Anaesthesia Flashcards

(32 cards)

1
Q

What type of physiological changes are expected with liver disease which may have an impact on anaesthesia and surgery?

A
  • Altered pharmacokinetics of anaesthetic drugs
  • Altered glucose metabolism
  • Reduced albumin production
  • Increased bleeding tendencies
  • Jaundice
  • Hepatomegaly
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2
Q

What features of gastrointestinal disease should be taken into account during anaesthesia?

A
  • Disturbances in fluid, electrolytes, acid-base balance, and protein levels
  • Hypovitaminosis, weight loss, and emaciation
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3
Q

Why should morphine and alpha2-agonists be avoided in patients with gastrointestinal disease?

A
  • These drugs induce nausea and vomiting
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4
Q

What modulates cerebral vascular resistance (CVR)?

A

Blood-gas values, especially PaCO2

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5
Q

What is the cerebral perfusion pressure?

A
    • Difference between carotid arterial blood pressure and jugular venous pressure
  • Cerebral perfusion pressure (CPP) is defined as the difference between the force driving blood into the brain (mean arterial pressure [MAP]) and the force resisting movement of blood into the brain (intracranial pressure [ICP] or central venous pressure [CVP], whichever is the highest).
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6
Q

What is the Monro-Kellie Hypothesis?

A

Any increase in volume in either of cellular component, ventricles, and blood vessels of the brain has to have a reciprocal decrease in the other two, or the intracranial pressure will rise

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7
Q

What is the cerebral central venous pressure (CVP)?

A

Pressure that resists movement of blood into the brain

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8
Q

Describe the physiological changes severe hyperventilation will cause in the brain.

A

Severe hyperventilation decreases CO2 pressure. A decrease in PaCO2 will cause vasoconstriction of cerebral blood vessels. Thus, a reduction in PaCO2 by hyperventilating can cause a rapid decrease in cerebral blood flow and intracranial pressure.

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9
Q

Describe the physiological changes severe hypoventilation will cause in the brain.

A

Severe hypoventilation will cause an increase in PaCO2 and will result vasodilation of cerebral vessels and increase in cerebral blood flow and intracranial pressure

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10
Q

How is cerebral blood flow calculated?

A

[Cerebral perfusion pressure]/[cerebral vascular resistance]

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11
Q

What are some options for treating intracranial hypertension?

A
  • Minimize central venous pressure
  • Modest hyperventilation
  • Use of diuretics
  • Use of steroidal anti-inflammatories
  • Use of cytoneuroprotectives
  • Induction of hypothemia
  • Craniotomy
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12
Q

What are some methods to minimize central venous pressure in the brain perioperatively?

A
  • Use of head-up position
  • Avoidance of fluid overload
  • Avoidance of coughing and gagging (causes the vessels in the head to expand)
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13
Q

What is Mannitol?

A
  • Osmotic diuretic
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14
Q

Name a steroidal anti-inflammatory.

A

Methylprednisolone

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15
Q

How can occular immobility be achieved for occular surgery?

A
  • Stay sutures
  • Retrobulbar block
  • Deep anaesthesia
  • Neuromuscular block
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16
Q

What is the occulo-cardiac reflex?

A

Decrease in pulse rate associated with traction applied to extraocular muscles (media rectus muscle, for example) and/or compression of the eyeball

17
Q

What should be considered when formulating an anaesthetic plan for an animal with endocrine disease?

A
  • Chronicity of the disease
  • Severity of the disease
  • Physiological pertubations caused by the disease
  • If the condition can be stabilized before anaesthesia
  • If the condition will be destabilized by the anaesthesia
  • If there are any contraindications for loco-regional anaesthesia
18
Q

Why must a hyperkalaemic patient be stabilized for anaesthesia? How can this be achieved?

A
  • A hyperkalaemic patient will be more likely to produce action potentials and changes the resting potential of the heart
  • Treament
    • Treat the underlying problem
    • Administer calcium
    • Administer bicarbonate therapy
      • Moves the potassium ions into the intracellular space
    • Administer glucose and insulin therapy
      • Moves the postassium ions into the intracellular space
19
Q

Why should metabolic acidosis be considered when making an anaesthetic plan?

A

Metabolic acidosis decreases excretion of certain drugs in the kidney

20
Q

How should ureaemia be considered when making an anaesthestic plan?

A

Uraemia causes reduced protein-binding which allows more free drug to be available

21
Q

What cardiovascular changes occur during pregnancy?

A
  • Decreased systemic vascular resistance
  • Increase in heart rate and stroke volume
    • If heart rate is not able to increase something else will have to decompensate
  • Uterine contractions
  • Cardiac output with changes to uterine flow
  • Decreased cardiac reserve
  • Oxytocin release
    • Increases blood flow to uterus to increase vasodilation and hypertension
22
Q

What haematological parameters change in the female during pregnancy?

A
  • Increase in blood volume
  • Increase in plasma volume
  • Increase in red blood cell mass
  • Decrease in haemaglobin and PCV
  • Decrease in oxygen-carrying capacity
  • Uterine blood reservoir increases
23
Q

What is Mendelson’s Syndrome?

A
  • Chemical pneumonitis caused by aspiration during anaesthesia
24
Q

What should be part of the anaesthetic plan to manage gastrointestinal conditons caused by pregnancy.

A
  • Full stomach should be avoided
  • Metoclopramide (prokinetic) given iv
  • Maropitant (anti-emetic) can be administered
  • Antacids can be administered
  • H2-antagonist (such as Ranitidine) can be administered
25
Describe some pulmonary changes that occur with pregnancy.
* Increase in oxygen consumption * Reduction in total pulmonary resistance * Increase in dead space * Reduciton in functional residual capacity * Increase in circulating progesterone and endorphins * Reduces minimal alveolar concentration (concentration of the vapour in the lungs that is needed to prevent movement (motor response) in 50% of subjects in response to surgical (pain) stimulus.)
26
What gastrointestinal changes accompany pregnancy?
* Decrease in gastric volume * Increase in gastric pressure * Lower oesophageal tone * Decreased gastric motility * Increase in gastrointestinal acid, chloride, and enyzmes
27
What hepatic changes accompany pregnancy?
* Reduction in plasma proteins * Slight increase in liver enzymes * Decrease in plasma cholinesterase
28
What renal changes accompany pregnancy?
* Increase in renal blood flow and increase in glomerular filtration rate
29
Describe the changes that occur to uterine vasculature during pregnancy.
* Decreased uterine blood flow (UBF) * * Causes hypotension, hypovolemia, uterine manipulation, contractions, anaesthesia * Increase in uterine vasculature resistance (UVR)
30
What are the most important factors to keep in mind when creating an anaesthetic plan for a pregnant female?
* There is a reduced cardiac reserve in these patients * There is reduced functional residual capacity (FRC) and O2-carrying capacity * There is a large increase in risk of regurgitation * Nephrotoxic drugs should be avoided * There is increased sensitivity to inhalants and local anaesthetics
31
What are some good induction agents for pregnant patients?
* Alfaxalone * Midazolam and lidocaine as co-induction agents * Fentanyl
32
List some ways in which hypothermia can impair cardiac function.
* Causes shivering and increases oxygen utilization * Depresses ventilation * 'Left shifts' oxygen-haemaglobin disassociation curve (ODC) * Arrhythmogenic