Respironics BiPAP Synchrony User manual

RProvider Manual
www.respironics.com
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BiPAP systems are the subject of one or more of U.S. Patents #5148802, #5239995, #531937,
#5433193, Canadian Patent #2, 024, 477, European Patent #EP0425092, German Patent
#69021681.5-08, and other pending U.S. and foreign patents. BiPAP is a registered trademark of
Respironics, Inc.
© 2002 Respironics, Inc. All Rights Reserved

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Table of Contents
Chapter 1: Warnings and Cautions .......................................................................1-1
1.1 Warnings ..............................................................................................................................1-1
1.2 Cautions................................................................................................................................1-3
1.3 Intended Use.........................................................................................................................1-4
1.4 Contraindications ................................................................................................................1-4
1.5 Patient Precautions..............................................................................................................1-4
1.6 Communication Statements for Optional Modem ...........................................................1-5
TYPES OF SERVICE ............................................................................................................................................................ 1-5
TELEPHONE COMPANY PROCEDURES .................................................................................................................................. 1-5
IFPROBLEMS ARISE.......................................................................................................................................................... 1-5
1.7 Industry Canada Notice ......................................................................................................1-6
Chapter 2: Introduction ..........................................................................................2-1
2.1 Synchrony Overview ...........................................................................................................2-1
2.2 Modes of Operation .............................................................................................................2-2
2.2.1 CPAP MODE ....................................................................................................................................................... 2-2
2.2.2 S MODE .............................................................................................................................................................. 2-2
2.2.3 S/T MODE ........................................................................................................................................................... 2-3
2.2.4 PRESSURE CONTROL MODE ................................................................................................................................... 2-3
2.2.5 TIMED MODE ....................................................................................................................................................... 2-3
2.2.6 MODE SUMMARY .................................................................................................................................................. 2-4
2.3 DigitalAuto-Trak Sensitivity™ ..........................................................................................2-4
2.3.1 LEAK TOLERANCE ................................................................................................................................................ 2-4
2.3.2 SENSITIVITY ......................................................................................................................................................... 2-4
2.4 Access Levels ........................................................................................................................2-7
2.5 Symbol Key ..........................................................................................................................2-8
2.6 Definitions, Acronyms, and Abbreviations........................................................................ 2-9
2.7 Service...................................................................................................................................2-9
Chapter 3: Controls and Displays ..........................................................................3-1
3.1 Control Panel .......................................................................................................................3-1
3.1.1 DISPLAY SCREEN .................................................................................................................................................. 3-1
3.1.2 CONTROL KEYS .................................................................................................................................................... 3-2
3.1.3 INDICATORS .......................................................................................................................................................... 3-2
3.2 Navigating the Screens ........................................................................................................3-5
3.3 Display Data .........................................................................................................................3-6
3.4 Patient Circuit Connection .................................................................................................3-7
3.5 Optional Oxygen Valve........................................................................................................3-7
3.6 Rear Panel ............................................................................................................................3-8

