Respironics Bipap Vision User Manual
®®®
Clinical Manual
®
TM
Clinical
Manual
BiPAP systems are the subject of one or more of U.S. Patents #5148802, #5239995, #5313937,
#5433193, Canadian Patent #2, 024, 477, European Patent #EP0425092, German Patent #69021681.508, and other pending U.S. and foreign patents. BiPAP, Harmony, Plateau, Whisper Swivel, Comfort
Flap, Spectrum, Monarch, Softcap, Quick Clip, Oasis, and Auto-Trak Sensitivity are registered trademarks of Respironics, Inc.
© 2000 Respironics, Inc. All rights reserved.
Contents
Chapter 1: Introduction..........................................................................................1-1
1.1 Vision Overview.................................................................................................1-1
1.2 Manual Overview...............................................................................................1-2
1.3 Symbol Key........................................................................................................1-3
1.4 Product Support..................................................................................................1-4
Chapter 2: Warnings, Cautions, and Notes...........................................................2-1
2.1 Warnings.............................................................................................................2-1
2.3 Notes...................................................................................................................2-4
2.2 Cautions..............................................................................................................2-4
2.4 Important Information Concerning CO
2.5 Intended Use.......................................................................................................2-6
2.6 Contraindications ...............................................................................................2-6
2.7 Patient Cautions..................................................................................................2-6
2.8 Invasive Applications ......................................................................................... 2-7
Chapter 3: Principles of Operation........................................................................3-1
3.1 Introduction ........................................................................................................3-1
3.2 Design and Operation.........................................................................................3-2
3.2.1 ELECTRONICS SYSTEM ......................................................................................................... 3-2
3.2.2 O
3.2.3 P
3.2.4 S
3.2.5 F
XYGEN MODULE ............................................................................................................... 3-4
NEUMATIC SYSTEM............................................................................................................. 3-5
TANDBY MODE .................................................................................................................. 3-6
LOW ANALYSIS ..................................................................................................................3-7
3.3 BiPAP® Auto-T rak Sensitivity™........................................................................3-8
3.3.1 LEAK TOLERANCE ............................................................................................................... 3-8
3.3.2 S
ENSITIVITY ........................................................................................................................ 3-9
3.4 Description of System Alarms..........................................................................3-12
3.4.1 CHECK VENTILATOR .......................................................................................................... 3-12
3.4.2 V
3.4.3 E
ENTILATOR INOPERATIVE .................................................................................................. 3-12
XHALATION PORT ALARM .................................................................................................3-12
3.5 User Interface ...................................................................................................3-13
3.6 Exhalation Port Test .........................................................................................3-14
Rebreathing ........................................2-5
2
i
Chapter 4: Controls and Displays ..........................................................................4-1
4.1 Overview ............................................................................................................4-1
4.2 Patient Circuit Connections................................................................................4-2
4.3 Adjustment Knob ...............................................................................................4-2
4.4 Soft Keys............................................................................................................4-3
4.4.1 SOFT KEY OPERATION ............................................................................................................4-3
4.4.2 S
OFT KEY DESCRIPTORS ......................................................................................................4-3
4.5 Hard Keys—Operational....................................................................................4-4
4.5.1 MONITORING HARD KEY ..................................................................................................... 4-4
4.5.2 P
4.5.3 M
4.5.4 A
ARAMETERS HARD KEY ..................................................................................................... 4-5
ODE HARD KEY ............................................................................................................... 4-5
LARMS HARD KEY ............................................................................................................4-5
4.6 Hard Keys—Graph Control ...............................................................................4-6
4.6.1 SCALE HARD KEY ............................................................................................................... 4-6
4.6.2 F
REEZE/UNFREEZE HARD KEY .............................................................................................4-6
4.7 Hard Keys—Alarm ............................................................................................4-7
4.7.1 ALARM SILENCE HARD KEY ................................................................................................ 4-7
4.7.2 A
LARM RESET HARD KEY ...................................................................................................4-7
4.8 Ventilator W arning Indicators ............................................................................4-8
4.8.1 VENTILA T OR INOPERATIVE INDICATOR.................................................................................... 4-8
4.8.2 C
HECK VENTILATOR INDICATOR ............................................................................................ 4-8
4.9 Graphic Display..................................................................................................4-9
4.9.1 MODE/MESSAGE AREA ........................................................................................................ 4-9
4.9.2 G
4.9.3 D
4.9.4 D
RAPHIC DISPLAY AREA ...................................................................................................... 4-9
ATA DISPLAY AREA ...........................................................................................................4-9
ATA VALUES ................................................................................................................... 4-10
4.10 Rear Panel ........................................................................................................4-13
4.10.1 POWER ENTRY MODULE ..................................................................................................... 4-13
4.10.2 S
4.10.3 O
4.10.4 D
4.10.5 N
4.10.6 G
TART/STOP SWITCH ..........................................................................................................4-13
XYGEN MODULE ............................................................................................................. 4-14
IAGNOSTIC CONNECTOR ...................................................................................................4-14
URSE CALL/REMOTE ALARM CONNECTOR ......................................................................... 4-14
ROUNDING STUD ............................................................................................................. 4-14
4.11 Internal Alarm Battery......................................................................................4-14
4.12 Parameter Retention .........................................................................................4-14
4.13 Options.............................................................................................................4-15
Chapter 5: Operational Flow Charts.....................................................................5-1
5.1 Start-up Flow Chart............................................................................................5-1
5.2 Change Mode Flow Chart ..................................................................................5-2
5.3 Modify Parameters Flow Chart..........................................................................5-3
5.4 Modify Alarms Flow Chart ................................................................................5-4
ii
Chapter 6: Setting Up and Starting the Vision System........................................6-1
6.1 Setting Up the Vision System.............................................................................6-1
6.2 Starting the Vision System .................................................................................6-3
