Anesthesiology Exam II Material Flashcards
Ocular reflexes are a good indicator of anesthetic depth. The bovine eye rotates __________ during light planes of anesthesia
ventromedially
T/F: Deracoxib is a selective cyclooxygenase inhibitor
True
Deracoxib selectively inhibits COX 2
T/F: Vasopressin and Epinephrine are useful in arrest situations because they both work well in acidic environments
False
Vasopressin if effective in acidic environments. Epinephrine is fairly ineffective once the patient is acidemic
If there is excess heparin in your syringe when you’re taking a sample for blood gas analysis, what would you expect to see with regard to the pH of the sample?
decreased pH
Local anesthetics act at the site of injection (locally). Which is typically desired: slow absorption or fast absorption into systemic circulation?
slow absorption
T/F: If a patient fractures its humerus, a brachial plexus nerve block is indicated
False
Brachial plexus nerve blocks provide anesthesia to the elbow and distal (radius/ulna fracture, toe amputation, carpal arthrodesis)
When monitoring anesthetic depth in equines, what drug makes eye reflexes less reliable?
Ketamine
What is the drug of choice to treat hypotension in equines?
Dobutamine
What is the normal PaCO2 range for arterial blood?
35 - 45 mmHg
When monitoring neuromuscular blockade, you will not see any response to tetanic stimulation or posttetanic facilitation during Phase ______ depolarization
Phase I
- You also won’t see Train of Four (TOF) during phase 1 depolarization.*
- get over it.*
Which of the following drugs would you give during cardiac arrest?
- Phenylephrine
- Epinephrine
- Dopamine
- Glycopyrrolate
- Ephedrine
Epinephrine!
Is phenylbutazone a selective or non-selective cyclooxygenase inhibitor?
Non-selective
Phenylbutazone is a COX 1 and COX 2 inhibitor
T/F: Epinephrine is the go-to drug to treat hypotension during anesthesia
False
Epinephrine should be administered during cardiopulmonary arrest! It can cause tachycardia very quickly, so go with other drugs for hypotension before turning to epinephrine.
“Curtis” is a 3 y.o. male intact sheep that is having a castration performed in the 7th semester surgery lab. This is your first blood gas sample under gas anesthesia. What primary acid-base disturbance is present in this patient?
Respiratory Acidosis
pH is very low and CO2 is very high.
Approximately how much blood does a 4x4 gauze square hold?
~ 5-10 mL
T/F: 2˚ AV block is considered to be generally normal in equine anesthesia
True
2˚ AV block is generally normal and is due to inherently high vagal tone. It should be abolished by exercise or excitement
Naloxone is a reversal agent for what class of drugs?
Opioids
What are the three most common causes of hypotension under anesthesia?
vasodilation, decreased contractility, and bradycardia
When vasopressors are administered to a patient, what happens to the patient’s heart rate?
reflex bradycardia
T/F: Pyridostigmine has a short onset of action and short duration
False
Pyridostigmine has a LONG onset of action and LONG duration
What is the minimum PCV at which cells can still carry oxygen to tissues?
21%
This correlates to 7 mg/dL Hb
Is aspirin a selective or non-selective cyclooxygenase inhibitor?
Non-selective
Aspirin inhibits COX 1 and COX 2
If you’re performing a blood-gas analysis and you determine that the SaO2 is >88%, are you dealing with an arterial sample or a venous sample?
Arterial
If SaO2 is < 88%, it could be a mixed sample, venous, or pulmonary disease
What is the drug of choice for treatment of malignant hyperthermia?
Dantrolene
Which of the four primary acid-base disturbances is present if your patient has a base excess?
Metabolic Alkalosis
Colloids exhibit less redistribution than crystalloids.
For every 1 mL of blood lost in a patient, how many mLs of colloids should be administered?
1 mL
For every 1 mL of blood lost in a patient, you should replace with 1 mL of colloids
Which of the following local anesthetics would you expect to have the slowest onset of action?
- Procaine
- Lidocaine
- Mepivacaine
- Bupivacaine
Procaine
Procaine has a pKa of 8.9. The higher the pKa, the slower the onset of action
Approximately how much blood does a cotton tip applicator (CTA) hold?
