Introduction; Principles Of Operation - Novametrix Medical Systems 511 User Manual

Section 1
Model 511 User's Manual
This manual describes the use and operation of the Model 511 Pulse Oximeter, from
Novametrix Medical Systems Inc.
The Model 511 is a lightweight, easy to use, pulse oximeter that provides reliable
measurement and displays for functional pulsatile oxygen saturation (SpO
The monitor is powered from four standard AA size alkaline batteries, or may be connected
to an optional external power source for continuous mains operation.
Numerical SpO and Pulse Rate information is presented on a liquid crystal display (LCD).
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A pulsatile signal activity bar, battery strength indicator, and general alarm indicators are
also displayed on the LCD. The Model 511 controls include a power on/off switch that also
controls display illumination, and an alarm key that enables/disables audible alarms, and
sets alert limits.
Model 511 monitors (Cat. No. 6416-00) are available with a serial communications option
which allows patient trend information to be downloaded into the Novametrix NovaCARD
Data Archive System or other communicating devices. Interfacing between the
communicating device and the monitor is via a simple cable connection. See "Serial
Communication Option" on page 23 for more information.

Principles of Operation

The Model 511 measures oxygen saturation and pulse rate with sensors that contain red and
infrared light sources, called LEDs. Since oxygen saturated blood absorbs different
amounts of light at each wavelength (red and infrared) as compared to unsaturated blood,
the amount of light absorbed by the blood in each pulse can be used to calculate oxygen
saturation.
The light energy from red (660 nm) and infrared (940 nm) LEDs is beamed through a
sample cell—a pulsating vascular bed, the patient's finger or toe for example. The
remaining light energy not absorbed by the sample cell reaches a light receptor, called a
photodiode, on the opposing side of the sensor. The data received at the photodiode is sent
back to the monitor where it is split into its red and infrared components, digitized,
processed by a microprocessor chip, and finally displayed as a numerical value for oxygen
saturation and a plethysmogram.
The Model 511 is calibrated to display "functional" saturation. This differs from the
"fractional" saturation value displayed by most co-oximeters. Functional saturation
represents the amount of oxyhemoglobin as a percentage of the hemoglobin that can be
01-May-96

Introduction

) and pulse rate.
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