6.3 Changing the Language......................................................................................6-7
Chapter 7: Performance Verification.....................................................................7-1
Chapter 8: CPAP Mode...........................................................................................8-1
8.1 Overview ............................................................................................................8-1
8.2 Changing to the CPAP Mode .............................................................................8-2
8.3 Modifying Parameters in the CPAP Mode .........................................................8-4
8.4 Modifying Alarm Parameters .............................................................................8-6
Chapter 9: S/T Mode ...............................................................................................9-1
9.1 Overview ............................................................................................................9-1
9.2 Changing to the S/T Mode .................................................................................9-3
9.3 Modifying Parameters in the S/T Mode.............................................................9-7
9.4 Modifying Alarm Parameters .............................................................................9-9
Chapter 10: Options Screen..................................................................................10-1
10.1 Overview ..........................................................................................................10-1
10.2 Using the Options Screen.................................................................................10-2
10.2.1 ERROR MESSAGES ............................................................................................................. 10-2
10.2.2 T
10.2.3 D
10.2.4 C
10.2.5 R
10.2.6 A
10.2.7 T
10.2.8 R
ESTING THE ALARMS ........................................................................................................ 10-3
ISPLAYING SYSTEM INFORMATION .....................................................................................10-4
HANGING THE GRAPHIC DISPLAY ......................................................................................10-4
ESETTING THE TIME AT PRESSURE ..................................................................................... 10-5
DJUSTING THE DISPLAY .................................................................................................... 10-5
OTAL OPERATING TIME .................................................................................................... 10-6
ETURNING TO THE MONITORING SCREEN ...........................................................................10-6
Chapter 11: Modifying Graphic Displays ........................................................... 11-1
11.1 Overview .......................................................................................................... 11-1
11.2 Modifying the Display Graph Scales ............................................................... 11-2
11.2.1 MODIFYING THE SCALES .................................................................................................... 11-2
11.2.2 R
ETURNING TO THE MONITORING SCREEN ........................................................................... 11-4
11.3 Summary of Display Graph Scale Ranges and Increments..............................11-4
11.4 Freezing and Unfreezing the Graphs................................................................ 11-5
Chapter 12: Alarms and Troubleshooting...........................................................12-1
12.1 Alarms Overview .............................................................................................12-1
12.1.1 ALARM INDICATIONS .......................................................................................................... 12-2
12.1.2 A
LARM SILENCE AND RESET ..............................................................................................12-2
12.2 Alarms ..............................................................................................................12-3
12.3 Mask Discomfort and Corrective Actions......................................................12-10
iii
Chapter 13: Oxygen Delivery with the Vision Ventilator...................................13-1
13.1 Overview ..........................................................................................................13-1
13.2 Oxygen Module ................................................................................................13-2
Chapter 14: Cleaning and Routine Maintenance ...............................................14-1
14.1 Overview ..........................................................................................................14-1
14.2 Cleaning the Vision Unit ..................................................................................14-1
14.2.1 CLEANING THE FRONT PANEL .............................................................................................14-1
14.2.2 C
LEANING THE ENCLOSURE ................................................................................................ 14-1
14.3 Replacing the Inlet Filter ..................................................................................14-1
14.4 Changing the System Fuses..............................................................................14-3
14.5 Voltage Selection..............................................................................................14-3
14.6 Preventive Maintenance ...................................................................................14-3
14.7 Internal Battery Maintenance ...........................................................................14-4
14.7.1 BATTERY FUNCTION ........................................................................................................... 14-4
14.7.2 L
14.7.3 C
OW BATTERY CONDITION .................................................................................................14-4
HARGING THE INTERNAL BATTERY..................................................................................... 14-5
Chapter 15: Accessories ........................................................................................15-1
15.1 Circuit Configurations ......................................................................................15-1
15.1.1 STANDARD NONINVASIVE CIRCUIT ......................................................................................15-2
15.1.2 N
15.1.3 I
ONINVASIVE CIRCUIT WITH HEATED HUMIDIFIER ................................................................ 15-2
NVASIVE CIRCUIT ..............................................................................................................15-3
15.2 Circuits and Accessories...................................................................................15-4
15.3 Exhalation Ports................................................................................................15-4
15.4 Masks and Related Accessories ........................................................................15-4
15.5 Humidifiers.......................................................................................................15-4
Chapter 16: Specifications ....................................................................................16-1
ENVIRONMENTAL ..........................................................................................................................16-1
P
HYSICAL ..................................................................................................................................... 16-1
E
LECTRICAL ................................................................................................................................. 16-1
P
RESSURE .....................................................................................................................................16-1
C
ONTROL ACCURACY .................................................................................................................... 16-2
ISPLAY ACCURACY...................................................................................................................... 16-2
D
T
RIGGER ......................................................................................................................................16-2
O
XYGEN MODULE INLET ...............................................................................................................16-2
I
NTERNAL BATTERIES .................................................................................................................... 16-2
I
NLET FILTER ................................................................................................................................16-2
URSE CALL/REMOTE ALARM CONNECTOR .................................................................................... 16-2
N
C
ONTROL RANGES & INCREMENTS ................................................................................................. 16-3
D
ISPLAY RANGES & INCREMENTS .................................................................................................. 16-4
CO
REBREATHING CHARTS—NON-INVASIVE APPLICATIONS ............................................................ 16-5
2
CO
REBREATHING CHARTS—INVASIVE APPLICATIONS .................................................................... 16-7
2
iv
Chapter 1: Introduction
1-1
1.1 Vision Overview The BiPAP
controlled positive pressure ventilatory assist system. The Vision system
incorporates a user interface with multifunction keys, real time graphic displays, and integral patient and system alarms. Figure 1-1 shows the contents of
the Vision package.
