Masimo SET Rainbow SET Rad-57 - Principles of Operation

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Rad-57 Signal Extraction Pulse CO-Oximeter Operator’s Manual
1
Overview
Principles of Operation
Pulse oximetry is governed by the following principles:
1. Oxyhemoglobin (oxygenated blood), deoxyhemoglobin (non-oxygenated blood),
carboxyhemoglobin (blood with carbon monoxide content), methemoglobin (blood with oxidized
hemoglobin) and blood plasma constituents differ in their absorption of visible and infrared light
(using spectrophotometry, see gure below).
Carboxyhemoglobin
Oxyhemoglobin
Methemoglobin
Deoxyhemoglobin
Absorption Spectra
Plasma
Absorption (1/mm)
0
0.5
600 800
1.0
1.5
2.0
2.5
3.0
3.5
4.0
1000 1200 1400 1600
Wavelength (nm)
2. The amount of arterial blood in tissue changes with your pulse (photoplethysography). Therefore,
the amount of light absorbed by the varying quantities of arterial blood changes as well.
The Rad-57 Pulse CO-Oximeter uses a multi-wavelength sensor to distinguish between oxygenated
blood, deoxygenated blood, blood with carbon monoxide, oxidized blood and blood plasma. The
Rad-57 utilizes a sensor with various light-emitting diodes (LEDs) that pass light through the site
to a photodiode (detector). See gure below. Signal data is obtained by passing various visible and
infrared lights (LED’s, 500 to 1000nm) through a capillary bed (for example, a ngertip, a hand, a
foot) and measuring changes in light absorption during the blood pulsatile cycle. This information
may be useful to clinicians. The maximum radiant power of the strongest light is rated at ≤ 25mW.
The detector receives the light, converts it into an electronic signal and sends it to the Rad-57 for
calculation.
GRAPHIC DOCUMENTATION AND APPRO VA L
GR-13315
DRO-10430
CONFIDENTIAL AND PROPRIETARY
© 2004 Masimo Corporation
All Rights Reserved
Page 1 of 1
FRM 1379 Rev A
DRO 5201
Approvals
Approvals
Document
Number
TitleProgram
Date
Kevin McHale
GR-13315 Adobe Illustrator 10.0 (.eps)Graphic, LED/Photo Detector Placment
10/5/04
Marketing Communications Date
2
1
1. Light Emitting Diodes (LEDs)
(7 + wavelengths)
2. Detector
Once the Rad-57 receives the signal from the sensor, it utilizes Masimo Rainbow SET signal
extraction technology to calculate the patient’s functional oxygen saturation (%SpO
2
), blood levels
of carboxyhemoglobin (SpCO*), methemoglobin (SpMet*) and pulse rate. The SpCO and SpMet
measurements rely on a multiwavelength calibration equation to quantify the percentage of: carbon
monoxide or methemoglobin in arterial blood. The maximum of the skin surface temperature is
measured at an ambient temperature of less than 106º F (41º C). This is verified by Masimo sensor
skin temperature test procedures.
*available in upgraded Instrument