Maquet Servo 900c User manual

SERVO VENTILATOR 900 C OPERATING MANUAL

CRITICAL CARE

Important

▲

General information

• Servo Ventilator 900 C must be operated only by authorized personnel who are well trained in its use. It must be operated according to the instructions in this Operating Manual.

• After unpacking, the ventilator must be checked and, if necessary, calibrated.

• All data on pressures for Servo Ventilator 900 C are given in cm H2O. 1 kPa (kilopascal) ≈ 10 cm H 100 kPa = 1 bar ≈ 1 atm ≈ 1 kgf/cm 100 kPa ≈ 15 psi

• Responsibility for the safe functioning of the equipment reverts to the owner or user in all cases in which service or repair has been done by a non-professional or by persons who are not employed or authorized by MAQUET, and when the equipment is used for other than its intended purpose.

•A full technical description – including circuit diagrams, parts list and service data – is contained in the service documentation, copies of which are held by your supplier.

(kp/cm2)

Connection

• When connected to a patient, the ventilator must never be left unattended.

•A check on functions must be done before a patient is connected to the ventilator.

• When anaesthetic gas is metered via a flow meter on the low pressure inlet, compressed air must not be connected at the same time.

• To avoid explosion hazards, flammable agents such as ether and cyclopropane must not be used in this machine. Only agents which comply with the requirements on nonflammable agents in the IEC standard “Particular requirements for electrical safety of anaesthetic machines” are suitable in this machine.

• As this machine is not suitable for use with flammable agents such as ether and cyclopropane, the use of antistatic breathing tubes and face masks is not necessary. The use of antistatic or electrically conductive breathing tubes when using high frequency electric surgery equipment, may cause burns and is therefore not recommended in any application of this machine.

• Never connect or disconnect auxiliary equipment to the outlet on the rear of the ventilator when the ventilator is connected to mains.

• All gases must fulfill the specifications for medical grade gas. The gases supplied must be dry and free from oil and dust. Air H2O< 5 g/m

Oxygen H2O< 20 mg/m Nitrous oxide/gaseous phase) H2O< 58 ppm

Oil < 0.5 mg/m

Operation

• The APNEA ALARM is not intended to and will not monitor for disconnections.

• The APNEA ALARM is not functional in VOL. CONTR., VOL. CONTR. + SIGH, PRESS. CONTR. or MAN.

• In the case of a power failure, manual ventilation using a Servo Ventilator 900 C is possible only with the help of power supply from external battery. A resuscitator should always be available, however, as an extra safety measure.

• The SV 900 C is certified, with regard to safety, to be compatible with electromagnetic environments complying with IEC 601-1-2. It is the responsibility of the user to take necessary measures in order to ascertain that the specified limits are not exceeded as this may impair the safety of the ventilator.

Such measures should include, but are not limited to: – normal precautions with regard to relative humidity and

conductive characteristics of clothing in order to minimize the build-up of electrostatic charges.

– avoiding the use of radio emitting devices in close

proximity of the ventilator, such as high-frequency surgery apparatus or cordless (mobile) telephones, resulting in a field level exceeding 3 V/m (IEC 601-1-2).

Magnetic fields of MR equipment having flux densities above 20 mT may cause deactivation of the ventilator functions and may result in permanent damage to the Servo Ventilator.

• To protect the patient against high pressures, the WORKING PRESSURE and UPPER PRESS. LIMIT must always be set at suitable values.

• Do not forget to set the manual ventilation valve to position AUT after completed manual ventilation. Otherwise the patient may be hypoventilated without any alarm from the ventilator. (Not applicable to manual ventilation accessory with motor).

• When mains supply is switched off or in the case of a mains power failure, the inspiratory and expiratory valves will automatically open. This may also occur in the case of an internal electronic failure. Thus, if the WORKING PRESSURE is set too high and the gas supply through the gas supply unit continues, this may result in increased airway pressure.

• When excess gas is being scavenged, the scavenging system must meet the following requirements: – At the point at which the scavenging system is connected to the ventilator, the sub-atmospheric pressure must not exceed 0.5 cm H the breathing system greater than 0.5 l/min. – With continuous air flows of 30 l/min and 90 l/min for not less than 5 seconds at the inlet of the anaesthetic gas scavenging system, the resistance in the system shall not exceed 0.25 cm H

The Servo Evac 180 basic evacuation unit meets these requirements.

• If the ventilator is equipped with electronic gas supply unit, the following applies: When mains supply is switched off or in the case of power failure, the gas supply is automatically blocked.

O or cause an induced flow from

O and 2.5 cm H2O, respectively.

Cleaning

• The ventilator must not be gas sterilized.

• The flow transducers must not be cleaned in a dish washing machine, by ultrasonic methods or by using agents that contain aldehydes.

