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Anesthesiology
Anesthesiology
242
Veterinary Medicine
Graduate
02/07/2013

Additional Veterinary Medicine Flashcards

 


 

Cards

Term
what are the three indications for anesthesia in veterinary medicine?
Definition
o humane treatment (pain relief
o restraint (imaging, sx, dx procedures, endoscopy, wildlife cases etc), safety
o satisfactory surgical condition (positioning, muscle relaxation,
Term
what are the three general classifications of anesthesia?
Definition
local, regional, general
Term
what are the three main objectives when performing anesthesia?
Definition
1. provide relief from pain for the patients during AND after surgery
2. provide optimal condition for surgery and other procedures (e.g. dx)
3. ensure patient safety and survival
Term
________anesthesia is a state of _________ produced by ________ and _______ drug-induced intoxication of the _________nervous system resulting in absence of _____ _________ over the entire body and a greater or lesser degree of ________ ___________
Definition
General anesthesia is a state of unconsciousness produced by controlled, reversible drug-induced intoxication of the central nervous system resulting in absence of pain sensation over the entire body and a greater or lesser degree of muscular relaxation.
Term
the triad of anesthesia is:
Definition
1. narcosis
2. muscle relaxation
3. analgesia
Term
what can be used to induce general anesthesia (general terms)
Definition
1. inhalants
2. injectables
3. combination
Term
what is the advantage of balanced anesthesia?
Definition
allows a lighter plane of anesthesia resulting in more stable CV and pulm function while reducing the requirement of inhalant used
Term
the anesthesiologist should pay close attention to these body systems in the preanesthetic exam.
Definition
CV, resp, nervous, endocrine, metabolic status
Term
what does ASA status IV mean?
Definition
patient with severe systemic disturbance which poses a constant threat to life and is incapacitating
Term
which ASA status is a patient with mild systemic disease with no functional limitations? what is an example?
Definition
II.
minor fractures, slight dehydration, skin tumors, obesity, asymptomatic heart murmurs
Term
what is ASA status V?
Definition
moribund patient not expected to survive 24 hours with or without surgery
Term
if the case in an emergency, what ASA status is used?
Definition
E
Term
what are some general important breed/species considerations with anesthesia?
Definition
larger dogs have slower metabolism and will require lower ends of dosing, smaller dogs will need higher end dosing. conditioned horses will have slower heart rates and need less anesthetic.
Term
a full stomach will increase the risk of:
Definition
regurgitation and aspiration
Term
an increase in body temperature may indicate (2):
Definition
infection or stress/excitement
Term
what are the two consequences of anemia in anesthesia?
Definition
low O2 carrying capacity,
decreased O2 delivery
Term
what are some preanesthetic preparations?
Definition
-informed consent
-withhold food (food and water in ruminants) (almost never withhold food and never withhold water in equines)
-rinse mouth, pick feet in equines
-optimize condition
-emergencies-e.g. GDV decompressing stomach to ease breathing, optimize patient, c-section
Term
what are the four general functions of the anesthetic machine?
Definition
-provide oxygen
-blend and deliver anesthetic mixture
-remove carbon dioxide
-support ventilation
Term
O2 tanks are what color?
Definition
green
Term
what do blue tanks contain?
Definition
N2O
Term
the amount of gas remaining in an E-cylinder is calculated how?
Definition
multiply the pressure gauge (psi) by 0.3 to get liters
Term
an E-cylinder contains how much O2?
Definition
700L
Term
volume is proportional to _______
Definition
pressure
Term
what is the temperature of liquid oxygen? what is its advantage?
Definition
-297F. cheaper in large amounts
Term
how is the amount of N2O left in a tank calculated and why is it different than O2?
Definition
N2O tanks are weighed and compared with empty tanks because the pressure will remain at 745 psig as long as there is any in liquid phase. Pressure will only fall when there is less than 25% left.
Term
at what percent of N2O will the pressure gauge finally start to fall?
Definition
25%
Term
what is DISS?
Definition
diameter index safety system. prevents delivery of hypoxic gas to patient via special connectors
Term
what is PISS?
Definition
pin index safety system. uses unique pins and hangers to prevent misconnection of gas cylinders to wrong inlets
Term
the cylinder pressure regulator of an E-tank reduces the pressure to approximately what psig?
Definition
40-45psig
Term
what is the common term for NO2?
Definition
laughing gas
Term
the flowmeter should be specific for:
Definition
the particular gas used
Term
what metal is the vaporizer usually made of? why?
Definition
copper. stabilizes temperature well
Term
what part of the float ball is used to determine oxygen flow?
Definition
the widest diameter
Term
what are the 8 characteristics of precision vaporizers?
Definition
  • copper (stabilizes temperature) 
  • out of the circuit-exhaled gas doesn’t go back through vaporizer 
  • concentration-calibrated=variable bypass- varies the amount of oxygen that flows over anesthetic
  • flow over –oxygen flows over anesthetic to vaporize  
  • temperature compensated-if room temp is hot, component expands to reduce oxygen that flows over anesthetic (as temp goes up, there is more vaporization) 
  • oxygen flow rate independent-does not change output % isoflurane with change in oxygen flow
  • agent specific-must be specific for anesthetic used
  • high resistance
Term
do not use oxygen flush on:
Definition
low volume circuits, non-rebreathing bags, when starting anesthesia
Term
the oxygen flush valve bypasses:
Definition
the vaporizer
Term
what is the rate of flow when using the oxygen flush?
Definition
35-75L/min. very high flow
Term
what are the four classifications of breathing systems? are they rebreathing?
Definition