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Chapter 4: Setting up and Starting the Synchrony ..............................................4-1
4.1 Preparing the Synchrony ....................................................................................................4-1
4.1.1 SUMMARY OF SETUP OPERATIONS .......................................................................................................................... 4-1
4.1.2 INSTALLING THE AIR FILTERS ................................................................................................................................. 4-2
4.1.3 ASSEMBLING THE PATIENT CIRCUIT ........................................................................................................................ 4-3
4.1.4 SUPPLYING POWER TO THE SYNCHRONY.................................................................................................................. 4-4
4.1.5 OPTIONAL INTERNAL MODEM ................................................................................................................................ 4-5
4.1.6 PERFORMANCE VERIFICATION ................................................................................................................................ 4-5
4.2 Setting Up the Synchrony ...................................................................................................4-5
4.3 Connecting the Patient ........................................................................................................4-5
4.4 Operating the System ..........................................................................................................4-6
4.5 Patient Operating Instructions...........................................................................................4-7
4.5.1 SETTING THE RISE TIME ........................................................................................................................................ 4-7
4.5.2 DIALING THE PROVIDER ........................................................................................................................................ 4-8
4.5.3 DATA TRANSMISSION ERRORS ................................................................................................................................ 4-9
4.5.4 USING THE RAMP FUNCTION ............................................................................................................................... 4-10
Chapter 5: Changing Parameters ..........................................................................5-1
5.1 Summary of Change Parameters Operations ...................................................................5-1
5.2 Change Parameters Screens ...............................................................................................5-2
5.2.1 CPAP MODE ....................................................................................................................................................... 5-2
5.2.2 S MODE .............................................................................................................................................................. 5-3
5.2.3 T, PC, AND S/T MODES ....................................................................................................................................... 5-3
5.3 Changing Synchrony Parameters ......................................................................................5-4
Chapter 6: Changing Modes...................................................................................6-1
6.1 Summary of Change Mode Operations .............................................................................6-1
6.2 Change Mode Setup Screens ..............................................................................................6-2
6.2.1 CPAP MODE SETUP SCREEN................................................................................................................................. 6-2
6.2.2 S MODE SETUP SCREENS ...................................................................................................................................... 6-2
6.2.3 T, PC, AND S/T MODES SETUP SCREENS ............................................................................................................... 6-2
6.3 Changing the Synchrony Mode..........................................................................................6-3
Chapter 7: Options ..................................................................................................7-1
7.1 Summary of Options Operations .......................................................................................7-1
7.2 Synchrony Options Menu ...................................................................................................7-2
7.2.1 TIME AT PRESSURE ................................................................................................................................................ 7-2
7.2.2 SYSTEM CODES .................................................................................................................................................... 7-3
7.2.3 PATIENT ALARM HISTORY ..................................................................................................................................... 7-4
7.2.4 MODEM SETTINGS ................................................................................................................................................ 7-5
7.2.5 PEV SETTING ...................................................................................................................................................... 7-9
7.2.6 CHANGING THE ACCESS LEVEL ............................................................................................................................ 7-10
7.2.7 UNLOCKING THE ACCESS LEVEL .......................................................................................................................... 7-10
7.2.8 CHANGING THE LANGUAGE ................................................................................................................................. 7-11
7.2.9 CHANGING THE ALARM VOLUME ......................................................................................................................... 7-12
7.2.10 EXITING THE OPTIONS MENU .............................................................................................................................. 7-12

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Chapter 8: Alarms ...................................................................................................8-1
8.1 Alarm Introduction .............................................................................................................8-1
8.2 Setting Alarm Parameters...................................................................................................8-2
8.2.1 ALARM PARAMETER OPERATION SUMMARY ............................................................................................................ 8-2
8.2.2 CHANGING THE ALARM PARAMETERS ..................................................................................................................... 8-3
8.3 Summary of Alarm Behavior .............................................................................................8-6
8.3.1 ALARM SOUNDS BEHAVIOR ................................................................................................................................... 8-6
8.3.2 ALARM LED BEHAVIOR ....................................................................................................................................... 8-7
8.3.3 DISPLAY BEHAVIOR ............................................................................................................................................... 8-7
8.4 Summary of UserActions During Alarm ..........................................................................8-8
8.5 Alarm Tables ........................................................................................................................8-9
8.5.1 HIGH PRIORITY ALARMS ....................................................................................................................................... 8-9
8.5.2 MEDIUM PRIORITY ALARMS ................................................................................................................................ 8-10
8.5.3 LOW PRIORITY ALARMS ...................................................................................................................................... 8-11
8.5.4 ALARM DEFINITIONS ........................................................................................................................................... 8-12
Chapter 9: Communications...................................................................................9-1
9.1 Communicating via Optional Modem ...............................................................................9-1
9.2 Communicating with Encore Software..............................................................................9-1
Chapter 10: Adding Supplemental Oxygen.........................................................10-1
10.1 Adding Supplemental Oxygen..........................................................................................10-1
10.2 Supplemental Oxygen Concentrations ............................................................................10-3
Chapter 11: Cleaning and Maintenance..............................................................11-1
11.1 Cleaning the Synchrony .................................................................................................... 11-1
11.2 Cleaning or Replacing the Inlet Filters............................................................................ 11-1
11.3 Maintenance ....................................................................................................................... 11-2
Chapter 12: Circuits and Accessories ...................................................................12-1
12.1 Circuit Configurations ......................................................................................................12-1
12.2 Circuits and Accessories.................................................................................................... 12-2
12.3 Masks, Exhalation Ports, and Related Accessories ........................................................12-2
12.4 Humidifiers ........................................................................................................................12-2
12.5 Software..............................................................................................................................12-2
Chapter 13: Operational Verification...................................................................13-1
13.1 S Mode Verification ...........................................................................................................13-1
13.2 S/T Mode Verification .......................................................................................................13-2
13.3 Alarm Verification ............................................................................................................. 13.3
Chapter 14: Specifications ....................................................................................14-1
Appendix A: External Modem Requirements......................................................A-1
A.1 Serial Cable .........................................................................................................................A-1
A.2 Modem Commands ............................................................................................................ A-1
A.3 Example Initialization Strings........................................................................................... A-2
Appendix B: Error Codes ...................................................................................... B-1
Index ......................................................................................................................... I-1

