Consideration when choosing Spo2 Sensor
· There are some general guidelines to choosing the right sensor. The ideal application site has good perfusion, does not generate movement artifact, is comfortable for the patient and allows easy application. Most sensors work on extremities such as a finger, toe or ear.
· The size of the application site determines what size sensor to use. The age of the patient is not a factor.
· If a sensor is too big or too small, the light emitting diode and the light detector may not line up. This could cause a false reading or an alarm.
· If a finger sensor is too large, it may slip partway off so that the light source partly
covers the finger. This condition, called optical bypass, causes incorrect readings.
· If a finger is inserted too far into the sensor it may be squeezed by the sensor, which
causes venous pulsation. The pulse oximeter recognizes arterial blood only by its pulsing motion, so in this case it also measures venous blood. This causes readings which are falsely low.
