Clinical induction and maintenance

What induction agents are there?

propofol

alfaxalone

ketamine

inhalation agents

others (thiopental, GGE, etomidate, po

What should you consider when selecting induction agents for dogs?

Wide variety of shapes sizes

Obesity

Brachycephalics

Temperament variable

Can induce to effect

IV access easy

What should you consider when selecting induction agents for cats?

Smaller in body mass

Can be ‘spikey’

IV access more challenging

Mask sub-clinical disease well

Care with repeated doses of propofol

Can induce to effect

What should you consider when selecting induction agents for horses?

Wide variety of shapes and sizes

Flight reaction to stressful situations

Large body mass

IV access easy

Do not lie down after sedation/ do not want to remain recumbent when recover

Cannot easily administer to effect

What should you consider when selecting induction agents for farm animals?

Must follow relevant food safety legislation → extremely limiting!!!

What injectable induction agents are licensed in which animals?

What are the routes of administration of different injectable agents?

propofol —> IV

alfaxalone —> IV + IM

ketamine —> IV, IM + transmucosal

thiopental —> IV

etomidate —> IV

What maintenance agents are there?

inhalation agents (isoflurane, sevoflurane)

propofol

alfaxalone

ketamine

others (thiopental, other inhalation agents —> halothane, desflurane)

What maintenance agents are licensed in which animals?

What determines how much inhalation agent is needed?

minimum alveolar concentration

How can injectable agents be administered?

bolus technique

infusion

What should you consider when administering maintenance agents to dogs + cats?

Dose dependent CV (vasodilation) and respiratory depression

Thermoregulation obtunded

What should you consider when administering maintenance agents to horses?

Like dogs and cats but proportionally much greater CV and respiratory depression

What should be done alongside maintenance of anaesthesia?

Analgesia

• Local blocks

• Opioids

• Ketamine

• α2 agonists

• Lidocaine

Positioning (cause myopathy in horses)

Monitor/maintain temperature

Monitor vital signs

What effect does anaesthesia have on the airway?

What can be used to manage the airway?

facemask

endotracheal tube

laryngeal mask (supraglottic airway device)

What are the uses of supraglottic airway devices (laryngeal mask/V-gel)?

bronchoscopy

cats

rabbits

What can be used in laryngeal spasm (cats/pigs/sheep/goats)?

use intubeaze/lidocaine spray

apply directly to larynx to prevent spasm

What can be done during difficult intubation?

Small animal

• Urinary catheter- bougie

• Stylet

• Tracheostomy

Large Animal

• Stomach tube- bougie

• Stylet

• Endoscopic guidance

• Tracheostomy

What can be used for emergency airway access?

urinary catheter

needle into trachea

tracheostomy