Unit 3 notes Flashcards
Define induction period
taking an animal from a conscious level to an unconscious level
should be the shortest component of GA
2 types of induction agents used
Injectable (preferred)
Inhalant
Route of injectable induction agents
IV (followed by inhalant, give slowly and titrate to effect)
IM (2-3 times IV dose, cannot titrate to effect, fractious animals only)
Injectable drugs used
Barbituate
Cyclohexamine
Propofol
What is the “blast em technique”
setting a high O2 flow rate, and a high vaporizer setting
Disadvantages of inhalant drugs
Waste gas exposure
Less patient cooperation
Dramatic vasodilation
2 Types of inhalant drugs
Isoflurane
Sevoflurane
Bast em technique
setting a high O2 flow and vaporizer setting to quickly induct patient
Nice way technique
setting a high O2 flow rate and gradually increasing the vaporizer settings by 1/2% every minute
Who should the Nice way and Blast em techniques NOT be used on?
Brachycephalics
2 Types of ET tubes
Murphy-eye tube: inflatable cuff
Cole
5 Indications for intubating
Provide airway Prevent aspiration Provide efficient gas delivery Decrease dead space Provide controlled ventilations
Disadvantages of ET tube use
Stimulation of vagus nerve Some species have difficulties Risk of bronchi insertion Risk of obstructed ET tube Can contribute to hypothermia
How to measure length of ET tube
Tip of nose to thoracic inlet
3 causes of difficult intubatioin
Poor patient positioning
Laryngospasms
Inadequate plane of anesthesia
Define maintenance period
Period of time following induction in which a STABLE level of anesthesia is reached
Stage I
PA period Voluntary excitement phase -Conscious -All protective reflexes present -Normal heart and RR -Disoriented -Slight decreased sensitivity to pain
Stage II
Induction period Involuntary excitement phase -goes to conscious to unconscious level -all protective reflexes present -normal heart and RR -patient may be struggling
Stage III Plane I
Light Anesthetic Plane
- Animal can be intubated
- Sluggish reflexes
- Jaw tone relaxed
- Unable to withstand sx
Stage III Plane II
Medium Anesthetic Plane
- Most sx procedures are done at this plane
- Most reflexes absent
- Slight increase in heart and RR due to sx stimulation
Stage III Plane III
Deep Anesthetic plane -Most reflexes absent -Muscle tone slightly more relaxed -No response to sx stimulation Requires very close monitoring!!
Stage III Plane IV
Overdose of anesthetic
- Patient in danger of cardiac arrest
- Significant depression of body systems
- Change planes immediately!!
Stage IV
CPR necessary for life!!
Crash cart
no longer GA— headed towards death
Palpebral reflex
“blink” reflex
gently touch medial canthis of the eye
lost at surgical plane
Pedal reflex
“toe pinch” reflex
pinch webbing of toes
lost at surgical plane
Nystagmus
Happens during middle of plane change
Eye rotation
Will rotate medial and ventral at stage III plane II
Ear flick
Only works with cats and equine
Jaw tone
Best reflex to watch
will never be completely gone
pull to 45 degree angle and feel for tone
BP normals
Systolic= 100-160mmHg Diastolic= 60-100mmHg Mean= 80-120mmHg
Hypotensive values
Systolic= <60mmHg
3 Things that contribute to BP
Blood volume
Cardiac output
Vascular resistance
Causes of hypotension
Hypovolemia
Overdose of anesthetic drugs
Decrease in cardiac output
Managing hypotension
Bolus IV fluids (20ml/kg/hr.)
+/- decrease anesthetic %
Give + inotropic drugs
3 ways to measure BP
Doppler machine
Oscillometric
Direct arterial BP
2 Parts to place with DOPPLER & how to hook up
Cuff- should be 40% the circumference of leg, placed proximal to the crystal and attached to sphygmomanometer
Crystal- placed on artery, concaved side down
Technique for using DOPPLER
Inflate cuff until you cannot hear pulse
gradually release pressure until you hear the pulse again
Pulse Oximeter values & normals
Values=
Amount of Hgb saturated with O2 reported out as SpO2 or PaO2
Pulse Rate
Normals= >95% (under anesthesia) >90% when awake 60-160bpm canine 110-220bpm feline 30-40 equine
How to place Pulse Ox
Must be placed onto a moist, non-pigmented area such as:
tongue, webbing of toes, vulva, prepuce
Causes for desaturation (Pulse Ox)
V/Q mismatch Disconnected from breathing system Blocked airway Inadequate flow rate Erroneous readings (most common) Hypovolemia
4 ways to monitor respiratory system
Capnograph
Res. Bag
Esophageal Stethascope, flutter valves, ET tub fog… etc
Rate and character
Capnograph gives you what 3 things?