• Agents used for cleaning must have a pH value between 4–8.5.

• Complete cleaning should be done after every 1000 hours of operation or, at the latest, after every six months.

Service

• The Servo Ventilator 900 C must be serviced at regular intervals by specially trained personnel. Any maintenance must be noted in the log book provided for that purpose, in accordance with national regulations. We recommend that service is done as a part of a service contract with MAQUET.

• The 1000 hours overhaul shall be done after every 1000 operating hours or, at the latest, every six months. In addition, the ventilator shall undergo a technical safety check twice a year, at six months intervals, according to national regulations.

• Service and repairs on the ventilator may be done only by MAQUET authorized personnel.

• Only original parts from MAQUET must be used in the ventilator.

Equipment combinations

• Only MAQUET-approved accessories and auxiliary equipment may be connected to the ventilator.

• In order to maintain system safety and integrity only accessories complying with IEC 601-1, or the safety of which has been verified in another way must be connected to the signal outputs on the rear of the ventilator. For details on connections and allowed voltages, please see Circuit Diagram.

Product information program

This Operating Manual is a part of a comprehensive information program for Servo Ventilator 900 C. The program is planned to contain the following:

Promotional and Scientific Publications

Brochure Servo Application Product Leaflet Reprints

Ventilator Brochures:

Concept

Operating and Service Instructions

Operating Brief Wall Diagram Service Manual Circuit Diagram

Manual Operating with Cleaning

Instructions Instructions

Intensive Care

Anesthesia

Transportation

Product Training Material

Training Advisory Slide Series “I am breathing The Patient’s

Instructions Booklet including through a ABSee

for Instructors Textbook ventilator” Cards

Film and and Poster

Booklet

Front Panel Panel Block Trainee’s set Video programs

Flip-chart Video guide

Video news

Servo Ventilator 900 C-Front

Operating instructions

Servo Ventilator 900 C is simple to operate. Operating instructions are found:

On the ventilator in the form of a panel and cleaning instructions on the lid of the pneumatic unit.

“Normal” settings are indicated in green on the front panel. Settings indicated in red should be used with caution, since these settings may involve a certain risk for the patient.

In the Brief Operating Instructions in the drawer under the ventilator.

A log sheet is available with the Brief Operating Instructions. After certain routines, e. g. cleaning etc., the person responsible for the work should complete and sign the log sheet. The log sheet can then be filed.

On a separate wall poster with cleaning instructions.

In this Operating Manual.

The inside of the cover shows a picture of the ventilator. This picture can be used as a foldout when reading the manual.

The following information is found in the corresponding chapters:

Description ............................................ 1-3

Operating............................................... 4-9

Maintenance......................................10-13

Technical specifications ......................... 14

Contents

1. Arbetsprincip

1. Basic principles

2. Kontrollpanel och ventilationssätt

2. Control panel and ventilation modes

3. Patientsäkerhet

3. Patient safety

4. Uppställningar

4. Set-ups

5. Förberedelser

5. Preparations

6. Funktionskontroll

6. Check on functions

7. Anslutning till patient

7. Connection to patient

8. Klinisk bedömning och felsökning

8. Clinical judgement and troubleshooting

9. Registrering

9. Recording

10. Rutinrengöring

10. Routine cleaning

11. 1000-tim.-översyn med fullständig rengöring

11. 1000 hours overhaul with complete cleaning

12. Utbyte av O2-cell

12. Replacement of O

13. Kalibrering

13. Calibration

14. Tekniska specifikationer

14. T echnical specifications

cell

Chapter 1

Basic principles

In this chapter:

General design .................1:2

Pneumatic unit..................1:3

Rear ...................................1:4

General design

Pneumatic unit

The pneumatic unit comprises the gas conduction system, pressure and flow transducers and control valves.

The control of flow and pressure is done by a feed-back system. The transducers continually measure the flow and pressures. The information is compared with the panel settings and a difference between the actual and the preset values results in correction signals to the control valves.

For detailed description, see chapter “Basic principles” in the Training Instructions.

Low pressure

High pressure

Electronic unit

The electronic unit contains a number of plugin PC-boards with the circuits for regulation, alarms and monitoring.

The unit effects the electronic control of the

pneumatic unit.

Servicing of the ventilator is facilitated by the spare parts exchange system. The faulty parts are replaced by factory trimmed exchange parts.

Service on the electronic unit must be done by MAQUET, or by MAQUET authorized personnel only.

Pneumatic unit

Gas connection. The upper inlet, not visible in the picture, is used for low pressure gas and the lower inlet is used for high pressure gas. For anaesthesia, a gas supply unit with three inlets is available.

The gas supply is regulated by a valve so that a constant pressure is maintained in the bellows.