1. open- no rebreathing

2. semi-open- no rebreathing

3. semi-closed- partial rebreathing

4. closed- complete rebreathing

Term
what is a Mapleson's?
Definition
non-rebreathing system
Term
what is the main CO2 absorber in soda lime? what are the other components and what do they do?
Definition
  • Ca(OH)2.
  • NaOH-speeds up process
  • KOH-speeds up process
Term
how can you tell if soda lime is old?
Definition
tank is cold, hard to crumble, dyes purple, tastes salty (DON'T EAT IT)
Term
what is the main product when soda lime is old?
Definition
CaCO3
Term
unidirectional valves go in which direction from what pressure?
Definition
  • inspiratory disk raises from negative pressure
  • expiratory disk raises from positive pressure
Term
how is the breathing bag size determined?
Definition
6 x (tidal volume 10mL/kg) so: kgx60, and ROUND UP
Term
what are the functions of the breathing bag?
Definition
allows accumulation of fresh and expired gases and prevents rapid increase in pressure
Term
what does the Y piece contain?
Definition
dead space. does not participate in gas exchange, mixing of inspired and expired gas
Term
what is the most dangerous part of the anesthesia machine?
Definition
pop-off valve (adjustable pressure limiting valve). can be left closed and causes accumulation in pressure, can pop lungs
Term
what are the two problems with rebreathing systems?
Definition
resistance to breathing and dead space in small animals
Term
the main source of leak is the:
Definition
negative pressure relief valve
Term
what is the purpose of the negative pressure relief valve?
Definition
allows entry of room air into the circuit, especially if there is no oxygen source or if there’s lots of suction
Term
the reaction in soda lime is:
Definition
exothermic
Term
non-rebreathing systems are used for what patients?
Definition
7-10kg BW
Term
why is the oxygen flow rate so high in non-rebreathing systems?
Definition
hi flow oxygen is driving CO2 out of the circuit.
Term
what are the approximate oxygen flow rates in non-rebreathing and circle systems?
Definition
  • 200-300mL/kg/min for non-rebreathing
  • 30mL/kg/min in circle system
Term
what is the Bain Coaxial System?
Definition
fresh gas tube is inside the corrugated tube to warm the fresh gas with the expired gas
Term
what are the three disadvantages of the non-rebreathing system?
Definition
  • dry, cold gas-->hypothermia
  • hi flow O2-->lots of wasted vaporized anesthetic = $$$ more 
  • pollution
Term
what three things should be checked on the patient in the pre-op evaluation in terms of airway management?
Definition
  • open mouth
  • TMJ mobility-don’t induce without knowing you can open the mouth!
  • cervical spine mobility
Term
what are the benefits of facemasks?
Definition
convenient, short term, preoxygenate, gas anesthetic induction, difficult intubation patients
Term
what are the disadvantages of the facemask?
Definition
 inadequate seal, possible trauma to eyes, no protection from aspiration or obstruction, may require restraint
Term
T or F: it is sometimes safe to not intubate a bulldog.
Definition
False. always intubate for anesthesia
Term
what are the indications for intubation?
Definition

§  patent airway

§  prevent aspiration, esp in ruminants

§  positive pressure ventilation

§  problematic positioning (ophthalmic)

§  upper airway disease as in bulldogs 

§  mask not possible

§  route for tracheal suctioning

Term
what is a Murphy's eye and what is its purpose?
Definition
hole at end of trach tube, provides patent airway if beveled edge is pushed against tracheal mucosa
Term
the two types of disposal systems are:
Definition
active and passive
Term
what is f/air?
Definition
activated charcoal to scavenge anesthetic in passive systems
Term
how do you determine the proper length of the endotrach tube to be used?
Definition
from point of shoulder to tip of the nostrils
Term
which species is intubated in lateral recumbency?
Definition
horses
Term
what drug is used in cats to assist in intubation?
Definition
lidocaine drops or gel
Term
what are three types of vaporizers in terms of method of vaporization?
Definition
flow-over, bubble-through, injection
Term
what is the range of endotrach tube size in vet med?
Definition
2-40mm
Term
what are the types of trach tube?
Definition
  • red rubber
  • PCV
  • silicone
  • metal
  • Cole
  • reinforced
  • PCV without writing (Sheridan YAG)
Term
what are the most commonly used trach tubes in vet med?
Definition
PCV and silicone
Term
why are normal PCV trach tubes contraindicated for certain procedures?
Definition
markings are combustible with laser use
Term
Describe a Cole tube.
Definition
the patient end is smaller in diameter, and the shoulder of the tube sits at the lies against the larynx to provide a good seal. used in birds, horses, and cows
Term

which endotrach tubes can damage mucosa with ischemia?

 

Definition
low volume high pressure cuffs
Term
what are metal endotrach tubes used for?
Definition
laser sx of oropharyngeal area
Term
how can you check for esophageal intubation?
Definition
  •   palpate neck for two tubes 
  •   squeeze bag and watch chest and abdomen
  • no condensation in tube
  •   watch bag
  •   Capnography (CO2)

 

 

 

Term
what are some intubation complications?
Definition
  •  esophageal intubation
  •  CV changes
  • aspiration
  • hypoxemia/hypoventilation
  • laryngospasms
  • intraocular pressure
  • intracranial pressure
  • trauma/hemorrhage
  • endobronchial intubation-only one sided ventilation!
  • biting tubeàaspirating foreign body

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Term
which is more common during intubation: tachycardia or bradycardia?
Definition
tachycardia and hypertension more commonly seen. bradycardia in patients with high vagal tone
Term
what are the possible complications when the endotrach tube is already in place?
Definition
  •  endobronchial intubation with movement
  • accidental extubation
  • bronchospasm-rare
  • kinking of tube
  • mucus thickened, blood clot obstruction
  • herniation of the cuff with older tubes-goes in front of the beveled edge and obstruct airway
  •  fire with laser surgery
  • compression of tube lumen instead of trachea expanding, obstructs tube
Term
what are the possible complications with extubation and after extubation?
Definition
  •  bitten endotrach tube-WATCH THEM DURING RECOVERY
  • overinflate cuffàtracheitis, tracheal tear (esp in cats)
  • subcutaneous emphysema
  • dysphonia
Term
what are the species-specific extubation protocol?
Definition
  • brachycephalics-wait even after swallowing, challenge them to prove independent breathing
  • dogs and cats-swallowing
  • horses: taped and kept until horse is up
Term
what are the four categories of premedication?
Definition
anxiolytics, sedatives, opioids, anticholinergics
Term
what are the three reasons for premedication?
Definition
minimize stress, decrease requirement (injectable, inhalant), synergism
Term
what is neuroleptoanalgesia?
Definition
sedative +opioid
Term
how are drugs selected for premedication?
Definition
species, age, physical status (ASA), animal attitude, procedure, duration of procedure, experience with drugs used
Term
what are neuroleptics?
Definition
major sedatives
Term
what are three anticholinergics?
Definition
atropine sulfate, glycopyrrolate, scopolamine (human)
Term
what are the five effects of anticholinergics?
Definition

o   ↓secretions

o   bronchial dilation

o   ↑anatomic and physiologic dead space

§  nares, bronchia, trachea

o   ↓GI motor and secretory activity

o   ↓vagal influence in HR

 

