Pulse Oximetry

Question 1

What is pulse oximetry?

Answer 1

Non-invasive measurement of estimated saturation of arterial haemoglobin with oxygen

Question 2

What areas of the body can you use pulse oximetry?

Answer 2

Finger nail

Toe nail

Ear lobe

Question 3

How does pulse oximetry measure oxygen saturation?

Answer 3

Uses light of two different wavelengths is passed through to a photo detector

Light is partly absorbed by haemoglobin - which differs depending on how oxygenated the haemoglobin is

A FULLY oxygenated haemoglobin is DARKER

Question 4

What are the 2 readings on a pulse oximeter?

Answer 4

Arterial saturation of haemoglobin with oxygen

Heart rate

Question 5

What is a normal value of SpO2?

Answer 5

> 95%

Question 6

When does the oxyhemoglobin curve becomes steep and what does this mean?

Answer 6

90%

Desaturation becomes more rapid

Question 7

Explain the validity and reliability of pulse oximetry?

Answer 7

Readings tells you how ‘full’ the haemoglobin is but if number of haemoglobin in the blood is low then total oxygen will be reduced

Body temperature

Nail polish

Poor peripheral circulation

Some drugs cause peripheral vasoconstriction