Anesthetic Monitoring Flashcards

1
Q

anesthetic goals

A
  1. Provide a stage of reversible unconsciousness for surgical and diagnostic procedures
    a. adequate analgesia
    b. muscle relaxation
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2
Q

stages of anesthetic? which can result in problems?

A
  1. pre-med
  2. induction
  3. maintenance
  4. recovery

> all stages can result in problems

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3
Q

what are some ocular signs we look for during manual monitoring?

A

i. Palpebral reflex - brisk response is a light depth and injectable protocols
ii. Spontaneous blinking
iii. Nystagmus
iv. Eyelid tone
¡Open / wide or narrowed eyelid aperature
v. Tear Production and Ocular lubrication
¡ should remain moist
¡ if dry – too deep
vi. Ocular position & changes

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4
Q

types of palpebral reflex we look at for manual monitoring of SA? which is stronger and when is each lost?

A

i. Lateral Palpebral Reflex
reflex weakens and lost during anesthetic induction for SA

i. Medial Palpebral Reflex
stronger and will remain in SA until they deepen on the inhalant anesthetic

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5
Q

what should we use as a sign for intubation in SA?

A

loss of lateral palpebral reflex
¡ At this stage able to open mouth, check jaw tone and proceed to endotracheal intubation safely

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6
Q

will medial palpebral remain in SA with injectable?

A

yes

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7
Q

how do we evaluate palpebral reflex in LA? what do we expect to see ? how often should we check?

A

Not evaluated with medial or lateral touch

¡Perform by lightly running fingertip on upper eyelid to determine if animal will blink
¡Reflex remains with injectable & inhalant
¡Strong palpebral with injectable ¡ Field injectable
¡ Triple drip protocols
¡Don’t check too frequently ¡ will blunt the response

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8
Q

what does spontaneous blinking under anesthesia mean in large and small animal anesthesia?

A

Large Animal
* Present under equine injectable anesthesia
* If noted during inhalant anesthetic, the horse is lightening and may be too light

Small Animal
* Present with injectable anesthesia
* too light inhalant

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9
Q

if we see nystagmus in LA or SA anesthesia what does this mean? when might we expect to see this?

A

-Small and Large Animals
-typical with equine injectable – ketamine based
-If noted during inhalant anesthetic, the horse is too light and requires additional injectable
-May see in recovery in SA

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10
Q

what do we expect to see in terms of eyelid tone under anesthesia?

A

¡ As animal deepens, eyelids have less tone and open or widen
¡ Positioning in dorsal or edema will make this harder to visualize
¡ Will remain with maintenance of anesthesia with injectables

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11
Q

what should we watch for in terms of tear production and ocular lubrication under anesthesia?

A

¡ As animal deepens, eye-lids wider with less tone and the eyes become dry
¡ With equine anesthesia excessive tearing is related to lightening of anethesia

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12
Q

what will we see in terms of ocular position as anesthetic depth increases?

A

awake - looking and blinking
too light - may roll back on induction or nystagmus
light - medial
medium - lateral
too deep - staring
dead - big pupil

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13
Q

what is periodic ocular rotation in the equine and when do we expect to see it?

A

With Inhalant Anesthesia Only at good surgical plane
¡ Each eye rotates in opposite direction every 5-10 min

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14
Q

what type of muscle relaxation signs should we look at under anesthesia?

A

-body relaxed
>heavily based ketamine protocols will increase muscle tone without other agents
>twitching may be seen on induction with propofol

-jaw tone
-pedal reflex
-ear of whisker flick in cat

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15
Q

how does haw tone relate to anesthetic depth in SA?

A

Tighter the tone fits = lighter
* Adds to other signs of light anesthetic depth

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16
Q

when will we see strong jaw tone under anesthesia?

A

-when too light in SA
-Strong during ketamine induction or maintenance

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17
Q

what age of animals will have minimal jaw tone always?