The O2 cell measures the O2 concentration in the gas.

The gas flows through a bacteria filter.

The respiratory gases are mixed and stored at a constant pressure in the bellows.

The working pressure is set with an adjustment screw.

A manometer shows the working pressure.

A safety valve opens if the bellows is overfilled, or if the pressure exceeds approx. 120 cm H

(

The flow transducer on the inspiration side measures the gas flow to the patient.

The inspiration valve regulates the inspiratory gas flow. It is closed during the pause and expiratory parts of the respiratory cycle.

The pressure transducer on the inspiration side measures the airway pressure.

The flow transducer on the expiration side measures the gas flow from the patient.

To prevent condensation, the transducer is

heated to approx. 60°C.

The pressure transducer on the expiration side measures the airway pressure.

The expiration valve is closed during inspiration. During the expiratory phase it is either fully open or regulating the PEEP level.

The flap valve prevents a back flow of exhaled gases. It is also necessary for the trigg function.

Rear

Operating time meter

Equipotential socket On/Off switch

Fuse holders

Outputs for auxiliary equipment

Control terminal

Recorder output

Rear of Servo Ventilator 900 C

To the right on the electronic unit are the mains inlet socket, fuse holders, On/Off switch, voltage rating, equipotential socket and operating time meter.

To the left on the electronic unit are three

15-pole sockets for auxiliary equipment.

The 37-pole socket is used for recording of

pressure and flow curves.

There are labels with the serial number of the apparatus on both the pneumatic unit and the electronic unit.

Mains inlet socket

Control terminal

Under the secured lid, there is a connector for external control of ventilation.

For details see separate Operating Manual.

Chapter 2

Control panel and ventilation modes

In this chapter: Panel design

and symbols ................... 2:2

Panel functions............... 2:3

Working pressure........... 2:3

Mode selection ............... 2:3

Respiratory pattern ........ 2:4

I:E ratio............................ 2:5

Expired minute volume.. 2:6

Special functions............ 2:7

Airway pressure ............. 2:8

SIMV ................................ 2:10

alarm........................... 2:11

Parameter selection ....... 2:11

121

Controlled ventilation .... 2:12

Supported ventilation .... 2:13

Spontaneous ventilation. 2:15

Manual ventilation .......... 2:16

Panel design and symbols

For easy operation, the panel is divided into fields. Each field is described in this chapter.

“Normal” settings are indicated in green on the front panel. Settings indicated in red should be used with caution since these settings may involve a certain risk for the patient.

A number of knobs and the EXPIRED MINUTE VOLUME meter have dual scales.

The blue scale is always to be used when the low range is selected.

Power on is indicated by a green lamp.

A yellow lamp is either an indication of a certain setting or a reminder to set an alarm limit.

A red lamp always indicates an alarm.

! Working Pressure @ Mode Selection # Respiratory Pattern $ Expired Minute Volume % Special Functions ^ Airway Pressure & SIMV * O

Concentration Alarm

( Monitoring

Panel functions

Working pressure

The working pressure is set with an adjustment screw and is read on the manometer WORKING PRESSURE.

The working pressure must always be set at a value somewhat higher than the highest airway pressure.

Mode selection

The Servo Ventilator 900 C can be operated in 8 different modes, which are selected by means of the mode selector.

The modes are described in special sections in this chapter.

Controlled ventilation

Volume controlled ventilation (VOL. CONTR.) Volume controlled ventilation + sigh (VOL. CONTR. + SIGH) Pressure controlled ventilation (PRESS. CONTR)

Supported ventilation

Pressure supported ventilation (PRESS. SUPPORT) SIMV (Synchronized Intermittent Mandatory Ventilation) SIMV + Pressure support (SIMV + PRESS. SUPPORT)

Spontaneous ventilation

CPAP (Continuous Positive Airway Pressure)

Manual ventilation

MAN

Panel functions

PRESET INSP. MIN. VOL./min

100 110

120

25 50

INSP. TIME %BREATHS/min

PAUSE TIME 10 %

(INSP. PAUSE)

Respiratory pattern

Preset inspiratory minute volume

The inspiratory minute volume is set with the knob PRESET INSP. MIN.VOL. l/min. The knob has a locking button on the underside.

A suitable initial value can be calculated by, for instance, using a Radford nomogram. The minute volume can be readjusted after indication from a CO auxiliary equipment for the Servo Ventilator.

The setting range is 0.4-40 l/min. The tidal volume = PRESET INSP. MIN. VOL. l/min

BREATHS/min

The tidal volume can be read on the digital display.

At extremely high flows it may be necessary to increase the working pressure in order to obtain the desired minute volume.

