Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

My 2016 RUSVM Anesthesia > Premedication Dr. Ambrisko > Flashcards

Premedication Dr. Ambrisko Flashcards

1
Q

what is sedation

A

induction of CNS depressioun & drowsiness by use of drugs (not unconsciousness)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is tranquillization

A

used somewhat synonymously to sedation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is analgesia

A

aka antinociception

loss or reduction of pain sensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is general anesthesia

A

controlled & reversible loss of consciousness, nociception & mobility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is balanced anesthesia

A

using multiple drugs to achieve the goals of general anesthesia w/ less side effects than using a single agent (e.g. a combo of an anesthetic, analgesic & muscle relaxant)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is dissociative anesthesia

A

form of general anesthesia characterized by a catatonic state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is neuroleptanalgesia

A

state similar to general anesthesia produced by a sedative & an analgesic agent (e.g. phenothiazine + opioid)

  • very deep sedation + very deep pain mgmt*
  • usually no unconsciousness*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is inhalationa anesthesia

A

general anesthesia using inhalational drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is TIVA

A

Total Intravenous Anesthesia

achieved soley by injectable drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is PIVA

A

combination of injectable drugs & lower concentration of inhaled anesthetic agent

basically balanced anes!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is local anesthesia

A

loss of sensation in a smaller, circumscribed body area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is regional anethesia

A

loss of sensation in larger but limited body area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is purpose of premedication

A

sedation & analgesia

anesthetic sparing effect

reduction of stress & catecholamine release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

types of premedication d2rugs

A

anticholinergics

alpha2 agonists

phenothiazines & butryophenones

benzodiazepines

opiods

muscle relaxants

antihistamines & antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what do anticholinergics do

name 2

A

inhibit PSNS

antagonists on muscarinic ACh receptors

Atropine

Glycopyrrolate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Atropine

solubility

route

A

crosses BBB & placental barrier

lipid soluble

IM, SC, PO, IV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Glycopyrrolate

solubility

route

A

onset slower & duration longer than atropine

doesn’t cross BBB & placenta

H2O soluble

IM SC, PO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

indications for use of anticholinergics

A

Routine use not recommended

incr HR

  • opioid induced bradycardia*
  • tx of reflex bradycardia*
  • young & brachycephalic breeds*

decr salivation & bronchial seccretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

contraindications for anticholinergics

A

tachycardia

hyperthyroidism

most cardiac dz except when tx bradycardia

narrow angle glaucoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

CV side effects of anticholinergics

A

2° AV block

bradycardia

cardiac arrest

tachycardia

hypertension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what happens if you combine an alpha2 agonist + atropine

A

vasoconstriction

tachycardia

hypertension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

T or F

Routine co-administration of an alpha2 agonist & anticholinergic is contraindicated

A

TRUE!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

other effects of anticholinergics

A

relaxes lower esophageal sphincter (regurg)

mydriasis (may trigger acute glaucoma)

bronchodilation (increases airway dead space)

dries airway secretions

Intestinal paralysis (may cause colic in horses)

CNS toxicity: crosses BBB may cause sedation, coma

Tx w/ physostigmine (not neostigmine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is special about rabbits & atropine

