Lecture 12 10/14/24 Flashcards
What are the main zoonotic concerns when working with ruminants?
-Cryptosporidium
-Rabies virus
-Listeria monocytogenes
-Toxoplasma spp.
-Mycobacterium spp.
-Tuberculosis
Which pathogens cause occult/old bronchopneumonia in ruminants?
-Mycoplasma spp.
-Pasteurella spp.
-Bordatella spp.
-Mannheimia spp.
-Parainfluenza
What is the importance of identifying occult/old bronchopneumonia in ruminants?
animal can have a smaller tidal volume, which can lead to hypoxemia
What are the general trends in vitals between adult and young animals?
young animals have higher HR and RR, while BP is lower
Why is it important to consider a ruminant’s complex stomach when placing them under anesthesia?
-fasting for 24 hrs decreases fermentation and increases functional residual capacity of the lungs
-want to avoid excessive fasting and its adverse effects
Why is it important to consider a ruminant’s eructation when placing them under anesthesia?
-ruminants cannot eructate under GA
-methane must be vented out
What are the possible complications when placing a ruminant under anesthesia?
-regurgitation
-bloating
-choking
What are the effects of ruminal tympany/overfilling of gas?
-reduced functional residual capacity
–hypoventilation and hypoxemia
-compression of great vessels
–hypotension
How is ruminal tympany accounted for?
-animal placed in sternal or right lateral recumbency
-stomach tube passed to evacuate gas
When does regurgitation occur in ruminants under anesthesia?
-during intubation/active
-during GA/passive
-in any recumbency (sternal and R lateral best for avoidance)
What should be avoided in order to prevent regurg?
-esophageal intubation
-intubation under a light plane of anesthesia
What steps can be taken to prevent regurg?
-make sure ET tube is cuffed properly
-tilt head down
What are the characteristics of salivation?
-production continues under sedation/anesthesia
-must replace the fluid lost
-can obstruct the airway; tilt head down
What are the characteristics of anesthesia in neonatal/juvenile ruminants?
-can be considered monogastric if still on milk
-limited fasting
-monitor for hypoglycemia; increased risk
What are other considerations that must be taken into account when placing a ruminant under anesthesia?
-drug residues entering food chain
-ability to move them
-health status
-temperament
-type of surgery/procedure
What are the general characteristics of dairy cow anesthesia?
-used to being handled
-mild physical restraint + local/regional sedation
-light sedation and lower doses of sedatives/anesthetics for standing procedures
-endotracheal intubation for GA
-smoother recovery
What are the general characteristics of beef cattle anesthesia?
-infrequently handled
-require more physical restraint
-heavy sedation and larger doses or sedatives/anesthetics
-endotracheal intubation for GA
-rougher recovery
What are the uses/purposes of sedation in ruminants?
-restraint
-minor diagnostic procedures
-medical procedures
-improving quality of GA induction, maintenance, and recovery
What are the general characteristics of sheep and goat anesthesia?
-easier to handle
-most procedures done with mild physical restraint, light-to-moderate sedation, and local anesthesia
Which drug classes are used in ruminants?
-opioids
-benzos
-alpha2-agonists
-acepromazine
Why are sedatives reversed in ruminants?
-speeding up recovery time
-emergency treatment for adverse effects
Which reversal agents are used to reverse alpha2-agonists in ruminants?
-yohimbine (least selective)
-tolazoline
-atipemazole (most selective)
Which reversal agent is used to reverse opioids in ruminants?
naloxone
Which reversal agent is used to reverse benzos in ruminants?
flumazenil
Which veins are used for IV access in ruminants?
-jugular vein
-caudal auricular vein
What are the characteristics of alpha2-agonist use in ruminants?
-VERY sensitive to xylazine
-increased CNS sensitivity compared to horses
-need very small amounts
-avoided in neonates/juveniles when possible due to profound sedation
What are the side effects of alpha2-agonists in ruminants?
-increased uterine tone/abortion
-placental crossing
-GI stasis
What are the adverse effects of alpha2-agonists specifically in sheep?