Term
why should anticholinergics not be used with ketamine to decrease secretions during surgery?
Definition
  •    ketamine also a sympathetic stimulant, increases O2 use by myocardia, so atropine will stress heart.  can just use gauze to clean mouth
Term
what is the indication for anticholinergics?
Definition

o   anti-muscarinicàmore NEàblock parasympathetic tone. increase HR. decrease vagal response.

o   for bradycardia and hypotension that is not alleviated by reducing anesthetic. bradycardia will get worse before it gets better.

Term
why is it crucial that young animals not become bradycardic?
Definition
young animals' CO is very dependent on HR bc SV is smaller.
Term
what is the difference between atropine and glycopyrrolate?
Definition
atropine crosses the BBB and the placenta and has a shorter duration and high lipid solubility
Term
the most common causes of bradycardia are (2):
Definition
loss of temperature and opioids
Term
what are the two major tranquilizer categories and examples of each?
Definition

o   phenothiazines

§  acepromazine

§  chlorpromazine

§  levomepromazine

o   butyrophenones

§  droperidol

                    § azaperone 

Term
what can be given as an anti-emetic before opioids?
Definition
acepromazine
Term
what are the six uses for acepromazine maleate?
Definition

o   potent sedative and anxiolytic

o   cheap

o   anti-emetic

o   anti-arrhythmic properties (decreases sympathetic tone, blocks α receptors)

o   ↓dose requirement of other drugs

o   enhances analgesia of opioids

Term
what breed may be sensitive to acepromazine, especially those born outside the US? what are the signs, and what can be done?
Definition
  • boxers
  • hypotension, post-anesthestic comatose
  • look at the medical records to see if it's been given before
Term
what are the side effects of acepromazine?
Definition

§  ↓ BP and vasomotor reflex

§  cardiac depression

§  peripheral α1-adrenergic blockade

§  relaxation of vascular smooth muscle

§  vasodilator (caution with brain, renal (potential for hypotension), hepatic failure (potential for hypotension))

§  persistent or permanent penile paralysis-in horses 1/10k stallions and geldings-so use an α2 in horses!!!!

§  blocks both α1 and 2, but α1 is more predominant

NOT REVERSIBLE

Term
which tranquilizer is used in pigs?
Definition
azaperone
Term
what ar ethe effects of benzodiazepines?
Definition

o   inhibits inhibitory first, then excitatory,  so initial excitation, so give slow and mix with others to inhibit excitatory first.

o   anxiolytic

o   sedative

o   muscle relaxant

o   anticonvulsant

            o   anterograde amnesia

Term
benzodiazepines are lipid (soluble/insoluble):
Definition
highly soluble
Term
benzodiazepines are great in which patients?
Definition
really sick and older patients
Term
which drug should always be given alone and never mixed with anything? why?
Definition
diazepam. propylene glycol vehicle
Term
which drug can cause phlebitis in cats with prolonged use? what route should never be used?
Definition
diazepam. IM (poorly absorbed and stings)
Term
which benzodiazepine is water soluble? which route is used?
Definition
midazolam. can be given IM
Term
compare midazolam and diazepam
Definition
  • midazolam is water soluble, diazepam is lipid soluble
  • midazolam can be mixed with other drugs
  • midazolam is more potent
  • diazepam is longer acting
  • both cross BBB and placental barrier
Term
midazolam becomes lipid soluble when:
Definition
pH>4, immediately absorbed
Term
what is the most potent benzodiazepine in vetmed? what is a practical limitation?
Definition

zolazepam

EXPENSIVE, and needs to be used in days (Efficacy drops off)

Term
what is the reversal for benzodiazepines?
Definition
flumazenil
Term
what are the effects of α2 agonists (7)?
Definition

o   anxiolytic

o   sedative and muscle relaxant

o   analgesia

o   ↓ADH binding

o   ↓insulin release

o   hypertension followed by hypotension

o   reflex bradycardia

Term
when using α2 adrenergic agonists, patients must be 
Definition
healthy, bc CO drops by half
Term
do not give atropine with:
Definition
α2 agonists (except xylazine ok)
Term

in a young pregnant yorkie, you want to increase the heart rate during surgery. the drug of choice is:

a. atropine

b. acepromazine

c. glycopyrrolate

d. epinephrine

e. lidocaine

Definition
c. glycopyrrolate
Term

in what type of patients should acepromazine be avoided?

a. cardiac

b. brain occupying lesions

c. acute renal

d. hepatic failure

e. all of the above

Definition
e. all of the above due to vasodilation
Term
what is the fastest barbiturate, and why with a half-life of four hours, does the patient wake up quickly? what must be done to prevent the patient from waking up?
Definition

thiopental. wakes up quickly due to redistribution. 

it is cumulative, so repeated doses until threshold where patient wakes up from elimination instead

Term
what are the side effects of thiopental?
Definition

o   splenic engorgement (capsule is α-related, relaxation, engorgement)

o   CV-myocardial depression

§  decrease in CO

§  decrease in BP

§  àincrease HR

§  bigeminal rhythm (VPC followed by sinus rhythm)

o   respiratory:

§  decrease in Vt

§  hypoventilation (rise in CO2), not necessarily hypoxia

·         minute ventilation (resp rate x tidal volume)