The system operates in the Continuous Positive Airway Pressure (CPAP) and
Pressure Support (S/T) modes.
The Vision ventilator contains a variety of integrated safety and self-diagnostic
features. All system functions are checked at start-up and during operation.
Pressure regulation is achieved by monitoring proximal airway pressure and
adjusting flows accordingly to ensure that the set pressure equals the proximal
pressure.
®
Vision ventilator, shown in Figure 1-1, is a microprocessor-
EPAP
cm H
Rate
12
BPM
V
T
1000
IPAP
15
cm H
O
2
6
O
2
Vol (ml)
Flow (L/min)
ml
MinVent
MODE: S/T MONITORING
P (cm H
O)
2
PS = 9
%O
2
cm H
2
O
55
%
14
L/min
PIP
15
cm H
O
2
Options
The First Name In Innovative Respiratory Care
Vision Ventilator Vision Clinical Manual
Figure 1-1. Contents of the Vision Package.
Clinical
Manual
NOTE: This manual is for use only in the United States and its territories.
BiPAP Vision Clinical Manual
1-2
1.2 Manual Overview
This manual describes the Vision ventilator and its operation.
Chapter 1 Introduces the Vision unit.
Chapter 2 Lists the Warnings, Cautions, Notes and
Contraindications for the Vision ventilator. Also contains
information concerning rebreathing.
Chapter 3 Describes the theory of operation.
Chapter 4 Provides an overview of the output, controls, and
graphic display.
Chapter 5 Provides operational flow charts as an introduction andquick
reference.
Chapter 6 Provides the set up and start-up procedures for the
Vision ventilator.
Chapter 7 Provides the performance verification procedure.
Chapter 8 Details the operation of the CPAP Mode.
Chapter 9 Details the operation of the S/T Mode.
Chapter 10 Details the Options Screen.
Chapter 11 Describes the graphic displays, including modification of
display scales.
Chapter 12 Describes the alarms and alarm conditions and provides
troubleshooting guidelines for mask discomfort.
Chapter 13 Provides information for adding oxygen to the Vision patient
circuit.
Chapter 14 Provides cleaning instructions and routine maintenance
procedures.
Chapter 15 Describes the accessories and circuits to be used with the
Vision ventilator.
Chapter 16 Lists the Vision ventilator specifications.
NOTE: Occasionally, cosmetic changes may be made to the product that do not affect the performance or
specifications of the product. These kinds of changes do not warrant a reprinting of this manual.
Illustrations are for reference only.
BiPAP Vision Clinical Manual
1-3
1.3 Symbol Key
Symbol Meaning
MONITORING
Vent Inop
Check Vent
The following symbols are used on the Vision unit:
Ventilator Inoperative
Check Ventilator
Audible Alarm Silence
Alarm Reset
Display the Monitoring Screen
PARAMETERS
ALARMS
SCALE
FREEZE/UNFREEZE
PRESSURE
MAIN POWER
Display the Parameters Screen
Display the Change Alarms Screen
Adjust the graphic scales
Freeze or Unfreeze the graphic display
Attachment port for proximal pressure line
Indicates unit is connected to power source
Adjustment
Type BF
Fuse
Attention, consult
accompanying documents
BiPAP Vision Clinical Manual
1-4
1.4 Product Support
You may contact Respironics, Inc. with any questions or for product support at
the following location:
BiPAP Vision Clinical Manual
Chapter 2: Warnings, Cautions, and Notes
WARNING: Indicates the possibility of injury to the patient or the operator.
CAUTION: Indicates the possibility of damage to the device.
NOTE: Places emphasis on an operating characteristic.
