Anesthesia & Analgesia Flashcards
In the study, “Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine, or Carprofen After Periodontal Treatment in Dogs” what were the significant values pertaining to VAS values?
Butorphanol had significantly lower values than saline. And bupivicaine had significantly lower values than saline and lidocaine.
In the study, “Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine, or Carprofen After Periodontal Treatment in Dogs” what were the significant values pertaining to UMPS values?
Bupivicaine had significantly lower values than saline, butorphanol and lidocaine. And carprofen had significantly lower values than lidocaine and saline.
In the study, “Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine, or Carprofen After Periodontal Treatment in Dogs” what were the significant values pertaining to cortisol values?
Lidocaine post tx had significantly higher values than saline, bupivacaine and carprofen.
Serum cortisol levels post tx were also significantly higher in lidocaine and morphine compared to pre-tx values.
Bupivacaine had lower post-tx values compared to pre-tx values.
In the study, “Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine, or Carprofen After Periodontal Treatment in Dogs” what were the significant values pertaining to glucose values?
Plasma glucose levels were significantly higher in control, morphine and lidocaine compared to pre tx values.
What was the main take away in the study, “Duration of Action of Bupivacaine Hydrochloride Used for Palatal Sensory Nerve Block in Infant Pigs”?
Bupivicaine has a relatively short and variable duration of action far below what is expected based on its pharmacokinetic properties.
What is MAC?
Minimum steady state alveolar concentration of an inhalation anesthetic required to prevent gross purposeful movement to a noxious stimulation in 50% patients
What was the main takeaway in the study, “Area of Desensitization Following Mental Nerve Block in Dogs”, JVD 2011.3?
The mental block does not reliably provide generalized desensitization to tissues of the incisive and rostral regions of the mandible.
So… then why do we use it… shrug
Systemic opioid adiminstration is most effective at decreasing nociceptor pain associated with what nerve fibers?
Lumb and Jones
C-fibers (slow-conducting, unmyelinated nerves)
What opioid is a partial mu agonist?
Lumb and Jones
Buprenorphine
Butorphanol is what type of opioid?
Lumb and Jones
Mu antagonist
Kappa agonist
What type of opioids cause a diuretic response?
Lumb and Jones
Kappa agonists
Which of the following is correct regarding cardiac output?
A. Bradycardia diminishes cardiac output by reducing stroke volume
B. Tachycardia diminishes cardiac output by reducing stroke volume
C. Afterload impedance to cardiac output is a common problem under GA
D. Cardiac output determines systemic vasomotor tone
Lumb and Jones
B. Tachycardia diminishes cardiac output by reducing stroke volume
Stroke volume is determined by what two factors?
Lumb and Jones
Preload
Myocardial contractility
Cardiac output is determined by what two factors?
Lumb and Jones
Heart rate
Stroke volume
What two factors determine blood pressure?
Lumb and Jones
Cardiac output
Peripheral vasomotor tone
What is the important determinant of peripheral tissue perfusion?
Lumb and Jones
Peripheral vasomotor tone
What is the important determinant of brain and heart perfusion?
Lumb and Jones
Arterial blood pressure
What two factors determine blood oxygen content?
Lumb and Jones
Hemoglobin concentration
Oxygenation
What two factors determine oxygen delivery?
Lumb and Jones
Oxygen content
Cardiac output
What is allodynia?
Pain due to a stimulus which does not normally provoke pain.
What are three common causes of bradycarida that are not responsive to pharmacological treatment?
Lumb and Jones
Severe hypothermia
Cardiac conduction abnormalities
Severe myocardial hypoxemia
Are anticholinergics parasympatholytic or sympathomimetic?
Lumb and Jones
Parasympatholytic
What is the defintion of systolic pressure?
Lumb and Jones
Highest intra-arterial pressure of each cardiac cycle
What is mean pressure?
Lumb and Jones
The average of the area under th pulse pressure waveform of the measured systolic and diastolic pressure
What are ASA physical statuses I, II, III?
