Anesthesia Monitoring Flashcards

1
Q

What is the first stage of Anesthesia?

A

Awake

inducement, excitement, miosis, voluntary struggling

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2
Q

What is the second stage of anesthesia?

A

Delirium

obtunded reflexes, mydriasis, still excited, involuntary struggling

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3
Q

What are the 3 planes for the third stage of anesthesia?

A
  1. Light
  2. Medium
  3. Deep (early overdose)
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4
Q

What is the fourth stage of anesthesia?

A

Overdose

Very deep anesthesia; respiration ceases, CV function depresses and death ensues immediately

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5
Q

Autonomic changes, physical and clinical signs are all a(n) ____ method for assesseing anesthesia depth.

A

Subjective

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6
Q

E

ECG activity is a(n) ____ method for assessing anesthesia depth.

A

an objective

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7
Q

What is a reliable way to assess anesthesia depth in carnivores?

A

Eye positioning
- Central for light and deep, rotated for adequate anesthesia

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8
Q

What reflex should all species maintain while under general anesthesia?

A

Corneal reflex

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9
Q

What is a cardinal sign of light anesthesia in horses? What can also stimulate it?

A

Nystagmus
- hypoxia and hypercapnia can also induce nystagmus

hypercapnia = increased CO2

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10
Q

When is the palpebral reflex present/not present in dogs/cats, horses, and camelids?

A
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11
Q

What is the Bispectral Index?

A

Exerts an objective value to indicate anesthesia depth via EEG-derived parameters ranging from 0-100

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12
Q

What CNS and PNS signs are sued to assess anesthesia depth?

A

Ocular reflexes/positioning + muscle tone

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13
Q

Why must cardiovascular function be assessed under anesthesia?

A
  1. minimize organ damage
  2. decrease morbidity and mortality
  3. monitor for the #1 complication: hypotension
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14
Q

Where can pulse be palpated for assessing circulation during anesthesia?

A
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15
Q

What do injected mucous membranes indicate?

A

Vasodilation

Septicemia

Sepsis: causing endothelial cells to relase excess nitric oxide (NO), which is a vasodilator

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16
Q

What do Systolic vs MAP vs Diastolic BP indicate?

A

Systolic: cardiac contractility (90-140mmHg)
MAP: tissue perfusion (60-90mmHg)
Diastolic: peripheral vascular resistance (50-60mmHg)

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17
Q

Common causes for low systolic BP readings?

A
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18
Q

Common causes for high systolic BP readings?

A
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19
Q

Common causes for low or high MAP BP readings?

A

Low: low systolic, diastolic or both
High: high systolic, diastolic or both

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20
Q

Common causes for low diastolic BP readings?

A
21
Q

Common causes for high diastolic BP readings?

A
22
Q

A patient has a low MAP; what other signs of decreased tissue perfusion will be seen?

A

Pale mm
CRT > 2s

23
Q

What are the two major components of MAP?

A

CO and SVR

BP = CO x SVR

24
Q

What triggers a ventricular arrhythmia in an anesthetized patient?

A

Impaired blood flow: compromised CO, BP or tissue perfusion

25
Q

What drug classes can be used to treat bradycardia under anesthesia?

A
  • Anticholinergics (atropine, glycopyrrolate)
  • Sympathomimetics (epinephrine)
26
Q

What drug classes can be used to treat tachycardia under anesthesia?

A
  • Sodium channel blocker (e.g., lidocaine), +/- beta blocker (-olol)
27
Q

Two phases of Dexmedotomidine

A

Phase 1: short-lived hypertension + bradycardia
Phase 2: reflex hypotension + bradycardia

don’t use anticholienrgic until phase 2

28
Q

Systemic Arterial Pressure (SAP):
Pre-hypertensive, hypertensive/moderate risk of TOD, and severe hypertensive/TOD mmHg values.

A
29
Q

Factors of situational hypertension

A

Most likely to occur during anesthesia: pain, incr. in sympathetic tone, light plane of anesthesia

Prevention: adequate analgesia protocol

30
Q

Secondary versus idiopathic hypertension?

A
31
Q

MAP and SAP hypotension readings

A

MAP: < 60mmHg
(large animal = < 70mmHg)

SAP: < 80mmHg

32
Q

A patient develops hypotension; there is adequate anesthetic depth, and you cannot decrease the anesthetic requirement. What other ways can you increase blood pressure?

A
  • Balance anesthesia: administration of combo of drugs to create the anesthetic state.
  • Multi-modal analgesia
33
Q

Frank-Starling Law regarding contractility?

A

A greater preload (EDV) results in increased SV

e.g., bolus, maintenance

34
Q

At what % blood loss should you begin a blood transfusion

A

> 30% blood loss

35
Q

When is administering an anticholinergic to increase HR and MAP contraindicated?

A

if an alpha-2 agonist (dexmedetomidine, xylazine) was given b/c of their hypertensive effect

36
Q

Define Tachyphylaxis

A

when a drug loses clinical effect in the body after giving consecutive doses

37
Q

Why is Ephedrine only given as single-dose boluses and never as a CRI

Ephedrine is a central nervous system (CNS) stimulant that is often used to prevent low blood pressure during anesthesia. It is a sympathomimetic.

A

Because tachyphylaxis will develop after prolonged and repeated doses (b/c drug depletes endogenous norepinephrine stores)

38
Q

SPO2 versus PaO2

A

SPO2 = measures saturation % of oxygenated Hg in arterial blood

PaO2 = measures partial pressure of arterial oxygen - most accurate!

39
Q

PaO2 hypoxemia value

A

PaO2 < 60mmHg

hypoxemia -> hypoxia -> cyanosis

40
Q

What does Respirometry measure

A

Minute Ventilation = Vt x RR

41
Q

Why is PaCO2 measured? What are its values in hypercapnia versus hypocapnia?

A
  • PaCO2: to assess and monitor ventilation efficiency (via blood gas analyzer)
  • WNL = 35-45mmHg
  • Hypercapnia = > 45mmHg (hypoventilation -> respiratory insuffiency)
  • Hypocapnia = < 35mmHg (hyperventilation)
42
Q

What is permissive hypercapnia

A

slight elevation above normal PaCO2, which can be beneficial for anesthetized patients. < 56 mmHg

43
Q

ETCO2 reflects the PaCO2 where?

A

in the alveoli

44
Q

On a capnograph, when the wave hits close to zero, is this inhalation or exhalation, and why?

A

Inhalation – little-to-zero CO2 is normally inhaled

45
Q

When a hypoventilating patient’s tidal volume is compromised (e.g., anesthesia) and respiratory rate increases, will hyperventilation occur?

A

NO- the increased RR is bc the body is trying to compensate for the compromised Vt –> patient’s minute ventilation (MV) stays the same // hypoventilation

MV determines the elimination of CO2

46
Q

PaO2 is ~how much of FiO2?

A

PaO2 ~5xFiO2

47
Q

SaO2 vs SPO2

A

SaO2 is the oxygen saturation of arterial blood, while SpO2 is the oxygen saturation as detected by the pulse oximeter

48
Q

When pulse oximeter reads 90% SpO2, what is the PaO2?

A

PaO2 = 60mmHg = hypoxemia!