Essentials of monitoring

Question 1

What’s the problem with GA being too light/heavy?

Answer 1

too light - can’t perform surgery
too heavy - deteriorating physiological function => death

Question 2

What animal has highest % of anaesthetic death?

Answer 2

horse - 1% of healthy horses

Question 3

Why monitor? (5)

Answer 3

1.maintain physiology
2.Maintain adequate anaesthetic depth
3.Prevent suffering + pain
4.Safety to personnel
5.Legal implications

Question 4

What of the CNS can you monitor?

Answer 4

• Reflexes: palpebral, corneal
• Anal tone
• Eye position / eye movement
• Lacrimation
• Changes in autonomic tone: sweating / CV changes
• Muscle tone: tension in muscles (jaw tone v. sternocephalicus m.)
• Movement: light (or about to die)
• Response to surgical stimulation

Question 5

What to monitor in the CV system?

Answer 5

• Auscultate, palpate, observe
• Pulse / heart rate:
• Horse: 20-40 bpm
• Dog: 50-100 bpm
• Cat: 80-160 bpm
• Pulse quality:
• subjective
• MM colour: indicator of oxygenation and perfusion
• CRT: indicator of blood volume and capillary tone
• Haemorrhage

Question 6

What to monitor in the Respiratory system?

Answer 6

• Listen, observe, touch, smell
• Rate:
• Horse: 4 - 10 breaths/ min
• Dog: 10 - 20 breaths/ min
• Cat: 15 – 30 breaths/ min
• Rhythm
• Auscultation
• Reservoir bag movement- estimation
• MM colour

Question 7

What are the normal arterial blood pressures?

Answer 7

• Systolic pressure: 80 - 140mmHg
• Diastolic pressure: 50 - 90mmHg
• Mean pressure: 60 - 90mmHg

Question 8

Pros/cons of invasive blood pressure monitoring?

Answer 8

• Gold standard
• Continuous readings
• Takes times to place indwelling
  arterial cannula
• Expensive equipment

Question 9

Pros/cons of non-invasive blood pressure monitoring?

Answer 9

• Quick and easy to apply cuff
• Intermittent readings
• No risk of infection
• Need correct cuffs

Question 10

What is a normal pulse oximetry reading?
what does it measure?

Answer 10

> 95%
* Measures % saturation of haemoglobin
with oxygen

Question 11

What are the limitations of using pulse oximetry?

Answer 11

• Hypoperfusion/ vasoconstriction
• Bright lights
• Movement
• Anaemia
• Probe can blanch capillary bed

Question 12

What does a capnograph measure?
What are normal values?

Answer 12

• Measures end tidal CO2
• Normal end tidal CO2 is 35-45mmHg
• Inspired CO2 should be zero

Question 13

What does a capnograph measure?
What are normal values?

Answer 13

• Measures end tidal CO2
• Normal end tidal CO2 is 35-45mmHg
• Inspired CO2 should be zero