Anesthesia monitoring

Question 1

lateral palpebral - when lost? when to intubate?

Answer 1

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

¡ At this stage able to open mouth, check jaw tone and proceed to endotracheal intubation safely

Question 2

medial parlpebral
- when lost?
- on injectable?

Answer 2

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

¡ Will remain in SA with injectable

Question 3

nystagmus - when may we see?

Answer 3

May see in recovery in SA or with induction excitement

Question 4

eyelid tone - what happens as animal deepens

Answer 4

Eyelid tone – as animal deepens, eyelids have less tone and open

Question 5

twitching may be seen on induction with what drug?

Answer 5

propofol

Question 6

jaw tone will be tighter if using what drug for induction or maintenance

Answer 6

ketamine

Question 7

what method of monitoring HR gives best indication?

Answer 7

palpation of pulse and counting over 30 seconds
- the more peripheral is taken the more useful for your assessment

Question 8

doppler BP measurement in cats and small dogs - accuracy

Answer 8

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

Question 9

how do we properly size a cuff for the oscillometer or doppler
- what if too large?
- what if too small

Answer 9

¡Width of cuff = 40% of limb circumference
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- 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

Question 10

capnography
- what does it measure?
- what is it useful for determining?
- normal values?

Answer 10

¡Measures end-tidal CO2 and inspired CO2
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Useful in determining:
¡ Hypoventilation
¡ Hyperventilation
¡ Apnea
¡ Disconnection
¡ Rebreathing of CO2
¡ Respiratory obstruction
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Normal under GA - 35-45 mmHg (higher may be ok in normal anesthetized patient)

Question 11

pulse oximetry = SPO2
- what is it?
- tells us what?

Answer 11

Oxygen saturation (SpO2) is a measurement of how much oxygen your blood is carrying as a percentage of the maximum it could carry
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Related to O2-Hgb dissociation curve
¡The lower the arterial oxygen tension, the lower the oxygen saturation
¡Pulse oximetry is an indirect measurement
¡Pulse oximeter probe type and placement important

Question 12

PaO2 vs SaO2

Answer 12

It is important to note the difference between oxygen saturation (SaO2)which is the percentage of hemoglobin bound to oxygen and partial pressure of oxygen in the blood (PaO2) which is the amount of oxygen dissolved in the blood.

Question 13

if SpO2 is 90, what is PaO2? why is this significant?

Answer 13

SpO2 of 90 corresponds to PaO2 of 60
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This is the minimum oxygen concentration providing enough oxygen to prevent ischemia in tissues. Once the O2 sat falls below 90%, the PaO2 drops quickly into the dangerously hypoxic range as fewer and fewer oxygen molecules are bound to Hgb. We want to try to keep O2 saturation above 90%.
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A PaO2 of less than 60 mm Hg marks severe hypoxemia and treatment should be implemented.

Question 14

what does a SpO2 of 94 correspond with for PaO2 why is this a significant value

Answer 14

SPo2 = 94 corresponds to PaO2 = 80
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Hypoxemia is usually defined as a PaO2 < 80 mm Hg.

Question 15

when might our SpO2 monitor be innacurate

Answer 15

¡Slow or fast heart rates
¡ Hypotension
¡ Hypothermia
¡ Pigment
¡Vasoconstriction/Vasodilation
¡Dry mucous membranes
¡Compression at the site and reduced perfusion in area
¡Dysfunctional hemoglobins

Question 16

avoid body temp of what? why?

Answer 16

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