Lab Exam Flashcards
describe a basic anesthetic machine setup
oxygen cylinder→pressure reduction valve→ flowmeter→vaporizer→fresh gas inlet →breathing circuit
what is the metabolc requirement/ minimum O2 flow required
5-10ml/kg/min
E-cylinders
usually single
attached directly to anesthesia machine via yoke
H- cylinder
often in banks
supply central O2
pressure in the O2 tank is measured in _______
psi
breathing system pressure is measured in _______
cmH20
what is the capacity of most commonly used E-cylinders
660 L
what pressure are O2 tanks filled to?
2200 psi
what are some safety systems in place for different tanks
color-coded tanks
labellig
diameter index safety system
pin index safety system
quick connectors
what is a regulator
pressure-reducing valve
decreases tank pressure (approx 50 psi) which is supplied to flowmeter
what is a flowmeter
controls rate of gas flow through vaporizer (L/min)
enters at 50 psi leaves at 15 psi
T/F flowmeters are gas specific
True
O2 flowmeter is not accurate if used for N20
what is the minimum % O2 that should be delivered to patient
35%
T/F the quick flush bypasses the vaporizer
true
what is a possible complication of the quick flush
pneumothorax
anesthetic vaporizers
changes liquid into vapor
deliver selected % of anesthesitic vapour to fresh gas outlet
types of re-breathing systems
circle
universal F
types of non-rebreathing system
mapleson A-F
most common- bain/modified mapelsonD, mapelson F
how can you calculate bag size for small animal
body weight (in kgs) X 90
O2 flow rate for small animal induction and recovery
50-100 mL/kg/min
maintenance O2 flow rate for small animals
20-50 mL/kg/min
O2 flow rate for large animal induction and recovery
20-50 mL/kg/min
maintenance O2 flow rate for large animal
10-20 mL/kg/min
when are non-rebreathing systems used
< 3kg
how high should th eO2 flow rate be with non-rebreathing
2-3x tidal volume
~300 mL/kg/min
types of ET tubes
PCV, rubber, silicone
cuffed or uncuffed
murphy ETT
cuffed or uncuffed
has “murphy eye” - allows gas flow if end in obstructed
cole ETT
uncuffed
commonly used in avian patients - has shoulder that seals agaisnt the glottis
T/F ETT can be inflated without checking for leaks in ruminants
True
high risk of regurgitation
types of passive scavenging
exhaust directly into atmosphere - window/hole in wall
F air canister
ventilation is defined by ____
PaCO2
normal ≈ 35-45 mmHg
ventilation is monitored via ____
arterial blood gas
capnography
oxygenation is defined by _____
PaO2 or SpO2
monitored with arterial blood gas or pulse ox
hypoxemia: PaO2 < 60 mmHg, SpO2 < 90%
types of ventilation
spontaneous - patient determines, when and how
assisted - patient determines when and ventilator determines how
manditory - ventilator determines when and how
IPPV
intermittent positive pressure ventilation
positive pressure maintaned only during inspiration
IMV
intermittent manditory ventilation
predetermined number of positive breaths but patient can breath freely between mechanical breaths
CPAP
continuous positive airway pressure
spontaneous breathing with positive pressure during both inspiration and expiration
PIP
peak inspiratory pressure
inflates alveoli, opens atelactasis, causes barotrauma
indicationd for mechanical ventilation under anesthesia
decreased PaCO2
hypoxemia - breathing air
hypercapnia may be acceptable ____
up to 60-70 mmHg fr purpose to improve circulation
tidal volume, resp rate, and inspiratory time in healthy lungs
TV: 10-15 ml/kg
RR: 6-10 breaths/min
IT: 1-2 sec
2 modes of mechanical ventilation
volume controlled
pressure controlled
blood gas analysis measures:
pH
PaCO2
PaO2
normal pH of blood
7.35-7.45
normal HCO3 value
24 +/- 4 mEq/L
cats tend to be lower
herbivores tend to be higher
normal PaCO2 value
35-45 mmHg
normal base excess (BE)
0 +/- 4 mEq/L
positive = metabolic alkalosis
negative = metabolic acidosis
what can effect PaCO2 value
resp rate, tidal volume, breathing effort
PaO2 is interpreted in light of …
FiO2
ambient pressure
PaCO2
if breathing 100% O2, PaO2 should be…
> 500 mmHg
A-a difference if breathing 100% O2
<110 mmHg
causes for a high A-a difference
V/Q mismatch
right to left shunt
diffusion impairment
normal PaO2 / FiO2 ratio
>500 mmHg
5 causes for hypoexemia (low PaO2)
Low FiO2
hypoventilation
diffusion impairment
V/Q mismatch
right to left shunt
what is the common method for monitoring anesthetic depth
subjective monitoring of subcortical activities/reflexes
EEG gives information about
cortical but not subcortical activities
cental + dilated pupil can indicate ….
