WARNINGS AND CAUTIONS
Personnel operating the ventilator must become thoroughly familiar with the instruction manual prior to using the Hallowell EMC Model 2000 or Model 2002TMAnesthesia Ventilator with†animal†patients.
- ELECTRIC SHOCK HAZARD - DO NOT remove any of the ventilator covers or panels. Refer all servicing to an authorized service technician.
- DANGER - Possible explosion hazard if the unit is used in the presence of flammable anesthetics.
- Before using the ventilator, check that all connections are correct, and verify that there is no leak, per instructions on side plate of the controller.
- Any problems arising from an improperly functioning scavenging system is solely the user's responsibility.
- OPENING THE CONTROL UNIT BY UNAUTHORIZED PERSONNEL AUTOMATICALLY VOIDS ALL WARRANTIES AND SPECIFICATIONS. THE PREVENTION OF TAMPERING WITH THE CONTROL UNIT IS EXCLUSIVELY THE USER'S RESPONSIBILITY: THE MANUFACTURER ASSUMES NO LIABILITY FOR ANY MALFUNCTION OR FAILURE OF THE VENTILATOR IF THE CONTROL UNIT'S SEAL IS BROKEN.
- Compressed Supply Gas must be clean and dry to prevent ventilator malfunction.
The Hallowell EMC Model 2000 and Model 200TM Veterinary Anesthesia Ventilator is covered under the warranty expressed on the warranty card attached to the unit at the time of sale to the end user, which reads as follows:
†ONE YEAR LIMITED WARRANTY
This unit is warranted by HALLOWELL EMC to be free of defects in material and workmanship for a period of 1 full year from invoice date of original purchase.
This warranty does not cover unit damaged by abuse or where unit is operated outside the normal operating conditions.† The defective part will be repaired or replaced at our option when sent postage prepaid, insured to HALLOWELL EMC accompanied by a copy of original invoice.† HALLOWELL EMC shall not be responsible for any other incidental, contingent or consequential charges or damages.
All conditions of this warranty become null and void should the VOID seal (located under the Instruction Plate) be broken.
THE WARRANTY STATED HEREIN (INCLUDING ITS LIMITATIONS) IS THE ONLY WARRANTY MADE BY HALLOWELL EMC AND IS IN LIEU OF ALL OTHER WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.† HALLOWELL EMC SHALL NOT BE LIABLE FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES OF ANY KIND.
Prices, terms, and product specifications are subject to change without notice.
The Hallowell EMC Model 2000 and Model 2002TM Veterinary Anesthesia Ventilator was designed specifically for veterinary anesthesia use.† It is volume cycled with a choice of three bellows sizes, providing consistent IPPV for†animal†patients from rabbits to foals.
The Hallowell EMC Model 2000 and Model 2002TMincorporates experience resulting from over twenty years of ventilator design and manufacture.† The device is small, portable, and quiet in operation.† It has been designed to be economical in its consumption of supply gas.
The ventilator consists of two main assemblies:† the controller assembly, comprising all electronics, regulatory and control electronics and pneumatics; and the bellows assembly, comprising the bellows base with pop-off valve, the bellows and the bellows housing.† The bellows assembly is easily removed to facilitate cleaning and sterilization.† Equally as easily, the different size bellows and bellows housings may be interchanged on the same bellows base to minimize the ventilator's contribution to the compliance of the breathing system, and to provide increased resolution on the tidal volume scale in the 0-300 ml tidal volume range.†
The bellows base is of injection molded ULTEMTM a product of General Electric Plastics.† ULTEM‚ is a high temperature, high-impact resistant material that is unaffected by water or the presence of all state-of-the-art anesthetics.† In addition, the high temperature properties of ULTEMTM make it fully compatible with standard steam sterilization techniques.
The Hallowell EMC Model 2000 and Model 2002TM is shipped as a free standing unit with the bellows assembly mounted on top of the controller.† For custom installations such as for use in conjunction with MRI units, the bellows assembly may be separated from the controller and mounted in a location closer to the†animal†patient.† As supplied, the ventilator may be located on the anesthesia machine shelf or cart, or on a table top.† The rubber feet can be removed for installation on an optional heavy-duty stand with casters.† The stand increases the mobility of the unit permitting convenient use in multiple operating rooms.†† Optionally, Hallowell EMC provides mounting hardware for the Matrx VMC and Spartan, VMS and VML anesthesia machines.† Mounting hardware is also available for anesthesia machines manufactured by A.M. Bickford, Anesco, Delmarva Labs, Dispo-Med, SDI, and VetEquip (formally Omni Medical).
