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• Excessive patient movement.
• Placement of a sensor on an extremity with a blood pressure cuff, arterial catheter, or intravascular line.
• Exposure to a high pressure oxygen chamber.
• Arterial occlusion proximal to the sensor.
• Blood vessel contraction caused by peripheral vessel hyperkinesias or decreasing body temperature.
8.3.3 Pathological reasons for low SpO
2
measurements
• Hypoxemia, functional lack of HbO2.
• Pigmentation or abnormal oxyhemoglobin level.
• Abnormal oxyhemoglobin variation.
• Methemoglobin disease.
• Sulfhemoglobinemia or arterial occlusion exists near sensor.
• Obvious venous pulsations.
• Peripheral arterial pulsation becoming weak.
• Insufficient peripheral blood supply.
8.3.4 Clinical Limitations
• As the measurement is taken on the basis of arteriole pulse, a substantial pulsating blood stream is required.
For a patient with weak pulse, perhaps due to shock, low ambient/body temperature, major bleeding, or use
of vascular contracting drugs, the SpO
2
waveform (PLETH) will decrease. In this case, the measurement will
be more sensitive to interference.
• For those with a substantial amount of staining dilution agent (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
readings may be inaccurate.
• Drugs such as dopamine, procaine, prilocaine, lidocaine and butacaine may also be a major factor resulting
in serious SpO
2
measurement errors.
• As the SpO
2
value serves as a reference value for judgment of anemic anoxia and toxic anoxia, the measu-
rement result of some patients with serious anemia may also present as good SpO
2
value.
8.3.5 Points to be noted in SpO
2
and Pulse Measuring
• The finger should be properly placed (see the illustration to follow in this instruction manual), or else it may
cause inaccurate measurement results.
• Make sure that the sensor is lined up so the red and infrared LEDs pass through the capillary arterial vessels.
• The SpO
2
sensor should not be used at a location or limb with an arterial or blood pressure cuff attached or
receiving intravenous injection.
• Do not fix the SpO
2
sensor with adhesive tape, which may result in venous pulsation and consequential
inaccurate measurement result of SpO
2
.
• Make sure the optical path is free from any obstacles such as adhesive tape.
• Excessive ambient light (such as fluorescent lights, infrared heaters and direct sunlight) may affect the mea-
suring result.
• Strenuous activity of the patient or extreme electrosurgical interference may also affect the accuracy.
• Please do not use the SpO
2
sensor when having the MRI, or burn may be caused by faradism.
• Always observe the plethysmogram (waveform), which is auto-scaled within the range of 100. If the wave-
form is not smooth or is irregular, this may indicate that the SpO
2
readings are not accurate. If in doubt, rely
on your clinical judgment, rather than the Gima Vital Signs Monitor readout.
• A functional tester cannot be used to assess the accuracy of the pulse oximeter monitor or a SpO
2
sensor.
However, a functional tester, such as SpO
2
simulator can be used to check how accurately a particular pulse
oximeter is reproducing the given calibration curve. Before testing the oximeter, please determine that the
appropriate calibration curve is being used. If necessary, request this from the manufacturer and download
it into the test device.
8.4 Temperature Monitoring
The sensor is thermo-resistor type (25°C 5kΩ) with constant micro current. Calculating the temperature me-
asurement from the voltage. Temperature measurement can be obtained via two method: measure through
body surface temperature and through the temperature inside the body cavity (with oral or rectal placement
of the probe).
Normal value: body surface: 36.5°C~37°C; inside body cavity: 36.5°C~37.7°C.
Notes:
• Attach the TEMP transducer/sensor to the patient; ensuring good contact with the skin if this method is
chosen.
