Inhalant anesthetics, Recovery, Of the Dog, Fluid Therapy

In what part of the brain do inhalants cause unconsciousness?

cerebral cortex

In what parts of the brain do inhalants cause amnesia?

hippocampus, amygdala

In what part of the brain do inhalants cause unconsciousness?

cerebral cortex

In what parts of the brain do inhalants cause amnesia?

hippocampus, amygdala

inhalation agents produce anaesthesia via their effects in the _____

CNS

Does anesthesia go into the body tissue or brain first?

body tissue

Will increasing the flow rate of O2 increase the rate the inhalant and concentration?

yes

What is maintenance O2 rate for SA?

30 ml/kg/min

How do you calculate alveolar ventilation?

RR x alveolar vol

Using blood/gas partition coefficient, explain why we prefer to use iso rather than sevo?

iso has a lower blood/gas PC, meaning it takes a shorter time to reach the required concentration in the body than sevo

What are the 3 benefits of using an agent with a low PC?

more rapid induction, more precise control of depth, more rapid elimination of agent

oil/gas PC correlates directly with _____

anesthetic potency

Most anesthetic agents used have high or low oil/gas PC?

high lipid solubility

does a high CO encourage or hinder the alveolar PP rise?

hinders it

What is MAC and what does it tell us?

mean alveolar concentration, what percentage of the alveoli are taken up with the agent when stimulus is stopped

How can we get an idea of the concentration of anesthetic agent in the brain

look at the end tidial of the agent in the alveoli

If you Fi is 1.9 and your Et is 1.7, what does this tell you?

0.2 is being taken up by the body

If the patient has greater surface area, MAC will go ____

up

If MAC is the desired concentration in the alveoli of an agent, how will a young vs an old dog impact MAC?

young dog → increases MAC → since it has higher CO → requires higher percentage of agent to reach desired depth

what effects do inhalants have on cardiovascular systems?

neg inotropy, decreased CO, peripheral vasodilation, decreased BP

Why do inhalants cause increased intracranial pressure?

they cause increased cerebral blood flow (CBF)

What are the effects on the liver and kidney from both iso and sevo?

mild decrease in BF to kidney and liver, with inhibition of hepatic drug metabolism

What is the critical time period where death can occur after anesthesia?

0-3hr

What are some concerns with hypotension in equines during surgery?

myopathy/neuropathy, post-anesthetic spinal myelomalacia

How do you prevent bloating in cattle after anesthesia?

put in sternal immediately

patients with a slow recovey likely had a low or high MV and CO?

low MV and CO = slow recovery

what is a context sensitive half time?

time required for the concentration of a drug to decrease by 50% after discontinuation

Why do ketamine and alfaxalone have a rough recovery?

long context sensitive half time

What is the reversal for a-2 agonists?

atipamezole

what is the reversal for opioids?

naloxone

What is the reversal for benzodiazepines?

flumazenil

What is a consideration for recovey in sighthounds?

hypothermia, slow metabolism,

What is a consideration for recovery in herding breeds?

ABCB1 mutation, drugs can accumulate in the brain

How can agents impact the resp system causing hypothermia?

chemoreceptors not triggered → hypoventilation → hypothermia

mortality is likely at what temp?

<33C

what is the effect on blood during hypothermia?

viscosity increases, (PCV increases), prothrombin time increases (hypercoagulopathy),

Why will a patient in recovery start to have edema with hypothermia/

decreased metabolism → decreased elimination → cell Na pump doesnt work → cell edema

What endocrine issue can contribute to hypothermia?

hypothyroidism

Will you see hypo or hyperglycemia in a recovery emergency?

hypoglycemia

What are 3 drugs that cause dysphoria?

opioids, ketamine, benzodiazepines

emergence ddelirium will subside in ____ minutes

10

How long should you withold water and food before surgery for a healthy SA?

water until premed, food 4-6 hrs before

You have a SA with hx of regurg. How long should you with hold water and food before surgery?

water/food 6-12 hr premed

You have an 8 wk old puppy. How long do you withold water and food before surgery?

water until premed, withold food 1-2 hr before surgery (tiny, so don’t want to withold for long periods of time)

you have a diabetic. How long should you withold water and food?

water until premed, food 2-4 hrs before

Why would you give cisapride and metoclopramide before surgery?

gastroprokinetic, will empty stomach

Why do you give famotidine before surgery?

antiacid, to prevent esophageal regurgitation,

why do you give maropitant before surgery?

antiemetic

What are the goals of premed?

sedation, balance anesthesia/cardiovascular, analgesia

name the sedatives used in premedication

pnehothiazines, a2 agonist, benzodiazepines

list the anticholinergics used in premed

atropine, glycopyrrolate

What are the pros and cons of propofol?

con - apnea, pro - smooth induction and recovery

Waht are the pros of alfaxalone as an induction agent?

resp stability, no accumulation

What are the cons of etomidate as an induction agent?

painful injx, resp depression, short acting, crosses placenta

What are all the ways to verify intubation?

visualization of tube moving doqn, condensation in tube, Et CO2, air flow, lung sounds

What are two pairs of drugs you can use in debilitated animals and why?

opioids + benzodiazepines, midazolam + fentanyl → supports the heart and decreases stress

Will a more potent inhalant have a higher or lower MAC?

lower

SpO2 needs to stay above ____

95%

EtCO2 needs to stay above ___

35-45 mmHg

lactate needs to stay below ______

<2.5

HR needs to stay in what range?

50-150

SAP needs to stay in what range?

90-130

MAP needs to stay within what range?

60-90

DAP needs to stay above what?

>50

What is the rate of LRS for SA?

5-10 ml/kg/hr

What fluid type should be used to maintian fluid balance?

isotonic crystalloids

What are the maintenance rates for dogs, cats, and cardiac patients for maintenance with isotonics?

5 - all, 3 - cats, < 3 for diseased (ml/kg/h)

How do you know how much fluid to administer do a dehydrated patient?

10ml/kg for every 1% dehydrated (7% dehydrate = 70ml/kg)

HES is what type of fluid?

colloid

What are the shock doses (“blood volumes”) for cats, horses, and dogs?

50, 75, 90 ml/kg

What is the bolus dose for mild hypovolemia in catsa nd other species?

3-5 in cats, 5-10 in other species

What is the starting bolus for severe hypovolemia in cats and other species?

10 in cats, 20 in other spieces (ml/kg

What electrolyte imbalance can occur from hypertonic boluses?

hypernatremia

What is the amount of plasma given?

2-5 ml/kg

If you have severe ongoing bleeding or coagulation deficits, which colloid should you use?

blood products

Name the two acidifying solutions and the two alkalinizing solutions

acid: HSS and 0.9 NaCl base: LRS and Normosol-R

What effects do isotonic solutions have on plasma?

low expansion and short duration

What effects does HSS have on plasma?

rapid expansion of high magnitude, but short lived

T/F it is okay to give a repeated bolus of HSS

false, will cause hypernatremia