Exam 1 Flashcards
1
Q
How many animals are needed to generate a reference interval?
A
minimum of 40 animals
Davis uses about 100
2
Q
T/F: as prevalence increases, PPV increases and PVN decreases.
A
True
3
Q
What are the perfusion parameters? (list 6)
A
- mentation
- mucous membrane colour
- capillary refill time
- heart rate
- pulse quality
- extremities temperature
4
Q
Clinical signs associated with hypovolemia-vasoconstriction (gen. d/t decreased preload)
A
- obtundation
- pale mucous membranes
- slow capillary refill time
- tachycardia (cats-brady)
- poor pulse quality
- cold extremities
5
Q
Clinical signs associated with vasodilation (gen. d/t decreased afterload)
A
- obtundation
- hyperemic mucous membranes
- very fast capillary refill time
- tachycardia
- bounding pulse quality
- warm extremities
6
Q
Define: Sedation
A
mild to moderate depression of the CNS
7
Q
Sedation vs chemical restraint
A
chemical restraint is just heavier sedation
8
Q
Site of action for local anesthetics
A
- Nociceptors
- Nerves
- Spinal Cord
9
Q
Site of action for general anesthetics
A
- spinal cord
- thalamus
- cortex
10
Q
What are the two Risk Classification Schemes?
A
- ASA status ( only takes into account patient)
2. Operative Risk ( estimates overall risk)
11
Q
T/F: Emergency surgeries have the same level of risk as elective surgeries.
A
False: higher mortality rates for emergency
12
Q
Purpose of pre-anesthetic fasting
A
- reduce risk of vomiting/ regurgitation
- ruduce size of gi tract in Large Animals
13
Q
Why give anesthetic pre-medication (pros and cons)?
A
- decrease apprehension
- provide analgesia
- reduce dose of induction and maintenance drugs
- minimize undesirable autonomic reflexes
Cons:
- takes time/ organization
- concerns about polypharmacy
14
Q
Risk of mortality (during surgery) increases with:
A
- systemic illness
- emergency
- after hours
- lack of familiarity
15
Q
Define: pain
A
unpleasant sensory and emotional experience associated with actual or potential tissue damage
nociception =/= pain
16
Q
Pain Assessment (Physiological variables)
A
- not sensitive nor specific
- HR, RR, blood pressure, GI sounds
17
Q
Pain Assessment (Neuroendrocrine variables)
A
- indicator of disease severity =/= pain
- stress hormones, endorphins, acute phase proteins
18
Q
Pain Assessment (Objective Physical Measurements)
A
- weight and food consumption
- gait analysis
- activity level
- nociceptive threshold tests
19
Q
Pain Assessment (Subjective Assessments)
A
use of pain scales:
- one dimensional scoring system
- multidimensional
- good for bringing attention to and documenting many different parameters
20
Q
One dimensional scoring system (subjective)
A
- easy to sue
- not good for small changes
- high subjectivity
21
Q
Multidimensional scoring system (subjective)
A
- behavioral +/- physiological data
- n behaviour must be known + categorized
22
Q
Acepromazine (drug category, moa)
A
Category: phenotiazine
MOA: central dopamin receptor antagonist
23
Q
Acepromazine (4 Actions)
A
- mild sedation (highly variable)
- decreased alertness
- anesthetic sparing
- lasts a long time (4-6 hours)(non-reversible)
24
Q
Acepromazine (adverse effects)
A
- Vasodilation (peripheral alpha 1 antagonism)
- syncope reported in boxers
- no analgesic action
25
Alpha-2 Agonists (drug examples)
1. dexmedetomidine
2. Xylazine
3. Romifidine
4. Detomidine
26
Alpha-2 Agonists (6 Actions)
1. Sedation (rousable)
2. Analgesia
3. Anxiolysis
4. muscle relaxation
5. potent drug sparing
6. reversible effects
27
Alpha-2 Agonists (Adverse Effects)
1. CV effects (initial vasoconstriction followed by decreased sympa. output)
2. Diuresis, vomiting, reduced gi motility
- much more potent in cattle than horses
- sheep get pulmonary edema
28
Anticholinergics (dug examples, moa)
Drugs: atropine, glycopurrolate
MOA: muscarinic acetylcholine receptor antagonist (parasympatholytic)
