Respironics 950 Troubleshooting guide

English
Instruction and Service Manual
Model 950
Finger Pulse Oximeter
0459

iii
English
About the Manual
Shaded boxes draw attention to contraindications, warnings, cautions
and notes.
The boxed messages are important. Be sure to read them.
The information in this manual has been carefully checked and is
believed to be accurate. In the interest of continued product
development, RESPIRONICS, INC. reserves the right to make
changes and improvements in this manual and the products it
describes at any time, without notice or obligation.
Caution: Federal Law (USA) restricts this device to sale by or on the
order of a physician.
Respironics Georgia
175 Chastain Meadows Court
Kennesaw, Georgia 30144-3724
USA
Telephone: [phone]
Fax: [phone]
Customer Service Telephone: [phone] (USA and Canada)
Customer Service Fax: [phone] (USA and Canada)
www.respironics.com
Respironics Deutschland
Gewerbestrasse 17
82211 Herrsching
Germany
Telephone: [phone]
Fax: [phone]
Respironics Asia Pacific
3/F, Microtron Building
38 Hung To Road
Kwun Tong, Kowloon, Hong Kong
Telephone: [phone]
Fax: [phone]
is a registered trademark of Respironics, Inc.
Copyright © 2002 Respironics, Inc. All rights reserved.

v
English
Table of Contents
Contraindications, Warnings, and Cautions ........................ 1
Introduction ............................................................................. 3
Description................................................................................... 3
The 950 at a Glance ..................................................................... 4
Intended Use ................................................................................ 6
Operating Instructions............................................................ 7
Getting Started ............................................................................. 7
Lanyard and Lanyard Lock.......................................................... 8
Battery Requirements .................................................................. 9
Inserting New Batteries.............................................................. 10
Activating the 950...................................................................... 11
Verifying Operation................................................................... 12
Conditions That May Affect Use ............................................... 13
Maintenance........................................................................... 14
Storage Requirements ................................................................ 14
Theory of Operation ............................................................. 16
Oximetry .................................................................................... 16
950 Averaging............................................................................ 18
Specifications ......................................................................... 19
Parts and Accessories............................................................ 20
Parts ........................................................................................... 20
Accessories ................................................................................ 20
Technical Support ...................................................................... 20
Warranty................................................................................ 21
Troubleshooting Guide ......................................................... 22

vi
Figures
Figure 1. Top digital display illustration and bottom label. .... 4
Figure 2. Lanyard and lock. .................................................... 8
Figure 3. Inserting new batteries........................................... 10
Figure 4. Applying the 950................................................... 11
Figure 5. Maintenance choices.............................................. 15
Glossary of Symbols
SYMBOL DEFINITION OF SYMBOL
Attention, Consult ACCOMPANYING
DOCUMENTS
Type BF Applied Part:
(Patient isolation from electrical shock).
Canadian Standards Association
NRTL/C Meets both Canadian and United States
Standards.
0459
CE Marking indicating conformance to EC
directive No. 93/42/EEC concerning medical
devices.
Not for Continuous Monitoring
(No Alarm for SpO2)

1
English
Contraindications, Warnings, and Cautions
CONTRAINDICATIONS:
Do not use the 950 in an MRI environment.
Do not operate the 950 in an explosive atmosphere.
Do not use the 950 on infant or neonatal patients.
WARNINGS:
Batteries may leak or explode if used or disposed of improperly.
CAUTIONS:
Federal Law (USA) restricts this device to sale by or on the order
of a physician.
Read this entire manual carefully before using the Respironics 950
Pulse Oximeter.
The 950 determines the percentage of arterial oxygen saturation of
functional hemoglobin. Significant levels of dysfunctional
hemoglobin such as carboxyhemoglobin or methemoglobin may
affect the accuracy of the measurement.
Cardiogreen and other intravascular dyes, depending on the
concentration, may affect SpO2accuracy.
The 950 must be able to measure the pulse properly to obtain
accurate SpO2measurement. Verify that nothing is hindering the
pulse measurement before relying on the SpO2measurement.
Some situations that may contribute to erroneous pulse
measurement are:
•inadequate perfusion,
•excessive patient movement,
•pulse oximeter and blood pressure measurement on the
same limb, etc.
The 950 may interpret motion artifact of sufficient amplitude and
regularity as good perfusion (green).
Do not use the 950 in situations where alarms are required. The
950 has no audible alarms.
The 950 is intended for spot-checking or continuous monitoring by
an attending health care professional. Because the 950 has no
audible alarms, international labeling requirements (ISO 9919)
dictate it be labeled, “Not for continuous monitoring”.