I: Healthy patient
II: Patient with mild systemic disease, disease process is controlled and stable, patient exercise tolerant
III: Patient with severe systemic disease, manifests with clinical signs, patient has functional limitations
What are ASA physical statuses IV and V?
IV: Patient with systemic disease that is a constant threat to life, ex congestive heart failure, septic shock, DKA
V: A moribund patient not expected to survive without the operation, ex advanced septic shock, severe head trauma
What are the clinical measurements of cardiac preload?
Lumb and Jones
End diastolic diameter on echocardiography
Chest rads: diameter of posterior vena cava
Ease of jugular vein distension
What is the definition of central venous pressure?
Lumb and Jones
Luminal pressure of the intrathoracic vena cava
Normal CVP dogs and cats 0-10cm H20
Positive pressure ventilation impedes what three cardiovascular components?
Lumb and Jones
Intrathoracic venous return
diastolic filing of the heart
Stroke volume
Clinically can see a decrease in systolic and mean blood pressure, pulse pressure, pulse quality, pulse pressure waveform
What pulse pressure wavefroms are associated with large and small stroke volumes?
Lumb and Jones
Large stroke volume: bounding pulse, tall, wide waveform
Small stroke volume: thready pulse, short, narrow waveform
What is the trigger for transfusion in vet med?
Lumb and Jones
PCV 20-25%
What Doppler ultrasound based measurement/calculation can be used to measure myocardial contractility?
Lumb and Jones
Fractional shortening
What physiologic conditions cause vasoconstriction?
Lumb and Jones
Hypovolemia
Heart failure
Hypothermia
The venous-arterial PCO2 gradient increases as hypo or hypervolemia increases
As hypovolemia increases
Lactate is a measure of what?
Lumb and Jones
Poor tissue perfusion
Lactate is not as sensitive for detection of O2 deficiency in what tissues
Lumb and Jones
Tissues with low mass but high oxygen demand: brain, kidney
What measurements on blood gas increase with increasingly severe hypovolemia?
Lumb and Jones
Base deficit
Arterial-venous pH gradient
What is apneustic breathing and what drug is it associated with?
Lumb and Jones
Inspiratory hold
ketamine
What does arterial PaCO2 measure and what are normal values?
Lumb and Jones
Measure of effective alveolar minute ventilation
35-45mmHg
Venous PCO2 is usually how much higher than PaCO2?
Lumb and Jones
3-6mmHg higher than PaCO2
Can be used as a surrogate marker for PaCO2
An increased arterial-venous PCO2 gradient suggests what in terms of tissue perfusion?
Lumb and Jones
Decreased tissue perfusion
Is time or volume capnography used in clinical practice?
Lumb and Jones
Time capnography
What are normal PaO2 levels awake and during anesthesia?
Lumb and Jones
Normal at sea level (21%) O2: 80-110mmHg
PaO2> 110mmHg normal while under anesthesia
Due to breathing oxygen-enriched gas mixtures
How would you troubleshoot the following capnograph?
There is a slant to the upstroke portion of the expiratory phase of the breathing cycle - this may indicate a kinked endotracheal tube, an obstructed endotracheal tube, partial airway obstruction or bronchospasm.
How would you troubleshoot the following capnograph?
The baseline is not returning to zero, there may be exhausted CO2 absorbing granules, incompetent or absent unidirectional valves, decreased oxygen flow rate in a non-rebreathing circuit, or damaged non-rebreathing circuits.
How would you troubleshoot the following capnograph?
There is no plateau or an abnormal downstroke present on inhalation –> check the endotracheal tube cuff!
How would you troubleshoot the following capnograph?
If the capnograph is reading 0, check for apnea, cardiac arrest, airway obstruction, esophageal intubation, or a patient disconnect from the anesthesia circuit.
What is nociception?
Nociception is defined as the processing of a noxious stimulus resulting in the perception of pain by the brain.
What are the components of nociception?
