chapter 33. equipment checkout & maintenance
TRANSCRIPT
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Chapter 33
Equipment Checkout and MaintenanceP.932
A checkou t proc edure is analogous to the pr ef l igh t check for ai rl ine pilo ts an d is
intended to determine whether equipment is p resent, functioning properly, and
ready for use. Failure to check equipment properly is a factor in many crit ical
incidents (1,2,3,4,5,6,7,8,9,10 ,11,12 ). Properly checking equipment can reduce
equipment-related morbidity and mortality, improve preventive maintenance, and
educate the anesthesia provider about equipment ( 1,9,13 ,14 ,15,16,17). Defects
may be f ound even just after preventive maintenance has been performed (18).
Failure to perform a proper check before use is common
(4,19,20,21,22,23 ,24 ,25,26 ,27 ). Many anesthesia providers are unable to identify
intentionally created faults (28,29 ,30 ,31 ,32,33). With i ntensive training,
performance improves, but high rates of complet ion are not achieved (34).
User manuals that a re provided by anesthesia machine manufacturers h ave
detailed direct ions for checking. These should be read carefully. Unfortunately,
these procedures are often overly complicated. When a procedure takes too long to
perform, it is often abridged or skipped altogether.
The Food and Drug Administration (FDA), working with representatives of the
anesthesia community and industry, developed a preuse checkout procedure, which
was published in 1986 (35). Unfortunately, this l ist was too complicated for most
users, and a simplif ied, more user-fr iendly version was published in 1993. This is
shown in Table 33.1 . The new version retained or added checks of components that
fail more frequently than others and that can quickly injure the patient when they
fail (36 ). Components that fail infrequently and that do not immediately jeopardize
the patient when they do malfunction were not included in the 1993 ve rsion but
must st i l l be checked during routine p reventive maintenance. Checklists have been
published in other countries (16 ,17,37 ,38 ,39).
This chapter is constructed along the l ine of the 1993 FDA checkout procedure.
One of the deficiencies of the 1993 FDA checkout was that while it said to check a
certain item, it did n ot explain how. Many clinicians devised their own methods to
f i l l that void but in fact were not correct ly checking certain items. We have
recommended a number of test methods to overcome this deficiency. When an
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alternate test method is given, an attempt wil l be made to point out the advantages
and deficiencies of that method.
Since anesthesia machines from different manufacturers and different models from
the same manufacturer vary, the user should study the manufacturer's suggested
checking procedures and incorporate specif ic points into this generic checkout.
Parts of the checkout procedure described in this chapter wil l not apply to machines
with an electronic checkout. The user must determine which parts are checked
automatically and add those that are not covered.
The FDA checkout is designed for workstations with a c ircle system, venti lator,
capnograph, oxygen analyzer, respiratory volume meter, and ai rway pressure
monitor. Clinicians who use equipment that does not conform to this configuration
may need to modify the procedure to accommodate differences. For example, if a
Mapleson system is to be used, the checking procedure should include this. Such
modifications should have appropriate peer review. The manufacturer's user manual
should be consulted for s pecial procedures.
A copy of th e checkout proced ure sho uld be kept in, on, or nea r the an esthes ia
machine. A record that the checklist was used should be made and kept. A printed
checklist may present a more organized and systematic approach than if the
anesthesia provider uses a mental checklist and may result in i mproved fault
detection (9 ,33). A pictorial checkout may be easier to read and follow than a
typewrit ten l ist (5).
Electronic checklists have been developed (40,41 ). Unlike the electronic checkout
(see below), these only l ist what the anesthesia provider should do. An electronic
checklist may be more extensive than a paper checklist.
Electronic Checking
Many of the newer anesthesia machines provide an electronic checking procedure
(Fig. 33.1). When the machine
P.933
P.934
is turned ON, it reminds the user to start the checkout. Before an electronic
checkout is performed, all components that are to be used for the anesthetic should
be in place. I f the breathing tubing is to be extended, it should be extended to the
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desired length prior to beginning the checkout. During the checking procedure, the
machine may prompt the anesthesia provider to make certain adjustments such as
opening or closing t he adjustable pressure-l imit ing (APL) valve, occluding the Y-
piece, or adjust ing the gas f lo ws.
