiotoxic)
- provides consistent and prolonged analgesia and reduces the need for systemic analgesics
265
Intravenous regional anesthesia (IVRC)- Beir block
- distal extremity procedure
- less than 60-90 mins (exsanguinate limb-don't want it to get necrotic)
- provides minimal blood loss and clear surgical field
- place IVC as distal as possible on limb, exsanguinate, place tourniquet at proximal aspect, remove limb bandage, local anesthetic, release tourniquet slowly
- complications: tourniquet pain, ischemia/nerve injury, limb swelling, hematoma, local anesthetic toxicity
266
What is THE ONLY local anesthetic that you can use in Beir Block
-lidocaine-only one without systemic toxicity
267
Retrobulbar block
- indicated for: enucleation, evisceration/prothesis, intraocular sx
- nerves effected: CN:III, IV, V, VI, ciliary ganglion
- advantages: post-op analgesia, globe immobility during sx, decrease anesthetic and neuromuscular blocker requirements
- complications: retrobulbar hemorrhage, damage to nerves, globe penetration, intravascular injection, intrathecal injection
- ASPIRATE BEFORE INJECTION- IF THERE'S HIGH RESISTANCE YOU MAY BE IN OPTIC NERVE SHEATH AND IT CAN BE FATAL
268
Dental blocks
- maxillary n. block- sensory branch CN V, anesthesia for ipsilateral: maxilla, teeth, soft tissue, lateral aspect of nasal mucosa
- infraorbital block: branch of maxillary nerve, anesthesia for 3rd premolar and teeth rostral, rostral maxilla, soft tissues
- inferior alveolar n. block- branch of mandibular nerve- anesthesia for: mandibular teeth, rostral lower lip, intramandibular space, may also desensitize lingual nerve (sensory to rostral 2/3 of tongue)
- mental nerve block: middle mental n.- anesthesia to rostral lip only
269
Thoracic limb blocks
- cervical paravertebral- less common, difficult, won't ask but provides anesthesia for entire thoracic limb and joint
- brachial plexus block
- RUMM block
- block for declaw (sad kitty)-bupivicaine (not gonna even write more cause this is outdated)
270
Brachial plexus block
- anesthesia for thoracic limb, distal to elbow
- C6-->suprascapular
- C7-->musculocutaneous
- C8--> radial
- T1--> median and ulnar
- use nerve locator or ultrasound, advance needle parallel to chest wall- can cause pneumothorax if you puncture thorax
271
RUMM block
- radian, ulnar, median, musculocutaneous nn.
- anesthesia for distal thoracic limb including carpus
- 2 injection sites- one medial, one lateral
272
Pelvic limb
- femoral and sciatic nerve blocks are usually together
| - anesthetizes distal to mid-femur- effective for stifle sx
273
intracostal n. block
- indications- anesthesia for thoracotomy, rib fractures, etc
- block at incision space and 2 spaces cranial and caudal
- aspirate before injection, avoid thoracic cavity
274
intrapleural regional block
- local anesthetic injected into thoracic cavity
- post-thoracotomy- through chest tube
- affected side down, gravity pushes LA to side
- generally safe and effective
275
Epidural
- heavily sedate before
- positioning: sternal- easier to palpate landmarks, can pull legs forward with hips flexed to maximize L-S space
- lateral also possible
- techniques- loss of resistance, hanging drop, nerve locator (not common)
- injection volume- the more, the more cranial it will spread, inject over 30 seconds
- local anesthetic and opioid- (ex: bupivicaine and morphine) morphine good choice because spreads more cranially (can cause analgesia to thoracic wall and limb), longer duration
276
Loss of resistance- epidural
- resistance to plunger depression occurs when needle in ligaments
- when epidural space entered will "pop" and have loss of resistance
- inject saline or epidural drug not air
277
hanging drop technique- epidural
- fluid in hub of needle- will be aspirated into epidural space upon entry
- only in sternal
- less reliable in small patients
278
complications of epidural
- use half amount if CSF obtained
- avoid neural toxicity by using preservative free
- use sterile technique to avoid infection
- hypotension
- opiod complications- urinary retention, pruritis (uncommon)
279
equine eye local
- auriculopalpebral block- prevents blinking for optho exam (orbicularis oculi mm paralyzed) , motor block only- eyelid and cornea remain sesitive
- supraorbital n. block- sensory to 2/3 upper eyelid and palpebral motor- placement of sub-palpebral lavage catheter
- retrobulbar block- globe and extraocular structures for enucleation
280
equine dental local
- infraorbital n. block- desensitizes lip, nose, teeth rostral to first molar, maxillary sinus, roof of nasal cavity
- mental n. block- rostral to mental foramen, desensitize lower lip
281
special considerations- equine epidural anesthesia
- do caudal- first coccygeal space because you do not want to lose hindlimb motor function- horse will freak out, it'll be bad
- local anesthetic- small volume- limit cranial spread- lidocaine
- alpha 2 agonists- xylazine, detomidine, local analgesia and systemic alpha 2 effects (sedation, 2nd degree AV block, ataxia, etc)
- morphine- analgesia- no risk of weakness or motor blockade- for hindlimb trauma or severe laminitis
- detomidine and morphine- common, excellent for hind limb pain
282
intraarticular morphine
- analgesia post-arthroscopy
- analgesic and anti-inflammatory
- minimal systemic absorption
- duration of action about 24 hrs
283
Ruminant eye nerve block
- auriculopalpebral nerve block- paralysis of orbicularis oculi mm. (can't blink)- opthalamic exam, motor block only- apply sterile lubricant to eye to protect
- retrobulbar block- enucleation or sx
- Peterson block- same indications as for retrobulbar- no sensory block to upper eyelid, safer and more effective if performed correctly
284
Ruminant dehorning
- cattle-cornual branch of zygomaticotemporal n.
