•When influenced by abnormal hemoglobin like carbon monoxide hemoglobin (HbCO) and methemoglobin

•When pigments such as cardiogreen, intravascular dyes and indocyanine greenare present in the blood

•When finger nails are polished

•Tables 1 and 2 below show the errors which may occur due to these hemoglobins.

Difference from the SaO2 value to displayed value

<Table 1>

<Table 2>

Foreword

SaO2

 

HbCO

 

1%

5%

10%

 

50

-0.1

-0.7

-1.5

70

-0.1

-0.7

-1.5

90

-0.2

-0.8

-1.6

100

-0.2

-0.8

-1.7

Measured value is always lower than the actual value.

SaO2

Methemoglobin

1%

5%

10%

 

50

+0.2

+1.3

+3.2

70

-0.6

-2.3

-3.2

90

-1.5

-6.0

-9.6

100

-1.8

-7.5

-12.2

Displayed value is sometimes higher than the actual value if SaO2 is around 50%.

9