~ 0.2 mL
You take a blood gas analysis of your patient and the PaCO2 is 20 mmHg. Is your patient hypoventilating, ventilating normally, or hyperventilating?
hyperventilating
Normal range for PaCO2 is 35-45 mmHg
Why must we use caution when using Acepromazine as a premedication in breeding stallions?
potential penile prolapse
What is the normal PaO2 range for arterial blood on 100% O2?
~500 mmHg
T/F: Maxillary nerve block is useful for extraction of upper molars in canine patients
True
Maxillary nerve blocks desensitize ipsilateral upper dental arcade, maxilla
T/F: Dogs and cats must be blood-typed prior to receiving plasma transfusions
False
There is no need to test dogs for plasma transfusions; just whole blood and RBCs.
CATS must be tested prior to plasma transfusions!
What is the most common pathologic arrhythmia in horses?
Atrial Fibrillation
5 causes of hypoxemia… go!
- Decreased FiO2
- Hypoventilation
- V/Q mismatch
- Right to left shunt
- DIffusion Impairment
What fluid type should you consider if the patient has lost 10% - 20% of blood volume?
Colloids
If you have a patient on an NSAID and you’d like to switch them to another NSAID, how long should you ‘wash them out’ before starting the other NSAID?
7 days
T/F: Hypotonic fluids (such as 5% dextrose in H2O) should not be given in the same line as transfusion products
True
- If they are given in the same line, the hypotonic fluid will cause hemolysis of the transfusion product before it even reaches the patient*
- It is best to place an additional catheter if these products need to be given simultaneously*
Why are a2 agonists not recommended for use in sheep?
Sheep are at risk for developing pulmonary hemorrhage and edema, potentially resulting in severe hypoxemia
T/F: Ruminant patients are more likely to regurgitate if placed in dorsal recumbency
True
Cryo-poor plasma is high in what clotting factors?
II, VII, IX, & X
- Vitamin K-dependent factors!*
- Cryo-poor plasma is useful for treatment of rodenticide intoxication*
How long should you fast an adult pig prior to anesthesia?
6-12 hours
What is the approximate blood volume (in mL) for a 10 kg dog?
~900 mL
90 mL/kg x 10 kg
What is the approximate blood volume (in mL/kg) for ovines?
60 mL/kg
Pain caused by a stimulus that does not normally cause pain is termed:
Allodynia
T/F: Blood Gas Analyzers directly measure HCO3-, BE, and SaO2
False
- Blood Gas Analyzers directly measure pH, partial pressure of oxygen (PO2), and partial pressure of carbon dioxide (PCO2).*
- Blood Gas Analyzers calculate HCO3-, BE, and SaO2*
What is the normal pH range for arterial blood?
7.35 - 7.45
What is the normal PaO2 range for arterial blood in room air?
80 - 110 mmHg
Which of the following local anesthetics would you expect to have the longest duration of action?
- Procaine
- Lidocaine
- Mepivacaine
- Bupivacaine
Bupivacaine
Bupivacaine has ~95% protein binding and a duration of action anywhere from 180-600 minutes
T/F: NSAIDs have a fairly wide safety margin
No.
What value (in mL) represents 10% blood volume in a 15 kg canine patient?
135 mL
- 90 mL/kg x 15 kg = 1350 mL*
- 1350 mL x 10% = 135 mL*
T/F: Xylazine is more potent in equines than in ruminants
False
Xylazine is much more potent in ruminants than in equines. Typically ~ 1/10th of the equine IV dose is used for ruminants
Say “calcium gluconate protects the myocardium against cardiotoxic effects of hyperkalemia and prevents arrhythmias, but it does not lower [K+].”
Nice, you’re right!
T/F: In most cases, it is acceptable to give LRS in the same line as a transfusion product
False
LRS (or any fluid that contains calcium) can NOT be given in the same line as transfusion products. It will interfere with the anticoagulant properties and cause the product to clot
T/F: Malignant hyperthermia in swine is more prevalent in individuals with a high ratio of muscle to total body mass
True
What is the drug of choice for treatment of ventricular tachyarrhythmias?
Lidocaine!
Name the 5 parts of the pain perception pathway:
- Transduction
- Transmission
- Modulation
- Projection
- Perception
Titty Twisters May Produce Pain
Identify this ‘irregularly irregular’ arrhythmia in the horse:
Atrial Fibrillation
T/F: Dobutamine causes vasoconstriction
False
Dobutamine acts on β receptors and causes increased contractility and heart rate. Vasoconstriction occurs as a result of α receptor activity.