2
CAUTIONS:(Continued)
Check application site periodically (at least every thirty minutes) to
determine circulation, positioning and skin sensitivity.
The 950 may not work for all patients. If you are unable to achieve
stable readings, discontinue use.
Finger nail polish may reduce light transmission and thereby affect
SpO2accuracy.
A flexible circuit connects the two halves of the 950. Do not twist or
pull on the connection.
Do not use different types of batteries at the same time. Do not mix
fully charged and partially charged cells at the same time. These
actions may cause the batteries to leak.
Batteries must be removed if the 950 is going to be stored for more
than one month or batteries may leak.
Do not immerse the 950 in liquid to clean.

3
English
Introduction
Description
Respironics, Inc. has integrated the finger clip sensor and the
electronics of the Respironics Model 920 hand held Pulse Oximeter
into one unit, the Model 950. The 950 is very small (1.3 inch W x 1.3
inch H x 2.2 inch L) and lightweight (2 ounces).
The 950 displays numerical values for functional arterial hemoglobin
oxygen saturation (%SpO2) in percentage and pulse rate ( ) in
beats per minute on light emitting diode (LED) digital displays.
With each detected pulse, the Perfusion Display blinks. Patient
perfusion signals are graded as good, marginal or inadequate and are
indicated as such by the perfusion indicator changing color from green
to yellow or red respectively. This sophisticated, yet simple technique
provides a pulse-by-pulse visual indication of waveform signal
quality, without requiring the user to perform complex signal analysis
during critical patient care situations.
Two AAA battery cells power the 950 and operate it for
approximately 1,600 spot checksaor 18 hours of continuous operation
between battery replacement. When the batteries are low, the digital
displays will blink once per second. (Refer to page 9 for battery
specifications and page 10 for battery replacement instructions.)
aCalculated at 40 seconds per spot check using two AAA alkaline battery
cells.

4
The 950 at a Glance
Figure 1. Top digital display illustration and bottom label.
%SpO2Display
Heart Rate Display
Perfusion Display
Finger Grip
Battery
Polarity
Markings
Serial
N
umbe
r

5
English
•%SpO2Display
Numeric LEDs display the value of percent oxygen saturation,
calculated using a four beat exponential averaging technique.
(Refer to page 16, Theory of Operation, for information on
averaging.)
•Heart Rate Display
Numeric LEDs display the pulse rate in beats per minute,
calculated by an eight beat sliding averaging technique. (Refer
to page 18 for information on averaging.)
•Perfusion Display
Provides a visual indication of the signal quality, while
blinking at the corresponding pulse rate. It is a method of
alerting the user to changes in the pulse waveform signal that
may affect the SpO2data.
Green = good signal amplitude
Yellow = artifact or marginal signal amplitude
Red = inadequate signal amplitude
CAUTION:
The 950 may interpret motion artifact of sufficient amplitude and
regularity as good perfusion (green).
•Battery Low
Numeric LEDs flash once per second when batteries are low.
Replace the batteries as soon as possible. Refer to page 10,
Inserting New Batteries.
•Finger Removal
A minus (-) sign appears in the left most digit of the %SpO2
display when the 950 senses that the finger has been removed.
The last measured SpO2and pulse rate values freeze for ten
seconds, then the displays go blank.
•The label on the bottom of the 950 lists the model number,
serial number, CAUTION statement, and battery polarity
indicators.

6
Intended Use
The 950 is a portable device for spot-checking or attended-care
monitoring of adult or pediatric patients. Use the 950 with finger
thickness between 0.3 to 1.0 inches. The 950 is not recommended
where motion is expected or for relatively long-term monitoring, e.g.,
greater than 30 minutes.
CONTRAINDICATION:
Do not use the 950 on infant or neonatal patients.
CAUTION:
Do not use the 950 in situations where alarms are required. The
950 has no audible alarms.
CAUTION:
It is intended for spot-checking or continuous monitoring by an
attending health care professional. Because the 950 has no audible
alarms, international labeling requirements (ISO 9919) dictate it be
labeled, “Not for continuous monitoring”.
CAUTION:
Check application site periodically (at least every thirty minutes) to
determine circulation, positioning and skin sensitivity.
CAUTION:
The 950 may not work for all patients. If unable to achieve stable
readings, discontinue use.

7
English
Operating Instructions
Getting Started
1. Read this entire manual.
2. Thread the lanyard through the lanyard holes on the 950 following
the instructions on page 8, Lanyard and Lanyard Lock.
3. Insert the batteries following the instructions on page 10, Inserting
New Batteries.
4. Activate the 950 by inserting a finger.
5. Verify operation following the instructions on page 12, Verifying
Operation.