2-1
2.1 Warnings
• This manual serves as a reference. The instructions in this manual are
not intended to supersede the institution’s protocol regarding the use of
the Vision ventilator.
• The operator must verify that all gas connectors have color codes in
accordance with EN 60601-1/A13:1995.
• The following BiPAP Vision System operational characteristics differ
from conventional ventilators as described in ASTM F 1100 and
should be reviewed before use:
• The BiPAP Vision provides continuous positive airway pressure
(CPAP) and positive pressure ventilation and is indicated for
assisted ventilation. This system does not provide ventilation
with guaranteed tidal volume delivery. Patients requiring
ventilation at predetermined tidal volumes are not candidates for
pressure support or pressure-limited ventilation.
• The BiPAP Vision requires an intentional leak port instead of an
actively controlled exhalation valve to remove exhaled gases
from the circuit. Therefore, specific masks and circuits using an
intentional leak port are required for normal operation. The
pressurized air from the Vision causes a continuous flow of air to
exhaust from the leak port, flushing exhaled gas from the circuit.
The machine should be turned on and the intentional leak port
should be checked, both visually and using the exhalation port
test, before application. Use only Respironics-specified circuit
accessories.
• The continuous flow of air through the leak port flushes exhaled
gases from the circuit. The ability to completely exhaust exhaled
gas from the circuit is dependent upon the EPAP setting and I:E
ratio. At low EPAP pressures or with short expiratory times (i.e.,
high breathing rates) the leak rate through the intentional leak
port may be inadequate to clear all exhaled gas from the circuit.
Some rebreathing may occur.
• The Vision ventilator is an assist ventilator and is intended to augment
the ventilation of a spontaneously breathing patient. It is not intended
to provide the total ventilatory requirements of the patient.
• The Vision ventilator is intended for use with a Respironics, Inc.
patient circuit only. See Chapter 15 for approved patient circuit
configurations and accessories.
BiPAP Vision Clinical Manual
2-2
Warnings (continued)
• Proper operation of the Plateau™ Exhalation Valve or any other
exhalation port used with the BiPAP Vision must be regularly verified
by inspection during use. Occlusion or partial occlusion of the
exhalation port may result in asphyxia.
• To reduce the risk of contamination, a low resistance main flow
bacteria filter must be placed in-line between the unit and the patient.
• All patient settings must be determined via appropriate assessment and
monitoring as determined by the prescribing physician. Delivered
pressures must be monitored at the patient connection with the unit
cycling to validate pressure delivery.
• The Vision ventilator is not suitable for use in the presence of a
flammable anesthetic mixture with air or with oxygen or nitrous oxide.
• Oxygen supports combustion. Oxygen should not be used while
smoking or in the presence of an open flame.
• The functionality of this machine may be adversely affected by the
operation of high frequency (diathermy) equipment, defibrillators, or
short wave therapy equipment in the general vicinity.
• When the Oxygen Module is in use, the Vision ventilator will display
the set oxygen concentration, which may not be the actual oxygen
concentration delivered to the patient. An external oxygen analyzer,
added to the patient circuit, is recommended to monitor delivered
oxygen concentrations. See Chapter 13 for details concerning the use
of oxygen with the Vision ventilator.
• When using the Oxygen Module, the operator must verify that the
correct supply gas (O2) is connected to the O2 inlet.
• Do not use antistatic or electrically conductive hoses or tubing with the
Vision system.
• In the event of a power failure, an audible and visual alarm will
activate. Disconnect the Vision ventilator from the patient immediately. As in 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.
• The air flow for breathing produced by this device can be as much as
10 °F (5.5 °C) higher than room temperature. Caution should be
exercised if the room temperature is greater than 95 °F (35 °C).
• If the “Ventilator Inoperative” indicator illuminates, immediately
discontinue use, disconnect the patient circuit from the patient, and
contact Respironics, Inc. or an authorized service center.
• When the Vision ventilator is used with a humidifier, always position
the humidifier lower than both the ventilator and the patient.
• Never attach oxygen tubing or any positive pressure source to the
Pressure Port on the front panel of the Vision ventilator.
BiPAP Vision Clinical Manual
2-3
Warnings (continued)
• If you detect any unexplained changes in the performance or displays
of the Vision unit, seek the assistance of a Respironics-approved
service person.
• Repairs and adjustments must be performed by Respironics-authorized
service personnel ONLY. Service done by inexperienced, unqualified
personnel or installation of unauthorized parts could cause injury,
invalidate the warranty, or result in costly damage.
• To avoid electrical shock, disconnect the electrical supply before
changing the fuses.
• For continued protection against risk of fire, replace fuses with those
of the same type and rating only.
• Electrical cords and cables should be periodically inspected.
• To avoid electrical shock, unplug the Vision unit before cleaning it.
• The Nurse Call/Remote Alarm feature should be considered a backup
to the Vision unit’s primary alarm system. Do not rely solely on the
Nurse Call/Remote Alarm feature.
BiPAP Vision Clinical Manual
2-4
2.2 Cautions
• Federal law (U.S.) restricts this device to sale by or on the order of a
physician.