Transduction, transmission, and modulation
What is transduction?
Transduction is the conversion of a noxious stimulus (mechanical, chemical or thermal) into electrical energy by a peripheral nociceptor (free afferent nerve ending).
What is transmission?
Transmission involves impulse propagation from the site of oral injury primarily through the trigeminal afferent nerves.
What is modulation?
This occurs when neurons from fibers in the oral cavity synapse with nociceptive-specific and wide dynamic range neurons in the nucleus caudalis located in the medulla.
What neuropeptides facilitate the pain signals by binding to their receptors?
Substance P and glutamate
What is primary hyperalgesia?
An increased sensitivity within the injured area predominantly due to peripheral nociceptor sensitization.
x
What is secondary hyperalgesia?
Pain sensitivity that occurs in surrounding undamaged tissues.
What is wind up pain or central sensitization?
When peripheral sensitization remains untreated, the neurons that are subjected to repeat or high-intensity nociceptive impulses become progressively and increasingly excitable even after the stimulus is released.
What is an effective way of managing wind up pain??
Administering drugs that bind to the NMDA receptor so that glutamate cannot do so.
Local anesthetics block what pathways in nociception?
transduction, transmission modulation, and projection
What drug classes are known to affect the pain transduction pathway (peripheral sensitization inhibition)?
Local anesthetics, opiods,NSAIDS and corticosteroids
What drug classes will affect modulation (central sensitization inhibition)?
Local anesthetics, alpha 2 agonists, opioids, tricyclic antidepressants, cholinesterase inhibitors, NMDA antagonists, NSAID’s and anticonvulsants
What drug classes affect transmission (impulse conduction inhibition)?
Local anesthetics, alpha 2 agonists
Where are opioid receptors found?
The central and peripheral nervous system
What is the time of onset for fentanyl patches in dogs and cats respectively?
Dogs: 18-24 hours
Cats: 6-12 hours
What are examples of pure agonist opiods?
Morphine, hydromorphone, and fentanyl
What are examples of partial agonist opiods?
Buprenorphine and butorphanol
How are prostaglandins produced?
By the breakdown of arachidonic acid by COX enzymes that are released from various cell types at the site of tissue injury.
What is the reversal. For alpha 2 agonists?
Atipamezole
What are side effects of alpha 2 agonists like medetomidine and xylazine?
Sedation, analgesia, increased systemic vascular resistance, bradycardia, respiratory depression and vomiting
True or False: The use of an anti cholinergic like atropine is safe to use in combination with an alpha-2 agonist to offset bradycardia.
False, this is very controversial, and may result in cardiac compromise.
Describe the MOA of ketamine.
It is an NMDA antagonist.
Describe the MOA of tramadol and list what medications should not be used concurrently with this medication.
MOA - It is a reuptake inhibitor of serotonin and norepinephrine. It also possesses weak mu agonist characteristics. It should not be used with tricyclic antidepressants, SSRI’s or mono amine oxidase inhibitors due to risk of serotonin syndrome.
The pulse oximeter SpO2 is a surrogate marker of what physiologic parameter?
Lumb and Jones
Hemoglobin saturation with oxygen (SaO2)
At what SpO2 is the patient considered hypoxemic?
Lumb and Jones
Hypoxemia < 95%
Severe hypoxemia < 90%
What two wavelengths of light does pulse oximetry used?
Lumb and Jones
660-940nm
What are the categorical casues of hypoxemia?
Lumb and Jones
Low inspired oxygen
Hypoventilation
Venous admixture
Venous admixture: low ventilation/perfusion regions, atelectasis, diffusion defects, right ot left shunts
What is the lowest body temperature not associated with detrimental effects?
Lumb and Jones
96F
What body temperatures can cause ventricular fibrillation?
Lumb and Jones
72-74F
What body temperatures cause marked CNS depression?