Flow pattern switch

During VOL. CONTR. and VOL. CONTR. + SIGH, a constant or an accelerating inspiratory flow can be selected. Constant flow gives a lower peak pressure and is the pattern normally used.

A decelerating flow will be obtained in PRESS. CONTR.

Breaths per minute

The respiratory rate is steplessly adjustable within the range of 5 to 120 BREATHS/min.

Analyzer 930, which is

Inspiration time %

There are 6 fixed inspiration times, 20, 25, 33, 50, 67 and 80% of the breathing cycle.

Pause time %

There are 5 fixed pause times, 0, 5, 10, 20 and 30% of the breathing cycle.

Panel functions

I:E ratio

Insp. Pause I:E ratio

time time

20 0 1:4 20 5 1:3 25 0 1:3 20 10 1:2.3 25 5 1:2.3 33 0 1:2 25 10 1:1.9 33 5 1:1.6 20 20 1:1.5 33 10 1:1.3 25 20 1:1.2 20 30 1:1 50 0 1:1 33 20 1.1:1 25 30 1.2:1 50 5 1.2:1 50 10 1.5:1 33 30 1.7:1 67 0 2:1 50 20 2.3:1 67 5 2.6:1 67 10 3.4:1 67 20* 4:1 80 0 4:1

* Reduced to 13%

To the left is a conversion table for INSP. TIME % and PAUSE TIME % to I:E ratio for those who are more used to working with the latter.

On the basis of an I:E ratio, i.e. the relation of inspiration time to expiration time, the pause is allocated to inspiration time.

For example, insp. time 25% and pause time 10% = I:E ratio 35/65 = approx. 1:1.9.

If the ventilator has been set so that insp. time + pause time exceeds 80%, then expiration automatically begins when 20% of the respiratory cycle remains (safety function). The pause time is then reduced.

Example 1:

Preset insp. time = 67% ➞ 67% inspiration Preset pause time = 20% ➞ 13% pause

20% expiration

Example 2:

Preset insp. time = 80% ➞ 80% inspiration Preset pause time = 30% ➞ 0% pause

20% expiration

The settings are independent of changes in the patient’s compliance and resistance.

Inspiration time settings of 33%, 67% or 80% should be avoided in volumecontrolled respiration with accelerating flow patterns. With these settings patient triggering may cause the temporary partial blocking of the inspiration valve which, however, would be indicated by a minute volume alarm. Should the valve be blocked, the situation can be remedied immediately by switching over to a constant flow.

Inspiratory flow

In mode VOL. CONTR. (constant flow) or SIMV the inspiratory flow is calculated by:

PRESET INSP. MIN. VOL. l/min

INSP./TIME %

Example:

PRESET INSP. MIN. VOL. l/min = 8 l/min INSP. TIME % = 25% Results in an inspiratory flow: = 8 × 100/25

Adjustment of INSP. TIME% (use reverse value) 20% = 1/5= 5 25% = 1/4= 4 33% = 1/3= 3 50% = 1/2= 2 67% = 2/ 80% = 4/

× PRESET INSP. MIN. VOL = inspiratory flow (l/min)

1.5

1.25

= 1.5 = 1.25

= 32 l/min

Panel functions

Expired minute volume

EXPIRED MINUTE VOLUME is indicated on a meter which has dual scales: 0-40 l/min and 0-4 l/min.

The scale 0-4 l/min is intended for use when

greater accuracy, e. g. for infants, is needed.

The knobs for LOWER ALARM LIMIT and UPPER ALARM LIMIT also have the same dual scales.

The end stop positions for the knobs do not coincide with the end positions on the scale. This is correct and no attempt should be made to alter the range.

The desired scale is selected with the switch INFANTS/ADULTS.

The alarm limits for expired minute volume must always be set. If either of the knobs has been set in end position (out of scale), the yellow lamp SET MIN. VOL. ALARM flashes. The alarm limits are normally set at approx. 20% below and above the selected minute volume. The upper limit may be set at approx. 30% above the selected minute volume in the mode VOL. CONTR. + SIGH.

The APNEA ALARM is activated with audible signals and flashing light if the time between any two consecutive breaths, spontaneous or mandatory or a combination of the two, is greater than approximately 15 seconds (4 breaths per minute or less). The APNEA ALARM is not intended to and will not monitor for disconnections. The APNEA ALARM is operative in CPAP, PRESS. SUPPORT, SIMV and SIMV + PRESS. SUPPORT.

Failure of gas supply to the ventilator will result in visual and audible GAS SUPPLY ALARM signals. The GAS SUPPLY ALARM is not operative at respiratory rates over 80 breaths/min., and INSP. TIME % 20 or 25.