Before attempting to use this ventilator, it is important that you first thoroughly familiarize yourself with this manual.† After your review, you should complete the receiving and setup procedures, then perform the verification check with a test lung, as described herein.† Become familiar with the ventilator's controls during the verification check, and observe the effect of control adjustments on the breathing system.
If at any time you should have any questions, please do not hesitate to contact us at the address listed on the front page or visit our Web site at http://www.hallowell.com for the latest revisions to this manual as well other information posted there.
1.† Remove all components from the shipping carton.† Retain and store both original shipping cartons for use in the event that the unit has to be shipped.† (See "Returning For Service").
2.† Inspect the ventilator and accessories for any signs of damage that may have occurred during shipping.† If damage has occurred, immediately file a damage claim with the carrier.
Packed by _______________ Date ____/____/____ Controller SN_______________
Received by ________________ Date ____/____/____ Serial Number verified ________
3.† Check the items against the packing slip and report discrepancies immediately.
All ventilator models include and are shipped with the following:
- Hallowell EMC Model 2000 and Model 2002TMController
- Bellows Base Assembly (PN 000A0484)
- Tube, Driving Gas (7Ĺ" black rubber) (PN 000A0495)
- Airway Pressure Sampling Tee (PN 000A2420A )
- 36" x 22 mm Breathing System Tube (PN 201A1615 )
- Power Cord (not included for export) (PN 110A1118 )
- Warranty Card (DOCB0015)
- Operating Manual (DOCA0074)
The standard Model - our 300 - 1600 ml version - (PN 000A0090 ) also includes one each of:
- Bellows, 300 - 1600 ml (PN 000A0488 )
- Bellows Housing, 300 - 1600 ml (PN 200A2289 )
The 0 - 300 ml version (PN 000A0089 ) also includes one each of
- Bellows, 0 - 300 ml (PN 000A0487 )
- Adapter, Bellows, 0 - 300 ml (PN 000A0486 )
- Bellows Housing, 0 - 300 ml (PN 200A2288 )
The 1600 - 3000 ml version (PN 000A0088 ) also includes one each of:
- Bellows, 1600 - 3000 ml (PN 000A1866 )
- Bellows Housing, 1600 - 3000 ml (PN 200A1867 )
Numerous other optional parts may have been shipped with your order also.† Please refer to the packing slip for details.
NOTE:† If you ordered the optional LO 50 psi Supply Gas Alarm, (PN 000A2425) it is built into the ventilator and NOT a separate item.
4.† Complete and return the enclosed Warranty Registration card.
1.††††† Inspect the control unit for debris from shipping.† Inspect all three ports, the 50 psi Supply Gas, Exhaust, and Driving Gas ports on the back of the ventilator and remove any obstructions that may have become lodged inside during shipping and unpacking.
2.††††† Inspect the bellows assembly for debris from shipping.† Tilt the top of the bellows housing toward you and lift it off.† Remove the accessories from within the bellows housing.
3.††††† Ensure that all passages, ports, and chambers are free, clear and unobstructed.† Note that even a hair across the pop-off valve seat will produce an unacceptable leak in the breathing system.
If removal of the pop-off valve becomes necessary, remove the bellows by gently lifting it off to the side.† Unscrew the three red thumb screws.† Gently lift the pop-off valve off the bellows base assembly to reveal the pop-off valve seat and red silicone o-ring.† Do not damage the valve seat.† Do not touch the seat with any type of hard object--even a fingernail scratch--could permanently damage the seat.† Be sure the red o-ring remains in its gland in the bellows base.
4.††††† Reassemble the bellow assembly.† If removed, first install the pop-off valve with the three red thumbscrews.† Next install the bellows with its first convolution over the bellows-mounting ring.† Carefully hold the outer edge of the bellows disk (top of bellows):† lift and lower it quickly several times to puff out and remove any folds in the convolutions.† Place the bellows housing over the bellows, positioning the housing so that the tabs are to the immediate right of the bayonet locks.† Gently press the housing down, twisting the housing clockwise at the same time until the tabs engage with the bayonet locks.† The bellows assembly is now reassembled.
