Term
| Use of a chemical agent on sensory neurons to produce a disruption of nerve impulse transmission, leading to a temporary loss of sensation |
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Definition
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Term
| Advantages of Local Anesthesia |
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Definition
Low cardiovascular toxicity
Inexpensive
Excellent pain control immediately postoperatively
Minimum patient recovery time |
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Term
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Definition
Ruminant obstetric and abdominal procedures
Complement standing sedation in horses
In conjunction with general anesthesia for pain control
•Dental extractions, surgery on the mandible, leg amputations, orthopedic surgeries. Thoracic and abdominal surgeries |
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Term
| Immediate onset, shorter duration |
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Definition
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Term
| Slower onset of action; long duration |
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Definition
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Term
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Definition
| : tetracaine, proparacaine |
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Term
| Local Anesthetic Mechanism of Action |
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Definition
Drugs that affect primarily sensory neurons (nerves that convey sensations to the brain)-loss of nerve conduction
Drug must be placed in proximity to the neuron
Blocks sodium channels and prevents generation of electrical impulses (stops depolarization)
Reversal occurs as drug is absorbed into the local circulation
Metabolized in liver |
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Term
| Drugs that affect primarily motor neurons (nerves that control voluntary movement) |
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Definition
Cause temporary local paresis or paralysis
Seen in conjunction with sensory neuron loss of sensation
•e.g., Epidural block will result in loss of sensation and voluntary movement to all areas in the caudal abdomen and pelvic limbs |
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Term
| 3 types of Regional anesthesia |
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Definition
Paravertebral
Epidural
IV regional (Bier block) |
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Term
| type of Local A. that you spray into wound/laceration or surgical incision (declaw), soak gauze sponges in local anesthetic and saline |
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Definition
Splash block
Caution to not reach the toxic dose |
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Term
| type of Local A. that you use for catheter placement |
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Definition
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Term
| type of Local A. that cools the skin for biopsy, partial, short term |
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Definition
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Term
| Drug injected into tissues in proximity to the target nerve/nerves |
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Definition
Infiltration
Directly into tissues•Intradermal, subcutaneous, or intramuscular administration•Provides analgesia for surgery involving superficial tissues- skin biopsies, minor lacerations, removal of small skin tumorsNerve blocksLine blocks |
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Term
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Definition
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Term
| Lidocaine with or without epinephrine is most common? |
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Definition
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Term
| Why would we choose to use lidocaine with epinephrine? (3 reasons) |
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Definition
to produce a vasoconstriction effect
•Decreases absorption and prolongs effect of lidocaine
•Reduces toxicity, reduced amount of local anesthetic that enters circulation at any given time |
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Term
| When do we not use epinephrine with lidocaine? (3) |
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Definition
•In an incision-may delay healing and impair perfusion
•On the ears, tail, digits- compromise circulation
•When lidocaine is given IV- pain CRI |
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Term
| what gauge needles would you use to local anesthetic infiltration? |
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Definition
| Small-gauge needle (20-or 25-gauge) |
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Term
| onset of action for lidocaine (minutes) |
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Definition
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Term
| how to Test effectiveness prior to surgery for lidocaine and other local anesthetics |
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Definition
| gently prick skin with a 22-gauge needle |
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Term
| ____ ____ - injecting local anesthetic in proximity to a nerve |
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Definition
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Term
| Infiltration Techniques Nerve Block pros. name 3 |
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Definition
•Desensitizes a particular anatomic site
•Decreases amount of general anesthesia needed
•Provides short-term analgesia postoperatively |
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Term
| Infiltration Techniques Nerve Block most used in small or large animal? |
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Definition
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Term
| surgeries that use Nerve Block |
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Definition
Dental blocks in dogs and cats Intercostal nerve blocks for chest surgery
Limb amputations
Cat declaws
Paravertebral blocks for abdominal or obstetric procedures in cattle Cornualblocks for dehorning cattle Lameness examinations in horses |
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Term
| _____ _____ - a continuous line of local anesthetic placed between the target area and the spinal cord |
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Definition
line block
(type of Infiltration Technique) |
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Term
| _____ _____ - line of local anesthetic completely encircles an anatomic part |
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Definition
ring block
(type of Infiltration Technique) |
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Term
| Infiltration Line Block info |
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Definition
•Inserting the needle and gradually withdrawing the needle while injection a small amount of local anesthetic
•Used in food animal and equine surgery
•L-block: a line block used for laparotomy surgery in ruminants |
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Term
| _____ ______ - Local anesthetic injected into a nerve plexus or in proximity to the spinal cord |
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Definition
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Term
| type of local anesthetic that Affects a larger area such as an entire limb or caudal portion of the body |
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Definition
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Term
| Regional anesthesia produces ______ anesthesia in ruminants |
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Definition
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Term
| 2 examples of Regional Anesthesia |
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Definition
Epidural
IV regional (Bier block) |
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Term
| _____ ______ - A regional anesthetic procedure used in small and large animals that Blocks sensation and motor control of the rear, abdomen, pelvis, tail, pelvic limbs, and perineum |