RR
ETCO2
InCO2
Normal capnograph readings
RR= 8-20rpm ETCO2= 35-45mmHg InCO2= 0-5mmHg
2 Types of capnographs
Mainstream: connecter that connects between ET tube and Y tubing. Computer crystal inside tubing reads vitals
Side Stream: Connecter connects between Y and ET tubing. Takes sample of air away from patient and analyzes it inside machine (cheaper)
Define controlled ventilation
Controlling the volume of air, rate of respiration, and pressure of air being introduced into the animal
How often do you ventilate with controlled ventilation and why?
every 5 min to prevent: atelectesis blow off excess CO2 Prevent hypoxemia Prevent hypoventilation Counteract decrease in tidal volume
How to completely take over respirations
Res. bag
Mechanical ventilator
How to ventilate with Res. Bag
Ventilate 12-16rpm
after 3-5 min patient will stop breating on their own
decrease ventilations (8-12rpm for remaining time)
Wean off ventilator by gradually decreasing ventilations
How to ventilate with Mechanical Ventilator
Hook up machine to res bag port
Hook up to scavange
3 types of mechanical ventilators
Pressure cycle ventilator- Bird mark 7
Volume cycle ventilator- Ohio Metomatic
Time cycle ventilator- Drager
What 2 values does a ECG give you?
Heart rate
Heart rhythms
ECG leads
white= right axillary
black= left axillary
red=left inguinal
green= right inguinal
Most common artifacts on an ECG
movement
cautery pens
some dental equipment
drying out of electrodes
Ventricular means theres an issue with ____
the AV node
Sinus means
normal electrical function of heart
PVC
Pre ventricular contractions AV node firing before SA node wide appearance to QRS complex consistant R-Rs missing P wave QRS for every P Okay if occasional
Uniform PVC
all QRS complexes have the same configuration
Multiform PVC
QRS complexes have different configurations
Causes of PVCs
Electrolyte imbalance GDV Circulating catecholemines Drugs (barbiturates) Inhalant anesthetics (Halothane)
Treatment of PVCs
(if seeing multiple)
Find underlying cause
Ventilate patient and decrease gas
(if unsuccessful, give lidocaine)
Ventricular Tachycardia
3 or more PCVs in a row
Causes of V-Tach
Very bad cardiac output GDV Electrolyte imbalance Circulating Catecholemines Drugs
Treatment of V-Tach
lidocaine drip
V-Fib
Ventricular fibrillation
Usually a terminal rhythm
Treatment of V-fib
Defibrillator paddle
Asystole
Animal must be dead for 3-5 minutes before you will even see this
No electrical function (flat line)
Give epinephrine
Sinus Tachycardia
Increased heart rate
Regular rhythm
Patient is probably too light
deepen anesthetic plane
Sinus Bradycardia
Decreased heart rate
Regular rhythm
Patient is probably too deep
evaluate patient and either decrease gas if too deep or give anticholinergic if at a good plane
First degree AV block
Delay in conduction between SA node and AV node
Not a serious problem
everything appears normal, except there is an occasional delay between P and QRS waves
Second degree AV block
Some impulses between SA and AV node are blocked
Not life threatening yet (treat if seen!)
some P waves have no QRS complexes
Treat with anticholinergics
Third degree AV block
Have more than one lone P-wave in consecutive sessions
Life threatening
Treat with pacemaker
Broadened and Heightened T wave
caused by myocardial hypoxia
very wide and broad T wave
Spiked T wave
Caused by electrolyte imbalances (hyperkalemia)
Spikey and tall T wave
Treatment for abnormal T waves
Ventilate and decrease anesthetic %
Change fluids if consistent spiky T waves
Malignant Hyperthermia
a genetic disorder will have increased muscle activity leading to hyperthermia (very uncommon in small animals)
Hypothermia causes
Decreased muscle activity Decreased metabolic rate Intro of cold gas Surgical preparation Open body cavity
Ways to prevent Hypothermia
Always keep something between patient and table Circulating water blanket Bear Hugger Monitor the patient Gauze around feet will keep heat in Camping blanket
Hypothermia @ or above 96 degrees
No physiological effect on patient
Hypothermia between 90-94 degrees
decreased anesthetic requirement due to depressed body system
Hypothermia between 82-86 degrees
no anesthetic requirement due to significant depression of body systems
