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ENGLISH
(600nm~1000nm wavelength), by using these characteristics, SpO
2
can be determined. SpO
2
measured
by this oximeter is the functional oxygen saturation -- a percentage of the hemoglobin that can transport
oxygen. In contrast, hemoximeters report fractional oxygen saturation – a percentage of all measured
hemoglobin, including dysfunctional hemoglobin, such as carboxyhemoglobin or metahemoglobin.
Clinical application of pulse oximeters: SpO
2
is an important physiological parameter to reflect the
respiration and ventilation function, so SpO
2
monitoring used in clinical becomes more popularly, such
as monitoring the patient with serious respiratory disease, the patient under anesthesia during operation,
premature and neonate. The status of SpO
2
can be determined in time by measurement and find the
hypoxemia patient earlier, thereby preventing or reducing accidental death caused by hypoxia effectively.
3 Normal SpO
2
Range and Default Low Limit
In campagna area, healthy people’s SpO
2
value is greater than 94%, so the values below 94% are
determined as hypoxia. SpO
2
<90% is considered as the default threshold for determining anoxia by most
researchers, so SpO
2
low limit of the oximeter is set as 90% generally.
4 Factors affecting SpO
2
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
5 Factors causing low SpO
2
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
Appendix
Key of Symbols
Symbol
Description
Symbols
on the
screen
%SpO2
The pulse oxygen saturation
PI
Perfusion Index
PR
Pulse rate
(Unit: beats per minute)
Low battery voltage
Alarm Icon
Memory Icon
Memory full
