Lecture 13 Special Considerations in Anesthesia Part 1 Flashcards Preview

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Flashcards in Lecture 13 Special Considerations in Anesthesia Part 1 Deck (32)
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1
Q

What are 2 anesthetic concerns for liver disease

A
  1. —Glucose homeostasis
    • —Hypoglycemia
  2. —↓ Drug Metabolism
    • —Prolonged recovery
  3. —↓ Protein Synthesis
2
Q

What does decrease protein synthesis cause in patients with liver failure regarding anesthesia

A
  1. —Drug binding
    • —drugs protein bound
    • —↑ unbound drug, ↑ effect
  2. —Oncotic pressure
    • —albumin 80% oncotic pressure
    • —Hypotension
  3. —Coagulation Factors
    • —↑ hemorrhage, blood loss
3
Q

What are the liver assessment tests

A
  1. —ALT
    • —alanine transaminase
    • —‘leakage enzyme’
  2. —ALP
    • —alkaline phosphatase
    • —cholestatsis
  3. —Substances the liver makes
    • —BUN*
    • —Glucose*
    • —Albumin*
    • —Clotting Factors*
    • —Cholesterol
    • —Total Bilirubin, ↑indirect
    • —Bile Acids ​
4
Q
  1. What is the value of glucose you don’t want for anesthesia
  2. What can you do to fix it
A
  1. < 60-70mg/dl
    • —Intra-op monitoring every hour
  2. —Intra-op supplementation of —2.5-5% dextrose in IV fluids
5
Q
  1. clinical signs by hypoglycemia
  2. How can anesthesia affect these signs?
A
  1. —Seizures, CNS depression
  2. —Masked by anesthesia
6
Q

What are drugs that are not metabolized by liver used in anesthesia

A
  1. —Inhalants
    • —Isoflurane .17%
    • —Sevoflurane 3-5%
    • —Desflurane 0%
    • —Nitrous Oxide 0%
  2. —Propofol
    • —Extra-hepatic sites of metabolism
    • —Very short acting, 5-10 min
  3. —Drugs that are reversible
7
Q

Order the inhalants of least to most that are metabolized by liver

A
  1. —Desflurane 0%
  2. —Nitrous Oxide 0%
  3. —Isoflurane .17%
  4. —Sevoflurane 3-5%
8
Q

What are the —Drugs that are reversible and what reverses them

A
  1. —Opioids full mu agonists
    • —Morphine, Hydromorphone, Fentanyl
    • —Full reversal Naloxone
    • —Partial reversal Butorphanol
  2. —Benzodiazepines
    • —Midazolam, Diazepam
    • —Flumazanil $$$
  3. —Alpha-2 agonists
    • —Dexmedetomidine
    • Atipamazole
9
Q

—Drug Binding

—↓ dose, reversible drugs, drugs not metabolized by liver

A
10
Q
  1. Because there is —↓ Oncotic pressure because of ↓Albumin what fluids will you use?
  2. How will you treat hypotension
A
  1. —Collioids
    • —Plasma, if practical
    • —Hetastarch
  2. —Hypotension
    • —‘balanced anesthesia’ techniques, Isoflurane sparing
      • —Fentanyl CRI, nitrous oxide
    • —Vasopressors & positive inotropes
11
Q

What can you use to treat ↓ Clotting Factors during anesthesia

A
  1. —Fresh Frozen Plasma
    • —Provides albumin & clotting factors
    • —May not be practical in large dogs for oncotic support
      • —Need 45ml/kg to raise albumin by 1g/dl
  2. —Monitor Blood Loss
    • —Calculate total blood volume, allowable loss
    • —Quantitate blood loss intra-operatively
    • —Replace blood as indicated
12
Q

What % of tissues are found in the brain

A
  • —Brain tissue 80%
  • —CSF 10%
  • —Blood 10%
13
Q

What does the —Monroe-Kellie Doctrine say

A
  • —↑ in volume of one of the cranial constituents must be compensated by a ↓ in volume of another
  • —↓CSF production, ↑CSF absorption
14
Q

What are causes of patients with neurolgic disease

A
  1. —Brain tumor
  2. —Trauma with brain edema
  3. —Infectious disease/abcess
  4. —Seizures => brain edema
  5. —Hydrocephalus
15
Q
  1. What is the MAP that you want during anesthesia
  2. What do you want to do with cerebral blood flow (CBF)
A
  1. —60 – 150 mmHg
  2. —Do NOT ↑CBF
16
Q
  1. What drugs can you use that do not increase cerebral blood flow (CBF)
  2. Which drug to avoid?
  3. What parameter is the biggest determinant of CBF
A
  1. —Propofol, low dose inhalants
  2. —Avoid Ketamine
  3. —Keep PaCO2 in normal range =>
    • — 35 – 40mmHg
    • Use— IPPV ​
17
Q