• For pressure monitoring, use only the pressure tubing provided with
the Respironics circuit.
• Take care to avoid exposure of the Vision ventilator to temperatures at
or near the extremes of those specified in Chapter 16. If exposure to
such temperatures has occurred, the unit should be allowed to come to
room temperature before being turned on.
• The unit must be positioned on its base for proper operation.
• Always use an inlet filter when the Vision ventilator is operating.
• If using the Oxygen Module, do not exceed 100 psig oxygen supply
pressure.
• Connections to the rear-panel diagnostic connector must be made by
authorized service personnel only.
• Before making any connection to the rear-panel nurse call connector,
verify that the equipment being connected does not violate the
electrical specifications noted in Chapter 16.
2.3 Notes
• The Inspiratory Positive Airway Pressure (IPAP) and Expiratory
Positive Airway Pressure (EPAP) controls are coupled. The unit will
not deliver an EPAP level that is higher than the set IPAP level.
• This device contains a rechargeable NiCAD battery which is used by
the alarms in the event of a power failure.
Additional Warnings, Cautions, and Notes are located throughout
this manual.
BiPAP Vision Clinical Manual
2.4 Important Information Concerning CO2 Rebreathing
As with any ventilator used for mask ventilation, there are conditions under
which patient CO2 rebreathing can occur while using the Respironics BiPAP
Vision ventilator. The following guidelines are provided to alert the user to
these conditions and to suggest methods for reducing the potential for CO
rebreathing. If rebreathing is a significant concern for a particular patient and
these guidelines are not sufficient to acceptably reduce the potential for CO
rebreathing, an alternative means of ventilation should be considered.
• Never leave the mask on the patient while the BiPAP Vision unit is not
operating. When the BiPAP Vision unit is not operating, the exhalation port (Respironics Disposable Circuit, Whisper Swivel, or Plateau
Exhalation Valve) does not allow sufficient exhaust to eliminate CO
from the circuit. Substantial CO2 rebreathing will occur.
• Patient monitoring should be performed initially and with each change
in ventilator settings, circuit configuration, or patient condition to
detect changes in respiratory status that may indicate excessive CO
rebreathing
• In general, as pressure decreases, the potential for CO2 rebreathing
increases. Lower pressures produce less flow through the exhalation
port, which may not purge all CO2 from the circuit to prevent
rebreathing. Higher tidal volumes further increase the volume of CO
rebreathed by the patient in such circumstances. Testing performed
with the BiPAP Vision demonstrates that, under certain conditions,
CO2 rebreathing can occur. See Chart 1 in Chapter 16.
2-5
2
2
2
2
2
• In general, as inspiratory time increases, the potential for CO
2
rebreathing increases. A higher inspiratory time decreases exhalation
time, allowing less CO2 to be purged from the circuit before the next
cycle. In such circumstances, higher tidal volumes further increase the
volume of CO2 rebreathed by the patient. Testing performed with the
BiPAP Vision system demonstrates that under certain conditions, when
approaching an I:E ratio of 1:1, CO2 rebreathing may occur. See Chart
2 in Chapter 16.
• The Plateau Exhalation Valve reduces the level of CO2 rebreathing
compared to the level associated with the Whisper Swivel when low
pressures, long inspiratory time, and/or large tidal volumes are present.
Accordingly, Respironics recommends the Plateau Exhalation Valve
be used instead of the Whisper Swivel to help reduce CO2 rebreathing
in such situations. See Charts 1 and 2 in Chapter 16.
• Reducing deadspace can also lower potential CO2 rebreathing. Chart 3
in Chapter 16 provides the approximate total volume of each of the
patient interface accessories that can be used with the BiPAP Vision
ventilator. Note that except for the Respironics Mouthpiece Adapter,
the deadspace volume will be reduced when the mask is placed on the
patient’s face. Nevertheless, Chart 3 in Chapter 16 can be helpful in
selecting an appropriate patient interface to reduce the amount of
deadspace in the patient circuit. For comparison purposes, note that
the testing which produced the data in Charts 1 and 2 was conducted
using a medium nasal mask.
BiPAP Vision Clinical Manual
2-6
2.5 Intended Use
2.6 Contraindications
The Vision ventilator is intended for use in a hospital or alternate care setting as
an assist ventilator for the treatment of appropriate adult patients (30 Kg or
greater) with acute respiratory failure, acute or chronic respiratory
insufficiency, or sleep apnea syndrome.
The use of the Vision ventilator is contraindicated on patients with severe
respiratory failure without a spontaneous respiratory drive.
The use of the Vision ventilator for noninvasive positive pressure therapy may
be contraindicated on patients:
• incapable of maintaining life-sustaining ventilation in the event of a
brief circuit disconnection or loss of therapy,
• 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,
2.7 Patient Cautions
• 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 Chapter 12 for appropriate action.