the patient is either too light or too deep
T/F CV adverse effects are possible even if iso is not overdosed
True
most surgeries and intubation are performed at what stage
Stage 3 planes 2-3
stage 3 plane 1
light anesthesia
nystagmus
stage 3 plane 2
medium plane of anesthesia
weak palpebral, strong corneal reflexes
adequate muscle relaxation
stage 3 plane 3
deep anesthesia
some patients may have to be maintained at this stage but ideally should decrease to plane 2
T/F HR does not aid in determining anesthetic depth
true
spontaneous RR is high (> 20 br/min) may indicate
too light anesthesia
low lung volume
ACVAA monitoring guidelines at least ____, _____, ______, and ______ should be monitored
circulation
oxygenation
ventilation
temperature
pulse palpation in small animals
labial, digital, dorsal pedal
pulse palpation in large animals
auricular, transverse facial, facial
esophageal stethoscope
assess: heart sounds, rate, and rhythm and resp sounds and rate
insert at midline dorsal to ET tube, along palatine raphe
T/F ECG indicated that the heart is contracting
False
conduction system of small animals
mammalian type A - base to apex current flow
positive R wave
conduction system of large animals
mammalian B type - apex to base
negative R wave
normal HR and strong pulses indicate _____
adequate CO
common arrhythmias under anesthesia
sinus bradycardia and tachycardia
AV blocks (1st & 2nd degree)
hypotension in small animals
mean <60
systolic < 80
hypotnesion in large animals
mean < 70
systolic < 90
BP changes with respiration indicates
hypovolemia
crucial elements of CV function
HR (and rhythm)
contractility
circulating volume
vasconstriction
invasive BP
continuously via arterial catheter
gold standard- most accurate
non-invasive BP
intermittently using a pressure cuff
oscillometric and doppler
IBP should be used in horses if they are anesthetized longer than _____
45 min
arteries used for IBP in K9
dorsal pedal
metatarsal
artery used in IBP in sheep and goats
median
auricular
oscillometric cuff’s width should be about
40% of the circumference of the limb
advantages of oscillometry
provides systolic, mean and diastolic BP
placement of doppler sensor in sheep and goats
over median artery
if you can only afford a single anesthesia monitor, you should choose a ______
doppler
SaO2 if breathing pure O2
> 98%
pulse ox readings are affected by
hypoperfusion
pigmentation
movement
abnormal Hb species
when is it important to use a pulse ox
breathing room air
V/Q mismatch
resp disease
capnograph
continuously displays ETCO2 vs time on a graph
how can core body temp be measured
esophageal temp probe entered into mid thorax
normal temp for all species under anesthesia
98 -102.5
normal resp rate for all species
10-20 br/min
normal HR for K9 under anesthesia
50-160 bpm
normal HR for sheep under anesthesia
60-150 bpm
which dog breed has prolonged recovery with thiobarbituates, propfol, and alfaxalone
sighthounds
what premeds are typically used in K9 anesthesia
opioid + sedative IM before catheter placement
which species is the easiest to intubate
dogs
blood volume of K9
~90 ml/kg
how can aspiration be prevented under anesthesia
proper ETT cuff lube and inflation
what should be done if reguritation occurs in K9
postural drainage while anesthestized
swab or suction caudal oropharynx before extubation