Lumb and Jones
82-86F
Shivering will not occur → require artificial rewarming
Atrial arrhythmias may occur, O2 consumption reduced to 50%, heart rate + cardiac output about 35-40% of normal, arterial blood pressure to about 60%, cerebral metabolism ~25%
Cell damage starts at what hyperthermic temperature?
Lumb and Jones
> 108F
Oxygen delivery can no longer keep up with incr metabolism and O2 consumption
What is the MOA of malignant hyperthermia?
Lumb and Jones
metabolic heat production of disturbed intracellular calcium cycling +/- muscle hypertonicity
What is the definition of potency?
Lumb and Jones
the relative dose needed to elicit a response
Not related to duration of effect or efficacy
Why do dogs with an MDR1 mutation overdose?
Lumb and Jones
They do not have a functional efflux pump (P-glycoprotein efflux pump) which transports drugs out of CNS
Phenothiazine drugs affect what receptors?
Lumb and Jones
Adrenergic
Muscarinic
Dopaminergic serotonergic
Histamine
In Gruenheid’s 2018 study “Risk of anesthesia-related complications in brachycephalic dogs,” brachycephalic dogs were at a higher risk of experiencing complications in what anesthetic time periods?
JAVMA 2018
Peri and postanesthetic complications brachys higher risk
In Gruenheid’s 2018 study “Risk of anesthesia-related complications in brachycephalic dogs,” what factors were associated with a higher perianesthetic complication rate?
JAVMA 2018
Brachycephalic status
Longer duration of anesthesia
Risk decreased with increasing body weight and with orthopedic or radiologic procedures
In Gruenheid’s 2018 study “Risk of anesthesia-related complications in brachycephalic dogs,” what factors were associated with a higher postanesthetic complication rate?
JAVMA 2018
Brachycephalic status
Increasing ASA status
Use of ketamine plus benzodiazepine for anesthetic inductive
Invasive procedures
How do NSAIDs produce analgesia?
Rauser. Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine or Carprofen After Periodontal Treatment in Dogs. JVD 2020.
Inhibit cyclooxygenase enzyme in target tissue
Suppress pain transmission peripherally and centrally by blocking neuronal plasticity and central sensitization
What are the effects of inhibition of COX-1 and COX-2 on pain and inflammation?
Rauser. Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine or Carprofen After Periodontal Treatment in Dogs. JVD 2020.
inhibition of COX-1 and COX-2 prevents these enzymes from breaking down arachidonic acid and producing prostaglandins which perpetuate inflammation and sensitize neurons to chemical, mechanical and thermal stimuli
What is the mechanism of action of local anesthetics?
Rauser. Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine or Carprofen After Periodontal Treatment in Dogs. JVD 2020.
Act on sodium channels of nociceptive fibers by blocking influx and preventing generation of an action potential and its propagation to the spinal cord
What are the max doses of lidocaine and bupivacaine in dogs?
Rauser. Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine or Carprofen After Periodontal Treatment in Dogs. JVD 2020.
Lidocaine 4-6mg/kg
Bupivacaine 2mg/kg
In Rauser’s 2020 study “Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine or Carprofen After Periodontal Treatment in Dogs,” what was the methods used?
JVD 2020
84 client owned dogs with PD1 or PD2 that needed RP/C divided into 6 treatment groups:
Butorphanol (on induction), Morphine (on induction), Carprofen (on induction), lidocaine local block, bupivacaine local block, saline as control (on induction)
Scored with Visual Analog Scale for pain (VAS) and the modified University of Melbourne Pain Score (UMPS)
Blood glucose and cortisol measured prior to analgesic administration and 2 hours later
In Rauser’s 2020 study “Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine or Carprofen After Periodontal Treatment in Dogs,” what treatments were concluded to be superior to the others?
JVD 2020
Carprofen on induction, bupivacaine nerve block
In Rauser’s 2020 study “Early Analgesic Efficacy of Morphine, Butorphanol, Lidocaine, Bupivacaine or Carprofen After Periodontal Treatment in Dogs,” bupivacaine and carprofen each had lower pain scores than what treatments respectively?