5.††††† Connect the drive gas tube.† Locate the 7Ĺ" long corrugated black rubber drive gas tube, with 15 mm diameter cuffed ends.† Connect the tube between the bellows assembly DRIVING GAS port and the DRIVING GAS port of the control unit.† If the bellows assembly is being mounted remotely from the control unit, a longer 15 mm tube will be needed.† (A Ĺ" garden hose works well for the long runs to MRI units, but the shorter this tube can be, the better.)
6.††††† Position the ventilator.† Place the ventilator in an accessible location, close to the area where it will be used, both for convenience, and in an effort to keep the breathing system tubing as short as possible.
7.††††† Connect the ventilator to the breathing system.† Remove the breathing bag from the bag connector of the Anesthesia machine. Connect the 22 mm x 36" corrugated tube (PN 201A1615 ) to the BREATHING SYSTEM port of the bellows assembly and to the bag connector.† Use of the clear breathing circuit tubing is recommended so the user can see an excessive accumulation of condensation that may interfere with gas flows within the breathing system.
8.†††††† Insert the Airway Pressure Sampling Tee into the breathing system. Disconnect the†animal†patient breathing hose from the INHALE VALVE of the anesthesia machine. Connect the Airway Pressure Sampling Tee (PN 000A2420A ) to the INHALE VALVE and reconnect the†animal†patient breathing hose to the Airway Pressure Sampling Tee. Route the sampling tube as desired to the ventilator Pressure Transducer port on the rear panel. Trim sampling tube to length leaving enough slack for movement. Install Luer Lock fitting such that the hose barb is fully set into the tube. Attach fitting to ventilator Pressure Transducer port.
9.††††† Connect the ventilator to the scavenger.† Use a 19 mm corrugated tube (not provided) to connect the EXHAUST port of the bellows assembly to a properly functioning scavenger system.
Applying any negative or positive pressure to the EXHAUST port of the bellows base assembly will result in a more positive pressure in the†animal†patient breathing system and improper operation of the ventilator.
10.††† Connect the supply gas.† Connect the supply gas hose to the 50 psi Supply Gas port of the control unit, and to the supply gas source.† The unit is provided with a DISS 1240 male oxygen bulkhead fitting.† Gas consumption of the ventilator is very economical, therefore, the use of oxygen as a drive gas is recommended.† Oxygen use reduces the risk of unit malfunction due to contamination of the pneumatics.† Compressed air may be used, but it must be CLEAN and DRY.
The 50-psi source for the ventilator may be provided from a separate tank, wall or ceiling drop, or from a PTO (Power-Take Off) on the anesthesia machine.† Should none of the above be available, a common practice, for machines with DISS 1240 male O2 inlets, is to remove the O2 supply line to the anesthesia machine from the anesthesia machine, connect a demand wye (HEMC PN 150A1691 (GRN) or 150A1692 (WHITE)) to the inlet of the anesthesia machine and then reconnect the O2 supply line to the anesthesia machine via one of the two remaining connections to the wye.† This leaves one leg of the wye available to source the ventilator with O2, connect HEMC PN 000A0489 (GRN) or 000A0490 (WHITE) between the demand wye and the ventilator 50-psi inlet.
11.††† Connect the electrical power.
† PRIOR to connecting the electrical power, confirm that the power inlet module voltage selector switch is set appropriately for your location.
Export Customers Beware
Turning the ventilator on with the Power Inlet Module Voltage Selector switch set for 110 volts while the unit is plugged into a 208 - 240 volt source WILL damage the unit and void the warranty.
Special order 100Vac Japanese versions require no voltage selector setting and will work ONLY on 100Vac.
Plug the ventilator into a properly grounded power source.
Two controls, the RATE and VOLUME on the Hallowell EMC Model 2000 are used to directly set the amount of ventilation.
VOLUME Control (Model 2000) - A needle valve regulating inspiratory flow.† Use to adjust the minute ventilation of the†animal†patient.† Since the I:E ratio is held constant at 1:2, this is the only control that will effect minute ventilation.
Three controls, the RATE and VOLUME (COARSE and FINE) on the Hallowell EMC Model 2002TM, are used to directly set the amount of ventilation.†
VOLUME Controls (Model 2002) - Two needle valves (coarse and fine) further regulating inspiratory flow.† Use to adjust the minute ventilation of the†animal†patient.† The I:E ratio is also held constant at 1:2.