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Package Contents
• BiPAP Synchrony
• power cord
• flexible tubing (1.8 m x 2 mm I.D.)
• filter cap
• pollen filters
• ultra-fine filter
• optional modem cable (4.27 m)
• User Guide*
Ultra-fine Filter
Pollen Filters
BiPAP Synchrony Power Cord
Filter Cap
Flexible Tubing
Optional Modem
Cable
User Guide*
www.respironics.com
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User Guide
* Not included with all models.

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Chapter 1: Warnings and Cautions
WARNING: Indicates the possibility of injury to the patient or the operator.
CAUTION: Indicates the possibility of damage to the device.
CAUTION! US federal law restricts this device to sale by or on the order of a physician.
NOTE: Places emphasis on an operating characteristic.
• This manual serves as a reference. The instructions in this manual are
not intended to supersede the health care professional’s instructions
regarding the use of the Synchrony.
• The operator should read and understand this entire manual before
using the Synchrony.
• The Synchrony provides positive pressure ventilation and is indicated
for assisted ventilation. The Synchrony does not provide ventilation
with guaranteed tidal volume delivery. Patients requiring ventilation
at predetermined tidal volumes are not candidates for pressure support
ventilation.
• The Synchrony should be used only with masks and connectors
recommended by Respironics or with those recommended by the
health care professional or respiratory therapist. See Chapter 12 for
approved patient circuits. A mask should not be used unless the
Synchrony is turned on and operating properly. The exhalation port(s)
associated with the mask should never be blocked.
Explanation of the Warning: The Synchrony is intended to be used
with special masks or connectors that have exhalation ports to allow
continuous flow of air out of the mask. When the Synchrony is turned
on and functioning properly, new air from the Synchrony flushes the
exhaled air out through the mask exhalation port. However, when the
Synchrony is not operating, enough fresh air will not be provided
through the mask, and exhaled air may be rebreathed. Rebreathing of
exhaled air for longer than several minutes can in some circumstances
lead to suffocation.
• In the event of a power or device failure, audible and visual alarm
signals will activate. The Synchrony must be disconnected from the
patient immediately. As is the case with most ventilators with passive
exhalation ports, when power is lost, sufficient air will not be provided
through the circuit and exhaled air may be rebreathed.
• At low EPAP pressures, the flow through the exhalation port may be
inadequate to clear all exhaled gas from the tubing. Some rebreathing
may occur.
• If supplemental oxygen is added to the breathing circuit, the optional
oxygen valve must be installed and used as shown in Chapter 10. The
valve automatically stops the flow of oxygen when the blower is off.
• If oxygen is used with the Synchrony, the oxygen flow must be turned
off when the Synchrony is not operating.
Explanation of the Warning: When the Synchrony is not in operation,
and the oxygen flow is left on, oxygen delivered into the ventilator
tubing may accumulate within the Synchrony’s enclosure. Oxygen
accumulated in the ventilator enclosure will create a risk of fire.
• Oxygen supports combustion. Oxygen should not be used while
smoking or in the presence of an open flame.
1.1 Warnings

