Bistos BT-780, Operation Manual

Page: 34 / 51

BT-780 Operation manual
33
P/N : 780-ENG-OPM-EXP-R00 Bistos Co., Ltd. 2020.03
same limb.

Measurement results may be affected by posture and mental state of the patient.

If there are doubts on the measurement results, please use other blood pressure measurements and compare, if
necessary, contact the Equipment Division.
11.3 Measurement limits
According to the patient's condition, the oscillometric method has some limitations. This measurement is to look for the regular
pulse waves generated by arterial pressure. If the patient's condition makes this detection method difficult, the measured value
becomes unreliable, and pressure measurement time increases. The user should be aware that the following conditions may
interfere with measurement method, making the pressure measurement unreliable or extend the time. In this case, the patient's
condition does not allow measurement.
 Patient movement
If the patient is talking, moving, shaking or cramping, the measurement will be unreliable or even impossible, as these may
interfere with the detection of arterial pressure pulse, and extend the pressure measurement time.
 Arrhythmia
If the patient shows arrhythmia which results in irregular heartbeat, the measurement will be unreliable and even cannot be
done, and the pressure measurement time will be extended.
 Use of an artificial heart-lung machine
If a patient is connected to an artificial heart-lung machine, the measurement will be impossible.
 Pressure changes
If the arterial pressure pulse is being analyzed to obtain a measured value at a certain time and the blood pressure of the
patient changes rapidly, the measurement will be unreliable or impossible.
 Severe shock
If the patient is in severe shock or hypothermia, the pressure measurement will not be reliable, because the decrease of
blood flow to the periphery would cause decrease in arterial pulsation.
 Limit heart rate
If the heart rate is below 40bpm (beats / min) or above 240bpm (beats / min), the blood pressure measurement is impossible.

Obese patients
A thick layer of fat around a limb blocks the arterial oscillation so that it cannot reach the cuff. The accuracy is lower than
normal.

Environmental Requirements
Measuring blood pressure should meet the environment range as follow:
ambient humidity 30%
～
85%, no condensing,
ambient temperature 5
～
40
℃
,
Atmospheric pressure: 700hPa
～
1060hPa.
NIBP performance and measurement accuracy will be affected beyond the range.
11.4 Measurement procedure
11.4.1 Prepare the measurement
1.
Turn on the monitor, and check if it works properly.
2.
Verify the patient category, and make changes if improper. Depending on the current patient type, the patient type is
selected in the patient information interface.
3.
Connect the blood pressure cuff extension tube to the monitor.
4.
Select the cuff in accordance with the following method, make sure that the cuff is completely deflated, and then tie it to the
upper arm or thigh of the patient.

Determine the limb circumference of the patient.
 Select the appropriate cuff (marked with appropriate limb circumference). Cuff width should be 40% of the limb
circumference or 2/3 of the upper arm length. The length of the inflated part of the cuff should be sufficient for
50%~80% around the limb.
 Place the c uff on the upper arm or thigh of the patient, and ensure that the marking φ is located just above the
appropriate artery. Make sure that the cuff does not wrap too tight around the limb, or it may cause distal discoloration
or even ischemia.
11.4.2 Patient posture requirements during measurement
1.
Sit comfortable or lie down relaxedly.
2.
No crossing legs.
3.
Back and elbow should be supported.
4.
The center of NIBP cuff and the right atrium are at in the same level.
5.
Remind patients, no talking during measurement and try to relax.
NOTE

When have doubt about blood pressure measuring result, re-measure after the patient sit-in about 5 minutes. If
still have doubt, replace the blood pressure measuring equipment and measure again.

The operator should be in the position where he/she can readily operate the sphygmomanometer.
11.4.3 Start/stop measurement