Panel functions

INSP. EXP. GAS PAUSE PAUSE CHANGE HOLD HOLD

Special functions

Under the small hood below the UPPER ALARM LIMIT knob are three pushbuttons for special functions.

Inspiratory pause hold

When the pushbutton INSP. PAUSE HOLD is depressed, the valves close after inspiration and the pause is prolonged as long as the pushbutton is depressed.

This provides an exact measurement of the end inspiratory lung pressure. It may also give time for an equilibration of the blood gas and alveolar pressures.

Expiratory pause hold

The valves are closed, after the expiration, as long as the pushbutton EXP. PAUSE HOLD is depressed, i.e. a prolonged expiratory pause. This provides an exact measurement of the end expiratory lung pressure.

EXP. PAUSE HOLD must not be used in

SIMV or SIMV + PRESS. SUPPORT mode.

Two inspirations may occur at the same

time. However, the UPPER PRESS. LIMIT

is still functional.

Gas Change

The pushbutton GAS CHANGE is used, for instance, when it is desirable to rapidly alter the gas mixture to the patient. The concentration setting on the vaporizer/gas mixer/flowmeters must be altered first.

The inspiration and expiration valves open so that the pressure in the patient circuit is max. 20 cm H2O.

During the gas changing time, the EXPIRED MINUTE VOLUME meter is zeroed automatically.

Panel functions

Airway Pressure

Airway pressure meter

The meter continually indicates the airway pressure reading.

Upper pressure limit

The knob UPPER PRESS. LIMIT is used to set the upper limit for airway pressure. When this pressure limit has been reached, inspiration is immediately discontinued and there is a change over to the expiratory phase. Visual and audible alarms are activated.

Since the inspiration is discontinued, the complete tidal volume will not be delivered and, consequently, the LOWER ALARM LIMIT for EXPIRED MINUTE VOLUME may be activated.

Upper pressure limit is connected in all modes.

There are safety catches on the knob at 80 and 100 cm H

PEEP

PEEP is the setting of a Positive End Expiratory Pressure, e.g. used to counteract the formation of atelectasis.

The PEEP range is from 0 to 50 cm H2O. There are safety catches on the PEEP knob at 0 and at 20 cm H

In case of a leakage, e.g. if a tracheal tube without cuff is being used, the PEEP-setting may cause self-triggering. To avoid this, the TRIG. SENSITIVITY should be set at a somewhat lower value.

The PEEP knob is prepared for NEEP (Negative End Expiratory Pressure). In order to use NEEP, it is necessary to connect auxiliary equipment to the expiration outlet. The NEEP range is from 0 to -10 cm H

Panel functions

Trig. sensitivity

The knob TRIG. SENSITIVITY is used to set the value of negative pressure that the patient must produce in order to trigger a breath.

The TRIG. SENSITIVITY is relative to PEEP.

For instance, PEEP +10 and TRIG. SENSITIVITY -2 cm H2O mean that the patient must produce a pressure of -2 cm H to the setting to trigger a breath.

This corresponds to a pressure of +8 cm H

relative to atmospheric pressure in the patient’s airways.

The airway pressure, measured on the

expiration side, is compared with the preset TRIG. SENSITIVITY + PEEP. If the airway pressure drops below TRIG. SENSITIVITY + PEEP, a breath is triggered.

If it is desirable for the patient to be able to

easily trigger the ventilator, the knob is set at green value.

If it is undesirable for the patient to be able to

trigger the ventilator, the knob is set at

-20 cm H Trig. sensitivity is connected in all modes

except MAN. For further details, see description on different modes.

O relative

Inspiratory pressure level

The knob INSP. PRESS. LEVEL is used to set the constant inspiratory pressure, relative to PEEP, when any of the following modes of ventilation are used: PRESS. CONTR., PRESS. SUPPORT, SIMV + PRESS. SUPPORT.

A safety catch is located at 30 cm H2O.

The total inspiratory pressure level also includes PEEP. This is why there is a marking under the PEEP knob leading to the INSP. PRESS. LEVEL knob. At a PEEP of +5 cm H LEVEL of +15 cm H pressure level would be +20 cm H relative to atmospheric pressure.

O and an INSP. PRESS.

O, the total inspiratory

Panel functions

SIMV

SIMV (Synchronized Intermittent Mandatory Ventilation) means that the patient gets mandatory breaths controlled by the ventilator, and that he also has the possibility of breathing spontaneously.

The mandatory breaths are synchronized with the breaths of the patient so that he need not breathe against the ventilator.

SIMV-rate (SIMV BREATHS/min) is the rate of the mandatory breaths per minute. The rate is set between 0.4 and 4 breaths per minute on the LOW RATE scale, and between 4 and 40 breaths/min on the HIGH RATE scale. The desired rate is selected by means of a switch. There are two indicating lamps, one for each rate.