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Definition
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Term
| examples of Epidural Anesthesia surgeries |
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Definition
Tail amputation
Anal sac removal
Perianal surgery
Urethrostomies
Prolapse repair
Cesarean sections
Some rear limb operation |
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Term
| infiltration Techniques Epidural Anesthesia: Drug choice determined by procedure |
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Definition
Local anesthetic
Opioid and local anesthetic mixture
Deposit in epidural space |
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Term
| where do you place the epidural in a dog/cat |
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Definition
| between the last lumbar vertebra (L7) and the sacrum (cats: spinal nerves may be there, more caution) |
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Term
| Infiltration Techniques: Bier Block |
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Definition
•Intravenous regional anesthesia
•Provides short-term local anesthesia to a limb
•Lidocaine only (without epinephrine) |
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Term
| Bier Block: the Tourniquet is applied _____ to the superficial vein |
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Definition
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Term
| Bier Block: Lidocaine is injected into the ______ superficial vein |
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Definition
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Term
| Systemic Constant Rate Infusion of lidocaine |
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Definition
•Lidocaine administered to healthy anesthetized animals (or in combo with other drugs (MLK, FLK, etc)
•Reduces dose of general anesthesia or analgesic required
•Used in dogs, cats, and horses |
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Term
| Adverse Effects of Local Anesthetics (9) |
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Definition
1. Loss of motor neuron function
•Self trauma to tongue
•Cow may go down
2. Temporary or permanent loss of nerve function with direct injection into a nerve (should be avoided unless amputation)
3. Tissue irritation
4. Paresthesia during recovery- tingling, pain, or irritation during recovery from local anesthetic- self trauma
5. Allergic reactions from rash or hives to anaphylactic shock
6. Systemic toxicity : sedation, nausea, restlessness, muscle twitching, hyperexcitability, seizures, respiratory depression, coma
•Lidocaine
dogs < than 10mg/kg SQ, 4mg/kg IV
cats < than 4mg/kg SQ, 0.5mg/kg IV
•Bupivacaine
-dogs less than 2mg/kg SQ (not given IV)
-cats less than 1mg/kg SQ (not given IV)
7. epidural or spinal injection may traumatize the spinal cord or cauda equina
•Inflammation and fibrosis may occur if there are preservatives
•meningitis, myelitis if aseptic technique is not used
8. if local anesthetics infiltrate into the cranial portion of the spinal cord, serious toxicity or death may occur
•If it reaches mid-thoracic vertebrae, intercostal mm may be blocked and respiration affected
•Or the phrenic nerve that affects the diaphragm
•Keep the patient’s head elevated to avoid gravitational flow cranially
9. diffusion of local anesthetic into the cervical and thoracic spinal cord may also affect the nerves of the heart and blood vessels resulting in a sympathetic blockade with symptoms of bradycardia, deccardiac output and hypotension |
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Term
| ____________ - any procedure by which the anesthetist assists or controls the delivery of oxygen and gas to the patient’s lungs. |
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Definition
| Positive-pressure ventilation (PPV) |
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Term
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Definition
| Patient initiates inspiration Anesthetist makes sure an increased volume of air reaches the patient |
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Term
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Definition
Anesthetist delivers all air required by the patient
No spontaneous respiratory effort by the patient
Anesthetist controls respiratory rate and volume and pressure of gas inhaled |
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Term
| Ventilation in Anesthetized Animals |
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Definition
•Differs from ventilation in awake animals
•Reduced amount of air entering and leaving the lungs |
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Term
| what do Tranquilizers and general anesthetics do to the body |
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Definition
Decrease responsiveness of breathing center to carbon dioxide levels so inhalation doesn’t occur as often
Relax intercostal muscles and diaphragm so the chest doesn’t fully expand (VTis reduced)
•Normal tidal volume is 10-15 mL/kg |
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Term
| 3 Potential Problems in an anesthetized animal |
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Definition
Hypercarbia
hypoxemia
atelctasis |
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Term
| Related to less oxygen entering the lungs to be absorbed into the blood |
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Definition
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Term
| Related to decreased VTso alveoli don’t fully expand on inhalation, which can lead to partial collapse of the alveoli in some sections of the lung |
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Definition
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Term
| Related to the breakdown of carbon dioxide to bicarbonate ions and hydrogen ions, which can lead to respiratory acidosis |
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Definition
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Term
| Types of Controlled Ventilation (PPV) (3) |
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Definition
(Patient is intubated and connected to anesthetic machine)
•Manual ventilation or bagging
Anesthetist bags patient every 2-5 minutes
•Intermittent mandatory ventilation
Patient requires bagging throughout the anesthetic period
•Mechanical ventilation
Lungs are filled with oxygen by pressure of gas from a ventilator –when ventilation needed for a long period of time |
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Term
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Definition
•Lungs are filled with oxygen by pressure of gas entering airways
Anesthetist is squeezing the reservoir bag
Pop-off valve is fully or partially closed
Bag one to two breaths every 2-5 minutes (sighs)
Pressure manometer reading: <20 cm H2O (small animals)
6-12 bpm –can provide intermittent if not breathing on their own
Wean patient off assisted ventilation near the end of the surgical procedure |
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Term
| Muscle-paralyzing agents where Animals remain conscious and feel pain-inhumane to use in awake animals, only while under anesthesia |
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Definition
| Neuromuscular Blocking Agents |
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Term
| Neuromuscular Blocking Agents |
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Definition
•Limited use in veterinary medicine
Animals on mechanical ventilation-prevents spontaneous respiratory efforts (bucking the ventilator), useful for thoracic or diaphragmatic surgeries
Orthopedic surgery and ophthalmic surgery
Cesarean sections
Facilitate difficult intubation
Component of balanced anesthesia |
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Term
| Neuromuscular Blocking Agents: examples (4) |
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Definition
•Drugs: succinylcholine (depolarizing), gallamine, pancuronium, atracuriumbesylate, etc.
non-depolarizing agents are reversible |
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