8
Lanyard and Lanyard Lock
A lanyard is provided for the convenience of wearing the 950 around
the neck or wrist. The 950 will function with or without the lanyard.
1. Thread the ends of the lanyard through the lanyard holes as shown
below in Figure 2.
2. Push in the lanyard lock button, slide the lock onto the lanyard up
to the desired length.
3. Release the lock button to secure its position.
4. Reverse this procedure to remove the lanyard.
Figure 2. Lanyard and lock.
NOTE:
The lanyard must cross over the top of the 950 to permit full
opening of the sensor.

9
English
Battery Requirements
Respironics recommends using AAA alkaline batteries to power the
950. Two of these batteries are included with each new system.
Concerning the Use of Rechargeable Batteries:
Rechargeable nickel cadmium or nickel-metal hydride batteries may
be used. However, rechargeable batteries need more frequent
replacement as they have less capacity than non-rechargeable alkaline
batteries.
WARNING:
Batteries may leak or explode if used or disposed of improperly.
CAUTION:
Do not use different types of batteries at the same time or mix fully
charged and partially charged cells at the same time, as the
batteries may leak.
CAUTION:
Batteries must be removed if the 950 is going to be stored for more
than one month or batteries may leak.

10
Inserting New Batteries
1. Loosen the screw at the end of the 950 using a coin or a standard
flat screwdriver and remove the battery door.
2. Remove the old batteries and dispose of them properly.
Figure 3. Inserting new batteries.
3. Insert two new AAA batteries following the polarity markings
indicated on the battery door or bottom label of the 950. Proper
positioning of the batteries is critical.
4. Carefully position the battery door and firmly, but gently tighten
the screw. Do not force the door into place. The door only fits
when properly oriented. To avoid stripping screw threads, do not
tighten excessively.
5. Insert your finger into the 950 and verify operation. If the unit
does not turn on, remove the finger and wait two seconds before
reinserting a finger.
6. If the 950 still does not work, reinstall the batteries.

11
English
Activating the 950
Activate the 950 by inserting the patient's finger into the pulse
oximeter as shown in Figure 4. (The 950 determines that a finger has
been inserted and then automatically activates the display.)
Figure 4. Applying the 950.
1. Insert the patient's finger into the 950 as shown above, until the
fingertip touches the built-in stop guide.
2. Center the finger.
3. Verify operation. Turn to page 12, Verifying Operation.
NOTE:
The 950 performs best when used on fingers other than the thumb.
NOTE:
If 950 does not turn on, remove the finger and wait 2 seconds
before reinserting a finger.

12
Verifying Operation
1. When a finger is first inserted, the 950 executes an initialization
sequence.
2. After completing this sequence, the 950 begins sensing the pulse
(indicated by the blinking Perfusion display).
3. Allow the system to stabilize by observing at least ten seconds of
continuous green-colored Perfusion display pulses (consistent
with the patient's pulse) before relying on the displayed values.
4. If the Perfusion display blinks yellow or red, make sure
perfusion is not restricted. Try another finger.
5. If you are unable to achieve consistent green perfusion pulses and
stable readings, remove the 950 from the patient's finger and refer
to page 22, Troubleshooting Guide.
CAUTION:
The 950 may interpret motion artifact of sufficient amplitude and
regularity as good perfusion (green).
CAUTION:
Finger nail polish may reduce light transmission and thereby affect
SpO2values.
NOTE:
If the pulse signal is inadequate for a 2-minute period the 950 will
automatically power down.

13
English
Conditions That May Affect Use
•Environmental
Fluctuating or flickering light may affect measurements.
Use of the 950 outside stated temperature and humidity
specifications may affect measurements. Refer to page 1,
Contraindications, Warnings, and Cautions.
•Motion
Excessive or rapid movement may affect measurements.
•Sensor Position
Sensor position is critical for accurate SpO2measurements.
All emitted sensor light must pass through the finger before
reaching the detector. Do not allow positioning such that
some or all of the emitted light can by-pass the finger as
this will result in inaccurate SpO2values.
While on the finger, do not press the 950 against any surface
and do not squeeze or hold the 950. The external spring
provides the correct pressure on the finger; additional
pressure may affect measurements.
•Perfusion
The finger must have perfusion adequate to cause the
Perfusion Indicator to blink green in order to give
accurate readings.
•Nail Polish
Fingernail polish may reduce light transmission which may
affect SpO2values.
In addition, the following factors may degrade performance:
•an arterial catheter •moisture in the 950
•a blood pressure cuff •a finger outside the 0.3-1.0” size range
•an electrosurgical procedure •venous pulsations
•an infusion line •anemia or a low hemoglobin count
•cardiovascular dyes •the 950 not at heart level

