Spo2 Processing - Nellcor OxiMax N 5500 Service Manual

B. For data collection and the data analysis, Bland-Altman Plot is used.
C. On the systolic, diastolic, and MAP, the Deltas of all measurements shall be met
under +/- 5mmHg of mean difference (MD), and +/- 8mmHg of standard deviation
(SD).
(Delta = Intra-arterial or Auscultatory – Automated sphygmomanometer)
20
15
10
5
0
-5
-10
-15
-20
(EXAMPLE) Agreement between test and reference methods for systolic pressure. Hypothetical data
10.5 SpO Processing
2
Pulse oximetry works by applying a sensor to a pulsating arteriolar vascular bed. The
sensor contains a dual light source and photodetector. Bone, tissue, pigmentation, and
venous vessels normally absorb a constant amount of light over time. The arteriolar bed
normally pulsates and absorbs variable amounts of light during systole and diastole, as
blood volume increases and decreases. The ratio of light absorbed at systole and
diastole is translated into an oxygen saturation measurement (SpO
measurement of SpO
can interfere with this measurement.
Pulse oximetry is based on two principles: that oxyhemoglobin and deoxyhemoglobin
differ in their absorption of red and infrared light (spectrophotometry), and that the
volume of arterial blood in tissue (and hence, light absorption by that blood) changes
during the pulse (plethysmography). The monitor determines SpO
SYSTOLIC PRESSURE
Mean difference(MD): 0 mmHg
Standard deviation(SD): 6 mmHg
100 120 140
Average of test and reference methods (mmHg)
is dependent upon light from the sensor, excessive ambient light
2
N5500 Service Manual
System Processing Description
mean + 2 SD
mean - 2 SD
160 180 200
by passing red and
2
mean
. Because a
2)
89