·         shallow breathing

§  apnea

o   neurologic

§  decrease CMR02

§  decrease ICP

§  protective for brain ischemia

§  treatment for seizures

§  decrease EEG activity

Term
why is an IV catheter suggested for thiopental? in which breed should it not be given?
Definition

sloughing of skin if given perivascular due to alkaline pH 

sighthounds very sensitive

Term
what are propofol-induced "seizures"?
Definition

o   “seizure like activity”-propofol induction, gas is taking over, redistribution, excitatory, looks like seizures 10-15 min after induction

o   give benzos if this happens.

not a seizure

Term
the side effects of propofol are:
Definition

o   decrease in BP, CO, SVR

o   apnea

Term
opened, propofol has a short shelf-life because:
Definition

o   contains egg lecithin

§  contamination

§  6 hours, no more than 24 hours shelf life

Term
because ketamine is dissociative, _______________should not be assessed to evaulate anesthetic depth.
Definition
palpebral/swallow reflex
Term
how do cats handle ketamine differently?
Definition
eliminated unchanged in cats, norketamine still an active metabolite
Term
what are the side effects of ketamine?
Definition

o   cardio

§  symp stim

§  ↑HR and BP

§  careful in HCM (avoid)

§  may ↑IOP

o   respiratory

§  apneustic breathing

§  apnea

§  maintained laryngeal reflexes and PaO2

o   neurologic

§  ↑ICP and CBF

§  somatic analgesic (must use others)

·         can help with windup pain

§  excitement at emergence

·         motor activity

·         sensitivity to touch

·         violent recovery

o   clinical effects

§  ↑salivation and mucus

§  poor muscle relaxation

§  reflexes are maintained

§  rough recoveries (due to poor relaxation)

Term
what is telazol?
Definition
1:1 tiletamine and zolazepam
Term
what are the side effects of telazol?
Definition

o   cardio: similar to ketamine due to symp stim

neuro: maintained reflexes (cough, swallow, corneal) 

Term
what is a side effect and contraindication for etomidate?
Definition

o   ADRENAL SUPPRESSION (addisonian crisis, septic patients)

Term
what are the advantages of opioids as premeds?
Definition

can use in sick patients,

reversible

shortacting (fentanyl)

Term
what is alfaxalone, and what is the advantage of the newer formulation?
Definition

steroid anesthetic

lower histamine release

Term
thiopental is contraindicated in which patients?
Definition
hypoproteinemia (since it's protein bound), liver failure (P450), neonates, hypovolemia
Term

the extent of muscle relaxation in ketamine/telazol is:

what about etomidate?

Definition
poor. also poor
Term
what are the advantages and disadvantages of inhalant anesthetic?
Definition

Advantages

1.      better/faster control of anesthetic depth

2.      animal gets oxygen, ventilated via intubation

Disadvantages

1.      hi cost

2.      waste gas

Term
what are the four sites for the most exposure of staff to inhalants?
Definition

1.      masking inductions

2.      box induction (opening the chamber)

3.      hi oxygen flow without adequate scavenging

4.      recovery area-need hi flow in recovery area to min pollution

Term
the limit for exposure to inhalants for staff is_________, and you can tell by __________.
Definition

no more than 2ppm

if you can smell it, then it’s >2ppm

Term
which inhalant is the most potent? what relative MAC number would it have?
Definition
methoxyflurane with a LOW MAC
Term
what are six conditions that lower MAC (increase potency)?
Definition

a.      acidotic (↓pH, pCO2, HCO3),

b.      hypothermia

c.       old patients

d.      sick patients (sepsis, GDV, etc)

e.       pregnancy

f.        drugs: sedatives/tranquilizers, analgesics, inducting drugs

Term
what are two conditions that increase MAC (lower potency)?
Definition

a.      hypernatremia

b.      hyperthermia

Term
alveolar concentration reflects:
Definition
concentration in the brain
Term

the inhalant % achieved = 

and means:

Definition

(saturated vapor pressure/Atm pressure) x 100

(Atm=760mmHg at sea level)

means how much will be produced if just open container

Term
what are the considerations for inspired concentration?
Definition
fresh gas flow rate, absorption of anesthetic (by rubber), volume of circuit, time constant
Term
what is the time constant?
Definition

time constant= volume to fill/rate. to speed it up, use a small bag or an increased rate

↓time constant= ↓capacity/↑flow

Term
what is the partition coefficient? which gas has the lowest?
Definition

blood solubility-blood:gas partition coefficient (how much goes into blood vs gas) blood/gas

sevoflurane 0.6 

Term
a low blood:gas partition coefficient (low blood solubility) means(3):
Definition

a.      rapid induction,

b.      quick change in level of anesthesia,

c.       quick recovery 

Term
a high blood:gas partition coefficient (high blood solubility) means(2):
Definition

a.      longer to saturate blood,

b.      hard to maintain hi alveolar concentration

Term
when cardiac output is low, alveolar concentration:
Definition
rises quickly and onset of anesthesia is faster. (time for blood to pick up anesthetic)
Term
what are the side effects of inhalants? what can be done to reduce the risk?
Definition
  • CV: arrythmogenicity (rank: halothane, methoxyflurane, then iso/sevo)   
  • ALL depress CV/pulm in a concentration-dependent manner
  • use MAC sparing drugs!  (opioids, lidocaine, ace, hydromorphone, etc)
Term
what are the drawbacks to nitrous oxide use (5)?
Definition
  • pneumothorax (lots of nitrogen in room air infiltrating thorax, nitrous oxide travels to air pockets, exacerbates pneumos.
  • harder to scavenge
  • danger of hypoxic gas
  • abuse potential (whip-it)
  • bone marrow depression
Term

what steps should be taken with apnea?

what should NOT be used?

