Vet 267 inhalants and anesthetic induction

what are inhalant anesthetics
inhalant anesthetics can be used as induction agents as well as for the maintenance stage of anesthesia

what inhalant anesthetics are used?
sevoflurane, isoflurane, Nitrous Oxide, Halothane

what color is nitrous oxide color coded?
blue

what are the advantages of using inhalants as induction agents?
quick recovery time, NOT metabolized by liver or kidneys

what are the disadvantages of using inhalants as induction agents?
periods of excitement, regurgitation, aspiration, airway obstruction

what are the risks of mask induction?
potential for waste gas, patient may become overly stressed, struggling releases epinephrine and predispose the animal to cardiac arrhythmias, should only be used on calm or sedated patients, bad choice for animals that are excited or aggressive

what systems of the body are most affected by mask induction?
respiratory, cardiovascular

what is the proper way to induce with a mask?
place snug mask on face, start at just oxygen for several minutes to increase O2 in blood, slowly increase the amount of gas anesthetic

what are the advantages of chamber induction?
used for fractious or fearful animals, keeps staff safe

what are disadvantages of chamber induction?
cannot access in an emergency, epinephrine release, employee exposure, potential for airway exposure, smaller patients

what is MAC?
Minimum alveolar concentration

what is MAC used for?
used to determine the potency of the inhalant gases

what is the surgical depth of MAC?
1.5x MAC

lower MAC means what?
lower % is needed to cause anesthesia

what are the side effects of Isoflurane?
respiratory depression, hypotension, dose-dependent, irritation of larynx upon mask induction

what are advantages of Isoflurane?
induction and recovery is rapid, minimal metabolism by the liver, maintains CO (heart will keep beating as strong as before), good muscle relaxation

disadvantages to using Isoflurane?
employee exposure to gas through exhalation when waking and at induction, no analgesia

what color is Isoflurane coded?
purple

what is the MAC of iso?
MAC 1.3%

what is the induction % for iso?
3-5%

what is the maintenance for iso?
1.5-2.5%

what is Sevoflurane?
fastest acting inhalant because it is less soluble

what is the MAC of Sevoflurane?
MAC 2.3%

what is the color code of sevo?
yellow

how are iso and sevo different in dogs?
Dogs > iso 1.3% vs Sevo 2.3%

what is a big difference between iso and sevo?
needs higher concentration of sevoflurane vs. isoflurane to achieve appropriate depth of anesthesia

what is nitrous oxide color coded?
blue

what is the induction rate of sevo?
4-6% (when used alone)

what is the maintenance dose of sevo?
2.5-4%

what side effect is halothane most commonly associated with?
hepatic necrosis, and with Malignant hyperthermia

what color code is Halothane?
red

what is the MAC of halothane?
0.9%

what are the difference between IM and IV induction?
IM has a longer onset of action, IM has a longer duration, IM has a slower recovery

what is anesthetic induction?
process by which an animal leaves the normal conscious state and enters an unconscious state

what is the key points to patient care during induction?
position patient comfortably during anesthetic event, lubricate eyes, if one lung is abnormal then place the normal side up, do not move patient while connected to the machine

IV induction is usually given?
to effect; s/a propofol

how do you give an IV injection for induction?
use smallest dose necessary, give till effect, keep light but deep enough to intubate

with Ket/Val how do you give it IV?
given much slower than propofol, may not use as much

what drugs CANNOT be given IM?
Diazepam, thiopental, propofol

examples of injectable induction drugs
ket/val, telazol, propofol, etomidate, barbiturates

what do you avoid with Thiopental?
avoid in sighthounds and other thin animals, patients w/ low TP, underweight, high glucose, acidosis

actions of thiopental?
non analgesia

what is thiopental infused with?
lidocaine and saline

thiopental administration?
use catheter, infuse with saline if leak occurs to decrease risk

why is apnea sometimes prolonged after barbiturates are administered too rapidly?
barbiturates suppress the respiratory center, making it insensitive to CO2

what drug can be safely used in sight hounds?
Methohexital

what in Pentobarbitol?
used for euthanasia, intermediate acting

what is phenobarbital?
used for seizures, long acting

commen agents of Cyclohexamines?
ketamine and tiletamine

MOA of cyclohexamines?
disrupts nerve impulses by stimulating some parts of CNS and depressing others

effects of Cyclohexamines
profound amnesia superficial analgesia, catalepsy, psychosomatic effects such as hallucinations, confusion, agitation and fear

what goes with Catalepsy?
cyclohexamines

what is another word for cyclohexamine?
dissociative anesthesia

what gets increased with cyclohexamine?
heart rate, blood pressure, salivation, CSF pressure, apneustic breathing system

what species are cyclohexamines most popular
cats, many exotic species, and intractable patients

how are cyclohexamines metabolized?
by the liver and excreted by the kidneys

contraindications of cyclohexamines?
major organ dysfunction, heart disease, seizures, increased CSF or intraocular pressure

what is Ketamine-Diazepam dosed at?
1mL per 20lbs

advantages of Ketamine-Diazepam?
muscle relaxation of diazepam offsets muscle rigidity of ketamine

disadvantages of Ketamine-diazepam?
must be given IV

what is Tiletamine combined with?
combined with zolazepam (Telazol)

what does Zolazepam do?
reduce the risk of seizures during recovery, provides some skeletal muscle relaxation

what is Xylazine reversed with?
Yohimbine

when using xylazine/ketamine combo, the smallest dose of xylazine per kg is required in what species?
ruminants

Is ketamine an analgesia?
not an adequate analgesia by itself

what does propofol look like?
the resultant milky-white compound is a very good medium for bacterial growth

Propofol blue lasts how long?
6hr – 1 day

Propofol 28 green has a shelf life of how long?
28 days

cardiovascular effect of propofol?
bradycardia

is propofol an analgesia?
No, it does not provide analgesia

how often can propofol bolus be repeated?
IV every 3-5 minutes to maintain anesthesia for up to 20 mins

what is TIVA?
total intravenous anesthesia

contraindications of propofol?
respiratory disease

key things to know for Etomidate?
short acting, minimal changes RR + HR, NOT AN ANALGESIC, it is an induction agent

what is Alfaxalone?
a neuroactive steroid – analogue of progesterone, used as an induction agent

shelf life of Alfaxalone?
6 hrs

what does TIVA mean?
Total intravenous anesthesia

what does CRI stand for?
Constant Rate Infusion

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