keep cuff inflated or partially inflated for extubation
place in sternal recumbency ASAP
how long should sheep and goats be fasted
NPO 12-18 hrs
no water for 4 hours
common problems with ruminant anesthesia
reguritation and aspiration
ruminal tympany
salivation
cardio-resp effects
catheter size for sheep and goats
16-18 gauge
because of its pulmonary effects, _________ are not recommended in sheep and goats
alpha 2 agonists
bronchoconstriction, increase pulmonary vascular resistance, pulmonary edema
T/F atropine can be used to reduce production of saliva
False
does not reduce saliva production but makes it more viscid
T/F intubation of small ruminants can be blind or by direct visualization with a laryngoscope
True
what can effect the accuracy of the capnograph readings with ruminants
exhaled methane
how should ruminants be recovered
ETT removed with cuff inflated - regurge & aspiration
support in sternal - tympany
check temp & use heating blankets in small ruminants/calves
acepromazine duration of action
long acting
4-8hrs, 48 for liver patients
phenothiazines act on which receptor(s)
dopamine
serotonin
alpha 1
histamine
main indications for phenothiazines
sedatiion (++)
antiemetic effect
antiarrhythmic
no analgesia
CV & resp effects of phenothiazines
vasodilation
hypotension
phenothiazine: contraindications
hypovolemia, hemodynamically instable
boxers - sensitive (bradycardia)
breeding stallions- penile prolapse
butorphanol is what class of opioid
mixed agonist antagonist
butorphanol acts on which receptor(s)
kappa - agonist
mu - antagonist
CV & resp effects of opioids
minimal bradycardia
main indication for propofol
injectable anesthestic
status epilepticus
propofol acts on which receptor(s)
GABA agonist
CV and resp effects with propofol
hypotension
vasodilation
apnea possible (give slow)
main indication for isoflurane
inhalant anesthetic - vapor
MAC of isoflurane for a dog
1.3%
duration of action for isoflurane
short induction and recovery
what is the main muscarinic receptor that acts on the heart
M2
bradycardia
T/F atropine crosses the BBB and placenta but glycopyrrolate does not
True
T/F glycopyrrolate can be used during emergency cases
False
slow onset (1-5 min, compared to ~1min with atropine)
common class 1B anti-arrhythmic
lidocaine
MOA of lidocaine
Na channel blocker
Main indication for lidocaine as an anti-arrhythmic
hypotension/ inadequate perfusion
R on T phenomenon
multiple VPCs
HR >180
what are the mixed inotropes and pressors
dopamine
ephedrine
norepi
epi
adverse effects for ephedrine
reflex bradycardia - vasconstriction
CNS stimulation
increases MAC
indications for epi
CPR or anaphylactic shock
vasopressin
aka ADH
non-adrenergic sympathomimetic - vasoconstriction via V1 receptor
indicated for refractory shock or non-responsive hypotension as CRI
blood volume of dogs
90 mL/kg
blood volume of sheep
60 mL/kg
maintenance fluid rate under anesthesia
10mL/kg/hr
10mL/kg fluid boluses (within 15min) can be given in cases of _____
hypotension
what would be the fluid rate for a 45kg sheep (drops/sec) if using a 15 d/mL administration set
≈2 drops/sec
- 45kg X 10mL/kg/hr = 450mL/hr*
- (450mL/hr)/(60min/hr) = 7.5mL/min*
- (7.5mL/min)/(60 sec/min) = 0.125 mL/sec*
- 0.125 mL/sec x 15 drops/mL = 1.875 drops/sec ≈ 2 drops/sec*