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Warnings (continued) • When administering fixed-flow supplemental oxygen, the oxygen
concentration may not be constant. The inspired oxygen concentration
will vary, depending on the IPAP and EPAP settings, patient breathing
pattern, and the leak rate. Substantial leaks around the mask may
reduce the inspired oxygen concentration to less than the expected
concentrations shown in Chapter 10. Appropriate patient monitoring
should be used.
• Operation of the Synchrony may be adversely affected by
—electromagnetic fields exceeding the level of 10 V/m in the test
conditions of EN 60601-1-2
—the operation of high frequency (diathermy) equipment
—defibrillators, or short wave therapy equipment
—radiation (e.g., x-ray, CT)
—magnetic fields (e.g., MRI).
• The Synchrony is not suitable for use in the presence of flammable
mixtures such as gases, anesthetics and liquids.
• Do not use the Synchrony at room temperatures above 35°C. If the
Synchrony is used at room temperatures above 35°C, the temperature
of the airflow may exceed 41°C, which could cause thermal irritation
or injury to the patient’s airway.
• Do not operate the Synchrony in direct sunlight or near a heating
appliance because these conditions can increase the temperature of the
airflow delivered to the patient.
• To reduce the risk of contamination, a low resistance main flow
bacteria filter may be placed in-line between the Synchrony and
the patient.
• The Synchrony does not have an alarm to detect occlusion of the
exhalation port. Before each use, inspect the patient circuit to verify
that the port is not occluded. Occlusion or partial occlusion can reduce
airflow and result in rebreathing of exhaled air.
• Do not use antistatic or electrically conductive hoses or tubing with the
Synchrony.
• When the Synchrony is used with a humidifier, position the humidifier
such that the water level in the humidifier is lower than the patient, and
the humidifier is on the same level or lower than the Synchrony.
• If you detect any unexplained changes in the performance of the
Synchrony, if the Synchrony is dropped or mishandled, if water is
spilled into the enclosure, or if the enclosure is broken, seek the
assistance of Respironics or an authorized service center.
• Repairs and adjustments must be performed by Respironics or an
authorized service center. Service done by inexperienced or
unqualified personnel, or installation of unauthorized parts could cause
injury, invalidate the warranty, or result in costly damage.
• Electrical cords and cables should be periodically inspected for
damage or signs of wear.
• To avoid electrical shock, unplug the Synchrony before cleaning it.
• Verify the operation of the patient disconnect alarm with any changes
in the patient circuit.

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1.2 Cautions • The Synchrony may only be operated at temperatures between 5°C and
35°C.
• Do not immerse the Synchrony or allow any liquid to enter the
enclosure or the inlet filter.
• Condensation may damage the Synchrony. Always allow the
Synchrony to reach ambient temperature before use.
• Use the AC cable retainer to keep the AC power cord from falling out.
Additional Warnings, Cautions, and Notes are located throughout
this manual.
Warnings (continued) • Verify that the Patient Disconnect alarm is active if required for
medical reasons.