JVD 2020
Bupivacaine: lower than saline, butorphanol, lidocaine
Carprofen: lower than saline and lidocaine
In Holman’s 2014 paper “Duration of Action of Bupivacaine Hydrochloride Used for Palatal Sensory Nerve Block in Infant Pigs,” what duration of action of bupivacaine was found?
1-3 hours
shorter than previous studies which may be due to neonatal pig model
What is the definition of minimum steady state alveolar concentration (MAC)?
minimum steady state alveolar concentration of an inhalation anesthetic required to prevent gross purposeful movement to a noxious stimulation in 50% patients
What are palpation landmarks for the infraorbital foramen in a horse?
The nasoincisive notch and the rostral border of the facial crest, midway between is the infraorbital foramen.
In Synder and Synder’s 2016 study “Effects of Buprenorphine Added to Bupivacaine Infraorbital Nerve Blocks on Isoflurane Minimum Alveolar Concentration Using a Model for Acute Dental/Oral Surgical Pain in Dogs,” did both treatment groups (bupivacaine vs bupivacaine +buprenorphine) significantly reduce MAC?
Yes, no statistically significant differences between the two due to sample size
In Synder and Synder’s 2016 study “Effects of Buprenorphine Added to Bupivacaine Infraorbital Nerve Blocks on Isoflurane Minimum Alveolar Concentration Using a Model for Acute Dental/Oral Surgical Pain in Dogs,” what percent of dogs had ~20% MAC reduction 48 hours and 96 hours post block administration for the bupivacaine vs bupivacaine vs bup groups respectively?
JVD 2016
Bupivacaine: 48 hrs 25%, 96 hours 0%
Bupivacaine + bup: 48hrs 50%, 96hrs 25%
In Synder and Synder’s 2016 study “Effects of Buprenorphine Added to Bupivacaine Infraorbital Nerve Blocks on Isoflurane Minimum Alveolar Concentration Using a Model for Acute Dental/Oral Surgical Pain in Dogs,” what major conclusions were made?
JVD 2016
Bupivacaine as a local anesthetic may have analgesic effects for greater than 24 hours (24-72hrs)
Addition of buprenorphine may extend duration of analagesia 48-96hrs
In Krug’s 2011 study “Area of Desensitization following Mental Nerve Block in Dogs,” unilateral mental nerve blocks were not very successful. What was the anatomic rationale for this finding?
JVD 2011
Collateral/redundant circulation: buccal branch of CNV innervates soft tissues; contralateral inferior alveolar nerve overlaps; CNVII may also have some sensory fibers; mylohyoid nerve (motor to digastricus) may also have sensory
What is being depicted in this image?
The levator labii superioris muscle is being elevated with the operators thumb prior to inserting the needle.
In Krug’s 2011 study “Area of Desensitization following Mental Nerve Block in Dogs,” what was cited as the minimum length of nerve desensitization needed for a successful nerve block?
JVD 2011
6mm of nerve (~3 nodes of Ranvier required to block saltatory transmission in myelinated nerves)
In Krug’s 2011 study “Area of Desensitization following Mental Nerve Block in Dogs,” what was the main conclusion?
JVD 2011
The area of desensitized tissue was smaller than expected and highly variable so other modes of analgesia should be considered
Used 0.4ml per block
What methods of analgesia block input to the CNS for perception of pain?
Verstraete Chp 4
NSAIDs (block prostaglandin production)
Stimulation of opioid receptors
Blocking alpha-1 adrenergic receptors
In the horse where does the maxillary nerve lie?
Within the pterygopalatine fossa
What analgesics reduce the result of the pain input to the CNS?
Verstraete Chp 4
Stimulation of opioid receptors
Alpha-2 receptors
Serotonin
NMDA antagonists
Lidocaine CRIs have what negative cardiovascular effects in cats?
Verstraete Chp 4
Reduce cardiac output
What is the definition of systolic and mean hypotension in mmHg?