The tidal volume and the frequency can be read on the digital display.

Minute volume, respiratory rate, inspiration time and pause time must be set for the SIMV mode. These functions determine the respiratory pattern of the mandatory breaths. The BREATHS/min must always be set higher than the SIMV BREATHS/min to allow time for the spontaneous period.

The SIMV cycle is divided into SIMV period and spontaneous period. See page 2:14.

Panel functions

O2 alarm

Alarm limits for O2 concentration are set with the knobs UPPER ALARM LIMIT and LOWER ALARM LIMIT. The SET O alarm limits have not been set.

The end stop positions for the knobs do not coincide with the end positions on the scale. This is correct and no attempt should be made to alter the range.

The alarm limits are set as follows:

• Set O2 concentration on the gas mixer/

flowmeters.

• Set the parameter selector at O

and read the value.

• Set the alarm limits at approx. 6% by volume

(3 scale divisions) below and above the O

concentration reading on the digital display.

Visual and audible alarms are activated when any of the alarm limits is exceeded.

If the O the ventilator, the O If not, the LOWER ALARM LIMIT will activate alarm.

If no O2 cell is mounted, neither digital displays nor alarm is activated when the parameter selector is set at O2 CONC. %.

cell is expended but still mounted in

ALARM flashes if the

CONC. %

cell has to be disconnected.

Parameter selection

A digital display of the O2 concentration is given when the selector is set in position O

Other displayable parameters are:

INSPIRED TIDAL VOLUME ml—the volume provided by the ventilator at each breath.

EXPIRED TIDAL VOLUME ml—the volume produced by the patient at each breath (with no leakage in the patient circuit).

EXPIRED MINUTE VOLUME l/min—(also indicated on the EXPIRED MINUTE VOLUME meter).

PEAK PRESSURE cm H2O—the pressure at the end of the inspiration phase.

PAUSE PRESSURE cm H the end of the pause. This pressure normally corresponds to the maximal alveolar pressure in the lungs.

MEAN AIRWAY PRESSURE cm H2O—the mean value in the patient circuit, continually measured.

BREATHS/min—the respiratory rate of the patient. In controlled ventilation, this value equals the set respiratory rate plus eventual patient triggered breaths. In the SIMV mode, it is the sum of the spontaneous and the mandatory breaths. In the CPAP and PRESSURE SUPPORT modes, the value represents the spontaneous breaths/min of the patient.

O—the pressure at

CONC. %.

Controlled ventilation

Insp. Exp.

l/s cm H

Flow Pressure

WORKING PRESSURE and UPPER PRESS. LIMIT must always be set at adequate values. This is extremely important when treating infants.

Pause

Sigh

Volume controlled ventilation

Volume controlled ventilation (VOL. CONTR.) ensures that the patient receives a certain preset tidal volume.

Servo Ventilator 900 C delivers a specific tidal volume at a specific rate during a specific time (preset values).

If the patient makes inspiratory efforts so that the airway pressure falls below the triggering level, a preset tidal volume will be delivered earlier and the expired minute volume will increase.

A constant or an accelerating flow can be selected.

A patient trigg initiates a breath with the preset values.

Volume controlled ventilation + sigh

In this mode of operation, the Servo Ventilator 900 C delivers a sigh every hundredth breath. At sigh, double tidal volume is delivered since the flow is constant and the inspiration time is doubled.

The first sigh will occur at the second inspiration after setting the mode selector to VOL. CONTR. + SIGH.

The UPPER ALARM LIMIT for EXPIRED MINUTE VOLUME may have to be set somewhat higher in this mode.

Pressure controlled ventilation

In the mode PRESS. CONTR., gas is delivered at a constant pressure during the set inspiration time.

The pressure is set with the knob INSP. PRESS. LEVEL.

The flow is decelerating in this mode.

The set inspiratory pressure, respiratory rate, and inspiration time determine the volume the patient will receive.

Servo Ventilator 900 C works with a constant pressure during the entire inspiration.

The minute volume can be read on the EXPIRED MINUTE VOLUME meter.

Tidal volume can be read on the digital display with the parameter selector in position INSP. TIDAL VOLUME or EXP. TIDAL VOLUME.

In case of leakage in the system, e.g. due to the use of a tracheal tube without cuff, a pause time of 0% is recommended to ensure that the measurement of the expired minute volume will be as correct as possible.

A patient trigg initiates a breath with the preset values.

Supported ventilation

Trig.

Flow Pressure

Pressure supported ventilation

PRESS. SUPPORT is a spontaneous breathing mode in which the patient must trigger breaths.

Some applications for PRESS. SUPPORT are: weaning, patients suffering from asthma or, in post-operative use, when the patient’s own breathing efforts are insufficient.