| - goats have 2 nerves to block- cornual branch of zygomaticotemporal nerve and cornual branch of infratrochlear nerve
285
Ruminant flank laparotomy
- infiltration- line block- lidocaine along incision line
- inverted L block- lidocaine into area caudodorsal to last rib and ventrolateral to lumbar transverse processes- away from injection site so minimizes complication at incision
- proximal paravertebral thoracolumbar-doesn't disrupt incision line, faster than line block but technically difficult, scoliosis (leaning to effected side)may make wound closure difficult, can penetrate great vessels, can lose motor control if migrates to femoral n.
- distal paravertebral thoracolumbar- lack of scoliosis, less risk of penetrating major blood vessels, need larger amounts local anesthetic, may be less effective
286
caudal epidural- adult cattle
- obstetric manipulation or surgery for caudal structures
- common and easy
- S5- Co1 or Co1-Co2 space
- local anesthetics- alpha 2 agonists, morphine
287
lumbosacral epidural
- good for immature cattle, small ruminants, camelids, pigs
- L6-S1 space
- alpha 2 agonists
- similar to dogs
288
teat and udder blocks
- teat lacerations and other injuries- multiple methods
- udder- paravertebral block for cranial aspect of udder and teats, high caudal epidural or L-S epidural for caudal aspects of teat and udder
289
Foot block in ruminants
- common site of injury/dz
- ring block
- IVRA-similar to small animals
290
testicular block for castration
- lidocaine
| - volume dependent on sizeof patient DON'T GIVE SHEEP A COW DOSE
291
phsyiologic pain
-normal response to noxious stimulus, produces protective behavioral responses to potential or actual tissue damage
292
acute pain
-sudden onset, may be severe, disappears when stimulus removed
293
chronic pain
-several weeks to months, persists past expected healing time
294
somatic pain
-originates from damage to bone, joint, muscle, skin- well localized
295
visceral pain
-internal organs, poorly localized, i.e. colic
296
neuropathic pain
- injury to peripheral or CNS
| - nerve transection or compression
297
inflammatory pain
-tissue damage
298
referred pain
-originates from one part of body, perceived as being in another
299
transduction
- peripheral pain receptors activated by stimulus
- mechanoreceptors- stretching, compressing, crushing
- thermoreceptors- temp
- chemoreceptors- chemicals (NT, etc)
300
transmission
- signal communicated via alpha delta and c nerve fibers to spinal cord
- alpha delta fibers- myelinated, fast transmission, accurately localized sharp, rapid onset pain
- c fibers- non myelinated, slow transmission, chronic, diffuse, burning, aching pain
301
modulation
- nociceptive input modified at spinal cord
- afferent nerves enter spinal cord through dorsal roots-->synapse in lamina of dorsal horn grey matter-->ascend via spinothalamic and spinoreticular tract to brain
302
perception
-conscious recognition of pain at cerebral cortex
303
primary modulatory substances in spinal cord- facilitary/excitatory (increase pain)
- substance P--> NK1 receptor
| - glutamate- AMPA, NMDA, ketamine receptors
304
modulatory substances in spinal cord- inhibit pain
-GABA< endogenous opiods
305
Spinothalamic tract
- terminates at thalamus and somatosensory cortex
- transmits: localized, superficial pain
- tested by brief skin pinch
306
spinoreticular tract
- terminates in reticular formation
| - deep and visceral pain- deep pain test (pinch periosteam across base of toenail)
307
descending inhibitory pain pathways
- input received from cerebral cortex and ascending pain pathways--> midbrain
- axons (from paraaqueductal grey matter and nucleus raphe magnus release endorphins (seratonin, NE) which inhibit pain transmission at level of dorsal horn
- pharmacological target for pain control
308
head pain
-mediated by trigeminal n
309
systemic consequences of unmanaged pain
- stress response- think cortisol, stress hormones, and neurotransmitters (epi, NE)
- CV: tachycardia, hypertension, increased cardiac workload
- respiratory: atelectasis, hyper/hypoventilation, hypoxia
- GI: delayed gastric emptying, nausea, ileus
- renal: oliguria, urinary retension
- hematologic- hypercoaguability, risk of thrombosis
- immunologic- impaired immune function
- muscular- muscle weakness and fatigue
- physiologic- anxiety, fear, suffering (me rn)
310
allodynia
-pain from not usually painful stimulus
311
hyperalgesia
-increased or exaggerated response to normally painful stimulus
312
peripheral sensitization
- tissue damage stimulates local inflammatory cells, nociceptive nerve endings, sympathetic terminals