Definition
  • ·         call for help
  • ·         check pulse
  • ·         ventilate (2-3 breaths per minute)
  • o   apneic threshold (graph)
  • o   anesthetic pushes threshold to right, needs higher PaCO2 to spontaneously ventilate. do not wait for the animal to breathe spontaneously. allow O2 to be delivered and CO2 to accumulate.
  • dopram should not be used, as it is inconsistent and stimulates the CNS
Term
what is a major cause of apnea?
Definition
injectable agents
Term
what are the causes of partial respiratory obstruction?
Definition

§  long procedure

§  overinflated cuff

§  mucus, pus

Term
how can you tell a partial respiratory obstruction? what can be done?
Definition
  •  exaggerated movement-think obstruction
  •  squeeze bag-easy to inflate lungs? then no obstruction. good to check at beginning for baseline. shouldn’t need a lot of pressure to inflate the lungs.
  • change endotracheal tube when in doubt, may need to use suction to clear tube
  • use reinforced endotracheal tube if the neck needs to be flexed
Term
what are the causes of hypercapnia?
Definition

§  hypoventilation

·         ↓resp rate (but can be normal and still be hypercapnia)

·         ↓tidal volume

·         ↓minute ventilation

·         ↑PaCO2 and PetCO2

§  obesity contributes (also might wake up on table)

§  abnormal positioning

§  main culprit is inhalant

§  exhausted soda lime

§  non-rebreathing system

·         O2 flow not fast enough to remove CO2

Term
when should a dog be ventilated?
Definition
  • 50mmHg squeeze bag from time to time
  • >60mmHg- ventilate

 

Term
when should a horse be ventilated?
Definition
  • 70mmHg-squeeze
  • >80mmHg-ventilate

 

Term
MAP of hypotension is:
Definition
<60mmHg
Term
what are four causes of hypotension?
Definition
  • most anesthetics
  • shock
  • blood loss
  • deep anesthesia
Term
what are the steps to take if a patient is hypotensive?
Definition

·         any doubt: reduce vaporizer setting! if at good plane of anesthesia
·         fluids!  increase preload
·         10ml/kg over 10 minutes (maintenance rate given over shorter time)
o   fluid boluses
·         positive inotropes- ↑contractility
o   dopamine-acts on β1 receptors –CRI
§  3-20μg/kg/min
o   dobutamine-pure β1 agonist (horses)
§  0.5-5μg/kg/min
o   ephedrine-mixed β1 and α
§  0.01-0.2mg/kg

 

 

Term
T or F: a pulse means a good BP.
Definition
false. a good pulse just means a good difference between systolic and diastolic pressure, but both could be low or high
Term

what is this, and what do you do?[image]

Definition
  • VPC
  • causes: hypoxemia, hypercapnia, cardiomyopathy, traumatic myocarditis, GDV, electrolyte imbalance
  • tx: lidocaine- look at overall picture (perfusion of animal, BP). bc literature disagrees on numbers (5-15VPC’s per min). when in doubt, give it.
  •  unifocal-may not need to treat right away
  • multiform VPC (different shapes and sizes) –treat ASAP
  • runs of VPC’s, look over one minute
  • if lidocaine doesn't cut it, (ventricular bigeminy or ventricular fibrillation), go to procainamide
 

 

 

 

Term

what is this and what do you do?

[image]

Definition
  • sinus bradycardia
  • cats<100bpm
  • dogs <50-60bpm
  •  causes: oculocardiac reflex
  • abdominal exploration
  • laryngeal stimulation
  • hypothermia
  • opioids
  • tx: manage underlying problem
  • atropine (quicker) or glycopyrrolate (slowly developing ones)
Term

what is this and what do you do?

[image]

Definition
  • second degree AV block
  • P wave without QRS
  • due to high vagal tone
  • if HR is low also, give anticholinergic (atropine or glyco)
Term

what is this and what do you do?

[image]

Definition
  • sinus tachycardia
  • >180bpm dogs
  • >200bpm cats
  • >75bpm horses
  •  causes: light anesthesia
  •  if not light: hypovolemic shock, sepsis, hypercapnea
  • manage underlying problem, check blood gas
  • turn up gas or analgesic (unless due to pheochromocytoma or hyperthyroidism, then use β-blocker)
Term
what are the causes and treatments for hypothermia?
Definition
  • causes: loss of body temp regulation, reduced periph vasoconstrictor tone, large SA in relation to mass, nonrebreathing (cold air), surgical exposure of tissues and body cavities, IV cold fluids, coold operating room, wet drapes, excess clipping, scrub with alcohol
  • prev/tx: use heated water blankets, admin warm fluids, avoid excessive clipping/alcohol scrub, keep room temp >70F, monitor body temp, lavaging with warm solutions
Term
the requirements for a good recovery area are:
Definition

o   well ventilated

o   quiet

o   minimal traffic

o   controlled intensity of light

o   has supportive O2 available

o   crash cart

o   heat source

o   soft surface, especially for horses to prevent neuropathies/myopathies, pull lower front leg forward

o   sternal recumbency with head higher (to prevent regurg) in small ruminants/camelids

o   person for monitoring!

Term
for small animals, the postanesthsia procedure goes:
Definition

o   turn off vaporizer, turn up O2 (remove inhalants from patient and machine)

§  can worsen hypothermia

o   HR, BP, RR, ETCO2, mm, temperature, etc. still monitored

o   disconnect fluids

o   leave catheter in unless fractious

o   apply heat and dry

o   wait for swallow

§  deflate cuff and remove tube

·         monitor resp, pulse, monitor temp (every 30 min until normothermic)

Term
what is the postanesthesia procedure for horses?
Definition

·         horses- disconnected from everything, IV catheter kept, decrease inhalant concentration as much as possible. neosynephrine up nostrils-(phenylephrine) vasoconstriction. towel over eyes. secure endotrach tube to horse,  injection (missed it),  watch for horizontal nystagmus, restrain, check bilateral nasal flow