-pulmonary edema
-increased airway pressure
-parenchymal damage
-bronchospasm
-venospasm
-hypoxemia
-cardiorespiratory collapse
-death
How do alpha2-agonists impact the alveoli of sheep?
-macrophage response
-release of cytokines
-damage to alveolar type 1 cells, endothelium, and lung parenchyma
What are the characteristics of butorphanol use in ruminants?
-synergistic effects with other sedatives
-no MAC reduction
-mild analgesia
What are the characteristics of morphine use in ruminants?
-usually sedative
-reduces MAC
-moderate/profound analgesia
What are the characteristics of benzo use in ruminants?
-short term sedation
-no analgesia
-mainstem of pediatric sedation
-mainstem of induction when combined with ketamine
What is a ketamine stun used for?
dose dependent sedation/immobilization, usually with recumbency
What are the original ketamine stuns?
IM or IV xylazine + ketamine
What are the modified ketamine stuns?
-IV butorphanol, ketamine, and xylazine
-IM butorphanol, ketamine, and xylazine for aggressive cattle
Which supplies are necessary for large ruminant intubation?
-your arms
-mouth gag/speculum
-appropriate size ET tube
What are the characteristics of large ruminant intubation technique?
-always performed if under GA
-done in sternal recumbency
-palpate/use hand as guide for ETT
Which supplies are necessary for small ruminant intubation?
-appropriate size ETT
-laryngoscope
-stylet
What are the characteristics of small ruminant intubation technique?
-always performed if under GA
-done in sternal recumbency
-neck hyperextended to 180 deg. angle
-visualization of arytenoid cartilages and tracheal opening
-lidocaine used to prevent laryngospasm
What should be expected when intubating a ruminant?
-regurg. and upper airway obstruction
-thick epiglottis and base of tongue
-small, far target with small opening between maxilla and jaw
What are the complications that arise from placing the ET tube too far?
-blockage of the tracheal bronchus
-V/Q mismatch and hypoxemia
What steps should be taken when positioning a ruminant for a procedure?
-use mats for padding
-avoid stretching limbs
-pull dependent limbs forward
-tilt head down to drain oral contents
What are the characteristics of neuropathy/myopathy complications?
-depend on patient’s weight and time in recumbency
-superficial nerves compressed on hard surfaces (radial, femoral, peroneal)
-heavy muscular masses on hard surfaces
-poor tissue perfusion due to hypotension leads to ischemia
What are the characteristics of bovine anesthesia maintenance?
-injectable or inhalant-based
-similar side effects to other species
-machine and ventilation similar to horses
-mechanical ventilation recommended
-on FiO2 of 1
What are the characteristics of small ruminant anesthesia maintenance?
-injectable or inhalant-based
-similar side effects to other species
-machine and ventilation similar to large dogs
-mechanical ventilation recommended
-on FiO2 of 1
Which drugs are used for injectable maintenance of anesthesia?
-guaifenesin
-ketamine
-xylazine
How are the eyes positioned in the anesthetized bovine?
-ventral when in Plane III Stage 1 or 2
-central when in Plane III Stage 3 or Plane IV
What are the characteristics of eye position in anesthetized small ruminants?
-inconsistent and unreliable
-generally central
-jaw tone used to assess depth
What is the cut-off for hypotension in ruminants?
80 mmHg
How is temperature monitored in ruminants?
-nasopharynx
esophagus
What are the key points regarding ruminant recovery?
-always in sternal recumbency to favor eructation
-always elevated with a supported head
-extubate when ruminating motions are consistent
-always keep IV catheter in as long as possible
What are potential post-anesthetic complications in ruminants?
-regurg.
-airway obstruction
-choking
-ruminal tympany
-prolonged recovery
-neuropathy
-myopathy
-hypothermia
What are the characteristics of drug residues?
-use of off-label drugs is protected by AMDUCA
-very few drugs labeled for use in small ruminants
-consult FARAD for withdrawal recs
-provide withdrawal recs for each drug to every client, even if a pet
-phenylbutazone prohibited in female dairy cattle older than 20 months
