DATREND Systems Oxitest Plus 7, Руководство по эксплуатации

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OXITEST PLUS 7 OPERATING MANUAL
5. Test Usage Guidelines
5.1 General Rules
In an ideal world, testing a pulse oximeter would simply involve placing the oximeter sensor on the
test probe and observing the results. However, due to the many implementations of the basic
oximetry technology and many configurations of sensors, there are some practical problems you will
inevitably run into in testing oximeters. The problems generally fall into two categories: 1)
interpretation of results; and 2) the probe/sensor interface.
5.1.1 Interpretation of Results
Although pulse oximeters provide an indication of heart rate, it is the oxygen saturation estimated by
these devices (SpO
2
) which is of greater concern when discussing the "accuracy" of a particular
make or model. Manufacturer's accuracy specifications for SpO
2
can be confusing - just what does
±2% ± 1 standard deviation actually mean? In developing the calibration curve for an oximeter,
commonly known as the "R-Curve", the response of the device is statistically compared to the
response from invasive oxygen content readings from a large population of individuals. The
specification cited above can be translated as: the oxygen saturation value measured by this oximeter
will be accurate to within 2% for 65% of the population.
This specification has very little to do with what you should expect from testing the oximeter with a
tester. The R-Curve is well-defined in the oximeter's electronics. An oximeter tester such as
Oxitest Plus 7 is microprocessor controlled, and as a result outputs a precisely regulated, calibrated
optical signal. Therefore, although there may be some uncertainty introduced by the sensor and the
sensor/tester interface, the response from an electro-optical simulation should be within the tester's
specification limits of ±1%. In some cases, a response outside of these limits is an indication that
the sensor is slightly out of tolerance and replacement should be considered.
Test Useage/Chapter 5
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