When the patient triggers the ventilator, an inspiration pressure support is given at a preset constant pressure.

The ventilator regulates the pressure during inspiration so that it corresponds to preset INSP. PRESS. LEVEL + PEEP.

The pressure during expiration drops to 0 cm H

occurs when the flow decreases to 25% of the peak inspiratory flow.

change from inspiration to expiration, for instance in the case of a leakage.

has closed the inspiratory valve and the airway pressure has increased to +3 cm H the preset INSP. PRESS. LEVEL + PEEP or after 80% of the preset respiratory cycle. Because of this safety function the respiratory rate should always be set with the knob BREATHS/min.

O, or alternatively to PEEP-level.

The change from inspiration to expiration

There are also safety functions to control the

Expiration will then start when the step motor

O above

Supported ventilation

SIMV cycle 10 s SIMV cycle 10 s

SIMV period 4 s Spontaneous period 6 sSpontaneous period 6 sSIMV period 4 s

Flow Pressure

A patient trig. during the SIMV period initiates a mandatory breath. After that, spontaneous breathing.

SIMV

SIMV (Synchronized Intermittent Mandatory Ventilation) means that a preset number of breaths are ventilator controlled, mandatory breaths (SlMV BREATHS/min). The patient may breathe spontaneously between those breaths.

Breathing pattern and tidal volume for the mandatory breaths are selected with the knobs PRESET INSP. MIN. VOL., BREATHS/min, INSP. TIME % and PAUSE TIME %.

The time in seconds for one SIMV cycle is calculated from the formula

preset SIMV freq.

The SIMV cycle is divided into SIMV period and spontaneous period.

The spontaneous period consists of spontaneous breathing time if the patient has triggered a mandatory breath during the previous SIMV period.

If the patient has insufficient spontaneous breathing, the maximum time between two mandatory breaths is just over one SIMV cycle, (cp 1 to 2 in the picture above).

During the SIMV period no breath has been triggered. The next period begins with a mandatory breath. After that, spontaneous breathing.

To ensure adequate ventilation, apnea alarm is activated if the time between two breaths exceeds approx. 15 sec., and the minute volume alarm is activated if any of the preset alarm limits is exceeded.

Either of these alarms is a command to take the necessary action (e.g. clinical judgement of the patient, increased SIMV frequency, altered trig. sensitivity).

The SIMV period is approx. equal to one respiratory cycle.

The spontaneous period is calculated as SIMV cycle-SIMV period.

Example:

BREATHS/min 15 ➞ SIMV period = SIMV BREATHS/min 6 ➞SIMV cycle = Spontaneous period ➞10-4 = 6 s

A patient trig during the SIMV period initiates a breath with the preset values. A patient trig during the spontaneous period opens the inspiratory valve, and the patient can breathe through the ventilator.

60 = 4 s

60 = 10 s

Supported and spontaneous ventilation

SIMV cycle 10 s

SIMV

period 4 s

Flow Pressure

These settings determine the SIMV period. This setting determines the SIMV cycle.

SIMV cycle

SIMV period Spontaneous period

Spontaneous

period 6 s

SIMV + pressure support

The main difference between this mode and the SIMV mode is that the spontaneous, triggered breaths are pressure supported.

The level of support is set with the control INSP. PRESS. LEVEL. The level also includes PEEP.

See also description of pressure support on page 2:13.

INSP. PRESS. LEVEL

0 or PEEP-level

TRIG. SENSITIVITY

Flow Pressure

Mandatory breath Pressure supported

spontaneous breaths

TRIG. SENSITIVITY

Flow Pressure

PEEP

Care should be taken in setting the preset

BREATHS/min, so that the spontaneous

pressure-supported breaths are not

prematurely time-cycled rather than flow-

cycled to expiration.

Spontaneous ventilation CPAP

In this mode, CPAP (Continuous Positive Airway Pressure), the patient breathes spontaneously through the ventilator at an elevated pressure level. The positive pressure is set with the PEEP control.

The TRIG. SENSITIVITY control must be set at a position which allows the patient to trigger the ventilator. Upon triggering, the inspiration valve opens, and the patient can inspire through the ventilator and control the tidal volume and respiratory rate.

To avoid self-triggering due to leakage, the trig. level should be set at a low value.

If CPAP (PEEP) = 0, it will be possible to check the patient’s ability to breathe spontaneously without help from the ventilator.

The minute volume, tidal volume and respiratory rate can be monitored.

Manual ventilation

Electronic unit

MAN

AUT

Mode selector

If the breathing bag becomes overfilled, the expiratory valve in the ventilator may go to a locked position.

To unlock the valve:

• Set UPPER PRESS. LIMIT below 20 cm

• Squeeze the breathing bag and check that

the pressure in the bag is lowered.

