Assessment of CRS function

Question 1

How is blood oxygen content measured

Answer 1

Shows effective lung function & ventilation

Assessed by:

Mucous membrane color
Estimation of oxygen content
Cyanosis is serious problem
Indicates deoxygenated Hb

Pulse oximetry
Use 2 wavelengths of light to measure oxygenated Hb
Also measures pulse rate
Should be 90+

Blood gas analysis

Question 2

What is capnography

Answer 2

In normal circumstances metabolic rate doesn’t alter much, so ventilation determines arterial CO2

Arterial CO2 tells us about ventilation

CO2 in exhaled breath can be measured by capnography

Tells us lungs, heart & metabolism are working

Question 3

How can oxygen delivery be measured

Answer 3

What we want to measure is oxygen delivery

What we can measure is:
Tissue perfusion
Blood oxygen content

Question 4

Invasive method of measuring MAP

Answer 4

Real time

Gives more information from trace

More accurate

Insert cannula into peripheral artery & connect to transducer

Reported as systolic/diastolic

Question 5

What is this

Answer 5

Sphygmomanometry
Non-invasive way of measuring MAP

Question 6

What is this

Answer 6

Oscillometric
May not be accurate as stress can elevate BP
Non-invasive way of measuring MAP

Question 7

What is this

Answer 7

Doppler
Makes audible sound that can be heard during surgery
Non-invasive way of measuring MAP

Question 8

What is central venous pressure

Answer 8

CVP measures pressure of blood returning to right side of heart

Usually reflects volume of blood returning

Question 9

What are the advantages & disadvantages of pulse oximetry

Answer 9

Advantages:
Cheap
Fast
Accurate

Disadvantages:
Oxygen carrying capacity - How many RBC? Is animal anemic?
Assisted oxygenation - Anaesethised animals on 100% oxygen
Smoke inhalation - Carbon monoxide poisoning?