Term
what are the six post-anesthetic complications?
Definition
  1. ventilatory
  2. CV
  3. hypo/hyperthermia
  4. regurgitation/gastroesophageal reflux
  5. delayed return of consciousness
  6. emergence dysphoria
Term
what are the causes and treatment for delayed return to consciousness?
Definition

o   drug overdose/residual

o   deep plane of anesthesia

o   hypothermia

o   hypoglycemia

o   hypotension

o   decreased drug metab (cardiac, liver, kidney patients)

o   CNS disease

o   hypoventilation

o   tx: PE, monitor, circulatory shock check, cerebral injury check 

Term
what are the signs of circulatory shock and what is the treatment?
Definition

o   weak pulse

o   tachy (compensatory phase)/bradycardia (decompensating)

o   CRT>3 sec

o   cold extremities, cyanosis, hypoxemia, pale mm, hypotension

o   tx: supplement O2, fluids, dopamine/dobutamine, lidocaine, antisedan (atipamezole)

Term
what are the possible causes of abnormal respiration/dyspnea post-extubation?
Definition
  • airway obstruction
  • central depression of ventilation (opioids)
  • hypoxemia or hypercapnia
  • stimulation of respiratory centers (hyperthermia/pain)
  • failure of neural control (herniation of cerebellum/medulla)
Term
what does froth and fluid in the endotracheal tube represent? what should be done?
Definition
possible pulmonary edema. discontinue IV fluids and give furosemide
Term
T or F: a patient can go into cardiac arrest if body temp <90F
Definition
true
Term
what are the causes of regurgitation, and what do you do if it happens postanesthesia?
Definition

o   esophagitis, strictures, aspiration pneumonia

o   lower head immediately, cuff well-inflated, suctioning contents, lavage with tap water, extubate with still partially inflated cuff to remove any aspirated material

Term
what are the signs and treatment for emergence dysphoria?
Definition
  • can be due to full μ-agonist opioids, benzodiazepines, or ketamine
  • excitation or hysteria
  • vocalization or whining
  • violent, uncoordinated movements or padding
  • disorientation
  • restlessness or pacing
  • dilated pupils
  • inability to console or calm patient
  • determine if  pain or dysphoric
  • can give sedative (ace; dexmedetomidine if does not respond), treat for pain
  • can give reversal (naloxone, butorphanol, flumazenil)
Term
what are the 6 general negative consequences of pain?
Definition
  • ↑cardiac workload/  ↑myocardial O2 consumption 
  •  catecholamine-->neutrophil suppression-->delayed healing
  • hypoventilation
  • ileus/decreased gastro motility
  • water retention, changes in body fluid balance
  • excitation/violence/self-mutilation
Term
what are 9 strategies used for pain control?
Definition
  1. distraction
  2. systemid opioids
  3. NSAIDS
  4. tranquilizers/sedation
  5. nerve blocks, regional analgesia, wound diffusion catheters
  6. cold compress
  7. epidurals
  8. acupuncture
  9. transcutaneous electrical nerve stimulation
Term
which pain control strategy used depends on:
Definition
  • analgesics used preop/intraop
  • how painful patient appears
  • how painful procedure appears to be
  • analgesics available
  • does mentation/ambulation need to be observed as part of postop?
  • critically ill or can't otherwise show pain behavior?
  • cardiopulm function compromised?
  • how quickly patient needs to return to function
  • chronic pain or wind-up?
Term
what are the signs of light plane of anesthesia?
Definition
fast palpebral reflex, central eye position, hypertensive, tachycardic
Term
what are the signs of a good plane of anesthesia?
Definition
+/- palpebral eye reflex, rotational eye position, normotensive
Term
what are the signs of deep plane of anesthesia?
Definition
no palpebral reflex, central eye position, hypotensive, decreased tear production
Term
oxygen delivery=
Definition

DO2=CaO2 x CO

  • oxygen delivery = oxygen content and cardiac output
  • where CO= blood pressure/vascular resistance               
  • and oxygen content= ([Hb x 1.34]x % saturation) + 0.003 x PO2)

 

 

 

Term
what are the macro and microcirculation monitors?
Definition

·         macro-circulation

o   capnograph

o   BP

o   ECG

·         micro-circulation

o   mm

o   lactate

o   urine output

Term
what two lightwaves are used in a pulseox? what do they measure? What is the law behind it?
Definition
  • red 660nm light- absorbed= deoxyhemoglobin
  • infrared 920 nm light=saturated (oxyhemoglobin)
  • Beer's law
Term
a good pulseox reading would be_____. what happens when the SaO2 falls to 90%?
Definition
98%, at/after 90%, PaO2 falls dramatically to 60% (hence, the difference between 98% and 90% is huge)
Term
what can affect the pulseox accuracy?
Definition

§  vasoconstrictive patient

§  low pulse pressure

§  anemia

§  dyes

§  icterus

§  motion

§  dyshemoglobins

§  external light sources

Term
which is superior in detecting apnea: pulseox or capnograph? what are its other advantages?
Definition
capnograph. can also confirm correct intubation and nasal esophageal feeding tube placement and  can guide CPR
Term
what are the three forms of CO2 in the body and their relative prevalence?
Definition
  1. bicarb (60-70%)
  2. bound to proteins (20-30%)
  3. dissolved in plasma (5-10%)
Term
end tidal CO2 (ETCO2) ~______? which means  _____ is the ventilatory gold standard.
Definition

arterial CO2

ABG (arterial blood gas)

Term
what would be the likely problem for a high ETCO2 and stair-stepping inspirtatory baseline?
Definition
rebreathing (dead space, low flow on non-rebreathing, soda lime is old). also: intubating the stomach in drunk humans
Term
what would be the likely cause of a ETCO2 with a cleft in the expiratory plateau?
Definition
curare
Term

label the four phases: 

[image]

Definition

[image]

or A-B phase 1

B-C phase 2

C-D phase 3

D-E phase 0

Term
how is Q (blood flow) calculated? is BP a good indicator of Q?
Definition

o   Q=BP/SVR (systemic vasc resistance)

§  high BP does not mean good blood flow

§  vasoconstrictors will increase BP, but can decrease Q, and vice versa

§  blood pressure does not equal perfusion

Term

what is this (lower image in art waveform), and what could be the cause?

[image]

 

Definition

pulse alternan.