Verstraete Chp 4
Systolic < 90mmHg
Mean < 70mmHg
What is the recommended injection technique for the equine maxillary nerve block and describe it.
The extraperiorbital fat body injection technique. This infiltrates the fat body lying deep to the masseter muscle and superficial to the maxillary nerve.
Landmarks: 10 mm ventral to the facial crest from a line perpendicular to the dorsal contour of the skull and in the plane of the caudal third of the orbit. A 89 mm spinal or Tuohy needle is inserted perpendicular to the skin.
Central venous pressure is a reflection of what physiologic parameters?
Verstraete Chp 4
Vascular volume
Intrathoracic pressure
Ability of right heart to pump blood forward
What is the standard for determining efficiency of ventilation under anesthesia?
Verstraete Chp 4
Blood gas analysis
What is the definition of hypoventilation in mmHg for dogs and cats respectively?
Verstraete Chp 4
Dogs PaCO2 > 43mmHg
Cats > 35mmHg
But no Tx until >65
What block are they performing in the picture? And what muscle are they elevating?
Mental nerve block
They are elevating the levator labii inferioris to facilitate entry into the mental foramen
When performing the equine extraoral inferior alveolar nerve block, what landmarks show you where the mandibular foramen is?
The white line depicts the imaginary occlusal surface of the mandibular cheek teeth. The black line depicts a line from the lateral canthus of the eye to the mandible. Where they intersect is the approximate position of the mandibular foramen.
What are two unique characteristics of methadone?
NMDA receptor antagonist
Does not tend to cause vomiting
What is the following a picture of?
Intraoral approach to the inferior alveolar nerve. Alligator forceps are grasping a 19-25 mm butterfly catheter and inserted into the oral mucosa overlying the rostral ramus just caudal to the mandibular third molar, at the level of the occlusal surface of the tooth (black arrow)
What premedications should be avoided for patients with renal disease?
Alpha-2 agonists
Cause sig vasoconstriction and bradycardia and reduce cardiac output and renal blood flow
What induction agent should be avoided particularly at high doses in patients with renal compromise?
Ketamine
In the cat it is excreted mainly throught the kidneys
What inhalant is not recommended for patients with chronic kidney disease?
Sevoflurane
Produces compound called compound A that is toxic to the kidneys when in contact with CO2 absorbents
What inhalant is contraindicated in patients with hepatic disease?
Halothane
Clinically significant hepatotoxicity
What is the Cushing’s reflex
(Bradycardia hypertension)
Late marker of increased intra-cranial pressure where MAP increased suddenly in the face of increased ICP to maintain cranial perfusion pressure.
Baroreceptors in carotid and aortic bodies respond to acute hypertension by sig decreasing heart rate
What are strategies to prevent increases in intracranial pressure?
Maintain low normal PaCO2 30-35 mmHg
Prevent significant hypoxemia
Maintain adequate MAP
Prevent significant alterations in acid-base status
What percent of crystalloid volume will be extravasated within the first hour after administration?
75-90%
What are the effects of low and high dose ketamine administration on patients with intra-disease/ increased ICP?
Low doses: may be beneficial since ketamine decreases NMDA receptor activation by glutamate the major excitatory neurotransmitter in the brain
High doses/induction with ketamine: should be avoided
What is the ideal agent to maintain general anesthesia in a patient with increased ICP?
Propofol TIVA
Drugs that cause vasoconstriction or vasodilation should be avoided in patients with advanced mitral valve degeneration?
Avoid vasoconstriction: increase in afterload increases regurgitation, can precipitate heart failure
What is the treatment of ventricular tachycardia?
lidocaine bolus
What heart rate is considered bradycardic in the dog?
HR < 60bpm
How is sinus bradycardia treated?
Atropine/anticholinergics
What are the characteristics of first degree AV block?
Prolonged P-R interval
What are the ECG characteristics of Second degree AV block?
