EDAN M3 Service Manual

M3 Vital Signs Monitor Service Manual
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2.4.2 NIBP
Blood pressure monitors commonly measure arterial pressure, which is produced by the
contraction of the heart and constantly changes over the course of cardiac cycle. Three blood
pressure values, expressed in millimeters of mercury above atmospheric pressure, are typical
obtained. The systolic pressure is the maximum cycle pressure; which occurs during ventricular
contraction. The diastolic pressure is the minimum cycle pressure, occurring during the
ventricle’s filling stage between contractions. The means arterial pressure (MAP) is the mean
value of the blood pressure over the cardiac cycle.
The monitor measures non-invasive blood pressure using the oscillometric method. Following are
detailed measurement procedures. Inflate the cuff encircled the upper arm until the pressure in the
cuff blocking the blood flow in the artery of the upper arm. Then deflate the cuff gradually
according to the requirement of certain arithmetic. With the decreasing of the pressure in the cuff,
the artery blood will palpitate with the pulse, which results in palpitation in the cuff. Through the
pressure sensor connected with the inflating pipe of the cuff, a palpitation signal palpitating with
the pulse will be generated. After being filtered by a high-pass filter (about 1Hz), this signal
becomes pulsating signal and is amplified. Then the amplified signal is converted into digital
signal by A/D. After using the singlechip to process this digital signal, we may obtain systolic
pressure, diastolic pressure and mean pressure. Be careful to choose appropriate cuffs for
neonatal, pediatric and adult patients so as to avoid generating measurement error. NIBP module
also has protection circuit to prevent the cuff from being inflated to a very high pressure.
Following are the main operating modes of NIBP.
a. Adult/pediatric/neonate: select according to the patient shape, weight and age.
b. Manual measurement/auto measurement/continuous measurement: Manual measurement
is also called single measurement. It means the monitor performs only one measurement
for each time. Auto measurement means to perform one measurement within selected
cycle. Time interval can be set up as 1, 2, 3, 4, 5, 10, 15, 30, 60, 90, 120, 240 and 480
minutes. Continuous measurement means after being activated, the monitor will perform
quick measurement continuously within 5 minutes. Continuous measurement is effective
in monitoring changes in blood pressure.
2.4.3 SpO
2
SpO
2
is based on the absorption of pulse blood oxygen to red and infrared light by means of
finger sensor and SpO
2
measuring unit. The light-electronic transducer in finger sensor converts
the pulse red and infrared light modulated by pulse blood oxygen into electrical signal, the signal
is processed by hardware and software of the unit. The PLETH curve and numeral value of SpO
2
will be obtained.
By tracing the pulse waveform in the fingertip, using specified arithmetic and consulting the
clinical data table, we can obtain the SpO
2
value. The SpO
2
sensor consists of two LED and a
photodetector. The two LED are respectively red diode and infrared diode, which are lighted on
according to certain time sequence. When the capillary vessel of the fingertip congests repeatedly,
the light of the LED is absorbed by blood vessels and organs and then projected onto the
photodetector. The photodetector can detect the light intensity varying with pulse changes and

EDAN M3 Specifications

General

Brand	EDAN
Model	M3
Category	Monitor
Language	English