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Technical Information
SpO
2
Principles of Operation
Pulse oximetry is a non-invasive method that passes red and infrared light
through perfused tissue and detects the fluctuating signals caused by arterial
pulses. Well-oxygenated blood is bright red, while poorly oxygenated blood is
dark red. The pulse oximeter determines functional oxygen saturation of arterial
hemoglobin (SpO
2
) from this color difference by measuring the ratio of absorbed
red and infrared light as the volume fluctuates with each pulse.
SpO
2
Accuracy Testing
During no-motion conditions at an independent research laboratory, SpO
2
accuracy testing was conducted during induced hypoxia studies on healthy, male
and female, non-smoking, light- to dark-skinned subjects that were 18 years of
age and older. The measured arterial hemoglobin saturation value (SpO
2
) of the
sensors was compared to arterial hemoglobin oxygen (SaO
2
) value,
determined from blood samples with a laboratory co-oximeter. The accuracy of
the sensors in comparison to the co-oximeter samples measured over the SpO
2
range of 70 – 100%. Accuracy data was calculated using the root-mean-squared
(A
rms
value) for all subjects, per ISO 80601-2-61, Medical Electrical
Equipment—Particular requirements for basic safety and essential performance
of pulse oximeter equipment.
SpO
2
Accuracy Testing in Presence of COHb and MetHb
During no-motion conditions at an independent research laboratory, SpO
2
accuracy testing in the presence of COHb and MetHb was conducted during
induced hypoxia studies on healthy, male and female, non-smoking, light- to
dark-skinned subjects that were 18 years of age and older.
The measured arterial hemoglobin saturation value (SpO
2
) of the sensors was
compared to arterial hemoglobin oxygen (SaO
2
) value, determined from blood
samples with a laboratory co-oximeter. The accuracy of the sensors in
comparison to the co-oximeter samples measured over the SpO
2
range of 80 –
100%, range 0 – 15% COHb and SpO
2
range of 80 – 100%, range 0 – 15%
MetHb.
Accuracy data was calculated using the root-mean-squared (A
rms
value) for all
subjects, per ISO 80601-2-61, Medical Electrical Equipment—Particular
requirements for basic safety and essential performance of pulse oximeter
equipment.
Pulse Rate Accuracy Testing
This test measured pulse rate oximeter accuracy with and without motion
artifact simulation introduced by a pulse oximeter tester. This test determines
whether the oximeter meets the criteria of ISO 80601-2-61 for pulse rate during
simulated movement, tremor, and spike motions.