14
Maintenance
The advanced digital circuitry within the Respironics 950 requires no
calibration or periodic maintenance other than battery replacement.
Field repair of the 950 circuitry is not possible. DO NOT attempt to
open the 950 case or repair electronics. Opening the case will damage
the 950 and void the warranty. If the 950 is not functioning properly,
refer to page 22, Troubleshooting Guide.
CAUTION:
A flexible circuit connects the two halves. Do not twist or pull on
the flex circuit.
CAUTION:
Do not immerse the 950 in liquid to clean.
NOTE:
The 950 may be sterilized using ethylene oxide (EtO) (cold cycle).
Remove the battery door and batteries before EtO sterilization.
Follow the instructions on page 10, Inserting New Batteries.
NOTE:
Hold the 950 top and bottom together when the spring is released.
The two halves are held together by the flex circuit only.
Storage Requirements
Store the 950 within the stated temperature and humidity storage
specifications. Refer to page 19, Specifications.
CAUTION:
Batteries must be removed if the 950 is going to be stored for more
than one month or batteries may leak.

15
English
Figure 5. Maintenance choices. Cleaning and replacing the spring and the gripping insert.
TO DISENGAGE THE SPRING:
•Turn the 950 bottom side up. •Following the arrows on the label, gently pull the
spring up (to get it out of the retaining groove) and then swing it forward, bringing the spring past the finger cavity.
BOTTOM
BACK
TOP
Pivot hole
Finger cavit
y
BOTTOM
1.14"
RE-ENGAGE THE SPRING
Distinguish spring
design for proper
assembly.
•To clean the inner surfaces. •To replace the spring. •To replace the gripping insert.
1.39"
FRONT
FRONT
BACK
SPRING DESIGN B
Pivot hole
TOP
Retaining groove
SPRING DESIGN A
Retaining groove
Finger cavit
y
TO REPLACE THE SPRING:
•
R
emove the old spring, carefully pulling the ends from the pivot holes on either sid
e.
•
Insert the ends of the new spring into the pivot holes and swing the spring up and
past the finger cavity, then seat the spring into the retaining groove.
•Carefully peel the old gripping insert away from the surface. •Remove any residual adhesive with an isopropyl alcohol solution. •Peel the backing paper off the new gripping insert, uncovering the adhesive back. •Position the new insert as shown above and gently press it in place.
Carefully peel from surface
(Top Half)
Front Edge
(Top Half)
TO REPLACE THE GRIPPING INSERT:
A gripping insert adhered to the upper interior surface of the 950 provides a more secure fit to the finger. The 950 will function with or without the gripping insert, however Respironics recommends that the insert be in place during normal operation.
TO CLEAN THE INNER
SURFACES:
•Wipe exposed surfaces with a
soft cloth dampened with an isopropyl alcohol solution or a mild detergent solution.
•Dry with a soft cloth or allow
to air dry.
•Surfaces should be
thoroughly dry before re-engaging the spring.
Gripping Insert
Flex Circuit
Bottom Half
Top Half

16
Theory of Operation
Oximetry
The pulse oximeter shines red and infrared light through the tissue and
detects the fluctuating signals caused by arterial blood pulses. The
ratio of the fluctuation of the red and infrared light signals received
determines the oxygen saturation content. Conditions such as steady
venous blood flow, skin thickness, fingernail thickness, etc., do not
affect the saturation reading because they are constant and do not
cause fluctuations.
The function, f, depends on the physical properties of the LEDs
producing the light. These physical properties are fixed by the
manufacturing material and processes.
Note that the pulse oximeter readings do not depend upon the absolute
light intensity, rather upon the fluctuations in light intensity.
Characteristics such as thick skin or skin pigmentation will affect the
min and max proportionally, thus the ratio min/max does not
change. However, if too little light passes through, the pulse oximeter
will not display values. Pulse oximeters use two different wavelengths
of light (red and infrared), providing the ability to determine one
component of blood. The pulse oximeter is calibrated to closely
approximate functional oxygen saturation values. These values will
closely approximate laboratory instrument fractional saturation values
if the dysfunctional hemoglobin saturation levels are negligible.
In summary, because the pulse oximeter performs all computations
from the internal software and there are no critical parts to drift, no re-
calibration is needed.