Not all P waves followed by QRS complexes
But all QRS complexes have a P wave
What is the difference for low and high grade second degree AV block in terms of treatment?
Low grade AV block is atropine responsive
High grade is atropine unresponsive
What are the characteristics of third degree AV block?
Slow heart rate
P wave and QRS complexes disassociated
What is the treatment for third degree AV block?
Pacemaker
when complete AV dissociation present
How are atrial fibrillation and flutter treated?
Rate control: Slow AV node conduction with diltiazem or beta blocker
Rhythm control: Quinidine, amiodarone, cardioversion if non-responsive
In Kellner’s 2023 paper “Liposomal Bupivacaine in Dentistry and Oral and Maxillofacial Surgery,” how many studies showed no significant differences between bupivacaine and Nocita?
JVD 2023
5/12
In Pascoe’s 2016 study “The effect of lidocaine or a lidocaine-bupivacaine mixture administered into the infraorbital canal in dogs,” the authors concluded that what teeth could be blocked with the infraorbital nerve block?
AJVR 2016
Canine teeth
They recommend using a different block to desensitize caudal to the canine teeth
In the 2020 study “Anesthetic risk during subsequent anesthetic events in brachycephalic dogs that have undergone corrective airway surgery: 45 cases (2007-2019)” what was the % decrease in odds of postanesthetic period complications following brachycephalic airway corrective surgery?
JAVMA 2020
79%
In the 2020 study “Postoperative regurgitation and respiratory complications in brachycephalic dogs undergoing airway surgery before and after implementation of a standardized perianesthetic protocol” what gastroprotectant drugs were used in the pre-op protocol?
JAVMA 2020
Famotidine and metoclopromide
In Costa’s 2020 study “Postoperative regurgitation and respiratory complications in brachycephalic dogs undergoing airway surgery before and after implementation of a standardized perianesthetic protocol,” the implemented perianesthetic protocol included what?
JAVMA 2020
Preoperative metoclopramide and famotidine
Restrictive use of opioids
Recovery of patients in ICU
In Costa’s 2020 study “Postoperative regurgitation and respiratory complications in brachycephalic dogs undergoing airway surgery before and after implementation of a standardized perianesthetic protocol,” what group (A: retrospective group prior to implemented changes, B: implemented changes group) had sig lower postoperative regurgitation
JAVMA 2020
Group B (9%)
Group A 35%
In Davis’s 2021 study “Cadaveric Evaluation of Injectate Distribution for Two Maxillary Nerve Block Techniques in Cats,” they cite that in order to be effective what is the critical length of nerve that must circumferentially associated with an anesthetic drug to have an effective nerve block?
Hoyer, Rawlinson Frontiers 2021
6mm
3 nodes of Ranvier in myelinated nerves
Frog sciatic nerve model
The sensory root of the trigeminal nerve exits the cranium from what foramen, courses through what fossa over what muscle to enter the infraorbital canal?
Rostral alar foramen –> pterygopalatine fossa –> medial ptyeroid muscle –> infraorbital canal
What nerve branches exit the infraorbital nerve and maxillary nerve in the pterygopalatine fossa to innervate the caudal maxillary teeth?
Caudal and middle superior alveolar branches
What techniques have been described to anesthetize the maxillary nerve in cats?
Davis “Cadaveric Evaluation of Injectate Distribution for Two Maxillary Nerve Block Techniques in Cats,” Frontiers 2021
Maxillary tuberosity (caudal intraoral)
Percutaneous (subzygomatic)
Infraorbital foramen
In Davis’s 2021 study “Cadaveric Evaluation of Injectate Distribution for Two Maxillary Nerve Block Techniques in Cats,” what two techniques were compared and what volumes?
Hoyer, Rawlinson. Frontiers 2021
Infraorbital
Percutaneous injection technique
0.2 vs 0.4ml
In the figure below what maxillary nerve block technique is shown and what do the black and white arrows represent?