• The following are potential side effects of noninvasive positive
pressure therapy:
Ear discomfort
Conjunctivitis
Skin abrasions due to noninvasive interfaces
Aerophagia (gastric distention)
BiPAP Vision Clinical Manual
2-7
2.8 Invasive Applications
The Vision ventilator may be used to provide invasive ventilation to appropriate patients. The following guidelines should be considered prior to use:
• The Vision ventilator is an assist ventilator and is intended to augment
the ventilation of a spontaneously breathing patient. It is not intended
to provide the total ventilatory requirements of the patient.
• The Vision uses a single limb circuit and requires an intentional leak
port instead of an actively controlled exhalation valve to remove
exhaled gases from the circuit. Therefore, the Respironics invasive
circuit and accessories illustrated in Chapter 15 are required for
normal operation.
• A heated humidification system should always be used during
invasive applications. See Chapter 15 for recommendations concerning humidification.
• In general, as pressure decreases, the potential for CO2 rebreathing
increases. Lower pressures produce less flow through the exhalation
port, which may not purge all CO2 from the circuit to prevent
rebreathing. The Plateau™ Exhalation Valve reduces the level of CO
rebreathing compared to the level associated with the Whisper
Swivel® when low pressures are present. Accordingly, if CO
rebreathing is a concern, use the Plateau Exhalation Valve instead of
the Whisper Swivel at low EPAP levels.
2
2
• Occlusion of the exhalation port could lead to patient asphyxia.
Always visually inspect the exhalation port and perform the Exhalation Port Test prior to patient use as described in this manual. The
Exhalation Port Test will allow the BiPAP Vision to identify an
occluded exhalation port prior to administering therapy. Also, the
BiPAP Vision has an exhalation port alarm which is intended to
identify a low flow condition (which could be caused by a partial or
total occlusion of the exhalation port) during therapy. The exhalation
port alarm is not a substitute for operator vigilance in ensuring that the
exhalation port remains clear at all times. Periodically check the
exhalation port during therapy.
BiPAP Vision Clinical Manual
2-8
BiPAP Vision Clinical Manual
Chapter 3: Principles of Operation
This chapter describes the BiPAP Vision ventilator design and methods of operation. System and patient safety functions are described as well.
3-1
3.1 Introduction
The BiPAP Vision ventilator is a microprocessor-controlled assist ventilator
that operates in either a Continuous Positive Airway Pressure (CPAP) Mode or
a Spontaneous/Timed (S/T) Mode.
The BiPAP Vision ventilator draws ambient air through an inlet filter, pressurizes it in the blower assembly, and then regulates it at the preset pressure level.
An oxygen module can provide a controlled source of supplemental oxygen, up
to 100%, to the patient. The ventilator continuously monitors machine pressure
(set pressure) against proximal airway pressure (patient pressure) to ensure
accurate and responsive delivery of pressure, despite most circuit leaks.
The unique design and operation of the ventilator makes it especially suited for
mask applications. Designed with the BiPAP® Auto-Trak Sensitivity™ feature
that automatically adjusts to changing circuit conditions, the ventilator is
capable of ensuring optimum patient-ventilator synchrony despite changes in
breathing patterns and circuit leaks.
The patient circuit consists of a smooth inner lumen 22 mm ID tube, a proximal
pressure line, and an intentional leak port known as the exhalation port. The
exhalation port continually exhausts gas from the circuit during inspiration and
expiration.
The BiPAP Vision ventilator incorporates a number of safety features and selfdiagnostic systems. All system internal functions are checked automatically at
startup and periodically throughout normal operation. Malfunctions of a
principal component or system are announced by audible and visual alarms.
Integrated patient alarms are provided and are announced on a message display
area, as well as with an audible tone.
A Liquid Crystal Display (LCD) video screen mounted on the front of the unit
provides the primary user interface for operation of the ventilator. The display
includes real time graphics for pressure, volume, and flow, control features,
calculated patient parameters, and alarm conditions. User interaction with the
device is accomplished by panel selections and rotation of the adjustment knob.
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3-2
3.2 Design and
Operation
3.2.1 ELECTRONICS SYSTEM
NOTE: Pressure generated by the
PAS is compensated to atmospheric
conditions (ATPS).
The modular system design employs subsystems, each of which provides a
specific function. Modules are used to expand the capability of a subsystem.
The major subystems and modules are shown in Figure 3-1.
AC
Inlet
Power
Switch
Power Supply
Sub-System
(PSS)
Main Controller
Sub-System
(MCS)
Display/Control
Sub-System
(D/CS)
Keypad and LCD
Blower
IPAP
15
cm H2O
EPAP
6
O
cm H
2
Rate
12
BPM
MODE: S/T MONITORING
P (cm H2O)
Vol (ml)
Flow (L/min)
V
T
1000
ml
MinVent
Pressure Air Flow
Sub-System
To MCS
%O
2
55
PS = 9
cm H2O
Options
PIP
15
cm H2O
14
L/min
(PAS)
Air Flow
Module
(AFM)
%
Air Filter
PVA
PVA
(pressure valve
(pressure valve
assembly
assembly)
Exhaust
Injection
O
2
AFM
(mass airflow
sensor)
Ambient
Air
Point
KEY
Power Distribution
Data Flow
Air Flow
Figure 3-1. BiPAP Vision Electronics and Air Flow Systems.
