SpO
2
Monitoring
élance
Vital Signs Monitor Operations Manual
Page 12-2
Note:
Because SpO
2
measurements depend upon light from a sensor,
excessive ambient light can interfere with the pulse oximeter’s
measurements.
This pulse oximeter measures functional saturation, which is essentially
the percentage of hemoglobin that can transport oxygen
(oxyhemoglobin). Pulse oximeters do not detect significant amount of
dysfunctional hemoglobins, such as carboxyhemoglobin or
methemoglobin, which cannot carry oxygen. Saturation measurements
from pulse oximeters cannot be directly compared to measurements
from a laboratory co-oximeter. Co-oximeters provide a fractional
saturation (SaO
2
) value by measuring each type of hemoglobin
individually. This fractional value is the ratio of oxygenated hemoglobin
to all measured (oxygenated and dysfunctional) hemoglobins.
A pulse oximeter SpO
2
measurement may not match the saturation
calculated from a blood gas partial pressure of oxygen (PO
2
). The most
likely reason is that the calculated saturation value was not corrected to
reflect the effects of variables that alter the relationship of PO
2
and pH.
Such variables can include temperature, the partial pressure of carbon
dioxide (PCO ), 2,3-DPG, and fetal hemoglobin.
2
The Spacelabs oximeter function is designed to follow the Nellcor
calibration curve produced on a calibrated simulator; The Masimo
oximeter function is designed to follow a Masimo calibration curve; and
the Nellcor OxiMAX oximeter function is designed to follow the Nellcor
OxiMAX calibration curve. All may be produced on a variety of
simulators.
Note: According to international performance standards, Pulse
Oximeter simulators, though calibrated, are merely functional testers
which cannot be used to assess the accuracy of pulse oximeter probes
or monitors.
For additional information about biocompatibility or sensor disposal,
refer to the manufacturer's instructions enclosed with each sensor.
l
Pu
n
sa
ht
ab
er a pulsating arteriolar bed. Pulse oximetry is also
Th
EDs). These LEDs
to
de
xygen saturation as
Th
g
systole, a
ular bed, increasing the blood volume
eir
low
ce
be
(systole and diastole, respectively).
se oximetry is used to continuously and noninvasively measure functional oxyge
turation in the blood. Pulse oximetry is measured by using changes in lig
sorption, as the light passes ov
used to continuously and noninvasively measure pulse rate, using a SpO
2
sensor.
e pulse oximetry sensor contains two light-emitting diodes (L
emit specific wavelengths of red and infrared light, which are measured by a pho
tector. The
élance
Vital Signs Monitor displays this functional o
percent SpO
2
.
e amount of light absorbed by the arteriolar bed varies during pulsations. Durin
pulse of arterial blood enters the vasc
and light absorption. During diastole, blood volume and light absorption reach th
est point. The pulse oximeter’s SpO
2
measurement depends on the differen
tween the maximum and minimum absorption
