Principles of Operation
114
O
XI
Max
N-65 Operator’s Manual
A pulse oximeter determines SpO
2
by passing red and
infrared light into an arteriolar bed and measuring
changes in light absorption during the pulsatile cycle.
Red and infrared low-voltage light-emitting diodes
(LED) in the oximetry
O
XI
M
AX
sensor serve as light
sources; a photo diode serves as the photo detector.
Because oxyhemoglobin and deoxyhemoglobin differ in
light absorption, the amount of red and infrared light
absorbed by blood is related to hemoglobin oxygen
saturation. To identify the oxygen saturation of arterial
hemoglobin, the monitor uses the pulsatile nature of
arterial flow.
During systole, a new pulse of arterial blood enters the
vascular bed, and blood volume and light absorption
increase. During diastole, blood volume and light
absorption reach their lowest point.
The pulse oximeter bases its SpO
2
measurements on the
difference between maximum and minimum absorption
(measurements at systole and diastole). By doing so, it
focuses on light absorption by pulsatile arterial blood,
eliminating the effects of nonpulsatile absorbers such as
tissue, bone, and venous blood.
Automatic Calibration
Because light absorption by hemoglobin is wavelength
dependent and because the mean wavelength of LEDs
varies, an oximeter must know the mean wavelength of
the
O
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M
AX
sensor's red LED to accurately measure
SpO
2
.
During monitoring, the monitor's software selects
coefficients that are appropriate for the wavelength of
that individual
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XI
M
AX
sensor's red LED; these
coefficients are then used to determine SpO
2
.
Содержание OxiMax N-65
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Страница 12: ...Safety Information 6 OXIMax N 65 Operator s Manual ...
Страница 14: ...Introduction 8 OXIMax N 65 Operator s Manual ...
Страница 36: ...Set up the OXIMAX N 65 30 OXIMax N 65 Operator s Manual ...
Страница 92: ...OXIMAX Sensors and Accessories 86 OXIMax N 65 Operator s Manual ...
Страница 98: ...Performance Considerations 92 OXIMax N 65 Operator s Manual ...
Страница 108: ...Troubleshooting 102 OXIMax N 65 Operator s Manual ...
Страница 112: ...Maintenance 106 OXIMAX N 65 Operator s Manual ...
Страница 118: ...Menu Structure 112 OXIMAX N 65 Operator s Manual ...
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