How to Induce & Maintain Anesthesia

Question 1

what are routes of admin of anesthesia

Answer 1

IM

IV

inhalational

Question 2

when are IM inductions used and what is used

Answer 2

ex. feral cat

ketamine based

Question 3

when are inhalation induction agents used

Answer 3

some exotics, small mammals

cats, dogs, foals occasionally

Question 4

what are factors affecting the route of administration

Answer 4

1. access to vein
2. temperament of animal
3. speed of induction required

Question 5

what factors influence induction

Answer 5

1. speed of injection (too fast, too slow, premedication alters)
2. hypalbuminemia

Question 6

how do alpha 2 agonists affect the induction speed

Answer 6

there might be a slower response to the induction agent

Question 7

how does hypoalbuminemia affect induction

Answer 7

less albumin in the blood for the drug to bind to –> propofol is highly protein bound –> less albumin there might need a lower dose than expected

Question 8

what are medications used for co-induction

Answer 8

midazolam (beware excitation)

fentanyl

ketamine

Question 9

what are the purposes of co-indcution agents (2)

Answer 9

1. minimize doses
2. minimize CVS effects

Question 10

how is anesthesia maintained

Answer 10

inhalation agents most common

injection (IV)

Question 11

why are IV anesthetics not prefered for maintanence

Answer 11

can be expensive and they depress ventilation

Question 12

what can be used to supplement anesthesia and add analgesia

Answer 12

1. fentanyl
2. ketamine
3. lidocaine

Question 13

what are the options for airway management (3)

Answer 13

1. mask
2. supraglottic airway
3. endotracheal intubation

Question 14

what are the disadvantages of using mask induction

Answer 14

1. risk of leak of gases
2. difficult to hold in place
3. doesn’t protect against aspiration

Question 15

when is mask induction helpful

Answer 15

very small patients

Question 16

what are laryngeal masks

Answer 16

intermediate between mask and ETT

sits over larynx, doesn’t enter trachea

Question 17

how can ET tubes be inserted

Answer 17

orally

nasally

Question 18

what are the benefits of ETT

Answer 18

1. allows patent airway (relaxation of tissues)
2. allows anesthesia to support ventilation
3. protect against aspiration of material (regurgitation, hemorrhage, saliva)

Question 19

what are the methods of ET intubation

Answer 19

blind

manually assisted

laryngoscope guided

bronchoscope guided

Question 20

what are cats prone to when intubating with an ET and how do you prevent it

Answer 20

laryngospasm

lidocaine spray

Question 21

how are horses intubated

Question 22

how do you tell if the tube is in the trachea (5)

Answer 22

1. visual conformation
2. condesation in trasparent tubes
3. breathing system bag movement
4. palpation of tube
5. capnography

Question 23

what are the steps following intubation

Answer 23

1. secure tube
2. inflate the cuff (just enough to stop leak)

Question 24

should you always intubate a dog?

Answer 24

easy to intubate ususally

airway may be affected by the anatomy

regurgitation more likely in some dogs

Question 25

should you always intubate a horse?

Answer 25

maintain airway well evidence in cats may increase anesthetic risk so for short procedures/healthy animals not necessary to intubate

Question 26

should you always intubate a pig/rabbit?

Question 27

should you always intubate ruminants?

Answer 27

high regurgitation risk intubation very important if GA

Question 28

how long should the ETT be

Answer 28

not past point of the shoulder (can enter 1 bronchus)

Question 29

what are the risks of ETT intubation (8)

Answer 29

1. laryngospasm 2. trauma/swelling (post op) 3. endobronchial intubation 4. kinking ETT 5. obstruction with secretions (clots of blood) 6. obstruction of bevelled end 7. tracheal stenosis (rare) 8. tracheal rupture (rare)

Question 30

what are 2 good practices before induction

Answer 30

1. place IV line 2. pre oxygenate (if not stressful)

Question 31

how would you induce and maintain anesthesia in a 2 yo healthy lab for an ovariohysterectomy acepromazine + methadone IM pre med

Answer 31

IV propofol induction isoflurane maintenance

Question 32

how would you maintain anesthesia in a 7 yo GSD with a ruptured splenic mass poor pulse, pale methadone pre med

Answer 32

propofol induction in combo with medazolam so we have to use less propofol

Question 33

how would you induce a bulldog for airway surgery low dose alpha2 + methadone pre med

Answer 33

concerned about aspiration, and want quick recovery definetly pre-oxygenation induction: rapid in sternal recumbency until tube cuffed, if regurgitates, head down (drain) and have suction ready

Question 34

what is IPPV

Answer 34

intermittent positive pressure ventilation

Question 35

why is IPPV needed for anesthesia

Answer 35

anesthesia depresses ventilation or pathophysiology may require ventilation (diaphragmatic rupture)