On both units:
RATE Control - A potentiometer.† Use to set the respiratory rate in breaths per minute.† (BPM).
The MWPL is used to set a safety limit and the INSP HOLD is used to pause cycling.† All models with the exception of special order 100v ventilators for use in Japan have one additional control located on back panel. Each control is described in detail below.
I/O Power Switch - a toggle switch used to turn the ventilator on.† The green LED indicates the power is on when illuminated.
INSPiratory HOLD Control - A momentary pushbutton.† Use to pause the breathing cycle at the end of the current or next inspiration for as long as the button is held unless the set MWPL is exceeded.
Maximum Working Pressure Limit Control (MWPL) - A potentiometer.† Use to adjust an upper limit above which you wish the airway pressure never to exceed.
Voltage Selector - A switch adjacent to the power inlet module on the back panel.† Use to select either 105-125v or 208-240v operation.
Be absolutely sure the voltage selector switch is set to the appropriate setting BEFORE the ventilator is turned on.† Turning on a ventilator connected to at 208-240V source while the voltage selector switch is in the 110v position WILL damage the unit and VOID the warranty.
Maximum Working Pressure Limit (MWPL): The MWPL feature allows the operator to set an upper limit above which the airway pressure will not exceed.† The ventilator will terminate the inspiratory phase of the breathing cycle and begin an expiratory phase when the pressure transducer senses a pressure above the MWPL setting.† The MWPL is settable over a range from 10 to 60 cm H2O.† When the airway pressure reaches the set limit, the yellow light on the front panel blinks and a short tone is heard.† If the excessive pressure is not immediately relieved, cycling is paused and the alarm sounds continuously.† Note that the INSPiratory HOLD feature is designed to not function when the MWPL setting is exceeded.† Therefore, a holding inspiration will be released when the MWPL setting is exceeded.
Low Breathing System Pressure Alarm (LO BSP): The LO BSP alarm is activated at the end of inspiration if there is not at least 5 cm H2O pressure sensed by the pressure transducer.† This alarm is sometimes commonly referred to as a "disconnect" alarm; however, it should be understood that an†animal†patient disconnect is not always nor the only cause of low breathing system pressure.† During the alarm condition a yellow light is illuminated on the front panel and the sound of a raspy siren is heard.† The alarm is automatically reset at the end of the next inspiratory phase in which there is a minimum of 5 cm H2O pressure sensed by the pressure transducer.
Low 50 psi Supply Gas Alarm (Optional Feature): † The Low Supply Gas alarm is activated when the supply gas pressure drops below 35 psi (2.4 bar).† The sensor for this alarm is located downstream of the internal 40 micron filter and may also indicate a clogged filter condition.† During an Alarm condition, the yellow light on the front panel is illuminated and a steady, continuous tone is heard.† This alarm automatically resets when the pressure increases above 40 psi (2.7 bar).
VERIFICATION OF PROPER FUNCTION
A Note on Test Lungs
The most readily available test lung will probably be the breathing bag you removed to connect the ventilator.† A breathing bag is a very poor model of a lung.† It can be used if one understands how poor a model of the lung it is and how to avoid using it in such a way that it creates problems that will not occur with a real†animal†patient.
A far better test lung is a ridged walled container such as a gas can, water fountain bottle, or beer keg.† The compliance of these containers is equal to their volume in liters and will be linear as is that of a real lung over normal operating ranges.† Most importantly they will maintain a functional residual capacity (FRC) that is hard to maintain in a breathing bag.
The breathing bag has an unpredictable FRC from breath to breath if bumped or squeezed beyond the point of relaxation, more gas than would normally be popped off at the end of exhalation escapes from the breathing system.† The bellows then abnormally fails to remain at the top of the bellows housing at the end of exhalation.† To use the bag successfully, connect it to the†animal†patient wye, hang it vertically, and do not disturb it.
Verification of proper ventilator operation requires that you first complete the system setup, as described on page 6 and connect a test lung to the†animal†patient wye piece.† During verification, you will be observing the operation of the entire system configuration, checking for leaks, and monitoring the ventilator for consistent cycling.
- Install appropriate bellows assembly. Use the 0-300 ml bellows, bellows adapter, and bellows housing for tidal volume requirements below 300 ml.
- Connect a test lung to the†animal†patient wye and close the pop-off of the anesthesia machine.
- Fill the breathing system with the O2 flush until the bellows reaches the top of the bellows housing.