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1.3 Intended Use
1.4 Contraindications
1.5 Patient Precautions
The Synchrony is intended to provide noninvasive ventilation in adult patients
(>30 kg) for the treatment of respiratory insufficiency (a condition in which the
patient can continue without ventilation for some period, such as overnight) or
obstructive sleep apnea. The Synchrony may be used in the hospital or home.
The Synchrony is intended for use with nasal masks and full-face masks as
recommended by Respironics.
The use of the Synchrony is contraindicated on patients without a spontaneous
respiratory drive.
The use of the Synchrony for noninvasive positive pressure therapy may be
contraindicated on patients
• unable to maintain a patent airway or adequately clear
secretions,
• at risk for aspiration of gastric contents,
• with acute sinusitis or otitis media,
• with a history of allergy or hypersensitivity to the mask materials
where the risk from allergic reaction outweighs the benefit of
ventilatory assistance,
• with epistaxis, causing pulmonary aspiration of blood, or
• with hypotension.
• Advise the patient to immediately report any unusual chest discomfort,
shortness of breath, or severe headache.
• If skin irritation or breakdown develops from the use of the mask,
refer to the mask instructions for appropriate action.
• The following are potential side effects of noninvasive positive
pressure therapy:
—ear discomfort
—conjunctivitis
—skin abrasions due to noninvasive interfaces
—gastric distention (aerophagia).
WARNING! Do not connect any equipment to the Synchrony unless recommended by Respironics or the health care
professional. Verify that an exhalation port is present to exhaust CO2from the circuit. If circuit accesso-
ries other than those recommended by Respironics are connected to the Synchrony, then pressures must
be verified. Use of these accessories may alter the pressure received, reducing the effectiveness of
treatment.
NOTE: When assessing the relative risks and benefits, the health care professional should understand that the
Synchrony can be set to deliver pressures up to 30 cm H2O. Also, in the unlikely event of certain fault
conditions, a maximum static pressure of 40 cm H2O is possible.

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1.6 Communication Statements for Optional Modem
The Synchrony optional internal modem is designed to be used on standard
device telephone lines. It connects to the telephone line by means of a standard
jack called the USOC RJ-11C (or USOC FJ45S). Connection to telephone-
company-provided coin service (central office implemented systems) is
prohibited. Connection to party lines service is subject to state tariffs.
The goal of the telephone company is to provide you with the best service it
can. In order to do this, it may occasionally be necessary for them to make
changes in their equipment, operations or procedures. If these changes might
affect your service or the operation of your equipment, the telephone company
will give you notice, in writing, to allow you to make any changes necessary to
maintain uninterrupted service. In certain circumstances, it may be necessary
for the telephone company to request information from you concerning the
equipment that you have connected to your telephone line. Upon request of the
telephone company, provide the FCC registration number and the ringer
equivalence number (REN); both of these items are listed on the equipment
label. The sum of all the RENs on your telephone lines should be less than five
in order to assure proper service from the telephone company. In some cases, a
sum of five may not be usable on a given line.
If any of your telephone equipment is not operating properly, you should
immediately remove it from your telephone line, as it may cause harm to the
telephone network. If the telephone company notes a problem, they may
temporarily discontinue service. When practical they will notify you in advance
of the disconnection. If advance notice is not feasible, you will be notified as
soon as possible. When you are notified, you will be given the opportunity to
correct the problem and informed of your right to file a complaint with the
FCC. Contact your telephone company if you have questions about your phone
line. In the event repairs are ever needed on the Synchrony, they should be
performed by Respironics or an authorized representative of Respironics. For
information contact Respironics. (See page 2-9.)
TYPES OF SERVICE
TELEPHONE COMPANY
PROCEDURES
IFPROBLEMS ARISE
NOTE: An optional internal modem is available in models of the Synchrony sold in the United States and
Canada. If your model does not have this feature, you can connect the Synchrony to an external modem.
The following statements apply to use of the Synchrony with a modem through U.S. telephone lines.

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1.7 Industry Canada Notice
NOTICE: The Industry Canada Label identifies certified equipment. This certification means that the equipment meets
telecommunications network protective, operational, and safety requirements as prescribed in the appropriate Terminal
Equipment Technical Requirements documents. The Department does not guarantee the equipment will operate to the
user’s satisfaction.
Before installing this equipment, users should make sure that it is permissible to be connected to the facilities of the local
telecommunications company. The equipment must also be installed using an acceptable method of connection. The
customer should be aware that compliance with the above conditions may not prevent degradation of service in some
situations.
Repairs to certified equipment should be coordinated by a representative designated by the supplier. Any repairs or
alterations made by the user to this equipment, or equipment malfunctions, may give the telecommunications company
cause to request the user to disconnect the equipment.
Users should ensure for their own protection that the electrical ground connections of the power utility, telephone lines
and internal metallic water pipe system, if present, are connected together. The precaution may be particularly important
in rural areas.
CAUTION: Users should not attempt to make such connections themselves, but should contact the appropriate electric
inspection authority, or electrician, as appropriate.
Ringer Equivalence Number (REN): The REN assigned to each terminal device provides an indication of the maxi-
mum number of terminals allowed to be connected to a telephone interface. The termination on an interface may consist
of any combination of devices subject only to the requirement that the sum of the Ringer Equivalence Numbers of all the
devices does not exceed 5.