LV failure, alternating SV, cardiac tamponade

Term

what is this (art wave), and what could be the cause?

[image]

Definition

pulse paradoxus

hypovolemic, IPPV (intermittent positive pressure ventilation)

Term
what is the treatment for low BP?
Definition

·         fluids-not a great sense of how much you need.

o   preload monitoring

·         inotrope

·         decrease inhalants

Term
what do the relative CVP values mean? what is this test's limitation? what test is preferred?
Definition
  • hi CVP is overload,
  • low CVP-water column drops with hemorrhage
  • normal 0-12cmH2O
  • not that accurate!!!
  • pulse pressure variation
Term
what is an example of the diagnostic value of lactate? what else does it do?
Definition

septic abdomen

also prognostic and therapeutic value

Term
patients with upper airway disease are prone to:
Definition
  •  prone to hypoxia
  •  distress (catecholamine)
  •  prone to obstruction
  •  (pulm edema)
  •  airway obstruction after pre-oxygenation- takes longer to get to danger zone
Term
what precautions should be taken with patients with pulmonary disease?
Definition

o   avoid increase in O2 demand, avoid apnea

o   PREOXYGENATE

o   low dose opioid

o   propofol-one of fastest

o   assist ventilation

o   capnograph, pulse ox, blood gas

o   patient  position

Term
what precautions should be taken with CV disease patients?
Definition

o   mitral valve disease-want them to be vasodilated, tachycardic.

o   most anesthetic agents depress CV

§  exception is etomidate

o   low sodium, low volume

o   avoid arrhythmic agents

o   avoid vasoconstrictors

o   etomidate and low inhalant delivery

Term
what precautions should be taken in cats with HCM?
Definition
  • avoid tachycardia and vasodilation
  • stiff ventricle, poor diastolic function
  • left ventricle outflow tract obstruction (LVOT), walls touch each other and has no space
  •  worst LVOT (need to correct/avoid following):
  • tachycardia
  •  ↑contractility
  • vasodilation- sudden wall collapse with pressure drop
  •  NO KETAMINE, use dexmedetomidine instead
Term
what precautions should be taken with PSS patients?
Definition

  • do the Chem profile!
  • BUN
  • protein
  • use reversible drugs that don’t act on liver
  •  short acting drugs
  • opioids, midazolam
  • propofol
  • remifentanyl (only opioid which is destroyed by blood instead of liver) + isoflurane
  •  fluid: FFP, hetastarch, glucose

 

 

 

 

 

 

 

Term
precautions with brain disease include:
Definition

o   head trauma

o   ↑ICP

§  drugs

§  positioning

§  vomiting (opioids), cough, gag

§  CO2, O2, BP

§  Cushing’s reflex-LOW HR, HI BP

·         previews hi ICP and herniation.

o   avoid, vomiting

o   ↑ICP KETAMINE AND HALOTHANE

§  ketamine only induction with analgesic properties, so need to use something else for analgesia

Term
what are the precautions for renal patients?
Definition
  • promote renal blood flow (prone to hypotension!)
  • dopamine, acepromazine, fluids
  • opioid (maybe not morphine), low dose ace
  • Telazol ok.
  • avoid NSAIDS
  • dopamine CRI- INCREASE CONTRACTILTY- positive inotrope
  • some vasodilation to kidney
  • o   fluid therapy
  • o   low inhalants
  • o   ketamine in cats  with renal disease- can’t break down , lasts longer

 

 

 

 

 

Term
what are some causes of water/electrolyte/acid-base imbalances?
Definition
  • disease: GDV, impaction, acute abdominal crisis
  •  inhalants depress resp
  • surgical events: blood loss, ascites, drying exposed tissues
Term
ascites due to ruptured bladders should be dealt with how?
Definition
slowly removed, as sudden pressure decrease can cause CV issues
Term
what is hyponatremia, and what is the treatment?
Definition

Na<132mEq/L

·         ADH release from stress

·         some fluids with dextrose (not LRS)

·         ruptured urinary bladder (water resabsorbed)

·         signs

o   depressed, weak, inappetant, hypotension

·         tx

o   for severe: hypertonic saline 3% or 5%

o   if you correct rapidly, then myelin sheath will disrupt

Term
what are the three principles of fluid administration?
Definition
  1. fix prior to anesthesia
  2. preserve CO at all costs
  3. chronic fluid loss needs to be corrected slowly
Term
what are the signs of severe water intoxication? how is it handled?
Definition
cardiac dysrhythmias and cerebral edema. furosemide
Term
what is hypernatremia and how is it corrected?
Definition

Na>155mEq/L

·         hypertonic saline

·         evaporation from serosal cavity during surgery

·         diabetes insipidus

·         water deprivation

·         signs

o   CNS depressions, seizure, stupor, coma, dementia

·         tx: fluids low in Na, hi in water (with dextrose)

·         correct slowly,

o   chronic 2-3 day correction

§  cerebral edema if not corrected slowly

Term
what is hypokalemia and how is it corrected?
Definition

K <3.3mEq/L

·         K –poor fluids like 5%dextrose, 0.9%NaCl

·         GI losses (v/d)

·         metabolic alkalosis

·         furosemide

·         signs

o   altered ECG

§  small p wave

o   ileus

o   muscle weakness

·         LRS 4mEq/L K. so may need to add potassium chloride in sick patients

·         speed limit 0.5mEq/kg/hr

·         no increase in dysrhythmias with chronic levels of 2.6-3.5mEq/L

o   so not a lot of need to correct during anesthesia unless patient is sick; can use a pump.

