Biocare iM 12, Руководство пользователя

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Chapter 6 Parameter Monitoring
--66-- User Manual of Veterinary Monitor
7, 190, 985; 7, 194, 293; 7, 209, 774; 7, 212, 847; 7, 400, 919.
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No implied license
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Possession or purchase of this device neither means that you can replace one or some parts of the device,
nor means that you can use the patents of the device.
6.5 NIBP
6.5.1 NIBP General Description
Blood pressure measure includes invasive (by directly inserting sensors into blood vessel) and non-invasive
methods. The invasive method directly measures blood pressure through arterial retention needles; but this
method may put animals at some risk, so it is used only it is necessary for the animal‘s homodynamic. There are
several non-invasive measuring methods, among which the Coriolis sound method and the oscillation method are
more prominent. The Coriolis sound method is traditionally the measuring method by means of stethoscopes. The
oscillation method works as follows: an inflator is used for automatic inflation, then slow deflation follows, and a
computer is employed to record the changes in the cuff pressure while deflating and then to compute the blood
pressure values: first, the computer determines whether the measuring signals are good enough to ensure correct
calculation; if yes, then the pressure values are computed and if not (e.g. caused by sudden movement of limbs or
cuff touches), then the calculation is stopped.
The pressure changes are recorded by electronic sensors having sensitivity which is far higher than that of ears,
thus measure by the oscillation method has different measuring definitions on the diastolic pressure, mean
pressure and systolic pressure from that of the Coriolis sound method. The circuit of an oscillation measurer
separates the cuff pressure and amplitude indicating changes of the cuff pressure with pulses and defines the blood
pressure corresponding to the maximum cuff pressure amplitude as the mean pressure. In this method, the blood
pressure corresponding to a 50% reduction of cuff pressure amplitude is defined as systolic pressure, and the
pressure corresponding to an 80% reduction of cuff pressure amplitude as the diastolic pressure, both points
indicating a maximum change of pulse differential pressures. This is equivalent to the presence of pulse sound and
absence of pulse sound.
Figure 6.28 NIBP Cuff Socket
Comparison of Several Blood Pressure Measuring Methods:
In order to overcome the influence of deflating speed and doctor‘s sense of hearing on measuring accuracy in the
traditional Coriolis sound method, researchers have made huge efforts in automatic measure of blood pressure,
and the automatic blood pressure measuring system based on the principle of oscillation method was already quite
well-developed. However, many medical workers are always filled with all kinds of questions, for example: what
makes a lower or higher measure result in the oscillation method compared with the Coriolis sound method? Why
are the first measure results higher and the following measure results gradually lower? Why are the measure
results sometimes not obtainable causing useless inflations? Why are the measure results more discrete and even
sometimes unreasonable? We hope that these questions will be answered through this section.