11-5 
 
11.5 Measurement Limitations 
If you doubt the measured SpO
2
, check patient vital signs first. Then check the patient 
monitor and SpO
2
 sensor. The following factors may influence the accuracy of measurement:   
  Ambient light 
  Physical movement (patient and imposed motion) 
  Diagnostic testing 
  Low perfusion 
  Electromagnetic interference, such as MRI environment 
  Electrosurgical units 
  Dysfunctional haemoglobin, such as carboxyhemoglobin (COHb)and methemoglobin 
(MetHb) 
  Presence of certain dyes, such as methylene and indigo carmine   
  Inappropriate positioning of the SpO
2
 sensor, or use of incorrect SpO
2
 sensor 
  Drop of arterial blood flow to immeaurable level caused by shock, anemia, low 
temperature or vasoconstrictor. 
 
 
11.6 Troubleshooting 
This section lists the problems that might occur. If you encounter the problems when using 
the equipment or accessories, check the table below before requesting for services. If the 
problem persists, contact your service personnel. 
 
CAUTION
z  Never try to disassemble the equipment or supplied accessories. There are no 
internal user-serviceable parts.