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Chapter 2: Introduction
2.1 Synchrony Overview
NOTE: The Synchrony is available in two models. The BiPAP Synchrony Lab System is for use by
clinicians in a sleep lab setting. The BiPAP Synchrony Ventilatory Support System is for use in a
hospital or home setting. Throughout this manual, references to “Synchrony” will apply to both the
Lab System and the Ventilatory Support System unless otherwise noted.
The Synchrony, shown in Figure 2-1, is a low-pressure, electrically driven
ventilator system with electronic pressure control. The Synchrony’s pressure
controls are adjusted to deliver pressure support for patient ventilatory
assistance.
The Synchrony is intended to augment patient breathing by supplying
pressurized air through a patient circuit. It senses the patient’s breathing effort
by monitoring airflow in the patient circuit and adjusts its output to assist in
inhalation and exhalation. This assistance is provided by the administration of
two levels of positive pressure. During exhalation, pressure is variably positive
or near ambient. During inspiration, pressure is variably positive and always
higher than the expiratory level.
The Synchrony responds reliably to patient flow rates that indicate movement
to inhalation or exhalation, even in the presence of most normal leaks in the
patient circuit. Automatic adjustment of this trigger threshold in the presence of
leaks makes the system ideal for mask-applied ventilation assistance. The
patient-controllable Rise Time may enhance patient-ventilator synchrony and
patient comfort.
If the patient interface is disconnected, the Synchrony automatically reduces the
output flow to a low level. When the interface is replaced, therapy will typically
resume when the patient starts to breathe. If therapy does not resume when the
patient starts to breathe, the patient should press the RAMP/ALARM SILENCE
button to resume therapy.
A modem allows the patient to provide compliance data to the home care
provider with a few simple key presses. A communications port provides
communication to the Respironics Encore®or Encore Pro Data Management
Software.
The Synchrony operates in the following modes:
• Continuous Positive Airway Pressure (CPAP)
• Spontaneous (S)
• Spontaneous/Timed (S/T)
• Timed (T)
• Pressure Control (PC).
Figure 2-1 Synchrony
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NOTE: Throughout this manual, references to Bi-Flex apply only to the Synchrony Lab System.
WARNING: The Synchrony can operate on AC or DC power. The DC power option is not intended as a battery
backup during use of AC power.
CAUTION: When DC power is obtained from a vehicle battery, the Synchrony should not be used while the
engine of the vehicle is running. Damage to the vehicle may occur.

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The Spontaneous (S) mode of the Synchrony delivers bi-level pressure support.
The unit triggers to Inspiratory Positive Airway Pressure (IPAP) in response to
spontaneous inspiratory effort and cycles to Expiratory Positive Airway
Pressure (EPAP) during exhalation. Figure 2-2 illustrates the trigger and cycle
concepts.
In the Continuous Positive Airway Pressure (CPAP) mode, the Synchrony
delivers a continuous pressure support ventilation at one pressure level.
Inspiration
Trigger
Cycle
Expiration IPAP
Rise Time Inspiratory Time
EPAP
Figure 2-2 Triggering and Cycling in S Mode
2.2.1 CPAP MODE
2.2.2 S MODE
2.2 Modes of Operation
The level of pressure support (PS) delivered is determined by the difference
between the IPAP and EPAP settings (PS = IPAP - EPAP).
The Synchrony Lab System provides the Bi-Flex feature in S mode. The Bi-
Flex attribute adjusts therapy by inserting a small amount of pressure relief
during the latter stages of inspiration and during active exhalation (the
beginning part of exhalation). In the following diagram, the bold lines represent
Bi-Flex in comparison to the dashed line representing normal BiPAP therapy.
Bi-Flex levels of 1, 2, or 3 progressively reflect increased pressure relief that
will take place at the end of inspiration and at the beginning of expiration.
Figure 2-3 Bi-Flex in Comparison to Traditional Bi-level Therapy
Bi-Flex
IPAP
EPAP
Time
BiPAP
Bi-Flex 1
2
3