29
Anticholinergics (5 Actions)
1. increased HR
2. bronchodilation
3. decreased secretions
4. decreased GI motility
5. mydriasis
-- no sedative or analgesic properties
30
Benzodiasepines (drug examples, moa)
Drugs: Diazepam, Midazolam
MOA: GABA receptor agonist
31
Benzodiasepines (6 Actions)
1. Anxiolytic
2. Amnestic
3. Muscle relaxant
4. Anticonvulsant
5. Mild drug sparing
6. Reversible
32
Benzodiasepines (adverse effects)
1. agitation, mania, disinhibition in some healthy adults dogs/ cats
2. not analgesic
3. mixed resp. between young and old animals
33
Opioids (Mu agonist) (drugs, actions)
Drugs: morphine, oxymorphone, hydromorphone
Actions: Analgesia, Sedation (dogs, rabbits ruminants) or Euphoria (cats, horses)
34
Opioids (Mu agonist) (Adverse Effects)
- minimal CV effets
- resp. depression
- hot cats, cool dogs
- reversible
- variable drug sparing (dog > cat > horse)
35
Opioids (Mu antag/ Kappa agonist) (all)
Drugs: Butorphinol
Short duration of effect (about 1 hour)
limited analgesia + good sedation
36
Opioids (Mu partial agonist) (all)
Drugs: Buprenorphine
acts v similar to agonist, but with less effect for longer
high affinity for receptor = non-reversible
37
T/F: Therapeutic Index is a measure of drug safety (LD50/ED50) and so a higher TI means a safer drug.
True
38
What is the Selectivity of a drug?
the preference of a drug for its respective ligand
| normally expressed as a comparison between two receptors
39
Potency vs Efficacy
Potency: the dose needed to create a specific effect (hig potency means lower dose for the effect)
Efficacy: the maximal effect produced
40
T/F: Antagonists work by producing no intrinsic activity at the target receptor.
T: A reverse agonist is different than an antagonist
41
Non-competitive vs competitive antagonist
Non-competitive: decreased binding affinity of agonist to R
Competitive: can overcome antagonims w/ high enough [agonist]
42
Effects of untreated pain?
- increased SNS activity (change in healing rate)
- decreased mobility --> muscle wasting
- splinting of chest muscles and diaphragm
- decreased GI motility and urinary retention
43
Non-pharmacological pain management mechanisms (7 ways)
1. handling
2. nursing care
3. weight optimization
4. warm (chronic) and cold (acute) therapy
5. Acupuncture
6. dress wounds
7. env. modifications (ramps vs stairs)
44
3 Drug types for pharmacological pain management
1. Opioids
2. NSAIDs
3. Local Anesthetics
Also, alpha-2-agonists (dex, xylazine), NMDA receptor antagonists (ketamine, amantadine), Gabapentine/ pregabalin, Tramadol
45
Opioids (pain management)
- moderate to severe pain
```
CNS: sedation in dogs -- euphoria in cats/ horses
resp. depression
decreased HR (vagal tone decrease)
urinary retention
cool dogs, hot cats
```
46
Local Anesthetics
- Lidocaine, Procaine
- reversibly block Na channels to prevent nerve trans.
- [drug] and volume affects intensity and duration of effects
Dose dependent toxicity of CNS and CV
47
NSAIDs
- both acute and chronic pain
- COX-1,2 inhibitors reduce prostaglandins
- not behavior modifying + oral formulations
48
What are the routes of administration of Opioids?
IV, IM, SQ, Topical (fentanyl patch)
49
What are the effects of NSAIDs
- anti-inflammatory
- anti-thrombosis
- analgesia
- anti-endotoxin
50
Why would you pair Xylazine (alpha 2) with morphine?
Xylazine will have synergistic effects
51
Indications for Ketamine, Amantadine?
- chronic pain, antihyperalgesic
52
Define: hernia
defect in wall of body cavity that allows protrusion of an organ or organs
53
Hernia anatomy
- Ring (connective tissue)
- Sac
- Contents
54
True vs False Hernia
True - congenital or degenerative process w/ intact hernial sac (peritoneum)
False - no hernia sac; usually acute/ traumatic
55
4 Causes of hernia
1. congenital
2. acquired/ degenerative
3. traumatic
4. incisional
56
Why treat a hernia?
