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159 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Use of opiods
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preanesthetics
induction agents analgesics |
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opiods mode of action
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may act as agonists or antagonists on receptors
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opiod effects (2)
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1) CNS effects - depression or excitement. cats may exhibit bizzare behavior patterns.
2)Analgesia |
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neuroptanalgesia
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opiod + tranquilizer
state of profound sedation and analgesia |
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opiod adverse effects (3)
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1) depress respiration
2) increased peristalic movement 3) addiction |
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opiod reversability
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1) nalaxone
2) butorphanol (opiod) |
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4 components of general anesthesia
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preanesthesia
induction maintenance recovery |
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Variables to be accessed every 5min during anesthesia
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respiration depth and character
MM color CRT HR pulse strenght and rate jaw tone eye position palpebral reflex O2 rate & O2 tank pressure IV catheter placement & fluid administration rate Temp |
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titration
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drug given in a series of bolus injections, discontinuing when desired depth of anesethesia is reached
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Stage I
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immediately after induction
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Stage II
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involuntary excitement, not enough receptors hit
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Stage III
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under anesthesia
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Stage IV
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moribund
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respiration during stage 1
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normal, may be panting, rr 20-30bpm
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respiration during Stage 2
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irregular, may hold breath or hyperventilate
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respiration under Stage 3, plane 1
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regular 12-20
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respiration during
stage 3, plane 2 |
regular, may be shallow, 12-16
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respiration
stage 3, plane 3 |
shallow, <12bpm
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respiration under Stage 3 plane 4
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jerky
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respiration under stage IV
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apnea
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cardiovascular function under stage 1
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hr unchanged
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cardiovascular function under stage 2
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hr may increase
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cardiovascular function
stage 3, plane 1 |
pulse strong, hr > 90
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cardiovascular function
stage 3 plane 2 |
hr > 90
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cardiovascular function
stage 3 plane 3 |
60-90 CRT increased, pulse less strong
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cardiovascular function
stage 3 plane 4 |
<60 prolonged CRT, pale mm
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cardiovascular function stage 4
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cardiovascular collapse
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response to sx under anesthesia
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plane 1 may respond w movement
plane 2 hr and rr may increase |
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eye position during anesthesia
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stage 1 central
stage 2 nystagmus plane 1 central or rotated, nystagmus plane 2 rotated ventrally plane 3 central or ventral plane 4, stage 4 central |
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pupil size under anesthesia
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stage 2 may be dilated
plane 1 normal plane 2 slightly dilated plane 3 moderately dilated plane 4, stage 4 widely dilated |
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pupil response to light during anesthesia
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plane 2 sluggish
plane 3 very sluggish / absent plane 4, stage 4 unresponsive |
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muscle tone under anesthesia
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plane 2 relaxed
plane 3 greatly reduced plane 4, stage 4 flaccid |
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reflexes under anesthesia
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stage 2 exaggerated
plane 1 swallowing poor/absent plane 2 patellar, ear flick, palpebral, corneal |
2 PPEC
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normal rr
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dogs 15-30 bpm
cats 20-40 bpm |
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normal hr
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dogs 60-160 bpm
toy breeds - up to 180 cats 110-240 bpm |
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brick red mm
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increased perfusion, vasodilation
early shock, fever, sepsis, systemic inflammatory response |
sssirf
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brown mm
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intravascular hemolysis
acetaminophen toxicity in cats |
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petechiae mm (red splotching)
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coagulation disorder
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rr values during anesthesia
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dog 8-15 cat 12-18
dog <8 cat <10 dog <4 cat <6 |
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hr values during anesthesia
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dog 70-120
cat 130-170 |
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arterial blood pressure during anesthesia
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dog 100 cat 120
dog <60 cat <100 dog <50 cat <80 |
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temperature values during anesthesia
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100-102
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Two major cyclohexamine drugs
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ketamine
tiletamine (telazol) |
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Cyclohexamines mode of action
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disrupt pathways within the cerebrum and CNS stimulation
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Effects of cyclohexamines (4)
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muscle tone increased
reflexes exagerrated sensitivity to light & sound dissociative anesthesia |
mr sd
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Adverse systemic effects of cyclohexamines (2)
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cardiac - tachycardia
apneustic respiration (breath holding) |
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adverse effects of cyclohexamines (5)
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tissue irritation
increased salivation no eye closure stormy recovery personality changes |
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negative properties of barbiturates (2)
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high lipid solubility
long recovery - drug stays in body |
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barbiturates should not be given to (3)
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sighthounds - little body fat
animals in shock hepatic/renal disease |
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adverse effects of barbiturates (5)
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respiratory depression
reduction in tidal volume tissue necrosis cardiac arrhythmias excitement during induction/recovery |
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tiletamine/telazol
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cyclohexamine
less apneustic respiration prolonged recovery |
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Propofol - use, advantage, systemic effect
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may be used as sole agent
rapid recovery, regardless of amount given minimal cardiac effects |
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chlorofluorocarbons
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halothane, isoflurane, sevoflurane
methoxyflurane (lesser degree) |
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gas anesthetics mode of action
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inhibit breakdown of GABA, an inhibitory neurotransmitter. levels increase in brain and inhibit nerve function
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distribution, elimination, & action of inhalant agents
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concentration gradient between
alveoli, blood supply and brain |
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solubility coefficient
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measures distribution of gas between blood and gas in the body.
low = enters circulation and escapes to brain high = absorbed in other tissues and less "escapes" to brain with less concentration gradient in alveoli |
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properties of halothane (4)
advantage disadvantage vapor pressure |
fairly rapid induction & recovery
moderate rubber solubility high vapor pressure needs precision vaporizer |
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tiletamine / telazol
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less apneustic respiration
may be prolonged recovery |
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propofol advantages (5)
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minimal cardiac effects
safe in sighthounds rapid wakeup, onset, & duration (only 5-10min) may be titrated w/o prolonged recovery some muscle relaxation |
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propofol disadvantages (3)
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cannot be stored > 6 hours
some respiratory depression in 1st minutes no analgesia |
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propofol uses
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induction
sole agent for short procedures |
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list 1 advantage of etomidate and 3 disadvantages
type of drug |
Little systemic effects
Vomition IV injection - painful Phlebitis imidazole |
VIP
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qualities of ideal inhalation agents (8)
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1. minimal toxicity
2. ease of administraiton 3. rapid induction 4. good relaxation 5. good analgesia 6. cost 7. easy to handle 8. easy to control depth |
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Ether
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inhalation anesthetic
not used airway irritation increased salivation explosive |
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chloroform
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inhalation anasthetic
not used carcinogenic |
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nitrous oxide
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gas inhalant anesthetic
used more in human than vet medicine blue tank |
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chlorofluorocarbons (4)
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halothane
isoflurane sevoflurane methoxyflurane |
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mode of action of gas anesthetics
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Inhibit breakdown of GABA, an inhibitory transmitter.
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solubility of gas anesthitics in order from most to least
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methoxyflurane
halothane isoflurane sevoflurane |
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vapor pressure
if high, the drug is... Vapor pressure of halothane & iso vs sevuflurane |
Measure of the tendency of anesthetic molecule to evaporate at 20C (room temp)
Volatile = high vapor pressure Halothane & Isoflurane higher than Sevuflurane |
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low solubility coefficient
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rapid induction & recovery
enters circulation and escapes to brain |
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High Solubility Coefficient
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Slow recovery
Drug absorbed in other tissues and less "escapes" to brain with less concentration gradient in alveoli. |
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Minimal Alveolar Concentration
What is more potent? Anesthetics Lowest to Highest MAC |
Lowest concentration that produces no response in 50% of patients exposed to pain stimulus.
Low MAC = more potent. Lowest to highest: Methoxyflurane, Halothane, Isoflurane, Sevoflurane |
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Halothane adverse effects (8)
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Vasodilation & resp depression
Depressive effect on myocardium Sensitizes heart to catecholamines Increases vagal tone Moderate lipid solubility May cause livery toxicity Malignant hyperthermia Little analgesia |
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Isoflurane advantages (9)
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Quick recovery
Safer Highest MAC Low solubility coefficient Low rubber solubility Stable at room temp Does not effect myocardium Good muscle relaxation No malignant hyperthermia or liver toxicity |
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2 Advantages of Sevoflurane
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Very rapid induction & recovery
Easy adjustment of anesth. level |
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Tidal Volume
Which drug lowers it? |
Amount of gas inhaled
15ml/kg Barbiturates |
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Minute Respiration Volume
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amount inhaled in 1 minute
rr x (kg x 15ml) |
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Path of gas in anesthetic machine
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O2 tank, gas pressure gauge, gas pressure regulator/reducting valve
Flowmeter - Vaporizer - Fresh gas inlet Inhalation valve - Inhalation hose - ET tube - Patient - Exchalation hose - Exhalation valve - Pop-off valve - Reservoir bag scavanger, CO2 absorber canister |
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Contents of full E cylinger of oxygen
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2200 psi
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Contents of oxygen tank which is half full
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1100 psi
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Liters of oxygen in tank
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psi x 0.3
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Oxygen tank should be changed at
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100-200psi
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Advantages of cuffed ET tubes (3)
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1. Prevent leakage of waste gas
2. Reduces risk of aspiration of material into lungs 3. Prevents breathing of room air |
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Tank Pressure Gauge
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Indicates pressure of oxygen being delivered
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function of
Pressure-reducing valve / pressure regulator |
reduces oxygen pressure to 40-50 psi
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Flowmeter
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Sets gas flow rate to patient
L/min Reduces pressure from 50 to 15 psi |
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Function of vaporizer
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Converts liquid anesthetic to vapor state
Adds controlled amounts of vaporized anesthetic to carrier gas |
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function and components of breathing circuit
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Carries anesthetic and oxygen from vaporizer to patient and conveys expired gas away from patient.
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4 Functions of Reservoir Bag
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"Bagging" (manual ventilation)
Observation of respirations Movement of bag indicates that ET tube is within trachea Stores gas |
BOMS
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function of unidirectional valves
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Allows gases to flow in only one direction (toward the patient)
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Bagging
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Reservoir bag squeezed forcing 02 into lungs
1. Helps reverse atelectasis (alveoli collapse) 2. Flushes airways and alveoli with fresh gas, removing increase CO2 3. Artificial respiration |
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Minimum volume of reservoir bag
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60ml/kg
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Pop-off valve / Pressure release valve
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Allows access gas to exit from anesthetic circuit and enter scavenging system
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Carbon Dioxide Absorber
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Contains absorbing chemicals such as soda lime or barium hydroxide lime
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Oxygen Flush Valve
Rate of O2 delivery |
Allows oxygen to bypass the flowmeter and vaporizer and enter the machine between unidirectional valves.
Pure O2 is delivered directly to breathing circut at rate of 35-75 L/min. |
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function of pressure manometer
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Measures pressure of gases within the breathing system
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Negative pressure relief valve
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opens and admits room air to the circut if negative pressure (vacuum) is detected in circuit
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Etomidate is particularly well suited for induction of dogs with which of the following problems?
a) Severe cardiac disease b) Renal failure c) Orthopedic disease d) Pediatric (younger than 4wks) |
a) Severe cardiac disease
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True or False
Injectable drugs that are highly fat soluble are likely to be taken up by the brain more quickly that drugs that are not fat soluble. |
True
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Which of the following is an example of a dissociative anesthitic?
a) Thipental sodium b) Pentobarbital sodium c) Ketamine hydrochloride d) Propofol |
c) Ketamine hydrochloride
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True or False
One of the disadvantages of the drug methohexital is that animals that are anesthetized with it often may demonstrate excitement during recovery |
True
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True or False
Metabolism and elimination of ketamine hydrochloride are the same in the dog as they are in the cat |
False
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Compared with methoxyflurane, halothane is considered to have a
a) Higher vapor pressure b) Similar vapor pressure c) Lower vapor pressure |
a) Higher vapor pressure
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True or False
Halothane may sensitize the heart to catecholamines |
True
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True or False
Halothane is moderately soluble in rubber, which may result in the release of this gas from anesthetic equipment. |
True
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An anesthetic agent that has a low solubility coefficient will result in ___________ induction and recovery time
a) Slow b) Moderate c) Fast |
c) Fast
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Which of the following has the lowest solubility coefficient
a) Halothane b) Isoflurane c) Methoxylflurane d) Sevoflurane |
d) Sevoflurane
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As a rough guideline, to safely maintain a surgical plane of anesthesia, the vaporizer should be set at _________ x MAC
a) 0.2 b) 1 c) 1.5 d) 2 e) 2.5 |
c) 1.5
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True or False
Isoflurane is a more potent cardiac depressant than halothane |
False
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Propofol sometimes causes transient apnea. To avoid this, the anesthesiest should:
a) Give by infusion only b) Premedicate with opiods c) Administer IV only d) Titrate this drug in several boluses |
d) Titrate this drug in several boluses
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To be considered effective, nitrous oxide should be used at a minimum concentration of
a) 3% b) 30-40% c) 50-60% d) More than 80% e) None of the above ranges are correct |
c) 50-60%
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One problem frequently associated with recovery from tiletamine-zolazepam in dogs is:
a) Excitement b) Bradycardia c) Hypotension d) Laryngospasm |
a) Excitement
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Effects of halothane on the body include:
a) Vasodilation b) Nystagmus c) Sensitization of myocardium to catecholamines d) Depression of myocardial cells e) Respiratory depression |
a, c, d, e
No nystagmus |
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Effects that barbiturates may have on the body include:
a) Reduction of respiratory rate b) Tachycardia c) Cardiac arrhythmias d) Decreased blood pressure |
a, c, d
no tachycardia |
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The concentration of barbiturate entering the brain is affected by a variety of factors such as:
a) Perfusion of the brain b) Lipid solubility of drug c) Plasma protein levels d) Blood pH of the animal |
a, b, c, d
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Effects that are commonly seen after administration of a cyclohexamine drug include:
a) Increased blood pressure b) Increased heart rate c) Increased CSF pressure d) Increased intraocular pressure |
a, b, c, d
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Effects that isoflurane may have on the body include:
a) Hepatic toxicity b) Accumulation in body fat stores c) Depression of respiration d) Seizures during recovery |
c) Depression of respiration
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MAC will vary with:
a) Temperature of patient b) Age of patient c) Concurrent use of other drugs d) Anesthetic agent |
a, b, c, d
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Factors that may affect the speed of the induction process with a volatile gaseous anesthetic include:
a) Solubility coefficient of the agent b) Vaporizer setting c) MAC of the agent d) Concurrent use of atropine |
a) Solubility coefficient of the agent
b) Vaporizer setting |
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Nitrous oxide may be included as part of an anesthetic protocol because it:
a) May provide a second gas effect b) Will reduce the amount of volatile anesthetic needed c) Has minimal depressant effects on the respiratory or cardiovascular centers d) Can replace oxygen in the anesthetic circuit |
a, b, c
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When pentobartital sodium is used as an anesthetic, which of the following may be noted:
a) Relatively slow onset of action b) Respiratory depression c) Poor analgesia d) Slow recovery e) Easily reversed |
a, b, c, d
Not easily reversed |
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Which of the following drugs may be safely and effectively given IM or IV in a cat?
a) Thiopental sodium b) Telazol c) Ketamine hydrochloride d) Methohexital sodium |
b) Telazol
c) Ketamine hydrochloride |
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How are injectible anesthetics eliminated?
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redistribution
liver metabolism renal excretion |
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How are inhalation anesthetics eliminated?
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exhalation from lungs
some undergo liver metabolism and renal excretion |
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List 5 types of injectable induction agents
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barbiturates
cyclohexamines etomidate neuroptanalgesic agents propofol |
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Classes or barbiturates
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Intermediate acting (pentobarbital)
Short acting (thiopental) Ultrashort acting (methohexital) |
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How are barbiturates used
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Used as induction agents
Administered by titration |
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Pentobarbital
Class Adverse effects (4) |
intermediate acting barbiturate
analgesia - none respiratory depression recovery prolonged relaxation of muscle poor |
ARRR
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Doxapram (Dopram)
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respiratory stimulant
may accelerate arousal from barbiturate or inhaltation anesthesia |
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2 Disadvantages of Sevoflurane
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1) Reacts with KOH or NaOH in soda lime to produce Compound A that can cause renal tubular damage in rats.
2) Greater heart and respiratory depression than isoflurane |
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Properties of Sevoflurane
vapor pressure, solubility coefficient, Mean Alveolar Concentration |
Vapor pressure: lower than isoflurane
Solubility coefficient: very low MAC: greater than isoflurane |
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induction
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process by which animal leaves conscious state
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maintenance
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stable level of anesthesia achieved
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recovery
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concentrations decrease in brain
injectable drugs metabolized |
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Safety of general anesthetics
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1) use premeds
2) reduce quantitiy of anesthetic w/ appropriate premeds 3) double check doses 4) titration |
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Thiopental/barbiturate induction
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Stay within vein (use indwelling catheter)
1/2 dose over 10-15sec "bolus" Immediate entrance to stage 3 If intubation not possible after 30sec give 1/2 remaining dose |
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Ketamine/tranquilizer induction
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1) Inject total quantity over 30-60sec or
2) give 1/2 as bolus over 15-30sec & rest in halves every 45sec |
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Propofol induction
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slow IV
1/3 of dose every 30sec careful of apnea |
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Advantages of inhalation anesthesia (5)
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1) Greater margin of safety
2) Depth readily altered 3) Elimination via lungs 4) Constant delivery of O2 5) Emergency airway for mechanical ventilation |
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Disadvantages of inhalation anesthesia (2)
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Anesthetic machine required
Waste gas |
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Disadvantages of maintenance via injectable agents (4)
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1) Not easy to control
2) Low margin of safety 3) Constant IV injection 4) Non safety access |
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0-5% dehydrated
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Tent: skin immediately returns
CRT normal Eyes normal MM pink and moist |
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5-8% dehydrated
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Tent 2-4sec delay
CRT 2 sec Eyes slightly sunken in sockets MM slightly dry or tacky |
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8-10% dehydrated
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Tent 5-10sec delay
CRT 2-2.5sec Eyes sunken in sockets MM dry, slightly tacky |
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10-12% dehydrated
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Tent 10-30sec
CRT 3+ Eyes very sunken MM dry Depressed Signs of shock, cool extremities Rapid, weak pulse Tachycardia |
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12-15% dehydrated
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State of shock, death is probable
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Advantages ET intubation (4)
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1) efficient delivery of anesthetic gas
2) improves efficiency or respiration, decreases anatomic dead space 3) delivers O2 directly to patient 4) reduces risk of aspiration |
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Disadvantages of ET intubation (9)
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1) stimulate activity of vagus nerve
2) some species/breeds difficult to intubate 3) may damage larynx, pharynx or soft palate 4) many tubes designed for humans & are too long for vet use 5) pressure necrosis may result if cuff excessively inflated 6) may become obsructed by saliva, mucus, blood, foreign material 7) patient may chew tube in half 8) tubes reused - spread diseases, disinfectant may irritate tracha 9) irritation of tracha and larynx |
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reasons for hypothermia (6)
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1) anesthetic depression thermoregulation in brain
2) shaving 3) decreased metabolic rate 4) no shiver reflex 5) opened body cavities 6) pediatric/geriatric patients can't regulate temp well (decreased glucose) |
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murphy endoctracheal tube
murphy eye helps prevent complete obsruction of tube if bevel is plugged magill tube - no eye |
name, function
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cole endotracheal tube
used in small animals |
name, use
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tank pressure gauge
indicates pressure of O2 being delivered |
name, use
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precision vaporizer
designed to deliver exact concentration of gas selected |
name, use
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Mature fel
Strong pulse, HR 144, rr 20, pupils central, palpebral reflex, no pedal or ear flick reflex. Stage? Is intubation possible? What other tests should be done? |
Stage 3, plane 1
May be deep enough to intubate. Check jaw tone. |
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13yr k9, tumor removal, under 2% iso
Respiration shallow, rr 8, hr 90, no response to sx, no reflexes, central pupils. Adequate anasthesia? |
Stage 3, plane 3
Too deep, change to 1.5% |
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8yr k9, atropine, ket/val
hr 100, rr 8, moderate jaw tone, pupils central, no response to light, no reflexes Appropriate depth? |
Stage 3, plane 2 or 3
Uncertain of stage. Deep enough. |
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Collapse of alveoli
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atelectasis
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Collapse of alveoli
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atelectasis
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