Testing Summary; Cohb/Methb Principles Of Operation; Cohb Accuracy Testing; Methb Accuracy Testing - Nonin Sensmart H500 Operator's Manual

Technical Information

Testing Summary

COHb/MetHb Principles of Operation

An oximeter is a non-invasive device that passes several colors of light (from
red to infrared) 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 presence of COHb and MetHb causes other
color differences sensed only in the infrared. The oximeter analyzes the color
fluctuations caused by heart pulses so it can cancel out steady conditions (e.g.,
steady venous blood flow, skin thickness, bone, fingernails, etc.). The light
emissions of the sensor are measured in every color and then stored in the
sensor's embedded memory so light color caused by manufacturing variations
are canceled. With the patient in a steady state and the sensor light emissions
canceled out, the oximeter can estimate SpO
mathematics are fixed in the oximeter hardware and software; therefore, no field
calibration is needed. There are no adjustable parts within the oximeter that
affect the calibration. Nonin oximeters are calibrated to closely approximate
functional oxygen saturation, COHb fraction, and MetHb fraction values.

COHb Accuracy Testing

COHb accuracy testing was conducted at an independent research laboratory
on healthy, male and female, non-smoking, light to dark-skinned subjects that
were 18 years of age and older. The measured carboxyhemoglobin value
(%COHb) of the sensors was compared to simultaneous arterial blood samples
as assessed by co-oximetry. The accuracy of the sensors in comparison to the
co-oximeter samples measured over the COHb range of 0-15% with 95 – 100%
SaO . Accuracy data was calculated using the root-mean-squared (A
2
for all subjects, per ISO 80601-2-61, Medical Electrical Equipment-Particular
requirements for basic safety and essential performance of pulse oximeter
equipment.

MetHb Accuracy Testing

MetHb accuracy testing was conducted at an independent research laboratory
on healthy, male and female, non-smoking, light to dark-skinned subjects that
were 18 years of age and older. The measured methemoglobin value (%MetHb)
of the sensors was compared to simultaneous arterial blood samples as
assessed by co-oximetry. The accuracy of the sensors in comparison to the co-
oximeter samples measured over the MetHb range of 0 – 15% with 95 – 100%
SaO . Accuracy data was calculated using the root-mean-squared (A
2
for all subjects, per ISO 80601-2-61, Medical Electrical Equipment-Particular
requirements for basic safety and essential performance of pulse oximeter
equipment.
2 , COHb, and MetHb. The
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