GE Medical Systems marquette Dash 2000, Operator'S Manual, Page: 218 / 272

11-16 Dash 2000 Patient Monitor Revision C
2005873-001
What things can create
inaccurate pulse oximeter
readings?
Certain IV dyes, such as methylene blue, can affect the readings. Methylene
blue will give falsely low readings due to excess absorption of the red
wavelength.
Nail polish, especially violets and blues, can also reduce the reading due to the
same absorption. Removal of the polish is always recommended.
Long nails, and artificial or acrylic nails can interfere with good LED/detector
opposition through the tissue.
Patients with deeply pigmented skin may be tough to monitor, although finger
pigmentation is usually less than the rest of the body.
Patients with Sickle Cell Anemia undergoing a sickling crisis may have
erroneous readings due to the absorption spectrum of HbS being different than
for normal adult Hb.
Severely jaundiced patients have high levels of bilirubin in their blood. A
product of bilirubin metabolism is CO and thus high levels of
carboxyhemoglobin can be formed, causing the oximeter to read artificially high
SPO2.
Patients with severe anemia can have low SPO2 readings.
Patients with heavy smoke inhalation can have transiently high CO levels and
thus a high amount of Carboxyhemoglobin.
Certain antibiotics, such as the Sulfas, can create high levels of
methemoglobin. Methemoglobin is unable to bind O2 and will absorb light
similarly to reduced hemoglobin, thus giving an artificially low SPO2.