- pain
- protect viscera
- adhesions
- abnormal organ fx
- strangulation, incarceration, perforation, sepsis
57
Incarcerations vs strangulation
Incarceration - impeded organ fx
| Strangulation - impeded blood flow
58
Herniopathy ( 3 parts)
- reduction of contents
- repair of defect
- prevent recurrence
59
Oral Absorption (Cats vs Ruminants)
Cats:
- shorter GI
- intermittent eating
- slow esophageal transit time
Ruminants:
- degredation/ metabolism in rumen
- rumen dilution effects
- pH variation of rumen vs saliva
60
Drug Metabolism (cats vs dogs)
Cats: no glucoronidation
Dogs: no acetylation
61
Drug Clearance (variations)
- dogs have higher GFR than horses causing higher clearance rates
62
ADME in Pediatric patients
A: decreased
D: increased % of TBW
M: decreased hepatic enzymes
E: decreased renal fx
63
ADME in Geriatric patients
A: decreased
D: decreased CO, albumin; increased body fat
M: decreased hepatocyte #
E: decreased renal fx
64
Loading Dose Eq
(target C)(Vd) / (F)
65
What is the most common approach to the equine abdomen?
ventral midline
66
Possible approaches to the Equine abdomen?
1. Ventral midline
2. Paramedian
3. Parainguinal
4. Laprascopic
5. Flank
67
Ventral Midline Approach (Equine)
- most common approach
| - Most colic surgeries (allows exteriorization of 75% of GI w/ minimal hemorrhage)
68
Linea Alba
- extends from xyphoid to prepubic tendon
| - dense connective tissue made from the ext. abdominal oblique and transverse abdominus aponeurosis
69
Closure of the ventral midline
1. Linea Alba
2. Subcutaneous Layer
3. Skin
70
Paramedian Approach
- 8-12 cm lateral to midline
- more hemorrhage (going through muscle)
- main holding layer for closing is the external sheath of the rectus abdominus
71
Parainguinal Approach
- 12-14cm incision
- gain access to the bladder (for stones)
- used for cryptorchid fixing
72
Laprascopic Approach
- most commonly done standing w/ sedation
| - ovariectomy, cryptorchidism, exploratory, close nephro-splenic space
73
Flank Approach
- not common in horses
| - ovariectomy, uterine torsion, small colon
74
Equine Rectal Exam (purpose)
- look for gas distension, tight bands, impaction, distended small intestine
75
How to prevent rectal tears?
- lots of lube
| - gentle palpation, relax w/ contraction
76
IV vs Inhalent Anesthetic Induction
IV: must have vein, titrate dose to effect, rapid onset, typically smooth, (alfaxalone, ketamine, propofol)
Inhalent: when IV is difficult, stressful for animal, CV depression, env. pollution (isoflurane, sevoflurance, desflurane)
77
T/F: Injectable anesthetics cannot be removed and overdose can be fatal
T
78
What is the end effect of redistribution of anesthetic in the body
redistribution is the mech by which anesthetics move from CNS to other tissues to allow for waking up (in IV anesthetics; inhalants will saturate)
79
Why do we pre-oxygenate?
1. hypoventilation or apnea
2. delayed intubation
3. sensitive to hypoxemia
80
Alfaxalone (cat, MOA, Effects)
Category: neuroactive steroid
MOA: enhances GABA at GABAa receptors
FDA: dogs and cats (IM formulation available)
Effects: min CV depres, mod resp depres, rapidly metabolized --> suitable for total IV anesthesia (dogs), recovery can be rough
81
Ketamine (cat, moa, effects)
Category: cyclohexanones
MOA: NMDA receptor antagonist uncouples sensory and motor systems
FDA: cats and primates (IV, IM, SQ, PO)
Effects: anesthesia and some analgesia, muscle rigidity, sympa NS stimulant, min, resp depression
82
Propofol
Category: hindered phenol
MOA: enhances GABA at GABAa receptors
FDA: dogs
Effects: mod. CV and Resp depression (fast admin = apnea), anesthesia and no analgesia, caution for cats, smooth recoveries
83
IV Anesth. Maintenance (pros/ cons)
Pros:
- increase depth quickly
- limited costs/ overhead
- simple/ can be made complex
Cons:
- reduction in depth can be slow
- can be rough recovery
84
Inhalant Anesth. Maintenance (pros/ cons)
Pros:
- depth easily controlled
- recovery requires no metabolism
- admin via ET tube
- {drug} can be measured
Cons:
- need anesthetic machine
- atm. pollution and toxicity
- limited portability
85
Inhalant Maint. (common agents)
- Isoflurane
- Sevoflurane
- Desflurane
86
Minimum Alveolar Concentration (MAC)
- alverolar [inhaled anesthetic] at which 50% of subjects fail to move in response to supramaximal noxious stimuli
- ED95 =~ 1.3 MAC
87
Factors that decrease MAC
- sedatives, analgesics, inj. anesthetics
- systemic disease, hypothermia
- increasing age, pregnancy
88
Inhalant Solubility
Iso > Sevo > Des>
lower solubility = fast onset/ offset, but less potent
89
Inhalant Clinical Effects
CNS depression
NOT analgesic
dose dependent decrease in CO and BP (vasodilation and negative inotropy)
90
PE signs of dehydration (hydration parameters)
1. Skin Turgor
2. Mucous Membrane Moisture
3. Eye Position
4. Body Weight
91
How does BCS affect skin turgor test?