A

most rabbits have high levels of atropinase enzyme so atropine not effective

Glycoyrrolate is preferred!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are alpha2 agonists MoA
**strongest available sedatives (except pigs)** have important CV side effects **have specific antagonists** **competitive agonist of alpha2 adrenergic receptors** **suppress NE release by negative feedback**
26
what are effects of alpha2 receptors
cause sedation analgesia reduction of sympathetic outflow from brain decr stress response
27
where are important (to anesthesia) alpha2 receptors located & *what do they do*
wall of arteries & veins (along with alpha1) - *mediate vasoconstriction* pancreas ß cells - *inhibit insulin release ⇒ **hyperglycemia***
28
what are **CNS effects** of alpha2 agonists
**sedative effect** spp specific: **strong: dogs, cats, horses, ruminants** **weak: pigs (***alpha2 + benzo + opioid best combo)* **some anlagesic effects** *synergistic w/ opioids* **muscle relaxation**
29
what are **CV effects** of alpha2 agonists
**strong vasoconstriction ⇒ reflex bradycardia ⇒ low CO & tissue perfusion**
30
what are **respiratory effects** of alpha2 agonists generally ## Footnote ***_in horses_***
**mild respiratory depression** ***_In horses: upper airway resistance increases_*** * ***_relaxation of larynx, pharynx & narse_*** * ***_head dropping in horses: nasal edema_*** * ***_V/Q mismatch_***
31
what are **respiratory effects** of alpha2 agonists in ruminants
Bronchoconstriction V/Q mismatch lung edema & hypoxemia **_any alpha2 in any ruminant spp_** ***_xylazine in sheep is contraindicated_***
32
xylazine spp differences***,*** ***issues*** duration
Equine: better than for other spp ***intraarterial injection may cause excitement (seizure) Don't do it!*** ***Cattle: sensitive ≈ 10% of horse dose needed*** ***may cause uterine contraction & abortion in cattle*** Dogs: less preferred alpha2 for this spp duration: 20-40 min
33
indications for use of alpha2 agonists
**sedation of aggressive animals**
34
contraindications for alpha2 angonists
hemodynamic instability not suitable for risk patients
35
**Alpha2 agonists**/*antagonists (*reversal agents)
**Xylazine**/*Yohimbine (LA w/ exceptions)* **Dexmdetomidine/***Atipamezole* **Medetomidine** **Detomidine** **Romifidine**
36
In the order of highest to lowest, what are the alpha2/alpha1 receptor specificity of the alpha2 agonists?
Dexmedetomidine \>\>\> detomidine \> xylazine the main effects are very similar even with the specificity differences
37
In the order of highest to lowest, what are the alpha2/alpha1 receptor specificity of the alpha2 *antagonists*?
*atipamezole \>\>\> yohimbine \>\> tolazoline* yohimbine & tolazoline are "dirty drugs" acting on other receptors & have many side effects **Use atipamezole to antagonize any alpha2 agonist whenever possible, give IM except for emergency (IV)**
38
Medetomidine
**Not available in US** **50:50 racemic mix of demedetomidine & levomedetomidine** *Dexmedetomidine 2 x as potent as medetomidine*
39
Dexmedetomidine
most specific drug for alpha2 receptors mostly for SA use but may be used in horses
40
Detomidine RoA Duration
LA use IM, IV, sublingual 90-120 min
41
Romifidine use RoA duration
used in horses IM, IV 45-90 min ***thought to produce less ataxia than xylazine, preferred for standing dental surgery***
42
Alpha2 agonists In order of duration of action (minutes) from shortest to longest
Xylazine (20-40) \< Romifidine \< (45-90) \< Detomidine (90-120) \< Dexmedetomidine (30-120)
43
What are the premeds in the phenothiazine class how do they work?
**Acepromazine** Chlorpromazine, etc antagonist of multple receptor types: Dopamine Serotonin Alpha1 Histamine
44
Acepromazine duration of action
4-8 hours ## Footnote ***48 hours in liver pts***
45
CNS effects of phenothiazines
*weaker sedative effects compared to alpha2 agonists* **NO analgesic effect** antiemetic mild respiratory depression
46
CV effects of phenothiazines
**Alpha1 antagonist:** *causes vasodilation & hypotention*
47
other effects of phenothiazines
antihistaminic anty arrhythmogenic ***inhibits platelet function*** ***Penile prolapse in horses*** ***seizures?***
48
**Indications** for phenothiazines ## Footnote *Contraindications*
**mild sedation for premed or post op** **prevent/tx opioid dysphoria** **prevent emesis by morphine** **sedation of dogs w/ laryngeal paralysis** **enhance sedation of xylazine in horses** * Hypovolemia/hemodynamic instability* * vWD in dobes* * Boxers (bradycardia)* * Breeding stallions (penile prolapse)*
49
What drug family is similar to phenothiazines drugs in family spp most used with effects/*side effects*
Butyrophenones Droperidol & azaperone (Stresnil®) **Azaperone used for Pigs** sedative similar to aceprom less hypotensive, stronger antiemetic than aceprom less platelet effect antiarrhythmogeni, not seizurogenic *More likely to cause behavioral side effects*
50
Characteristics of benzodiazepines