Davis “Cadaveric Evaluation of Injectate Distribution for Two Maxillary Nerve Block Techniques in Cats,” Frontiers 2021
Percutaneous technique
White arrow: Maxillary foramen
Black arrows: superior alveolar foramina
In Davis’s 2021 study “Cadaveric Evaluation of Injectate Distribution for Two Maxillary Nerve Block Techniques in Cats,” what was the difference between technique and volumes regarding circumferentially stained nerve lengths?
Frontiers 2021
No significant difference between techniques or volume on nerve length staining
What is the length of feline infraorbital canal in mesaticephalic skulls?
Davis “Cadaveric Evaluation of Injectate Distribution for Two Maxillary Nerve Block Techniques in Cats,” Frontiers 2021
4-5mm
In Volk’s 2019 study “Ophthalmic complications following ocular penetration during routine dentistry in 13 cats,” what percent of cats had a transoral maxillary nerve block and what percent recieved enucleation?
NZ Vet Journal 2019
61% (8/13) transoral
54% enucleation
In Davis’s 2021 paper “Computed Tomography Analysis of the Feline Infraorbital Foramen and Canal,” what percent of brachycephalic skulls had redundant foramina?
Hoyer, Rawlinson. Frontiers 2021
67% (4/6)
In Davis’s 2021 paper “Computed Tomography Analysis of the Feline Infraorbital Foramen and Canal,” did the length of the infraorbital canal stat sig differ between mesaticephalic and brachycephalic cats and what were the lengths?
Hoyer, Rawlinson, Frontiers 2021
The length did not stat sig differ
4.4-4.6mm
In Davis’s 2021 paper “Computed Tomography Analysis of the Feline Infraorbital Foramen and Canal,” what was the relationship between the maxillary foramen to the ventral eyeball in brachycephalic vs mesaticephalic cats?
Hoyer, Rawlinson Frontiers 2021
Brachycephalic cats had sig shorter distance (3mm) than mesaticephalic cats (4mm)
brachycephalic cats may be at a higher risk for ocular injection than mesaticephalic cats when using the infraorbital approach due to distance from MF to eyeball
In Davis’s 2021 paper “Computed Tomography Analysis of the Feline Infraorbital Foramen and Canal,” was significant anatomic variability identified?
Rawlinson, Hoyer. Frontiers 2021
Yes, particularly among brachycephalic cats
What nerve block is being depicted in the following image?
Percutaneous maxillary nerve block
What are the black arrows and white arrow pointing to in the following image?
Black arrows - superior alveolar foramina
White arrow - maxillary foramen
In the study, “Inter-rate reliability of the feline grimace scale (FGS) in cats undergoing dental extractions,” what are the five action units?
Ear position, orbital
tightening, muzzle tension, whiskers change, and head position
In the study, “Inter-rate reliability of the feline grimace scale (FGS) in cats undergoing dental extractions,” what was the overall takeaway?
Total FGS scores showed good inter-rater reliability. The FGS is a reliable tool for pain assessment in cats undergoing dental extractions. The caregiver’s presence did not affect FGS scores.
In the JVD 2022 study, “Dental pain in cats: A prospective 6-month study” what were the Signs significantly associated with oral pain?
TR, missing teeth, hypersalivation
When monitoring anesthesia, when is intervention required for heart rates in cats and dogs?
Dog: < 60 bpm or >140 bpm
Cat: <80 bpm or > 200 bpm
When monitoring anesthesia when is intervention required for both systolic and mean blood pressures?
Systolic: <90 or >170 mmHg
MAP: <70 or >130 mmHg
What is the normal systolic and MAP for both dogs and cats?
Systolic - 110- 160 mmHg
MAP - 60 - 100 mmHg
What is a normal cat and dog heart rate?
Dog - 70 - 120 bpm
Cat - 130 - 170 bpm
A blood pressure cuff will give low false readings when?
The cuff is too large or too tight
A blood pressure cuff will give false high readings when?
The cuff is too small or too loose