fat holds onto water so BCS 8 dog can be dehydrated without presenting turgor test positive
92
How to correctly interpret BW for dehydration status?
only use for day to day measurements
93
Determining Deficity Volume
% dehydration (0.05 - 0.12) x BW(kg)
94
Crystalloid Fluids
LRS, Plasmalyte, 0.9% NaCl
| good when patient 165>Na>130
95
Maintenance Fluid Rates
2-4mL/kg*hour
96
Potassium Supplementation (fluids)
max safe = 0.5mEq/ kg*hour
| higher blood [K] means lower mEq/L KCl administered
97
Colloids in Fluid Therapy
Colloids - high MW molecules that largely remain IV to generate oncotic pressure
NAtural: Albumin
Synthetic: Hetastarch, Vetstarch
98
Colloids (possible adverse effects)
- coagulopathy
- increased risk of renal injury
- pruritis
- anaphylaxis (rare)
99
Why give IV fluids in anesthetized patients?
- replace fluid loss (evaporation)
- meet maintenance requirements
- compensate for losses (hemorrhage)
- replace deficits
- ultimate goal is to maintain tissue perfusion
100
Pre-existing fluid deficits and anesthesia?
try to rehydrate prior to anesthesia as dehydration may become more severe during surgery
101
Why give isotonic crystalloids?
- can give large columes
- minimal electrolyte imbalances
- bicarb precursors minimize pH changes
102
What's the problem with the traditional fluid plan (10-20mL/kg*hour)
- rates are likely excessive
| - leads to fluid accumulation (interstitial edema, decreased 02 transfer)
103
Why is there altered fluid balance during anesthesia?
- change in vascular tone/ blood pressure
- decreased urine production and output
- degradation of glycocalyx (endothelial protective layer) promotes extravasation
104
What is the most effective type of opioid analgesic?
- mu receptor agonists
105
Do alpha-2-agonists (Xylazine, dex) have a significant effect on the CV system?
yes
106
Can you use Xylazine to produce sedation w/out ataxia in a horse?
No
107
Meloxicam can be used as an analgesic in an aged cat with renal failure?
No, NSAIDs further reduce GFR making it not suitable
108
Glycopyrrolate offsets the vagally-mediated decrease in heart rate produced by initially giving morphine?
True
109
What drug combination would be the MOST appropriate choice for pre-anesthetic medication in a friendly but extremely hyperactive 12-month old 20kg dog prior to elective ovariohysterectomy (OVH) in student surgery lab?
Opioid (painful surgery) + Ace (anxiolytic/ sedation mainly)
110
Give an example of an ASA 1 animal.
18 month-old dog with a skin laceration
any minor wound that poses no threat to the animal's wellbeing overall
111
Which of the injectable benzodiazepines would be the best choice for IM administration?
Midazolam
Diazepam is not for IM as it is poorly soluble in water
112
Morphine causes a non-specific mast cell degranulation
True
113
Does Acepromazine do analgesia?
no
114
Does smaller suture mean tighter knots?
yes
115
Generally, you should always try to use the smallest suture that is suitable to use?