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2.2.3 S/T MODE The Spontaneous/Timed (S/T) mode of the Synchrony is similar to the S mode,
except that it also can deliver a machine-triggered breath if the patient does not
spontaneously breath within a set time.
The S/T mode ensures that patients will receive a minimum number of breaths
per minute based on the Rate setting. If the patient fails to initiate an inspiration
within the interval determined by the Rate control, the unit triggers a timed (or
machine-triggered) breath resulting in a pressure-control (pressure-limited,
time-cycled) breath at the set IPAP level. The rate of timed breaths is
adjustable. The duration of each timed breath is controlled by an Inspiratory
Time control. See Figure 2-4 for an example of patient-triggered and machine-
triggered breaths.
Figure 2-4 Example of Patient-Triggered and Machine-Triggered Breaths
Vol (ml)
P (cm H2O)
Time Interval
Exceeds Rate Setting
(approx. 6 sec)
11 1
1
2
11 2
1 = Spontaneously-triggered pressure support breaths.
2 = Time-triggered, pressure-limited, time-cycled breath.
IPAP = 14 cm H2O
EPAP = 6 cm H2O
Rate = 10 BPM
PS = 8 cm H2O
Example:
2.2.4 PRESSURE CONTROL
MODE The Pressure Control (PC) mode is similar to the S/T mode, except that all
breaths are machine-cycled. The PC mode is a pressure-limited, machine- or
patient-triggered, time-cycled mode. Therefore, the inspiratory pressure may be
triggered by the patient or by the Synchrony, but IPAP will be pressure-limited
with a set cycle time determined by the Inspiratory Time control.
2.2.5 TIMED MODE The Timed (T) mode provides mandatory pressure assist with bi-level
pressures. All breaths are machine-triggered and machine-cycled; the patient’s
breathing rate has no effect on the machine rate or pressure levels. The trigger
to IPAP is determined by the Rate control, and the cycle time is determined by
the Inspiratory Time control.

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Table 2-1 summarizes the initiation of triggers and cycles for each bi-level
mode.
2.2.6 MODE SUMMARY
Mode Trigger Limit Cycle
S Patient Pressure Patient or Device
S/T Patient or Machine Pressure Patient or Device
PC Patient or Machine Pressure Device
T Machine Pressure Device
Table 2-1 Initiation of Triggers and Cycles for Synchrony Modes
2.3 Digital Auto-Trak
Sensitivity™
A microprocessor monitors the total flow of the patient circuit and calculates
patient flow values.
1. Leak Estimation—Average and Parabolic
The Synchrony uses two leak estimation algorithms. A conservation of mass
algorithm is used to compute the average leak for a given pressure support
relationship. This average leak is used when large leak variations are present in
the system. Average leak is a high estimate during EPAP pressure and a low
estimate during IPAP pressure.
A better leak estimate, enabled by the digital system, is the parabolic leak
algorithm. Parabolic leak is proportional to the square of the patient pressure;
therefore, the leak estimate is correlated to the changing patient pressure. Both
algorithms include unintentional circuit leak and are averaged over several
breaths.
2. Patient Flow
The total circuit flow is comprised of the circuit leak and the patient flow. The
calculated patient flow is the total flow minus the circuit leak. Patient flow is a
primary input into the triggering and cycling mechanisms.
2.3.1 LEAK TOLERANCE
An important characteristic of the Synchrony is its ability to recognize and
compensate for unintentional leaks in the system and to automatically adjust its
trigger and cycle algorithms to maintain optimum performance in the presence
of leaks. This feature is known as Digital Auto-Trak Sensitivity. The
following sections examine this function in detail by describing the leak
tolerance function and sensitivity.
2.3.2 SENSITIVITY An essential feature of the Synchrony while operating in the S, S/T, and PC
modes is its ability to effectively sense spontaneous breathing efforts, which
causes the ventilator to trigger to IPAP and cycle to EPAP. Because no preset
sensitivity threshold can assure patient and machine synchrony with changing
breathing efforts and circuit leaks, the Synchrony continuously tracks patient
breathing patterns and automatically adjusts sensitivity thresholds to ensure
optimum sensitivity as breathing patterns change or as circuit leaks change.
The algorithms used to ensure optimum sensitivity are the Volume Trigger,
Shape Signal, and the Spontaneous Expiratory Threshold (SET).

