20
can transport oxygen.
In contrast, hemoximeters report fractional oxygen saturation - a per-
centage of all measured hemoglobin, including dysfunctional hemoglo-
bin, such as carboxyhemoglobin or metahemoglobin.
Clinical application of pulse oximeters: SpO
2
is an important physiologi-
cal parameter to reflect the respiration and ventilation function, so SpO
2
monitoring used in treatment has become more popular. (For example,
such as monitoring patients with serious respiratory disease, patients
under anesthesia during operation and premature and neonatal infants)
The status of SpO
2
can be determined in timely manner by measure-
ment and will allow finding the hypoxemia patient earlier, thereby pre-
venting or reducing accidental death caused by hypoxia effectively.
3. Factors affecting SpO
2
measuring accuracy (interference reason)
• Intravascular dyes such as indocyanine green or methylene blue.
• Exposure to excessive illumination, such as surgical lamps, bilirubin
lamps, fluorescent lights, infrared heating lamps, or direct sunlight.
• Vascular dyes or external used color-up product such as nail enamel
or color skin care.
• Excessive patient movement.
• Placement of a sensor on an extremity with a blood pressure cuff,
arterial catheter, or intravascular line.
• Exposure to the chamber with High pressure oxygen.
• There is an arterial occlusion proximal to the sensor.
• Blood vessel contraction caused by peripheral vessel hyperkinesias
or body temperature decreasing.
4. Factors causing low SpO
2
Measuring value (pathology reason)
• Hypoxemia disease, functional lack of HbO
2.
• Pigmentation or abnormal oxyhemoglobin level.
• Abnormal oxyhemoglobin variation.
• Methemoglobin disease.
• Sulfhemoglobinemia or arterial occlusion exists near sensor.
• Obvious venous pulsations.
• Peripheral arterial pulsation becomes weak.
• Peripheral blood supply is not enough.
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