General information on the use of pulse oximeters
METRAX GmbH
DefiMonitor XD 21324 / GB / K05
105 / 116
As the D-YS sensor has no housing, it can be used over a greater weight range, is suitable for
attachment in various positions and can be fixed in position with adhesive tape. This, however,
means that it takes longer to attach.
What factors can influence the SpO
2
value?
As the oxygen saturation is measured optically, the following factors may impair the result:
•
Direct sunlight
•
Strong ambient lighting (e. g. operating theatre lamps)
•
Infrared lamps
•
UV lamps (bilirubin lamps)
Influence of these factors can be minimised by ensuring that the sensor is attached correctly
and by covering the sensor with opaque material.
Further possible influences are:
•
Contamination of measurement point by dirt
•
Insufficient cleaning of the sensor
•
If light cannot pass through or colours are distorted at the measurement point, e.
g. by nail varnish
•
Patient moving vigorously
•
Injected contrast media (e. g. indiocyanine green or methylene blue)
•
High quantity of dysfunctional haemoglobin (e. g. carboxihaemoglobin)
•
Incorrect location of sensor (e. g. where there is a venous pulse)
•
Use of the pulse oximeter near strong energy sources, such as MRT scanners
•
Sensor fitted too tightly
•
Arterial occlusion in the vicinity of the sensor
•
Blood stasis, e. g. as a result of arterial catheter or blood pressure cuff.
Some of these factors are easily identified (e. g. nail varnish) and can be eliminated or an
alternative measurement point can be used to provide a reproducible result.
Other points (e. g. contrast media or defects in the blood serum) are not easily recognisable.
Due to the wide range of factors which can have a negative effect, SpO
2
measurement should
not be the only way that vital functions are monitored. Other parameters must also be
monitored (e. g. ECG, blood pressure, respiration ...).
However, if it is used correctly, if the sensor-specific warnings and information provided are
observed and the clinical symptoms taken into consideration, SpO
2
measurement is an
important instrument in the evaluation of a patient's condition.