EDAN VE-H100B User Manual page 85

VE-H100B Veterinary Pulse Oximeter User Manual
sensor to a pulsating arteriolar vascular bed, such as a finger or a
toe. The sensor contains a dual light source and a photonic
detector.
Bone, tissue, pigmentation, and venous vessels normally absorb a
constant amount of light over time. The arteriolar bed normally
pulsates and absorbs variable amounts of light during the
pulsations. The ratio of light absorbed is translated into a
measurement of functional oxygen saturation (SpO
measurement of SpO
excessive ambient light can interfere with this measurement.
Pulse oximetry is based on two principles:

Oxyhemoglobin and deoxyhemoglobin differ in their
absorption
(spectrophotometry).

The volume of arterial blood in tissue (hence light
absorption by the blood) changes during the pulse
(plethysmography).
The oximeter determines SpO
into an arteriolar bed and measuring changes in light absorption
during the pulsatile cycle. Red and infrared low-voltage
light-emitting diodes (LED) serve as light sources; a photonic
diode serves as the photo detector.
Because oxyhemoglobin and deoxyhemoglobin differ in light
is dependent upon light from the sensor,
2
of red
by passing red and infrared light
2
- 76 -
). Because a
2
and infrared light