Exam 1 Flashcards
what is the bare minimum bloodwork you would want to do before anesthesia
what if its an older, compromised patient?
PCV
TP
BUN
+/- glucose
CBC, chem, UA
physical status class:
normally, healthy (elective) (e.g. spay/neuter)
class I
physical status class:
mild systemic dz (e.g. mild mitral valve disease)
class II
physical status class:
moderate systemic dz (e.g. chronic renal disease, pneumonia)
class III
physical status class:
moribund (likely to die whether you anesthetize or not)
class V
physical status class:
severe dz (life threatening) (e.g. hemoabdomen, colic, septic)
class IV
what size patients would you use a rebreathing system
large patients > 5 kg
physical status class:
e.g. colic
emergent
pressure of a full oxygen tank
2000 psi
what size patients would you use a non-rebreathing system
small patients < 5 kg
what size patients do you not want to use the O2 flush valve on
small patients due to risk of damage
should the oxygen flow rate be higher in a rebreathing or non-rebreathing circuit
non-rebreathing to prevent rebreathing of CO2
5 ways to minimize anesthetic gas waste in the workplace
lower O2 flow rate
scavenge waste gas effectively
ensure leak-free
use good work practices with inhalants (e.g. fill vaporizer at end of day)
well ventilated rooms
mild hypoxemia
< 80 mmHg
< 95% SaO2
severe hypoxemia
< 60 mmHg
< 90% SaO2
differentials for hypoxemia
low inspired O2
low partial pressure (altitude or low PAO2)
hypoventilation (high CO2)
V/Q mismatch
anatomic shunt
diffusion impairment
most common cause of hypoxemia in horses
V/Q mismatch
4 methods to monitor oxygenation
- pulse oximeter
- blood gas or arterial O2 partial pressure
- cyanosis
- lactate (indirect)
what sample is required for a blood gas to measure oxygenation
arterial blood sample
when does cyanosis occur
PaO2 < 40 mmHg
3 methods to monitor ventilation
- capnography/capnometry
- blood gas or CO2 partial pressure
- acid-base balance (indirect)
what sample is required for a blood gas to measure ventilation (CO2)
arterial or venous blood sample
horse respiratory differences under anesthesia
high PCO2
affected by position
severe V/Q mismatch
cluster breathing
cat respiratory differences under anesthesia
low PCO2
mucus plug airway obstruction
difficult intubation
reactive airway
dog respiratory differences under anesthesia
depressed by opioids
brachycephalic syndrome
aspiration pneumonia
lab animal respiratory differences under anesthesia
difficult intubation
affected by position
difficult monitoring
mucus plug airway obstruction
marine animal respiratory differences under anesthesia
diving reflex
may drown
difficult intubation
amphibians respiratory differences under anesthesia
breathe through skin
difficult intubation and monitoring
bird respiratory differences under anesthesia
no alveoli or diaphragm
air sacs
no FRC
affected by position
mucus plug airway obstruction
inhalant sensitivity
complete tracheal rings
difficult to monitor
ruminant respiratory differences under anesthesia
difficult intubation
regurg/aspiration
affected by position
abdominal compression
bloat
salivation
high resp rate
smaller tidal volume
sheep hypoxic from alpha-2 agonists
camelid respiratory differences under anesthesia
difficult intubation
good oxygenation
regurg/aspiration
porcine respiratory differences under anesthesia
difficult intubation, easy to go into bronchi
small airway
unknown underlying diseases
how can you increase preload to increase stroke volume for increased CO
fluids
how can you increase contractility to increase stroke volume for increased CO
inotropic drugs - dobutamine, dopamine, ephedrine
how to increase heart rate to increase CO? what is the downside to increasing HR?
increase sympathetics with ephedrine
decrease parasympathetics with atropine or glycopyrrolate
will eventually cause stroke volume to decrease due to shortened diastolic (filling) period and increase myocardial work
how do we measure cardiac output?