**GABA receptor agonists** Sedative, anticonvulsant, muscle relaxant effects Minimal CV & respiratory effects **NO ANALGESIA!**
51
What are GABA receptors
GABA **main inhibitory neurotransmitter in CNS** Benzodiazeines allosterically activate (no maximal effect) Site of most anesthetics (notable **exception is ketamine**!)
52
Benzodiazepines used in vet med
**_Agonists_** **Midazolam** Diazepam Zolazepam (Zoetil or Telazol) **_Antagonists_** **Flumazenil**
53
spp specific sedation effects of benzos
**Dogs, cats, horses: disorientation, excitation may occur when used alone** **Better sedative effects in ruminants, camelids, pigs, birds & ferrets** Rarely used alone
54
indications for use of benzos
as Premed: *Combine with opiods a/o alpha2 agonists* for Induction: *Combine w/ dissociatives, barbiturates or propofol* ***Tx of seizures***
55
Diazepam characteristics RoA duration cautions
Lipid soluble formulated in propylene glycol or lipid emulsion **chemical compatibility limited** **IV,** *poor absorbtion & pain IM* hepatic metabolism *1-4 hours* _Oral may cause liver damage in cats_
56
Midazoam characteristics RoA duration caution
Water soluble (no propylene glycol) Good chemical compatibility more potent than diazepam hepatic metabolites inactive IM, IV or TM
57
Opioid characteristics
**strongest available systemic analgesics** **best choic for tx of acute pain** **decr anesthetic dose** **MINIMAL CV effects** **Suitable for most risk pts**
58
Types of opioid receptors
Mu (µ): strong analgesis, resp. depression, dependency Kappa (K): weaker analgesia Delta (ð): weaker (human)
59
classification of opioids
Full agonists: activate receptors & trigger full tissue response Partial agonists: activate receptors but do not trigger full tissue response even at high doses (butorphanol) Antagonists: bind to receptors but do not activate them Mixed agonist antagonist: activate one receptor type & inhibit another one e.g. Butorphanol mu antagonist & kappa agonist
60
CNS effects of opioids
**Analgesia** **decr MAC** spp dependent: primates \> dogs \> cats \> pigs \> horses *may incr MAC in horses!*
61
T or F Opioids may trigger or inhibit vomiting
TRUE stimulate CRTZ outside BBB triggering vomiting then cross BBB & inhibit water soluble opioids (**morphine**) enter BBB slowly: **cause more vomiting** **lipid soluble (fentanyl) enter BBB fast: no vomiting**
62
CV effects of opioids
**Minimal CV effects** **No direct negative inotropy or vasodilation** **Suitable for most risk pts**
63
Respiratory effects of opioids
May depress Antitussive effect May inhibit airway protective reflexes (coughing)
64
GIT effects of opioids
defecation obstipation
65
Other effects of opioids
Hypothermia ## Footnote **Cats: post OP hyperthermia** **Myosis (dogs), mydriasis (cats)** **inhibition of urination** **noise sensitivity**
66
indications for opioids
Premedication alone or in combo Perioperative analgesia Tx acute & chronic pain
67
RoA of opioids
IM, SC IV/CRI PO Epidural/spinal Transdermal (fentanyl) Oral (buprenorphine for cats)
68
Morphine
Preferred **full mu agonist** water soluble slow onset (30-45min) long duration (4-6 hr) **May cause hitamine release esp post high IV dose**
69
hydromorphone, oxymorphone
full mu agonist 4 hr duration No histamine release
70
Methadone
similar to hydromorphone ## Footnote **also acts as NMDA antagonist!**
71
Fentanyl
full mu agonist **fast onset, short duration (15-20 min)** no histamine release *may accumulate after long infusions*
72
Remifentanil
similar potency to fentanyl ## Footnote **very short acting (5 min), does not accumulate**
73
Butorphanol
**mu antagonist, kappa agonist** **_may worsen pain in case of strong pain_** **weak & short acting analgesic** *may antagonize full mu agonists*
74
Buprenorphine
partial mu agonist ## Footnote **stronger analgesic than butorphanol but weaker than full mu** **slow onset (20-40min IV) long acting 6-8 hours** ***often given to cats because may cause less excitation than full mu agonists*** ***Owners can give TM***
75
Tramadol
**Weak analgesic** **hepatic metabolite is mu opioid agonist** **tramadol itself inhibits NE & serotonin reuptake (analgesia)** **PO**
76
Opioid antagonists
**Naloxone** 30 min duration **Naltrexone** long acting (≈10 hrs) used to antagonize wild animals after long acting opioids e.g. carfentanyl or etorphine
77
Muscle relaxants
Centrally acting: **Guaifenesin** Peripherally acting **NMBD's** **Dantrolene**
78
Guaifenesin
aka glyceryl guaiacolate **(GG**) ## Footnote **large animal anesthesia** **minimal CV or resp effects** **NO ANALGESIA or Unconsciousness SHOULD NOT be used as sole agent!** **most common: 5% GG in dextrose** ***\>10% = thrombophlebitis*** ***Part of TIVA "Triple Drip" : GG + alpha2 + ketamine***
79
Dantrolene
muscle cells ## Footnote **used for tx Malignant hyperthermia (pigs mainly)**

My 2016 RUSVM Anesthesia (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions