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254 Cards in this Set
- Front
- Back
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the loss of sensation to the entire or any part of the body
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anesthesia
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general anesthesia is characterized by (5):
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hypnosis, muscle relaxation, analgesia, amnesia, hyporeflexia
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loss of sensation in a circumscribed area of the body (field block)
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local anesthesia
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loss fo sensation of an area of the body distal to the area supplied by a specific nerve or nerve trunk
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regional anesthesia
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centrally induces drowsiness but variably responsive to stimuli
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sedation
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behavioral change resulting in a decreased anxiety; more relaxed but aware of surroundings
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tranquilization
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drug induced deep sleep in which the patient is not easily aroused
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narcosis
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what 2 organ systems should you focus on our PE that will have the most immediate impact on anesthetic delivery
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cardiovascular and pulmonary
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anesthetic dosages should be calculated on the animals's (true or ideal/lean) BW
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ideal/lean - the blood flow to the fat is minimal and has little effect on teh action of the anesthetic; also consider alometric scale = BW:SA
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Lab work:
Young animal |
PCV and TP
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Lab work:
Older animal |
CBC and Chem Panel
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Physical Status Classification (PSC):
normal, healthy patient, minimal risk operation (OHE, castration) |
Class I
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PSC:
patient with mild systemic disease; slight risk operation (neonate, geriatric, mild dehydration, mild anemia) |
Class II
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PSC:
patient with severe systemic disease that limits activity but is not incapacitating (regulated diabetic, early stage renal disease) |
Class III
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PSC:
patient with incapacitating disease trhat is a constant threat to life (shock, GDV, severe heart and lung disease) |
Class IV
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PSC:
moribund patient not expected to live 24 hours with or without the intervention (terminal cancer, diffuse organ failure) |
Class V
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PSC:
emergency, immediate anesthesia is required |
Class E
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types of premeds (6)
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anticholinergics
phenothiazine tranquilizers butyrophenone tranquilizers benzodiazepines alpha 2 agonists opioids |
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why premed (10)?
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Modify behavior
Produce calming/sleep Reduce stress Prevent/eliminate pain Produce muscle relaxation dDcrease the dose requirement or subsequent anesthetic drugs Produce safer gen anes at induction, maintenance, and recovery Minimize the undesirable effects of other drugs Minimize autonomic reflex activity (vomiting, bradycardia, EPI release) Improve recovery from anesthesia |
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Anticholinergics do NOT produce (2):
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Sedation
Anesthesia |
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Anticholinergics are alos known as:
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Antimuscarinics (muscarinic receptors control parasympathetic system, which is part of ANS)
Nicotinic receptors are NOT affected by anticholinergics |
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Anticholinergic MOA
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Compete with neurally released ACh for access to muscarinic cholinoceptors); blocks effects of ACh
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Anticholinergics (inc or dec) glandular secretions in airways, oral cavity, nasal cavity, and GI
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Decrease
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Anticholinergics induce (mydriasis/miosis)
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Mydriasis
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Excessive secretion predisposes airway to:
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Upper airway obstruction
Laryngospasm |
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Anticholinergics cause (bronchodilation/bronchoconstriction)
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Bronchodilation (dead space ventilation may increase and effective ventilation may decrease)
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Why should you not use atropine in horses/cattle?
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Intestinal motility decreases/eliminated for hours causing ileus (horse) or bloat (cattle)
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Anticholinergics cause (bradycardia/tachycardia)
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Tachycardia (vagal effects are inhibited); increase SA discharge - transient secondary AV blocks - AV node increases in responsiveness - rate of ventricular contraction increases
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Causes for increased vagal stiumation (4):
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Traction on visceral organs during surgery
Pressure/traction on extraocular muscles (oculocardia reflex) Drugs/factors causing increased vagal tone (opioids, a2 agonists, digitalis, calsium, acidosis, hyperkalemia) Drugs that decrease sympathetic tone (barbiturates, propofol, inhalant anesthetics) |
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Drugs/factors that increase vagal tone (6):
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Opioids (fentanyl, morphine)
A2 agonists (xylazne, medetomidine) Digitalis Calcium Acidosis Hyperkalemia |
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Drugs decreasing sympathetic tone (3):
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Barbiturates
Propofol Inhalent anesthetics |
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Adverse effects of anticholinergic administration (4):
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Sinus tachycardia (decreases myocardial oxygen consumption, precipitates heart failure and pulmonary edema)
CNS depression in dogs and cats Bloat in ruminants Colic in horses due to ileus |
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Which has a longer DOA: atropine or glycopyrrolate
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Glycopyrrolate DOA = 2-4 hours
(atropine DOA= 60-90 min) |
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Why should atropine be used in C-sections?
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Crosses placental barrier so keeps baby's HR up (also crosses BBB)
(Glycopyrrolate does not cross BBB or placenta) |
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Why is atropine ineffective in what species??
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Rabbits (lots of atropinase which hydrolyzes atropine)
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Which is more potent: atorpine or gycopyrrolate?
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Glycopyrrolate (2x as potent as atropine), but slower onset of action than atropine
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What is the anticholinergic ipratropium (Atrovent) used for?
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Airway dilation (administered via MDI) for horses with bronchoconstrictive disease (COPD)
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Does Atrovent affect the mucociliary clearance?
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NO
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Even though anticholinergics decrease salivary secretions, why is it not used in ruminants (2)?
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Ruminal atony
Saliva becomes thick and more difficult to remove - instead just position head and neck so saliva drains from mouth |
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Use anticholinergics to (5):
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Prevent/treat drug-induced bradycardia (a2 agonists, opioids, oculocardiac reflex)
When excessive salivation is anticipated (ketamine, slobbery breeds) Brachycephalic breeds (have a high resting vagal tone) Premed for C-section (atropine) To accompany anticholinesterase reversal of neuromuscular blockade (atracurium reversal with neostigmine) |
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The only phenothiazine still in clinical use today
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Acepromazine
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MOA of phenothiazine
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Blocks dopamine receptors in limbic system and basal ganglia
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Acepromazine produces (2):
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Claming
Muscle relaxation |
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What prolapses with acepromazine (2):
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Third eyelid
Penis (stallions) |
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Acepromazine reduces the amount of injectable and inhalant anesthetics by:
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25-50%
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Acepromazine causes VD or VC?
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VD - this results in hypothermia and hypotension
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What do you do if animal given acepromazine has a hypotensive crisis?
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IV fluids (crystalloid/colloid)
Phenylephrine to increase vascular tone(NOT EPI) |
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What happens to the HR of animal given phenothiazine?
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Should not change much
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Are ventricular arrhythmias more or less likely to occur if a phenothiazine is given?
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less likely
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What do phenothiazines do to resp rate and tidal volume?
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decrease RR and increases tidal volume (if tidal volume does not increase then resp acidosis will occur)
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How is acepromazine metabolized?
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Liver
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Does acepromazine produce analgesia?
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NO -it enhances analgesic effects of other drugs (opioids)
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How does acepromazine effect clotting times?
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Prolonged clotting times - platelet aggregation is inhibited
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Problems with phenothiazines (4):
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Hypotension
Hypothermia Lowers seizure threshold (causes seizures in animals that have a history of seizures (ketamine causes seizures in animals that never had seizures) Prolonged bleeding times |
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Contraindictions for acepromazine (6):
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Platelet dysfunction and other coagulopathies
History of epilepsy Liver disease Hypovolemia Anemia Splenectomy) |
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Butyrophenones are similar to phenothiazines except (3)
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Produce less hypotension
Not likely to produce seizures Less of an effect on platelets |
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Azaperone used in what species
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Swine - prevents malignant hyperthermia
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Different effects of benzodiazepines on old vs. young animals
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Old - mild calming
Young - dysphoria |
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If animal is seizuring, give it
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Valium (Diazepam)
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Cardiopulmonary effects of benzodiazepines
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MINIMAL
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How is diazepam formulated?
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40% propylene glycol - can be toxic to myocardium so don't give in IV bolus; also pain on injection
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Keatmine and diazepam produce
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short term hypnosis/unconsciousness
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What does not mix well with other drugs (besides ketamine)?
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Diazepam
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What drug releases suppressed behavior
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Benzodiazepines
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How does medazolam (compared to diazepam) mix with ther drugs?
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Better!
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Premed with ___ if you want to place IV catheter or intubate pocket pets and birds
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Medazolam (used IN)
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What makes up telazol?
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Zolazepam and tilletamine
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How does zolazepam compare to diazepam in potency and duration?
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More potent
Longer lasting |
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TKX provides (2):
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Good muscle relaxation
Analgesia (but has long recoveries) |
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Benzodiazepine antagonist
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Flumazenil (Romazicon)
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A2 agonists provide (3):
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Sedation
Muscle relaxation Analgesia |
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A2 agonist MOA
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Produce CNS depression by stimulating A2-receptors in CNS and peripherally (reduces release of excitatory neurotransmitters - NE) (a2 receptors control how much NE released so if always bound it will decrease NE release)
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Cardiac effects (HR, CO, BP) of a2-agonists
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Increased vagal tone (decreased HR ad may see 1st and 2nd AV blocks)
Initial hypertension (caused by VC) CO decreases by 30-50% |
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Potential cardiac effect of xylaxine
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Increase myocardial sensitivity to catecholamine-induced arrhythmias
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Resp effects (RR and tidal volume) of a2-agonists
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Decreased respiratory rate
Increased tidal volume (Therefore PaCO2 and PaO2 stay relatively normal) May see respiratory stridor and dyspnea May cause pulm macrophage infiltrates and hypoxemia in sheep |
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GI effects of a2-agonists (5):
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Suppress salivation and gastric secretions
Decrease GI motility (bloat or colic) Vomiting Decreases swallowing reflex Decreases insulin secretion (glucosuria) |
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Renal effects of a2-agonists
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Diuresis due to tubular reabs of sodium
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A2-agonists are metabolized by....
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Liver (excreted via urine)
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Can you give an a2-agonist if patient has liver disease?
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YES- we have an antagonist
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Xylazine in horses
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Treat colic pain
Occasional unpredictable effects Used for caudal epidural Head hangs low but not recumbent |
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2 side effects of xylazine in cats and dogs
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Bradycardia and bradyarrhythmias (give atropine/glycopyrrolate)
Vomiting |
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Xylazine in ruminants
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100x potent!!
Used in combination with local anesthesia for surgery May become recumbent Produces oxytocin-like effects (milk let down and premature parturition) Resp depression Bradycardia and hypotension Bloat Diuresis Pumlonary infiltrates and hypoxemia in sheep |
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Medetomidine and dexmedetomidine potency and duration compared to xylazine
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More potent and longer lasting
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Medetomidine and dexmedetomidine dosage is greater in dogs or cats?
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CATS! (5X)
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What is Romifidine (Sedivet)?
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New a2-agonist for equine but with less ataxia than xylazine
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3 examples of a2-antagonists:
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Yohimbine (horses and dogs)
Tolazoline (Ruminants) Atipamezole (Dogs and cats) |
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Opioids provide (1) and may also produce (3)
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Reliably produce analgesia
May also produce dysphoria (add sedative), apprehension, and excitement |
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Opioids do not interfere with which 4 senses:
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Touch
Fibration (?) Hearing Vision |
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To produce neuroleptanalgesia, combine opioids with ____ or ____ to increase analgesia, increase sedative effects, and limit chance for excitement.
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Sedatives
Tranquilizers |
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Opioid MOA
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Reversibly combine with receptors in CNS, spinal cord, and periphery
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3 major types of opioid receptors and their functions
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Mu - analgesia
Kappa - analgesia Sigma - excitement |
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Potency of opioids is based upon the ________
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Affinity for opioid receptors
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Why must you give opioids parenterally?
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Does not make it past liver (first pass effect)
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How do dogs respond to opioids (4):
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Euphoric
Miotic pupils Hypothermic Small animals begin to pant |
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How do cats and horses respond to opioids (3):
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Mydriatic pupils
Hyperthermic Dysphoric |
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Cardiovascular effects of opioids (2)
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Bradycardia
VD (histamine release) (Morphine may increase myocardial contractility) |
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How do you treat the cardiovascular effects of opioids?
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Atropine or glycopyrrolate
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Respiratory effects of opioids (3)?
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RR and tidal volume are depressed
Cough suppressed Higher arterial PaCO2 are tolerated |
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GI effects of opioids?
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Increased salivation
Vomiting Defecation earlier then constipation later Sphincter contracts |
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With what drug will you see GI and urinary sphincter contration?
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Opioids
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Urinary effects of opioids?
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Decreased urine production
Increased ADH Tightened urinary sphincter |
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How are opioids metabolized?
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Liver
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What controls the duration of action of opioids (2)?
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Metabolism
Antagonists |
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How are opioids agonist-antagonists different than agonists?
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Analgesia is still produced
Less sedation Less cardiopulm. depression Less addictive |
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If small doeses of opioid antagonists are administered, what happens to sedation and analgesia?
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Sedation is reversed
Analgesia remains |
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What are the 2 components of neuroleptanalgesia?
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Sedation
Analgesia |
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What is special about morphine that is used as an epidural?
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Must be preservative free (Astramorph)
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Dissociatives are also known as _____
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Cyclohexylamines
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What is the most commonly used anesthetic drug in veterinary medicine?
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Ketamine (least potent of the dissociatives)
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How do dissociatives produce anesthesia?
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Interrupt ascending transmission from the unconscious to conscious parts of the brain.
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What does a cat given a dissociative look like (2)?
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Cataleptoid (rigid posture)
Open eyes |
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3 components of triangle of anesthesia?
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Analgesia
Unconsciousness Muscle relaxation |
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Why does ketamine sting when injected?
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pH 3.5
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Ketamine provides (1)
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Analgesia
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CNS effects of ketamine (11)
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Cataleptoid state
Open eyes Dilated pupils Maintained swallowing reflex Increased salivation Amnesia (people) Emergence reactions (vivid dreams, dysphoria, etc) Cerebral metabolic rate increases Cerebral blood flow increases Intracranial pressure increases Intraocular pressure increases |
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Where in CNS does ketamine act?
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Thalamo-Neocortical Projection (some activity at spinal cord and reticular formation)
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Why should ketamine not be used in patients with head trauma, intracranial masses, seizures, intraocular FB, or glaucoma?
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Cerebral metabolic rate increases
Cerebral blood flow increases Intracranial pressure increases Intraocular pressure increases |
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Resp effects of ketamine (3)?
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Decreased minute ventilation
Apneustic breathing Laryngeal swallowing reflexes maintained but depressed |
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Cardiovasc effects of ketamine (1)
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Indirect cardiovasc stimulation via SNS (increased MAP, HR, CO, VC)
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What happens if patient in hemodynamic shock and given ketamine?
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Direct myocardial depression
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How is ketamine metabolized and excreted in dog and horse versus the cat?
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Metabolized in liver of dog and horse
Excreted unchanged in urine of cats |
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Should you use ketamine in cats with renal failure? What about obstructed cats?
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Do not use in cats with CRF
Can use in obstructed cats |
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Why should you not use high doses of ketamine (4):
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Increased muscle tone
Tremors Occasional seizures "Stormy" recovery (Should combine lower doses of ketamine with opioids, sedatives, or tranquilizers) |
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What is in triple drip and what is it used for?
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Guafenesin
Xylazine Ketamine Used in equine and LA |
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What is MLK and what it is used for?
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Morphine
Lidocaine Ketamine Used for painful procedures |
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What is telazol?
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A 1:1 combo of tiletamine (a dissociative more potent than ketamine) and zolazepam (a benzodiazepine tranq more potent than diazepam)
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What is telazol used for?
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An immobilization and capture drug
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When using telazol, expect the following changes:
___ muscle relaxation ___ eyes ____ swallowing reflexes ____ coughing reflexes ____ salivation |
Good muscle relaxation
Open eyes Intact swallowing and couging reflexes Increased salivation |
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Cardiovascular effects of telazol (CO, HR, BP):
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CO is unchanged
Increased HR BP decreases then increases |
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Resp. effects of telazol (2)
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Resp depression
Apneustic breathing |
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What is propofol?
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An alkyl phenol; unrelated to any other anesthetic drug; rapidly acting; ultra-short hypnotic drug
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Why do you need to discard propofol within 6-7 hours?
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Solubilized in an emulsion of soybean oil, glycerol, and egg lecithin; supports microbial growth
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How can you reduce the pain when propofol is injected (3 classes of drugs)?
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Premed with opioid, tranq, or sedative
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What happens if propofol is given perivascularly
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NOTHING =)
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CNS effects of propofol (1)
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Enhances GABA
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Is propofol a good analgesic?
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NO
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Resp effects of propofol
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Potent resp depressant (APNEA)
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Cardio vasc effects of propofol (2)
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VD (and hypotension)
Decreased contractility |
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Negative side effects of propofol (2)?
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Heinz body formation in cats given propofol often
Regurgitation |
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Which barbiturates are...
Long acting (1) Short acting (1) Ultra-short acting (2) |
Long acting: phenobarbital
Short: Pentobarbital (Nembutal) Ultra short: Thiopental and Methohexital |
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Barbiturate MOA:
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Generalized CNS depression (GABA effects)
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Onset and duration of action of barbiturates are due to...
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Lipid solubility
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What happens to barbiturates in acidic solution (2):
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More unionized (active)
Less protein bound |
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What type of dogs should not be given barbiturates and why?
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Sight hounds
Decreased fat and decreased liver metabolism |
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What is pentobarbital used for (3)?
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Gen anes in lab animals
Treatment of refractory seizures Euthanasia solution |
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How does pentobarbital effect CNS, CV, and resp systems
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DEPRESSANT!
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How is induction and recovery of patients with pentobarbital?
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Poor quality - vocalization, paddling, shivering, and thrashing
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How many mL of sterile water should be added to 5 grams thiopental powder to make a 2.5% solution?
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200 mL
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Hoy many mL of 2.5% thiopental are needed to induce unconsciousness in a 20 kg dog? (Assume dosage = 10 mg/kg)
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8 mL
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A 0.5% solution is what concentration?
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5 mg/mL
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How long in thiopental good for after reconstitution?
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48 hours
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What happens if thiopental is administered perivascularly?
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CYTOTOXIC!! - cellulitis and sloughing
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What does acidosis do to thiopental?
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Increases amount of unionized (active) drug
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Thiopental cardiovasc effects (CO, BP, HR, vasc resistance. vent arr, PCV)?
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Decreased CO, BP, PCV (splenic engorgement)
Increased vasc resistance, vent arr |
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Splenic engorgement seen with
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Barbiturates
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Resp effects of thiopental (4)
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Apnea
Decrease in tidal volume and rate Laryngospasm Hiccups |
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Methohexital's shelf life:
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relatively long (unlike thiopental's 48 hour shelf life)
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Methohexital is similar to _____ except it can be used in _______
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Thiopental
sight hounds |
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If not premedicated, will see (3) when using methohexital
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Convulsions
Myoclonus Rough inductions |
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Etomidate is related to what class of drugs?
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Antifungals
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What is etomidate solubilized in?
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35% propylene glycol
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What will you see if you admin etomidate but you did not premed
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Myoclonus (short bursts of extension and rigidity)
Gagging Retching |
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What does etomidate do to adrenal gland?
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Suppresses cortisol release for severl hours
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How does etomidate effect cardiopulm system?
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Minimal changes!! Can be used in dogs and cats with unstable cardiovasc function
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What is the only FDA approved anesthetic for fish intended for food?
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Tricaine Methanesulfonate (MS-222, Finquel)
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How do you reverse Finquel effects?
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Transfer to water without drug
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Alternatives (3) to Finquel
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Clove oil
CO2 Inhalants |
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What don't the muscle relaxants do (2)?
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Hypnosis
Analgesia |
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What are the centrally acting muscle relaxants (2)?
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Benzodiazepines
Guaifenesin |
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Generall speaking, what is Guaifenesin used for (2)?
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Expectorant/secretagogue
Muscle relaxant (LA) |
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Soluntions greater than 7% (cows) and 10% (horses) of guaifenesin can cause ____?
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Hemolysis
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Guaifenesin's MOA?
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Acts at spinal cord and brainstem to block interneurons which couple the afferent-efferent reflex arc (produces skeletal muscle relaxation)
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Does guaifenesin affect smooth or cardiac muscle?
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NO
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How does guaifenesin effect the cardiopulm systems?
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Minimal effects (diaphragm not effected because innervated by phrenic n. - not the spinal cord)
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What is the prototype neuromusc. blocking drug?
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Curare
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What does curare do?
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Induces sk. musc paralysis
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What does curare NOT do (3)?
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No sedation
No unconsciousness No analgesia Patient is totally conscious but completely paralyzed) |
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How is ACh synthesized?
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Choline + acetate in presence of ACh transferase
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Why is ACh discharged from nerve?
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Calcium enters nerve terminal, combines with calmodulin, and facilitates discharge
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What enzyme hydrolyzes ACh?
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ACh esterase
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Duration of action of succinylcholine terminated by ____?
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Pseudochilinesterase
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How does succinylcholine works?
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Initially depolarizes muscle but receptors remain occupied and refractory to ACh (bag of worms effect)
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How do non-depolarizing drugs work?
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Interact with nicotinic ACh receptor but do not trigger it - compete with ACh for the receptor site(no bag of worms)
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Antagonists for non-depolarizing drugs
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Anticholinesterase drugs (neostigmine, pyridostigmine, edrophonium); results in increased ACh available to compete for NM binding sites; administer with atropine or glycopyrrolate to block muscarinic effects of increased ACh
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What should you also administer with non-depolarizing antagonists?
|
Atropine or glycopyrrolate (to block muscarinic effects of the increased ACh)
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Why use NM blocking drugs (what kind of procedures)?
|
*Intraocular surgery
Fracture reduction Abdominal surgery |
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If you administer a NM blocking drug, what must you do for the animal?
|
BREATH FOR THEM!!
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What don't the NM Blocking drugs produce (3)?
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Analgesia
Unconsciousness Sedation (never use without gen anes - recall has been reported in humans) |
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What is the target organ for inhalent anesthetics and what do they do to that organ?
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BRAIN - membrane permeability is altered and electrical activity of the cortex become desynchronized
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What gas is used to dilute te anesthetic gas?
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Oxygen (this increase FiO2 from 20% (room air) to 95-98%) - the balance (3-5% is the anesthetic gas)
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How are inhalation anesthetic drugs dosed?
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Percentage of inspired gas
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Why do patients on inhalent anesthetics wake up?
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They exhale the gas (metabolism plays a very minor role)
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Goal of inhalent anesthesia
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Establish and maintain the lowest partial pressure of anesthetic gas in the brain that produces anesthesia
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How is volatility measured?
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Measured as vapor pressure (mmHg)
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How do we control volatility on an inhalent anesthetic machine?
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THE VAPORIZER
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What is the primary determinant of anesthetic depth?
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THE VAPORIZER
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Delivery of anesthetic gas to the lungs depends on (2):
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Inspired concentration
Patient's alveolar ventilation |
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Finish this statement:
The faster the alveolar concentration of the anesthetic gas rises.... |
The faster the animal becomes anesthetized
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Why do animals with thiopental or propofol have trouble staying under anesthesia?
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Thiopental causes apnea
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Increasing alveolar ventilation (inc/dec) the rate at which the alveolar concentration rises?
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INCREASES (however very large increases in alveolar ventilation cause decreases in cerebral blood flow which may slow the rate of induction)
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T/F?
The rapid uptake of large volumes of one gas increases the uptake of a co-administered second gas? |
FALSE - Don't you just hate anesthesia "lore"?!?!
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3 factors affecting movement of gas from the alveoli into the blood
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Solubility of the gas in blood
Cardiac output Alveolar to venous gas partial pressure difference across the alveolar wall |
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What is the primary determinant of the speed of induction?
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Solubility of the gas in blood (the great the solubility the slower the rate of induction)
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Finish this sentence:
It's not the quantity of gas in the blood, but the ___ ___ |
Partial pressure (it takes a greater quantity of a highly soluble gas to raise the partial pressure)
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The partial pressure of the gas in the blood is responsible for....
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Its movement into the brain and other tissues
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The partial pressure of the gas in the brain is responsible for....
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Its anesthetic effect
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In high cardiac output states, the absolute amount of brain blood flow (dec, inc, same)
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STAYS THE SAME
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In high cardiac output states, induction is (faster, slower, same)
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SLOWER
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Initially the difference between the alveolar to venous gas partial pressure is (large/ small)
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LARGE (the difference decreases as induction progresses)
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3 factors affecting the delivery of anesthetic gases to the tissues:
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Blood flow to the tissue
Solubility of gas in tissue Blood to tissue pressure gradient |
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Vessel rich group (2)
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Brain
Viscera |
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Vessel moderate group (1)
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Muscle
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Vessel poor group (2)
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Tendons
Bone |
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If all gases are very fat soluble, why isn't there a lot of the gas in fat?
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Blood flow to fat is low, so the amount of fat has little effect on induction
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What is MAC?
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Minimum alveolar concentration - the concentration that prevents movement in response to stimuli in 50% of patients (approximately 50% of surgical partial pressure)
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The higher the MAC, the (higher/lower) its potency?
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LOWER
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Does duration of anesthesia affect the MAC?
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no
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Does hyper/hypoventilation affect MAC?
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no
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Does sex of the animals affect MAC?
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NO
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Does age of animal affect MAC?
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YES
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Does body temp affect MAC?
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yes
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Does disease (hypothyroidism) affect MAC?
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yes
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How much MAC is needed for surgical anesthesia?
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1.5x MAC
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Why is diethyl ether great as an inhalent anesthetic (4)?
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Excellent analgesia
Good muscle relaxation Minimal resp depression Minimal cardio depression |
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Why is diethyl ehter not used?
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High blood/gas solubility (slow induction and recovery)
Causes vomiting Flammable Explosive (used occasionally in lab an) |
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Is nitrous oxide flammable?
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NO - but it will support combustion of other materials
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Why is Nitrous oxide great (2)?
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Minimal cardiopulm side effects
Very fast onset and recovery (solubility = 0.49) |
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Does nitrous oxide produce anesthesia by itself?
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NOPE (to produce anesthesia it would have to be 60-70% of inspired gas mixture
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Why use nitrous oxide if it doesn't produce anesthesia (3)?
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Reduces dose of other agents
Inexpensive Speds induction |
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What are some problems with nitrous oxide (2)?
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Closed gas spaces will double in size in patients breath 50% N2O - pneumothorax, gastric torsion, bloat
Diffusion hypoxia during recovery (supplement with O2 5-10 minutes after N2O discontinued) |
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Isoflorane is (high/low) volatility, potency, rate of induction/recovery
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Very volatile (250mmHg)
Very potent (2.5%) Fast induction/recovery (1.41 bl/gas solubility) |
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Cardiopulm effects of isoflurane
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VD
Decreased RR and tidal volume (but resp remains within acceptable limits in SA) |
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Rate of induction and recovery of sevoflurane (fast/slow) and potency (compared to isoflurane)
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EXTREMELY FAST induction
Less potent (3-4% for maintenance and 5-7% for induction) |
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Which would you prefer to breath - sevo or isoflurane?
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SEVO (iso makes you cough), but both have an odor
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Why use sevo?
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When rapid induction and recovery is required - exotics and birds
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Is sevo metabolized?
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Yes (3-5%) compared to isoflurane (0.5% metabolized)
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What was bad about halothane?
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Animals more likely to have vent arr (but horse practitioners liked it)
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What was bad about methoxyflurane?
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VERY slow induction and recovery
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Why is desflurane annoying to use?
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Requires a heater vaporizer to maintain accurate anesthetic gas delivery (must be plugged into electircal outlet)
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What drugs are painful on injection (3)
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Ketamine (pH=3.5)
Propofol (glycerol) Etomidate(maybe?) (propylene glycol) |
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Which drugs produce apnea (2)?
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Propofol
Thiopental |
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Which drug protects against NMDA (a chemical liberated with chronic pain)?
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Ketamine
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Which drugs cause apneustic breathing (2)?
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Ketamine
Telazol (tiletamine) |
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Which drugs undergo redistribution (3)?
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Ketamine
Propofol Barbiturates |
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Which classes of drugs decrease glandular secretions (2)?
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Anticholinergics
A2 agonists |
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Which classes of drugs increase GABA (3)
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Benzodiazepines
Propofol Barbiturates |
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Which drug increases appetite in cats and cows?
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Diazepam
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Whichclasses of drugs have antagonists (5)?
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Benzodiazepine (flumazenil)
A2 agonists (yohimbine, tolazoline, atipamezole) Finquel (drug free water) Opioid (naloxone) Non-depolarizing drugs (neostigmine, pyridostigmine, edrophonium) |
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Which drugs are DEA controlled (3)
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Ketamine
Opioids Barbiturates |
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Which classes of drugs are antiemetics (2)?
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Acepromazine
Butyrophenones |
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Which drug has an antihistamine effect?
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Acepromazine
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Which drugs prevents MH (2)?
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Acepromazine
Butyrophenones |
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Which class of drugs are emetics?
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A2 agonists
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Which class of drug releases histamine?
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Opioids
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