True
116
Function of breathing circuits
- deliver O2 and anesthetic; remove O2
| - provide means of ventilation
117
Minute Ventilation
(Tidal Volume) * (Respiratory Rate)
118
What is the most popular type of non-rebreathing system?
Bain Circuit
119
Non-rebreathing system facts
- low resistance
- simple and inexpensive
- rebreathing prevented by high gas flow rate
- used w/ smaller animals (<10kg)
120
What type of rebreathing system would you use in smaller animals?
Non-rebreathing system
121
Minimum flow rate for a non-rebreathing system
FGF of 200 mL/ kg*min with an overall minimum of 500mL/ min
122
Bain Circuit facts
- inspired [anesth] = vaporizer setting
- very little time lag
- Gas is cool and dry (heat and h2o loss)
- + pressure ventilation possible
123
Rebreathing Circuit facts
- ability to remove CO2 from exhaled gases prior to rebreathing
- more parts/ complexity
- can use much lower gas flow rates
124
Track the path of a Circle System circuit
yeah . boi
125
Reservoir Bag
- provides a means by which to ventilate patient
- allows visible and tactile obersvation of breathing
- bag size = 5 * Tidal Volume
126
CO2 absorption (rebreathing)
- needs H2O
- Ca(OH)2 is main chemical
- Signs of exhaustion = granules harden, color change
127
In a rebreathing circuit how should flow rate and minute ventilation match up?
- They should be roughly equal during anesthesia
| - As anesthesia begins, it is ok to have higher flow rate to prime the line with anesthetic
128
Scavenging Waste Gases (anesthetic circuits)
- use a charcoal waste canister to collect the gases
129
Breathing Circuit hazards
- disconnection issues
- increased deadspace
- pressure buildup in circuit
130
Why place an ET tube?
- maintain patent airway
- ability to deliver gas
- ability to manually ventilate
- some protection against aspiration
131
Two cuff types
- high pressure, low volume
| - low pressure, high volume
132
Rule of Thumb: you should always try to place the largest ET tube that comfortably fits in the trachea
True
133
Where can a misplaced ET tube go?
Esophageal
| Pharyngeal
134
Intubation techniques (species differences)
- Blind (horses, rabbits)
- Manual (cattle)
- Direct Visualization (most domestic species)
- using a guide tube (difficult to visualize)
135
Laryngeal Sensitivity Scales
cats >> dogs > horses
136
What species is particularly sensitive to largyngospasm? How will you treat this?
Cats; treat by applying lidocaine to the arytenoids prior to intubating
137
How will you secure the ETT?
- gauze tie, plastic tube
| - tie onto tube ( do not constrict the tube and occlude)
138
Intubation complications
- upper airway trauma
- tracheal trauma (overinflated cuff)
- tracheal tears
139
Confirming ET tube placement
- visual
- bag movement
- fogging of tube
- gas out of tube
- palpation
140
What are Halsted's principles (6 of them)?
- good surgery practices
- gentle handling of tissues
- aseptic technique
- preservation of blood supply + careful hemostasis
- removal of dead space
- avoidance of tension
- accurate tissue apposition
141
What are the two types of suture needles?
1. Taper - sensitive tissues (GI, Bladder, muscle)
| 2. Cutting - easily cuts through increased collagen tissue
142
Things to consider in suture choice?
- rate of tensile strength loss (PDS - longterm strength)
- knot security (primary site of failure)
- handling characteristics
- tissue reactivity (suture granuloma)
143
Surgical Site Infection (SSI)
- not the same as tissue reactivity
- inflammation =/= infection
- amount of suture used is inversely related to number of bacteria needed in SSI
- use monofilament if possible
144
Suture Tension
- excessively tight suture can reduce blood supply
- too loose --> incision gap
- goal: hold tissue in apposition while leaving room for inflammation
145
Suture Handling Characteristics
- material memory
- tendency to return to original shape after deformation
- monofilament has more memory than multifilament
146
What color tank is oxygen?
green
147
Function of the pin index system (anesth. machine)
safety feature to prevent connection of wrong gases
148
O2 flush valve
- deliver 35-70 L/ min at 50-60 psi (very high flow and pressure)
- used to check or flush circuit when patient is disconnected
- never use on non-rebreathing circuit --> death
149
function of the control valve
- reduce pressure from 50-60psi --> 15psi