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The volume trigger is one method used to trigger IPAP during spontaneous
breathing in the S, S/T, and PC modes. The volume trigger threshold is 6 cc of
accumulated patient inspiratory volume. When patient effort generates
inspiratory flow causing 6 cc of volume, IPAP is triggered.
The shape trigger/cycle is another method used to trigger IPAP and/or cycle
from IPAP to EPAP during spontaneous breathing in the S, S/T, and PC modes.
This method continuously tracks patient inspiratory and expiratory flow and
adjusts the spontaneous trigger and cycle thresholds for optimum sensitivity.
The Shape Signal appears as a shadow image of the patient’s actual flow. The
shape signal functions as a sensitivity threshold at either inspiration or
expiration. When the patient’s flow rate crosses the shape signal the unit
changes pressure levels. Figure 2-5 illustrates how the shape signal is
superimposed onto the actual waveform to trigger and cycle off IPAP.
The shape signal is created by offsetting the signal from the actual patient flow
by 15 L/min and delaying it for a 300 msec period. This intentional delay
causes the shape signal to be slightly behind the patient’s flow rate. A sudden
change in patient flow will cross the shape signal, causing the pressure level to
change.
Tracking the patient’s flow pattern with the Shape Signal provides a sensitive
mechanism to trigger to IPAP or cycle to EPAP in response to changing
breathing patterns and circuit leaks.
Figure 2-5 Shape Signal
Shape Trigger/Shape Cycle
(EPAP to IPAP)
(IPAP to EPAP)
Volume Trigger
(EPAP to IPAP)
Shape
Signal
IPAP
EPAP
Crossover
Point
Cycle to
EPAP
Crossover
Point
Trigger to
IPAP
Estimated
Patient
Flow
PRESSURE
FLOW

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Spontaneous
Expiratory
Threshold
PRESSURE
FLOW
EPAP
IPAP
A second method used to cycle off IPAP during spontaneous breathing in the
S, S/T, and PC modes is called Spontaneous Expiratory Threshold (SET). The
SET rises in proportion to the inspiratory flow rate on each breath. When the
Spontaneous Expiratory Threshold (SET) and actual patient flow value are
equal, the unit cycles to EPAP.
A maximum IPAP time of 3.0 seconds acts as a safety mechanism to limit the
time spent at the IPAP level during spontaneous breathing in the S, S/T, and PC
modes. Once the time limit is reached, the unit automatically cycles off IPAP
to the EPAP level.
As flow begins to decrease during IPAP, a flow reversal can occur due to a
large leak around the mask or because the patient’s mouth is open. When the
Synchrony unit senses this flow reversal, the unit automatically cycles to the
EPAP level.
The sensitivity criteria for spontaneous breathing in the S, S/T, and PC modes
can be summarized as follows:
Spontaneous Trigger to IPAP
A transition from EPAP to IPAP will occur when one of the following
conditions is met:
• Patient flow exceeds the shape signal
• 6 cc inspired patient volume
Cycle to EPAP
The transition from IPAP to EPAP will occur when one of the following
conditions is met:
• Patient flow is less than the shape signal
• Spontaneous Expiratory Threshold (SET) is achieved
• A 3.0 second maximum IPAP time has occurred (safety feature)
• Flow reversal occurs during IPAP (safety feature)
Figure 2-5 Spontaneous Expiratory Threshold
Spontaneous Expiratory
Threshold
(IPAP to EPAP)
Maximum IPAP Time
(IPAP to EPAP)
Summary
Flow Reversal
(IPAP to EPAP)