Clinical signs of malignant hyperthermia in swine most commonly appear after exposure to what drugs?
Halothane or Succinylcholine
Duration, intensity, and recovery of neuromuscular blockades can be affected by a number of factors. What neuromuscular blocker would you likely avoid if your patient has hepatic insufficiency?
Vecuronium
~ 50% hepatic biotransformation with bile excretion
What is hyperesthesia?
increased sensitivity to sensation
You are monitoring anesthesia for a 10 kg dog. While making the incision, the Macarena comes on the radio and the surgeon begins to dance. Unfortunately in doing so he ends up adding 12 accidental incisions to the animal, resulting in significant blood loss.
Approximately how much blood (in mLs) could this patient lose before considering the need for a whole blood transfusion?
~180 mL
- The blood volume of a 10 kg dog is ~900 mL (90 mL/kg x 10 kg). Whole blood transfusions are considered after 20% blood loss.*
- 900 mL x 20% = 180 mL*
What fluid type should you consider if the patient has lost less than 10% of blood volume?
Crystalloids
Which cyclooxygenase is responsible for mucosal defense and platelet function?
COX 1
So for instance, if you give an NSAID that will block COX 1 , you may increase bleeding times
What is the minimum amount of hemoglobin necessary to carry oxygen to tissues?
7 mg/dL
“Wendy” is a 7 y.o. FS Lab that is in surgery for a total hip replacement. She is obese, so was placed on IPPV with 100% oxygen by your technician. This is the first blood gas sample taken. What primary acid-base disturbance is present in this patient? What are you going to do?
Respiratory Alkalosis
Note the increased pH, decreased CO2. Another indication of a respiratory problem is the PO2 value. This patient is on 100% O2 so we would expect the PO2 to be closer to 500 mmHg.
What is the most sensitive and specific test for hyperkalemic periodic paralysis (HYPP) in horses?
PCR
T/F: Phenylephrine is a significant vasoconstrictor
True
When using LRS on a patient, approximately how much stays in the intravascular space after 15 minutes?
20-30%
You must give 3-4x volume of blood lost when using crystalloids!
Recurrent laryngeal neuropathy usually occurs on the _______ side in horses
left
T/F: Calcium gluconate 23% and 0.9% NaCl both lower potassium concentration and are used for treatment of hyperkalemia
False!
- Both are used for treatment of hyperkalemia, but Calcium gluconate 23% does NOT lower [K+]. It protects the myocardium against the cardiotoxic effects of hyperkalemia and prevents arrhythmias*
- 0.9% NaCl dilutes the high serum [K+]*
T/F: Alpha2 agonists have an oxytocin-like effect on the uterus of pregnant cattle and sheep and may result in premature delivery during late pregnancy. Detomidine however does not seem to have this effect
True
Acetaminophen is approved for use in what veterinary patients?
None of them.
What does this diagram represent?
OxyHemoglobin Dissociation Curve
T/F: Phenylephrine causes vasoconstriction
True
What is generally the easiest location to gain IV access in a pig?
ears
Other IV access sites include cephalic vein, femoral vein, jugular vein, anterior vena cava, abdominal vein, medial caudal vein, & saphenous veins
What nerve block would be appropriate for excision of a canine, incisor, or premolar?
Infraorbital Nerve Block
You take a blood gas analysis of your patient and the PaCO2 is 65 mmHg. Is your patient hypoventilating, ventilating normally, or hyperventilating?
hypoventilating
Normal range for PaCO2 is 35-45 mmHg
T/F: Atropine is best utilized in vagal-induced asystole
True
T/F: Low doses of Dopamine cause vasoconstriction
False
HIGH doses of Dopamine can cause vasoconstriction. At low doses it causes increased contractility and doesn’t have much effect on vascular tone
Surpass® (diclofenac) is a topical NSAID drug commonly used to treat what equine condition?
Equine osteoarthritis
NAME THE AGENT THAT IS USED FOR REVERSAL OF NEUROMUSCULAR BLOCKERS ROCURONIUM AND VECURONIUM
SUGAMMADEX
THAT’S RIGHT, MOTHER FUCKERS!
What is the most common site to pull a sample for arterial blood-gas analysis in a dog?