A

puppies and kittens

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18
Q

what animals should we not use jaw tone as an indicator of anesthetic depth for? why? what other related sign can we look for?

A

Cannot use in swine, cattle or horses
* minimal jaw opening/mobility
* Ruminants and swine will chew when light

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19
Q

signs other than ocular and muscle we can look at to assess animal under anesthetic manually

A

-palpation of peripheral artery
-CRT, MM
-resp rate

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20
Q

cardioresp system monitoring parameters

A

Circulation
Ventilation
Oxygenation

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21
Q

what circulation signs can we look for manually while monitoring anesthetic?

A

¡CRT –capillary refill time
¡HR -Pulse, Auscultation, ECG, pulse oximetry
¡Blood pressure, Pulse quality, Capnography

¡ Cardiac output (research, referral)

22
Q

what ventilation signs can we look for manually while monitoring anesthetic?

A

¡RR - Thoracic wall movement, Reservoir bag movement, Auscultation
¡Capnography, Blood gases

23
Q

what oxygenation signs can we look for manually while monitoring anesthetic?

A

¡Mucous membrane color, Pulse-oximetry, Blood gases

24
Q

what factors contribute to a healthy animal’s heart rate under anesthesia?

A

age and size

25
Q

good ways to assess heart rate during anesthesia

A
  1. You & Auscultation or Palpation
  2. Esophageal Stethoscope
  3. Electrocardiogram

-also can use doppler, multiparameter monitor, pulse oximeter

26
Q

how should we use auscultation or palpation to assess heart rate during anesthesia? Advantages and disadvantages?

A

¡Palpation and counting of HR over 30 seconds- minute gives better indication of effectiveness of heart beat. The more peripheral is taken the more useful for your assessment
¡ADV: effective ; DisADV: takes skill

27
Q

how should we use an esophsgeal stethoscope to assess heart rate during anesthesia? Advantages and disadvantages?

A

¡Blind-ended tube - Inserted into thoracic esophagus ¡Hear heart sound, monitor HR/rhythm
¡ADV: - Easy to use and place, inexpensive
¡DisADV: - only gives HR – have to count

28
Q

how can we use an electrocardiogram to assess heart rate under anesthesia? advantages and disadvantages?

A

¡Recording of electrical activity of heart
¡ADV: - gives heart rhythm, morphology and HR
¡DisADV:- have to place leads and know morphology

29
Q

what blood pressure measurements should we be mindful of when a patient is under anesthesia?

A

¡Systolic (maximum pressure in a heart beat)
¡Mean (average pressure in a heart beat)
¡Diastolic (min pressure between 2 heartbeats

30
Q

acceptable and optimal BP values for animals under anesthesia

A

systolic - 90, 120-140
diastolic - 40, 70
mean - 60, 80-90

31
Q

acceptable and optimal BP values for neonates under anesthesia

A

systolic - 75, 100
diastolic - 40, 50
mean - 50, 75

32
Q

ways to measure arterial blood pressure under anesthesia

A

¡Indirect and Direct methods

¡Indirect- easy to set up
>Doppler techniques
>Oscillometric techniques

¡Direct – specialized equipment required
>Catheterization of artery
>Equipment expensive

33
Q

how do we use a doppler to measure BP?

A

¡Shave over peripheral artery
¡Place gel – concave side down
¡Detects changes in frequency of reflected sound wave

34
Q

advantages and disadvantages to using a doppler to measure BP

A

¡ADV: - accurate even if hypotensive and can hear arrhythmias, PVC’s, count HR in addition to monitoring BP with a cuff

¡DisADV: - know how to place, screeching sound can be heard or static
>People don’t like the noise

34
Q

how accurate is a BP measurement from a doppler?

A

¡Pressure obtained underestimates the SBP by up to 15 mmHg in cat
¡Add 15 mmHg to the value obtained, or ¡Some have suggested to interpret the obtained value as MBP
¡Trend is important!