Cushing reflex

A

pressure increases in brain and then body will have to increase systemic blood pressure

18
Q
  1. How do you monitor —Sudden, severe ↓ in HR
  2. How to treat
  3. What is a critical time for brain herniation
A
  1. Check MAP
  2. —Hypertonic Saline, mannitol
  3. —*Induction is critical time
19
Q

What are general strategies for Patients with Cardiac Disease

A
  1. —Maintain Cardiac Output
  2. —Maintain good oxygenation/ventilation
  3. —Avoid fluid overload
  4. —Avoid hypo- or hypertension
  5. —Avoid bradycardia or tachycardia
  6. —Avoid ↑ myocardial work & O2 consumption
  7. —Avoid drugs that cause arrhythmias & myocardial depression
  8. —Use drug with mild CV effects
  9. —‘Balanced Anesthesia’ & multi-modal approach
  10. —Low dose Acepromazine to ↓stress, promote forward flow
  11. —Judicious use of anti-cholinergics
  12. —Pre-oxygenate
  13. —↓ IV fluid rate
20
Q

What are drugs with mild cardiovascular effects

A
  1. —Opioids –
    • pure u-agonists: Hydromorphone, Oxymorphone, Fentanyl, Morphine
  2. —Benzodiazepines
    • Midazolam, Diazapam
  3. —Etomidate, alphaxalone
  4. —Nitrous Oxide
21
Q

What is the benefit of using Acepromazine for cardiac disease animals

A
  • —to ↓stress
  • promote forward flow so that BP and HR doesnt increase
22
Q

Why do you want to have a —Judicious use of anti-cholinergics for cardiac disease

A

If you decrease vagal tone you will increase HR

23
Q
  1. What is the —Most common degenerative heart disease in dogs
  2. Do you just need to know the diagnosis for this disease?
A
  1. Mitral Valve Regurgitation
    • enlargement of right atrium
    • back up into lungs
  2. —Progressive disease/need to establish extent of cardiac dysfunction
24
Q
  1. What is the common cardiomyopathy in cats
  2. What other disease is it associated with
A
  1. Hypertrophic cardiomyopathy
  2. —Associated with hyperthyroidism
25
Q
  1. What will yo usee to HR with a cat with hypertrophic cardiomyopathy
  2. BP?
  3. Organ status
A
  1. —Tachycardia, murmur, ‘gallop’ rhythm
  2. —Hypertension,
  3. renal failure
26
Q

How do you treat cats with hypertrophic cardiomyopathy or hyperthyroidism for anesthesia

A
  1. —Stabilize pre-op with anti-thyroid, cardiac meds
  2. —Avoid stress, tachycardia
  3. —Opioid
    • —+/- Alphaxalone
    • —+/- benzodiazepine
    • —+/- low dose Acepromazine
    • —+/- low dose Dexmedetomidine
27
Q

What are the 2 general patients with respiratory disease

A
  1. —Lower airway disease:
    • pneumonia, asthma, contusions
  2. —Extra-pulmonary disease:
    • pneumothorax, pleural effusion, Diaphragmatic hernia
      • —!! Evacuate air, fluid !!
28
Q

How do you anesthetize Patients with Respiratory Disease

A
  1. —Preoxygenate
  2. —Rapid IV induction/intubation
  3. —100% O2, +/- IPPV
  4. +/- Positive end expiratory pressure (PEEP)
    • will hold pressure in alveoli
29
Q

What are the different problems with Brachycephalic Syndrome

A
  1. —Stenotic nares
  2. elongated soft palate
  3. excessive pharyngeal tissue
  4. everted laryngeal saccules
  5. hypoplastic trachea => Upper Airway Obstruction
30
Q

How do you premedicate brachycephalic syndrome animals

A
  1. —+/- LOW dose Acepromazine
    • —relieve stress from uppper airway obstruction/hypoxemia
  2. —+/- Anticholinergics
    • —high vagal tone from uppper airway obstruction
  3. —Continuous observation
  4. —Variety of ET tube sizes 6.0-10mm
31
Q

How do you induce brachycephalic syndrome animals

A
  1. —Pre-oxygenate
  2. —Rapid IV induction/intubation
    • —Propofol drug of choice
      • quick recovery without residual effects
32
Q

How do you recover brachycephalic syndrome animals

A
  1. —Continue O2, monitor SpO2
  2. —Leave in IV catheter
  3. —Sternal position, head elevated
  4. —Quiet/dim light surroundings
  5. —Leave in ET tube as long as possible
  6. —Be prepared to re-intubate
    • —Laryngoscope, ET tube, induction agent, O2 source/IPPV (anesthetic machine)
  7. —Monitor SpO2 after extubation
    • —Sternal, prop open mouth, extend tongue