There are devices known as simulators. They work by
simulating a human finger but fail to reproduce the optical properties of blood.
These devices are mainly used for testing the entire pulse oximeter system, that
is the sensor and monitor. Their main use is in testing the software within the
monitor and in detecting broken wires in the pulse oximeter sensor. They have
been used as a basis for comparing the performance of systems from different
manufacturers with the assumption that all sensors are perfect.
assumed that there is no wavelength error in the sensor and that all sensors are
perfect in this respect. All of the sensors that have been identified by The
Lightman as being inaccurate and not suitable for use would have been passed as
fit for use by a simulator. This is backed up in The ISO Pulse Oximetry Standard
9919 where it is said that no simulator has the spectral resolution to enable it
to be used for calibration purposes.
The main source of error
confronting any user of pulse oximetry is that due to variability between pulse
oximeter sensors, the performance of the monitors is less questionable. Thus The
LightmanŽ is unique in its ability to assess the accuracy of a pulse oximeter