- Turn the VOLUME controls fully clockwise to the minimum setting, set the rate as desired and turn the ventilator on.
- Increase the VOLUME controls until the peak pressure of each breath is approximately 30 cm H2O.
- Depress the INSPiratory HOLD button long enough to verify that the breathing system is not leaking. The pressure should remain constant.
- Release the INSPiratory HOLD button. Observe that the ventilator is continuing to cycle, and that over time, ~ten cycles, the bellows is not falling significantly.
- Turn the VOLUME controls fully clockwise to the minimum setting and turn the ventilator off.
Note that this verification procedure is printed on each instruction plate on the ventilator sides.
IF THE VENTILATOR IS NOT PERFORMING IN ACCORDANCE WITH THESE EXPECTED OBSERVATIONS, DO NOT USE THE VENTILATOR.† REFER TO THE "TROUBLESHOOTING" SECTION.
Note that in the above procedure no fresh gas flow was used.† During actual operation of the system, the anesthesia machine will be set to deliver enough fresh gas to compensate for minor leaks in the entire breathing system and variations in†animal†patient uptake.† This fresh gas will keep bellows full between each Inspiratory cycle.
A TYPICAL USAGE SCENARIO
The Hallowell EMC Model 2000 and Model 2002TM is a time cycled volume ventilator with an adjustable pressure limit.† The more you understand of the ventilator, how it works, and what it does in response to your settings, the more comfortable you will be with it.† It will feel "right" to change a setting and get what you want from the ventilator.
Making the initial settings:
What are you going to do first?† If this is your first ventilator, you've probably spent many an hour bagging†animal†patients that required IPPV.† You are, by now, comfortable doing that.† Let's setup the ventilator to "bag" an†animal†patient as you would bag one yourself.† If you are convinced the ventilator is bagging the†animal†patient, as you would be, you can feel comfortable with what the machine is doing.
When you bag an†animal†patient, you're careful not to over inflate the lungs.† You have a feeling as to how hard to squeeze the bag.† Your feelings have grown out of experience:† checking the chest wall excursion and correlating that with a reading from the airway pressure manometer on the anesthesia machine.† In general, for a healthy†animal†patient, the peek inspiratory pressure (PIP) should be kept in the range of 15-20 cm H2O. †Animal patients with more compliant lungs may even require less pressure for adequate ventilation and visa versa.
After induction and intubations, when it is time to start IPPV, set the VOLUME controls fully clockwise to the minimum setting.† These controls are needle valves regulating inspiratory flow, with no or very little flow you will deliver no or a very small tidal volume (TV).† Set the maximum working pressure limit (MWPL) control to about 20 cm H2O.† The airway pressure will not exceed this setting regardless of what you do with the other controls.† Connect the ventilator to the breathing system (BS) as discussed in the Set-up Procedure, fill the bellows by turning up the fresh gas flow until the bellows reaches the top of the bellows housing.† Turn the ventilator on.† Set the RATE control to an appropriate rate for the patient.
There will be a pause before the first inspiration.† Watch the chest wall excursion and the airway manometer as you would when you bag.† Since we have started with the inspiratory flow very low, the first TV delivered will be too small to generate sufficient airway pressure.† Consequently, the Low Breathing System (LO BSP) alarm will sound -- don't be alarmed.† Now, increase the VOLUME controls breath by breath, a little at a time, until the chest wall excursions and PIP reach levels that you would seek to achieve while bagging.† At this point you can be comfortable that the ventilator "is squeezing the bag" as you would be.
Trimming the settings as the case proceeds:
At this point the ventilator is delivering an inspiratory flow, determined by your setting of the VOLUME controls, for a time as calculated from your setting of the RATE control.† This flow for a time results in a volume delivered to the bellows assembly that "squeezes the bag", I mean bellows, displacing the mixed gas within to the†animal†patient.
This delivery to the†animal†patient, these TVs at the set rate, results in the overall minute ventilation (MV).† It is the proper MV that must be delivered to the†animal†patient in order to maintain proper blood gas and pH levels.
This MV can be delivered in many ways from a few large TVs to a lot of small TVs. The most optimum combination is up to you to determine just as you would while bagging.
