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7.3.2 Points to be noted in SpO
2
and Pulse Measuring
1. The finger should be properly placed (see the attached illustration of this instruction
manual), or else it may cause inaccurate measurement result.
2. Make sure that capillary arterial vessel beneath the finger is penetrated through by red and
infrared lights.
3. The SpO
2
sensor should not be used at a location or limb tied with arterial or blood
pressure cuff or receiving intravenous injection.
4. Do not fix the SpO
2
sensor with adhesive tape, or else it may result in venous pulsation
and consequential inaccurate measurement result of SpO
2
.
5. Make sure the optical path is free from any optical obstacles like adhesive tape.
6. Excessive ambient light may affect the measuring result. It includes fluorescent lamp, dual
ruby light, infrared heater, and direct sunlight etc.
7. Strenuous action of the subject or extreme electrosurgical interference may also affect the
accuracy.
8. Please do not use the SpO
2
sensor when having the MRI, or burn may be caused by
faradism.
7.3.3 Clinical Limitations
1. As the measure is taken on the basis of arteriole pulse, substantial pulsating blood stream
of subject is required. For a subject with weak pulse due to shock, low ambient/body
temperature, major bleeding, or use of vascular contracting drug, the SpO
2
waveform
(PLETH) will decrease. In this case, the measurement will be more sensitive to interference.
2. For those with a substantial amount of staining dilution drug (such as methylene blue,
indigo green and acid indigo blue), or carbon monoxide hemoglobin (COHb), or methionine
(Me+Hb) or thiosalicylic hemoglobin, and some with icterus problem, the SpO
2
determination by this monitor may be inaccurate.
3. The drugs such as dopamine, procaine, prilocaine, lidocaine and butacaine may also be a
major factor blamed for serious error of SpO
2
measurements.
4. As the SpO
2
value serves as a reference value for judgement of anemic anoxia and toxic
anoxia, the measurement result of some patients with serious anemia may also present as
good SpO
2
value.