Dorsal Pedal Artery
Other sites include the auricular artery, femoral artery, caudal artery, and lingual artery
T/F: Carprofen is a selective cyclooxygenase inhibitor
False
Carprofen preferentially inhibits COX 2, but still exhibits some COX 1 inhibition
Which of the four primary acid-base disturbances is present if your patient has a base deficit?
Metabolic Acidosis
What is the recommended pre-anesthetic fasting time for sheep and goats?
NPO 12-18 hours, no water 4 hours
T/F: Infraorbital nerve block is useful for extraction of molars in canine patients
False
- Infraorbital nerve blocks desensitize the upper dental arcade adjacent and rostral to the injection site*
- (the molars are behind* the infraorbital foramen)
What is the most revealing sign of impending malignant hyperthermia in swine?
rapidly increasing ETCO2
What is the approximate blood volume (in mL/kg) for bovines?
60 mL/kg
What type of cardiac disorder do we commonly apply transvenous pacing?
Third degree heart block
T/F: Epinephrine can cause severe vasoconstriction and can lead to decreased perfusion of tisues
True
What artery do we use for Doppler blood pressure monitoring in the sheep?
Median artery
Which cyclooxygenase is upregulated during inflammatory states: COX-1, COX-2, or COX-3?
COX 2
In equine patients, MAP should remain above ______ to avoid postanesthetic myopathy
70 mmHg
Neonatal foals have lower BP than adults due to decreased vascular tone, so a MAP of 40-60 mmHg is acceptable
Neuromuscular blocking drugs are referred to as peripheral muscle relaxants and block neuromuscular transmission at ____________________
neuromuscular junction
The desired site of action is the nicotinic Ach receptor at motor nerver plate (skeletal muscle)
What 2 neuromuscular blocking agents (NMBAs) are we most concerned about with regard to histamine release?
Atracurium & Mivacurium
T/F: Meloxicam is a selective cyclooxygenase inhibitor
False
Meloxicam preferentially inhibits COX 2, but still exhibits some COX 1 inhibition
T/F: All cats should be blood-typed prior to receiving a transfusion, regardless of whether they have had a transfusion in the past
True!
TYPE and CROSSMATCH must be performed prior to _every_ whole blood, RBC, or plasma transfusion in cats
What is the pH range that is considered to be compatible with life?
6-8 - 7.8
T/F: Hypoproteinemic patients may exhibit greater side effects with the use of NSAIDs than those patients with normal protein levels
True
NSAIDs are highly protein bound, so if there is less protein in the body, there will be more drug circulating in the bloodstream. This can lead to increased risk of side effects
Name some significant side effects associated with administration of Phenylbutazone
GI ulceration & Nephrotoxicity
Phenylbutazone is a non-selective COX inhibitor used primarily in horses and cattle
Handheld peripheral nerve stimulators are often used to monitor neuromuscular blockades. What nerves do we use in dogs and cats to monitor blockades?
Peroneal (fibular) nerve and ulnar nerve
Ruminant patients are less likely to regurgitate if placed in _________ or _________ recumbency
Ruminant patients are less likely to regurgitate if placed in right lateral or sternal recumbency
T/F: Succinylcholine Phase I blocks can be reversed by anticholinesterase drugs
False!
However, Succinylcholine Phase II blocks are antagonized similarly to nondepolarizing agents!
T/F: Patients must be 3 weeks or older to receive NSAIDs
False
Patients must be > 6 weeks to receive NSAIDs
What is the approximate blood volume (in mL/kg) for felines?
65 mL/kg
Flumazenil is a reversal agent for what class of drugs?
Benzodiazepines
In epidural anesthetic procedures, what do you do if you puncture the dural sac?
Decrease volume by 50%
What is the most commonly desensitized nerve in the equine?
Supraorbital nerve
Which nerve(s) need(s) to be blocked when dehorning a goat?
Cornual br. of infratrochlear nerve and cornual br. of zygomaticotemporal nerve
Note that this is different than in the cow! In the cow, only ONE nerve needs to be blocked.
T/F: IPPV is positive pressure maintained during inspiration and expiration
False
IPPV (intermittent positive pressure ventilation) is positive pressure maintained only during inspiration
T/F: Anesthetic drugs and equipment dead space may be causes of respiratory acidosis
True