35
Q

advantages and disadvantages of oscillometric blood pressure measurement

A

¡Oscillations during inflation and deflation in a step wise manner
¡ADV: - easy to use and place
¡DisADV: - Arrhythmias, slow HR, shivering, make it difficult for machine to work, less accurate with low BP, takes time to work, HR inaccuracies

36
Q

how should we size a cuff for a oscillometer or doppler? what happens if it is too large or too small?

A

¡ Width of cuff = 40% of limb circumference

Too large:
¡ big surface area, easily occludes arterial flow and BP falsely lowered

Too small:
¡ small surface area, hard to occlude arterial flow and BP falsely elevated

37
Q

advantages and disadvantages to direct blood pressure measurements?

A

Advantages:
¡Accurate and reliable
¡Informative
¡Continuous

Disadvantages:
¡Skill to perform
¡Expense
¡Complications
>Risk of infection or hemorrhage
¡Monitors are more expensive

38
Q

how to monitor respiration/ventilation

A
  1. Visual–watching counting rate/pattern of chest movement
  2. Watching and counting movement of rebreathing bag
  3. Listening with hand held stethoscope
  4. Listening with esophageal stethoscope
  5. MM colour
  6. Monitoring end-tidal CO2
  7. Monitoringpulse-oximetry–SPO2
  8. Arterial blood gases–PaCO2;PaO2
39
Q

CO =

A

SV x HR

40
Q

minute ventilation (Ve) =

A

VT x RR

41
Q

what is capnography and what is it useful for?

A

¡Measures inspired CO2 and end-tidal CO2
¡Useful in determining:
¡ Hypoventilation
¡ Hyperventilation
¡ Apnea
¡ Disconnection ¡Rebreathing of CO2
¡Respiratory obstruction

42
Q

how do we expect insipred CO2 and end tidal CO2 to look under anesthesia?

A

Under GA - expected to be higher
¡ may be ok in normal anesthetized patient
>permissive hypercapnia

43
Q

what is SPO2? what does it tell us?

A

Pulse Oximetry = SPO2
¡Indication of the state of respiratory system
¡Related to O2-Hgb dissociation curve

44
Q

how do we measure SPO2?

A

¡The lower the arterial oxygen tension, the lower the oxygen saturation
¡Pulse oximetry is an indirect measurement
¡Pulse oximeter probe type and placement important

How it works:
¡Two red wavelengths pass through tissue
¡Oxygen rich blood blocks less red light than oxygen depleted blood
¡Machine algorithm gives a numerical % for this difference
¡Also gives HR
¡Accuracy of HR important and gives indication that SPO2 working well & accurate

45
Q

what is SPO2 a good estimate for

A

PaO2

46
Q

advantages to monitoring SPO2? where can we place the clip?

A

¡ADV: - easy to use, non-invasive, important monitoring tool

¡SPO2 clip probe can be placed on:
¡Tongue (most common)
¡ear, lip,
¡inguinal skin,
¡ toe web,
¡along achilles tendon, ¡prepuce, vulva
¡ rectal

47
Q

disadvantages to measuring SPO2?

A
  • SPO2 inaccurate if; ¡Slow or fast heart rates
    ¡ Hypotension
    ¡ Hypothermia
    ¡ Pigment
    ¡Vasoconstriction/Vasodilation
    ¡Dry mucous membranes
    ¡Compression at the site and reduced perfusion in area
    ¡Dysfunctional hemoglobins
48
Q

what temp issue is common under anesthesia?

A

¡Hypothermia common with anesthesia
¡Avoid temperatures less than 34.4oC
¡Extremes reduce drug metabolism, HR, CV stability, cell function

49
Q

what sites are good for monitoring temp during anesthesia?

A

¡Esophageal (core temp) with special probe
¡ Nasopharynx
¡ Rectal
¡Axillary (add degree –correlates with rectal)