User Manual for Vital Signs Monitor
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During measuring, do not move your arm or the cuff;
The measuring interval shall longer than 2 minutes, in continuous measurement, too short interval
may cause arm extrusion, blood quantity increases, then cause blood pressure increases.
Keep the patient still and stop talking before and during measuring;
The patient’s mood also can affect the measuring result, when exciting, the blood pressure goes up.
The measuring result also affected by time, lower in the morning and higher in the evening;
8.2.3 Clinical Limitations
1. Serious angiospasm, vasoconstriction, or too weak pulse.
2. When extremely low or high heart rate or serious arrhythmia of the subject occurs. Especially
auricular fibrillation will lead to unreliable or impossible measurement.
3. Do not take the measurement when the subject is connected with an artificial heart-lung machine.
4. Do not take the measurement when the subject uses diuresis or vasodilator.
5. When the subject is suffering from major hemorrhage, hypovolemic shock and other conditions with
rapid blood pressure change or when the subject has too low body temperature, the reading will not
be reliable, for reduced peripheral blood flow will lead to reduced arterial pulsation.
6. Subject with hyperadiposis;
In addition, statistics show that 37% people report blood pressure difference of no less than
0.80kPa(6mmHg) between the left and right arms, and 13% people report difference of no less than
1.47kPa (11mmHg).
Note:
Some practitioners may report big discreteness or abnormal value of the blood pressure
measures when the oscillating method is used. As a matter of fact, the so-called “big discreteness”
must be a term in the sense of statistical significance of mass data. Abnormal data may be observed
in some individual cases. It is normal in the scientific experiments. It may be caused by an apparent
reason, or by an unknown factor in some cases. Such individual doubtful experimental data may be
identified and eliminated using the special statistical technique. It is not a part of this manual. The
practitioner may eliminate the apparently unreasonable data according to the experience.
8.3 SpO
2
Monitoring
8.3.1 Measuring Principle
Based on Lamber-Beer law, the light absorbance of a given substance is directly proportional with its density or
concentration. When the light with certain wavelength emits on human tissue, the measured intensity of light
after absorption, reflecting and attenuation in tissue can reflect the structure character of the tissue by which the
light passes. Due to that oxygenated hemoglobin (HbO
2
) and deoxygenated hemoglobin (Hb) have different
absorption character in the spectrum range from red to infrared light (600nm~1000nm wavelength), by using
these characteristics, SpO
2
can be determined. SpO
2
measured by this monitor 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.
