Summary:
When supplementation of oxygen is inappropriate there is
chance of development of either hypoxia or hyperoxia.
During oxygen therapy, oxygen level should be maintained
within a target-able range through proper monitoring. Pulse
oximetry is a useful convenient and reliable monitoring
system. The principle of working of pulse oximeter is based
on the fact that oxyhaemoglobin and deoxyhaemoglobin
absorb light at the red end of the spectrum differently;
Deoxyhaemoglobin absorbs more red than infrared and
oxyhaemoglobin more infrared than red. The ‘emitter’ of
the probe of pulse oximeter sends equal intensities of red
and infrared light into the tissue. The ‘sensor’ detects the
ratio of red to infrared that emerges. From this information
the proportion of oxyhaemoglobin to deoxyhaemoglobinthat
is, the percentage saturation of hemoglobin with oxygen