BiPAP Vision Clinical Manual
Patient Pressure
Tubing
Patient
Circuit
3-3
PSS
MCS
PAS
D/CS
AFM
PVA
The Power Supply Subsystem (PSS) provides DC power to the Vision unit
from an AC source.
The Main Controller Subsystem (MCS) performs all control, data acquisition,
and calculations required to deliver the user-selected parameters. In addition,
the MCS performs the startup test and is responsible for reporting all errors.
This subsystem may also be called the Main Control (MC) Board.
The Pressure Air Flow Subsystem (PAS) controls the blower and valves to
regulate gas flow into the patient circuit to maintain the preset pressure at the
patient connection. This subsystem may also be called the Pressure Control
(PC) Board.
The Display/Control Subsystem (D/CS) processes user input from the keyboard
and passes information to the MCS. The D/CS receives relevant display data
for the display screen from the MCS. This subsystem may also be called the
Display Control (DC) board.
The Air Flow Module (AFM), including the mass airflow sensor, provides
measurement of gas flow from the PAS, allowing the PAS to measure total
flow in order to maintain the preset pressure.
The Pressure Valve Assembly (PVA) regulates system flow and pressure. The
In Line Flow Restrictor Valve (ILFR) and the Pressure Regulation Valve
(PRV) make up this assembly.
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3-4
3.2.2 OXYGEN MODULE
The Oxygen Module regulates and proportions oxygen into the air from the
blower according to the oxygen concentration level set on the Parameters
screen. At settings of 30 percent oxygen or less the delivered oxygen percentage will be the set percentage ± 3, except that the delivered concentration will
not be below the concentration in air (21 percent). At set concentrations above
30 percent the error range is proportional to the set concentration, and the
possible range of inspired oxygen can be estimated as the set concentration
± 10 percent of the set concentration. The selectable concentration range is
from 21% to 100%.
The graph in Figure 3-2 represents the set oxygen concentration possible for a
given circuit flow. The higher the oxygen concentration settings, the higher the
oxygen flow rates required from the oxygen module and the lower the air flow
rate from the blower.
1.0
0.9
0.8
0.7
0.6
Oxygen Concentration
0.5
0.4
240210190170150130
Total Circuit Flow, L/min
Figure 3-2. Total Flow Available to Maintain
a Set Oxygen Concentration.
An “O2 Flow” alarm is activated if the oxygen inlet supply is lost. See Chapter
13 for further information concerning the alarm.
Refer to Chapter 12 for additional information concerning the use of oxygen
with the BiPAP Vision ventilator.
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3-5
3.2.3 PNEUMATIC SYSTEM
Figure 3-3 provides a representation of the method for generation, control and
delivery of therapy.
Air Filter
Ambient
Air
Blower
PVA
Exhaust
To PAS
Proximal Pressure
Line
To
Patient
O2 Injection
Point
AFM
(mass airflow
sensor)
Figure 3-3. The BiPAP Vision Pneumatic System.
Ambient air is drawn through the air inlet filter and pressurized in the blower
assembly. System flow and pressure are then regulated at the blower outlet by
the Pressure Valve Assembly (PVA). There are two valves in the valve
assembly that work in tandem to produce the desired pressure in the circuit.
During the IPAP phase, flow from the blower is directed through the patient
circuit at the preset pressure. During expiration and transition to the EPAP
phase, the PVA responds as necessary to allow excess flow to be exhausted
from the system to attain EPAP.
A pneumotach located in the Air Flow Module (AFM) is positioned after the
PVA and immediately before the machine outlet. The AFM monitors total gas
flow and machine pressure and transmits the data to the main controller system.
The proximal pressure is measured at the patient connection and compared to
the set pressure. The delivered pressure is thereby controlled and maintained at
the patient connection.
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3-6
3.2.4 S
TANDBY MODE
The Standby mode, activated when the Standby key on the Monitoring screen
is pressed, decreases the output flow to an idle state. This feature allows the
clinician to place the ventilator in Standby while performing mask fittings,
setting the prescription, etc. The Standby mode may be selected when no
patient is connected to the Vision ventilator.
When the Standby mode is activated, the graph display area is blanked and
STANDBY flashes in the middle of the screen. All measured parameters are
zeroed.
In the Standby mode, all patient alarms are deactivated. Only the Vent Inop and
CheckVent alarms are active. The following keys remain active:
• PARAMETERS
• MODE
• ALARMS
• Options
If you make any changes to the system (e.g., parameters changes, alarm
settings, etc.), the changes are effective when you exit the Standby mode.
The Standby mode is manually deactivated by pressing the Standby key a
second time. As a safety feature, the Standby mode is automatically deactivated
if the Vision senses that a patient is connected to the circuit and is triggering
spontaneous breaths.
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3-7
3.2.5 FLOW ANALYSIS
Vision
Unit
The accuracy and responsiveness of the system is maintained by continuous
analysis of the delivered flow. The flow measured at the Air Flow Module
(AFM) is analyzed to derive a signal proportional to the Total Flow Rate (V
in the patient circuit. This signal contains a component derived from the flow
delivered to the patient (Estimated Patient Flow Rate, [V
component derived from circuit leaks (Estimated Leak Flow Rate, [V
]) as well as a
est
leak
]).