• Set UPPER PRESS. LIMIT back to the

lowest possible value for normal operation.

If the breathing bag becomes overfilled with the manual ventilation valve in posotition AUT:

• Remove the breathing bag.

• Exchange the manual ventilation valve.

Motor/

valve unit

Manual ventilation

The Manual Ventilation Accessory with Motor consists of two units:

• Electronic unit

• Motor/valve unit

With this accessory switching between manual ventilation and other modes is done with the mode selector.

The valve is automatically set to the correct position by a motor. The switch-over time is about 5 seconds. An alarm with audible signals and red light is activated if the positions of the valve and mode selector are not the same.

In position pressure of about 4 cm H valve closes.

When the breathing bag is squeezed, the gas flows to the patient via a non-return valve.

Always set UPPER PRESS. LIMIT at the lowest possible value for normal operation.

The APNEA alarm is inoperative during

manual ventilation.

In the case of a power failure, manual ventilation is not possible unless an external power pack is connected.

PEEP cannot be used in manual ventilation mode.

Set the mode selector to VOL. CONTR. immediately before connecting the ventilator to a patient. The reason is to zero the gas flow reading.

At spontaneous breathing during manual ventilation the following readings will be incorrect. – the displayed values for BREATHS/min.,

EXP. TIDAL VOLUME and EXP.

MINUTE VOLUME. – the alarm monitoring instrument

EXPIRED MINUTE VOLUME.

The accuracy of the EXPIRED MINUTE VOLUME meter reading decreases. After about 5 minutes, the accuracy is about ±2 l/min. To get a correct meter reading, the breathing bag should be squeezed at least every 5 minutes.

For spontaneous breathing, the PRESSURE SUPPORT mode is recommeded. The INSP. PRESS. LEVEL should be set at zero or at a low value. This enables continuous monitoring of pressure and volume.

MAN., the breathing bag is filled to a

O, then the inspiratory

Chapter 3

Patient safety

In this chapter:

Protective devices......... 3:2

Alarm schedule.............. 3:4

131

Protective devices

Alarms

There are a number of alarms on the ventilator which protect the patient by alerting ward personnel to any malfunctions. Alarms are given with audible signals and flashing red lights. An audible signal only is given as alarm for power failure and certain technical malfunctions.

Some audible alarms can be switched off for a period of approximately 2 minutes. For details see the alarm schedule on page 3:4.

In addition there are panel indicators with fixed or flashing yellow lights.

Examples are given in chapter 8, Troubleshooting, regarding actions for various alarms.

The patient is protected against high pressure by an electronic limiter, which is controlled by the knob UPPER PRESS. LIMIT.

If the value set with this knob is too high or if the limiting function should fail, the pressure is limited to the set WORKING PRESSURE.

The WORKING PRESSURE is prevented from exceeding the set value by a safety valve and cannot be set at values exceeding 120 cm H

As an extra patient safety protection against too high an airway pressure, there is a HIGH PRESSURE PROTECTION circuit incorporated when either of the modes CPAP, PRESS. CONTR. or PRESS. SUPPORT is selected. This protection circuit functions when the airway pressure in the inspiration channel for some reason, e.g. coughing, exceeds 30 cm H level.

O above INSP. PRESS. LEVEL/PEEP

Important!

The SV 900 is not designed to withstand severe negative pressures, which, if applied to the system may damage the internal pressure transducers rendering the unit inoperable.

Transducer pressure range

SV 900 up to and including SIN 188499 are factory equipped with pressure transducers that will tolerate pressures down to -100 cm H20(mbar), whereas units from S/N 188500 are factory equipped with pressure transducers that will tolerate pressures ranging from -500 cm H20(mbar) to +500 cm H20(mbar).

Earlier units may have been retrofitted with Transducer Upgrade EM12102/l featuring the same pressure tolerance as units with S/N ≥188500. Uppgraded units are identified with a label !Upgrade EMO12/02/l’ attached to the inside of the pneumatic unit lid.

If closed system suctioning is applied, the following must be considered:

A suctioning flow exceeding the flow delivered by the ventilator will result in a negative pressure affecting the patients airways as well as the ventilators breathing system.

Do not use the “Pause hold” function during the procedure.

All audible alarms, with the exception of upper pressure limit for airway pressure and alarm for mains power failure, are switched off for a period of 2 minutes when the button

2 min is depressed, while the red light

continues flashing. This means that no new audible alarm will be possible during approximately 2 minutes.

To switch off the power failure alarm, the button must be depressed until the audible alarm stops.

The APNEA ALARM is not intended to and will not monitor for disconnections.

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Maquet Servo 900c User manual

Specifications and Main Features

Frequently Asked Questions

User Manual