Our ventilator, for those of you familiar with the term, is considered a MV divider. For those unfamiliar with the term, the ventilator delivers a consistent MV to the†animal†patient and that MV is divided into different size TVs by the RATE control.† You can change the RATE control all you want without changing the total ventilation delivered to the†animal†patient.† Let me repeat that.† You can change the RATE control all you want and it will not effect the total ventilation delivered to the†animalpatient.**† In order to change the MV delivered you need only, in fact you must, change the VOLUME controls.† This point will be quite important when you go to wean the†animal†patient from the ventilator.
Remember, when you change the VOLUME controls it is the inspiratory flow that you are changing directly.† The rate and, therefore, the time that flow is delivered has not changed, thus the delivered TV will be either larger or smaller than before.† Stop and think about it, you are now delivering a different volume of gas to the same compliance of the†animal†patient; it follows that the PIP will be different.† This different PIP may be fine or it may be unnecessarily high or low.† In the high extreme the MWPL alarm will sound, a short steady tone, and the PIP will be limited to the set value or in the low extreme, the LO BSP alarm will sound, a warbling tone.
Back to the change being implemented, you have changed the MV as desired now, If needed, trim the delivered TV size with the RATE control to obtain a new TV that results in a more appropriate PIP, and no alarms.
Now do it and get comfortable with it.† Don't just put this document away - setup the ventilator and a test lung.† Read this again trying what is discussed as you read.
Note that no discussion has been made of I-time and E-time and the need to keep them in a proper relation to each other.† This relation is automatically held constant by the ventilator.† The I:E ratio is a consistent 1:2, no need to think about it - there will be enough time for exhalation.† For those of you that want to think about it, we offer the model 2KIE with an adjustable ratio from 1:1.5 to 1:4.† Even when the I:E ratio is adjustable that ratio is still held constant over the full range of rate settings.
**This statement is somewhat of a simplification as you deviate greatly from the current RATE setting.† There is a difference in MV delivered by the ventilator and the alveolar ventilation received by the†animal†patient.† This difference is related to the dead space and BS compliance.† With each TV delivered, a portion ventilates the dead space and BS, the more TVs per minute the greater the portion of the delivered MV that is not seen by the alveoli and, thus, is of no use to the†animal†patient. The significance of this difference is small unless the BS being used is severely mismatched with the†animal†patient or the deviation from the current setting is great.† Similarly the amount of variation is minimal with the small changes needed to trim the TV after adjusting the MV.
Output of the Hallowell EMC Model 2002TM is adjusted by only two controls; a linearly calibrated RATE control (breaths per minute), and a metering VOLUME (Coarse and Fine) control.
Follow the setup and verification procedures and be certain the pop-off valve on the anesthesia machine is completely closed.
DETAILED OPERATING INSTRUCTIONS:
1.†††††† When the†animal†patient is ready, reconnect the ventilator to breathing system.
2.†††††† ALWAYS set the VOLUME controls to its minimum setting before turning on the ventilator. †The VOLUME controls must be fully clockwise to be set to the minimum setting.
3.†††††† Set the maximum working pressure limit (MWPL).†
4.†††††† Turn on the ventilator. Set the RATE before any adjustment is made to the VOLUME.† Adjust the RATE to the desired breaths per minute setting.
NOTE:† As you proceed, continually observe the anesthesia system's breathing system pressure (BSP) gauge to ensure that excessive pressures are not being attained.
5.†††††† The volume controls, as noted above, are initially set after the appropriate RATE has been selected.† Turn the VOLUME controls counterclockwise to increase the tidal volume delivered, or clockwise, to decrease the tidal volume delivered.† Read the approximate tidal volume by noting the displacement of the bellows in ml as indicated on the bellows housing scale.† At a given RATE setting, the tidal volume can be increased or decreased in this manner.
6.†††††† Slight changes in he RATE and VOLUME controls can be made as the procedure continues but never make any gross adjustments to these controls with the†animal†patient connected.
Under no circumstances should the flush button on the anesthesia machine be used during the Inspiratory phase of the breathing cycle.† There is the extreme danger of rupturing a lung.† The flush button introduces 50 - 100 lpm, perhaps more, of oxygen flow into the breathing system.† During inspiration the discharge valve in the control unit is closed so that flush flow is added to the inspiratory flow generated by the ventilator and has no where else to go except to the animal†patient's lungs. It is recommended that the flush feature on the anesthesia machine NEVER be used with an animal†patient connected.† The oxygen flow valve can be opened further than normal providing a more controllable high flow of oxygen.