Circuit leaks are comprised of intentional leak through the exhalation port as
well as any unintentional leaks that may be present in the circuit or at the
patient connection (V
= intentional + unintentional leaks).
leak
V
= V
tot
(Intentional + Unintentional)
Leak (V
est
leak
+ V
)
leak
)
tot
Total Flow (V
)
tot
Figure 3-4. Data Locations for Flow Analysis.
Patient
Flow
(V
est
)
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3.3 BiPAP® Auto-T rak
Sensitivity
3.3.1 LEAK TOLERANCE
™
An important characteristic of the BiPAP Vision ventilator 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 Auto-Trak Sensitivity. The following sections examine this function in detail by describing the
leak tolerance function and sensitivity.
Leak tolerance is the unit’s ability to respond to changes in leaks. The BiPAP
Vision ventilator uses two primary mechanisms to identify and adjust to leaks.
1. Expiratory Flow Rate Adjustment
At end expiration the total flow in the patient circuit should equal the baseline
leak (V
) which consists of intentional (exhalation port) and unintentional
leak
(mask, mouth) leaks. Once the unit has been in EPAP for 5 seconds, the total
flow is compared to the originally established value of V
. At this point, the
leak
Vision flow sensing circuit makes the assumption that the patient’s flow is zero,
so that the total circuit flow, V
Thus, under this condition of assumed zero patient flow, if V
V
, the BiPAP Vision will adjust its calculation of the baseline leak. Figure
leak
3-5 shows graphically how V
, should be equal to V
tot
is adjusted in the case of an increase in leak.
leak
leak
.
is not equal to
tot
ORIGINAL
BASELINE
(V
)
leak
Spontaneous Trigger
INSPIRATION
ADDITIONAL
LEAK
TOTAL FLOW
(V
)
tot
CYCLE TO EPAP
END EXPIRATION
5.0 SECONDS
Figure 3-5. Expiratory Flow Rate Adjustment.
NEW BASELINE
Adjustment of
(V
)
leak
BiPAP Vision Clinical Manual
2. Tidal Volume Adjustment
Inspiratory (VTI) and expiratory (VTE) tidal volumes are determined by the
estimated patient flow, and compared on a breath-by-breath basis. If the
measured volumes during inspiration differ from expiration, the difference in
volume is assumed to be due to an unintentional circuit leak. The baseline
(V
) is adjusted in the appropriate direction to reduce the difference in
leak
VTI - VTE on the next breath. This prevents abrupt changes in sensitivity based
on random changes in the breathing pattern, and allows the baseline (V
leak
) to
accommodate to the new breathing pattern.
Tidal volume adjustment can be observed on the tidal volume waveform graph
as illustrated in Figure 3-6.
Additional
Leak
Introduced
New
Baseline
3-9
3.3.2 SENSITIVITY
V
est
V
0
Volume
Adjustment
0
T
Figure 3-6. Tidal Volume Adjustment.
An essential feature of the BiPAP Vision ventilator while operating in the S/T
Mode 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 BiPAP Vision ventilator 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).
BiPAP Vision Clinical Manual
3-10
Volume Trigger
(EPAP to IPAP)
Shape Signal
(EPAP to IPAP)
(IPAP to EPAP )
The volume trigger is one method used to trigger IPAP during spontaneous
breathing in the S/T Mode. The volume trigger threshold is 6 cc of accumulated volume above the baseline leak (V
inspiratory flow causing 6 cc of volume to accumulate above baseline (V
). When patient effort generates
leak
leak
),
IPAP is triggered:
Volume trigger threshold = 6 cc volume above V
baseline
leak
The shape signal is another method used to trigger IPAP and/or cycle off IPAP
to EPAP during spontaneous breathing in the S/T Mode. This signal 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 3-7
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.
PRESSURE
FLOW
IPAP
EPAP
Shape
Signal
Estimated
Patient
Flow
Cycle to
EPAP
Crossover
Point
Trigger to
IPAP
Crossover
Point
Figure 3-7. Shape Signal.
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.
BiPAP Vision Clinical Manual
3-11
Spontaneous Expiratory
Threshold
(IPAP to EPAP)
A second method used to cycle off IPAP during spontaneous breathing in the
S/T Mode is called Spontaneous Expiratory Threshold (SET). The SET is an
electronic signal that 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.
IPAP
PRESSURE
EPAP
Spontaneous
Expiratory
Threshold
FLOW
Maximum IPAP Time
(IPAP to EPAP)
Flow Reversal
(IPAP to EPAP)
Summary
Figure 3-8. Spontaneous Expiratory Threshold.
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/T Mode.
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
Vision unit senses this flow reversal, the unit automatically cycles to the EPAP
level.
The sensitivity criteria for spontaneous breathing in the S/T mode 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 volume accumulates above baseline flow (V
leak
)
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)
BiPAP Vision Clinical Manual
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