- release electrolytes and chemicals, increases intracellular calcium and induces intracellular signalling cascades
- increased sensitivity of nociceptors
- primary hyperalgesia (at the site)
313
windup
- temporal summation and cumulative depolarization of dorsal horn neurons
- continuous stimulation of neurons by peripheral pain stimulus
- increased dorsal horn excitability
- removes normal block on NMDA receptors- available for glutamate binding which increases pain transmission
- contributes to central pain sensitization
314
central sensitization
- increased in dorsal horn excitability- wind up
- decrease in inhibition at spinal cord level
- hyperalgesia, allodynia, spontaneous pain, pain memory (phantom limb pain)
315
Why should you give pre-emptive analgesia
- before painful stimulus- prevents peripheral and/or central sensitization
- decrease total analgesic requirement
316
interuption of transduction
- topical local anesthetics, tissue cooling
- infiltration of local anesthetic
- systemic NSAIDs to reduce inflammation
317
interuption of transmission
-local anesthetic nerve blockade- epidural
318
interruption of modulation
-opiods, alpha 2s, NSAIDs, NMDA antagonists
319
interruption of perception
-opiods, alpha 2 agonists, general anesthetics
320
canine pain behaviors
- lameness
- preying position= severe abdominal pain
- head tilt= ear pain
- guarding of painful site
- behavior change
321
feline pain behaviors
- hiding, social withdrawal
- decreased appetite
- decreased grooming or excessive licking of painful site
- lameness, reluctance to jump
- thinking outside the litter box
- squinting eyes, lowered ears
- aggression (more than usual)
322
equine pain behaviors
- lameness
- standing at back of stall
- decreased social interaction
- decreased appetite
- pain face
- colic: sweating, rolling, flank watching/biting, pawing, kicking, getting up and down
323
ruminant pain behaviors
- bruxism (teeth grinding)
- hypersalivation
- decreased appetite and rumination
- decreased milk production
- isolation from herd
- vocalization/grunting
324
biomarkers of pain
- not specific
| - cortisol, glucose, catecholamines, endorphins/encephalins, lactic acid and FFA
325
pain scales
- Glasgow composite pain scale- post op pain in dogs
- Colorado State pain scale
- equine pain scale- abdominal
- equine pain scale- orthopedic
326
local anesthetics as analgesics
- block Na-gated ion channels- prevent propogation of action potential
- may act on transduction or transmission
- effective but short acting
- transduction: topical
- transmission: IVRA, peripheral and central nerve blocks
327
opioids as analgesics
- highly effective, minimal and manageable side effects
- generally inexpensive
- titratable
- act on peripheral receptors (transduction),dorsal horn of spinal cord(modulation), brain (perception)
328
common opioids in vet med
- pure mu= morphine, hydromorphone, oxymorphone, fentanyl
- partial mu- buprenorphine
- u antagonist, kappa agonist- butorphanol
329
tramadol
- oral opioid for dogs and cats
- weak mu opioid activity
- inhibits serotonin reuptake- enhances descending inhibition of pain transmission
- dose high
330
topical NSAID for horses
-Diclofenac
331
NMDA antagonists
- act at NMDA receptors in spinal cord
- glutamate binds to NMDA receptors and facilitates pain
- blocking receptors inhibits transmission of pain at level of spinal cord (modulation)
- decreased central sensitization
- ketamine
- amantadine- occasionally used with NSAIDs- chronic pain (osteoarthrits, cancer)
332
alpha 2 agonists
- decrease release of norepinephrine peripherally, spinal cord, brain (modulation and perception)
- agonist at alpha 1 and alpha 2 receptors
- xylazine is least selective for receptors, dexmedetetomidine most selective
- potent analgesia in horses, less in other species
- adjunct analgesics as single dose or CRI with other
333
gabapentin
- analgesic adjunct
- neuropathic and chronic pain- modulation
- helps prevent central sensitization if given pre-op
334
So you're a smart baby vet and you totally remember Bucknoff chanting about NEVER GIVE A STEROID AND AN NSAID TOGETHER (thanks Dr. Bucknoff), but if you have a dog on Meloxicam post spay and it's not effective you can totally switch it to Carprofen right away cause they're both NSAIDs right?
NAH FAM YOU ALSO NEED A WASHOUT PERIOD BETWEEN NSAIDS TOO
335
kitty cat consideration for NSAIDs
-more sensitive to renal effects, can only give certain NSAIDs because lack certain liver enzymes, may become hypotensive during surgery
336
opiod that sucks for other species but is aight for cats
buprenorphine
RUSVM- anesthesia
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