blood pressure because measuring CO is invasive and cumbersome
alpha 1 drugs for cardiovascular support
vasconstriction
alpha 2 drugs for cardiovascular support
vasoconstriction
decrease heart rate
beta 1 drugs for cardiovascular support
increase cardiac output (contractility and heart rate)
beta 2 drugs for cardiovascular support
vasodilation
treatment for hypotension
- decrease anesthetic plane
- treat the cause
- fluids bolus - crystalloids
- increase contractility via inotropics
- fluid bolus - colloids or blood products
what is the most common arrhythmia in anesthetized patients
bradycardia
bradycardia treatment
- treat the cause
- anticholinergics (atropine or glycopyrrolate)
tachycardia treatment
- treat the cause
- beta-blockers (esmolol)
decreased contractility treatment
- decrease anesthetic plane
- inotropes (dobumaine, dopamine, ephedrine)
cardiac rhythm disturbance treatment
diagnose dysrhythmia with ECG and treat appropriately
vasodilation treatment
increase blood volume
vasopressors (phenylephrine)
increase CO
vasoconstriction treatment
reverse/stop vasoconstrictors
vasodilators (sodium nitroprusside, hydralazine, amlodipine, acepromazine)
subjective indicators of pre-anesthetic cardiovascular evaluation
demeanor/activity level
temperature
respiration
pulse rate, rhythm, quality
mucus membrane/CRT
objective indicators of pre-anesthetic cardiovascular evaluation
hydration status
cardiac auscultation
what is the most important cardiovascular parameter to monitor during anesthesia
blood pressure
direct measures of blood pressure
arterial catheter (most accurate!)
indirect measures of blood pressure
what are the differences
doppler (gives SAP)
oscillometric (gives SAP, MAP, DAP)
cuff width needs to be _____ the limb circumference
40%
how to treat hypovolemia
blood volume restoration only
difference between dehydration and hypovolemia
dehydration - usually hypovolemic
hypovolemic - not always dehydrated, could be hemorrhaging out
ruminant cardiovascular difference under anesthesia
hypertensive
- mostly cattle
birds, lab animals, reptile cardiovascular difference under anesthesia
hard to monitor
neonates cardiovascular difference under anesthesia
mildly hypotensive
horse cardiovascular difference under anesthesia
low heart rates
does an ECG measure cardiac performance?
NO - measures electrical activity of the heart, imperative for quantification of arrhythmias
how to measure correct ET tube size
tip of nose to point of shoulder
complications of a ET tube that is too short
no seal
damage to larynx
leaking
difficult to breathe
complications of a ET tube that is too long
endobronchial intubation
increased dead space
complications of cuff over-inflation
tracheal lesions
stenosis
rupture
when to use neuromuscular blockade drugs (cisatracurium, atracurium, vecuronium)
ortho procedures
optho procedures
precise procedures (CNS, amputation)
abdominal organs (c-section, colic)
ET intubation
what are the most important aspects of NM blockade
assisted ventilation
monitor
how to reverse NM blockade drugs
pharmacokinetics (wait until worn off)
drugs - neostigmine, edrophonium, sugammadex/rocuronium
what to consider when positioning an anesthetized animal
support bony prominences, superficial nerves, large mm groups
prevent abnormal positions and pressure points
support pre-existing fractures/arthritis
esp important in LA
parameters to consider of anesthesia recovery
temperature/hypothermia
pain
airway control
oxygenation
behavior
environment
what fluids do you use for a patient who is dehydrated
crystalloids (LRS, normosol, plasmalyte, physiologic saline 0.9% NaCl)
what fluids do you use for a patient who is hypovolemic
crystalloids
colloids
blood products
how do you want to administer crystalloids? why?
conservative dose (10-20ml/kg)
shock bolus can kill patient due to hemodilution (PCV, proteins, platelets, coag factors)
pros of colloids
stays in vasculature 6-8hr
economical
long shelf life
increase BV rapidly
may prevent edema
cons of colloids
hemodilution
coagulopathies
anaphylactic rxn
fluid overload
acute renal disease
components of fresh whole blood
RBC
platelets
proteins
coag factors
components of stored whole blood
RBC
proteins
coag factors
causes of increase anion gap
high Na+, K+
low Cl, HCO3
low Ca, Mg, NH4
high sulfates, phosphates, lactate, ketoacidosis, proteins, nonesterified fatty acids or ethylene glycol
treatment for hypoglycemia
dextrose administration
treatment for hyperglycemia
regular insulin BID
regular insulin CRI for DKA