Term
what is hyperkalemia and how is it corrected?
Definition

K >5.5mEq/L

·         acidosis

·         iatrogenic

·         renal failure

·         tissue trauma (cell damage)

·         main concern: dysrhythmias

o   ECG

§  no p wave

§  tall t wave

§  bradycardic, wide QRS-idioventricular rhythm-EMERGENCY

·         tx

o   0.9%NaCl to dilute

o   if acidotic-bicarb

o   insulin and 5%dextrose

§  drive potassium back into cell, prevent hypoglycemia

o   calcium gluconate if idioventricular rhythm, ecg changes (to raise normal threshold)

·         tigers are susceptible

Term
what are the causes of metabolic acidosis and what is the treatment?
Definition

 

·         ↓peripheral perfusion

·         renal failure

·         diarrhea

·         DM

·         tx

o   treat underlying problem

o   bicarb

o   correct base deficit (equation in notes)

o   different correction for younger animals

Term
what are the causes of metabolic alkalosis and what is the treatment?
Definition

·         abomasal displacement

·         vomiting

·         iatrogenic

·         hypokalemia, hypochloremia

·         tx

o   treat underlying

o   saline

Term
how is volume deficit calculated?
Definition

o   fluid L=% dehydration x BW

Term
what is the fluid infusion rate during anesthesia?
Definition
10mL/kg/hr
Term
why should dextrose be avoided in patients with a volume deficit?
Definition

·         patient is losing water. animal will develop hyperglycemia (mild). if arrests, the worst neurologic injury. once metabolized by liver, just delivering water, can drown patient and doesn’t help perfusion. only use when needed in:

o   DM

o   insulinoma

o   pediatric

Term
how can blood loss be estimated during surgery?
Definition
look at the suction jar and compare its PCV with patient's preop values
Term
what are the guidelines for crystalloid and colloid replacement?
Definition

o   replace 3:1 loss if <20% of blood volume, give crystalloid

o   1:1 if using colloid when >20% loss of blood volume.  (e.g. hetastarch, hypertonic saline)

Term
what are the blood volumes of the dog and cat?
Definition
  • dog: 8%BW 80ml/kg
  • cat: 6%BW 60mL/kg
Term
the three types of ventilation are:
Definition
  1. spontaneous
  2. assisted
  3. controlled
Term
what are the deleterious effects of controlled ventilation?
Definition

o   CV

§  forced gas in: great vessels are compressed. alters BP

§  cardiac tamponade-constricting movement of heart

§  ↓right ventricular outflow, ↓pulm blood flow

o   resp

§  ↑anatomical dead space

§  alveolar rupture

o   acid-base

§  respiratory alkalosis and acidosis due to inappropriate settings

Term
what are the indications for controlled ventilation?
Definition

·         resp depression

o   drugs

o   inhalants

·         brain tumor

o   ↑ICP

o   CO2↑, then ICP↑ further during anesthesia as more blood is diverted to brain

·         cardiac arrest

·         diaphragmatic hernia

·         drugs like atracurium-paralysis of diaphragm

·         obese

·         preggers

·         emaciated

·         thoracotomy-loss of neg pressure

Term
what are the ventilator guidelines?
Definition

·         tidal volume

o   small animals 20ml/kg

o   large animals 15ml/kg

o   10ml/kg normally

·         I:E ratio

o   always set inspiratory less than expiratory time. usually 1:4

·         peak inspiratory pressure

o   highest pressure during inspiratory phase 10-30cm H2O

o   higher in horses (closer to 30, up to 40cm H2O)

 

Term
how can spontaneous breathing be eliminated?
Definition
  • do nothing
  •             hyperventilate (lower CO2, decrease stim for breathing)
  •             neuromuscular blocker
  •             opioids (fentanyl)
  •  rhythmic lung inflation (Hering-Breuer reflex)
Term
if there is a delay in teh return to spontaneous breathing, then:
Definition
  • decrease resp rate 
  •             decrease tidal volume
  •             allow rebreathing of CO2
  •             add CO2 to inspired gas
Term
what are the full μ-agonists?
Definition

·         morphine and fentanyl. the more you give, the more side effects

Term
what is an example of a partial agonist?
Definition
buprenorphine
Term
what is an example of an agonist-antagonist?
Definition
butorphanol, can reverse mu side effects
Term
what are amide local anesthetics and what are some examples?
Definition

·         stable in solution

·         enzymatic degradation (liver)

·         no p=aminobenzoic acid metabolite

o   lidocaine

o   bupivacaine

o   mepivacaine

o   ropivacine

o   EMLA (ecstatic mixture of local anesthetic)

Term
what are ester local anesthetics? what are some examples and a major drawback?
Definition

·         unstable in solution

·         metabolized in plasma (cholinesterase enzymes)

·         p-aminobenzoic acid metabolite (allergic reactions)

o   cocaine

o   benzocaine

o   procaine

o   tetracaine

Term
for onset of local anesthetics, where should injections be made, how many nodes of ranvier are required, and which nerves are easier to anesthetize?
Definition
above site of inflammation (bc of acid status), 3 nodes, myelinated
Term
onset of a local anesthetic depends on:
Definition

o   lipophilicity

o   pKa 

o   concentration

o   dose + volume

o   proximity to nerve

o   type of nerve

Term
duration of local anesthetics depends on:
Definition

o   vascular effect

o   tissue blood flow

o   vasoconstrictor

o   dose

o   affinity to Na+ receptor

o   lipophilicity

Term
in what form do local anesthetics have to be to cause anesthesia?
Definition
ionized (corks up Na channels)
Term
never give ___________to distal extremities?
Definition
vasoconstrictores (NE, Epi)
Term
in lidocaine, neuro signs precede?
Definition
CV signs
Term
as a local anesthetic, bupivicaine binds __________ in the CV system, and fibrillation is _______. so never give __________
Definition

§  strongly binds, fibrillation is not reversible, so obviously never IV

Term
in epidurals in horses, the best sites are:
Definition
L6-S1, but more commonly more caudal so as not to let the horse fall
Term
to block the front limb,  the ___________ is blocked including these nerves:
Definition
brachial plexus. C6-T2, C6, radial, tipe of shoulder
Term
when doing an intercostal block, where do you inject? what about intrapleural
Definition
  • midway between ribs
  • cranial to rib
Term
what nerves are blocked for disbudding?
Definition
·         cornual branch of lacrimal and cornual branch of intratrochlear nerve
Term
what is a substitute for epidural and where is it given and what does it block
Definition

femoral compartmental block

psoas major

L4-5

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