TABLE 33.1 Anesthesia Apparatus Checkout Recommendations, 1993
This checkout, or a reasonable equivalent, should be conducted before administrationof anesthesia. These recommendations are only valid for an anesthesia system thatconforms to current and relevant standards and includes an ascending bellowsventilator and at least the following monitors: capnograph, pulse oximeter, oxygenanalyzer, respiratory volume monitor (spirometer), and breathing system pressure
monitor with high- and low-pressure alarms.Emergency Ventilation Equipment*1. Verify that backup ventilation equipment is available and functioning.High-pressure System*2. Check the oxygen cylinder supply.
a. Open the oxygen cylinder, and verify that it is at least half full (about 1000psig).
b. Close the cylinder.
*3. Check the central pipeline supplies.
Check that the hoses are connected and pipeline gauges read about 50 psig.Low-pressure System*4. Check the initial status of the low-pressure system.
a. Close the flow control valves and turn vaporizers OFF.b. Check the fill level and tighten vaporizers' filler caps.
*5.Perform a leak check of the machine's low-pressure system.
a. Verify that the machine master switch and flow control valves are OFF.b. Attach a suction bulb to the common (fresh) gas outlet.
c. Squeeze the bulb repeatedly until fully collapsed.d. Verify that the bulb staysfullycollapsed for at least 10 seconds.e. Open one vaporizer at a time, and repeat parts c and d above.f. Remove the suction bulb, and reconnect the fresh gas hose.
*6. Turn the machine master switch ON as well as all other necessary electricalequipment*7. Test the flowmeters.
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a. Adjust the flow of all gases through their full range, checking for smoothoperation of floats and undamaged flow tubes.
b. Attempt to create a hypoxic oxygennitrous oxide mixture, and verify correctchanges in flow and/or alarm.
Scavenging System*8.Adjust and check the scavenging system.
a. Ensure proper connections between the scavenging system and both the APL(pop-off) valve and ventilator relief spill valve.
b. Adjust the waste gas vacuum flow, if possible.c. Fully open the APL valve and occlude the Y-piece.d. With minimum oxygen flow, allow the scavenger reservoir bag to collapse
completely, and verify that the absorber pressure gauge reads about zero.
e. With the oxygen flush activated, allow the scavenger reservoir bag to distendfully and then verify that the absorber pressure gauge reads
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Manual and Automatic Ventilation Systems12. Test the ventilator systems and unidirectional valves.
a. Place a second breathing bag on the Y-piece.b. Set the appropriate ventilator parameters for the next patient.c. Switch to the automatic ventilation (Ventilator) mode.d. Turn the ventilator ON, and fill the bellows and breathing bag with and oxygen
flush.e. Set the oxygen flow to minimum and other gas flows to zero.f. Verify that during inspiration, the bellows delivers appropriate tidal volume
and that during expiration, the bellows fills completely.g. Set the fresh gas flow to about 5 L/minute.h. Verify that the ventilator bellows and simulated lungs fill and empty
appropriately without sustained pressure at end expiration.i. Check for proper action of the unidirectional valves.
j. Exercise the breathing circuit accessories to ensure proper function.k. Turn the ventilator OFF, and switch to manual ventilation (Bag/APL) mode.l. Ventilate manually and assure inflation and deflation of artificial lungs and
appropriate feel of system resistance and compliance.m. Remove the second breathing bag from the Y-piece.
Monitors13. Check, calibrate, and/or set alarm limits of all monitors.Capnometer
Pulse oximeterOxygen analyzer
Respiratory volume monitor (spirometer)Pressure monitor with high and low airway alarms
Final position14. Check the final status of the machine.
a. Vaporizers OFF.b. APL valve open.c. Selector switch to Bag.d. All flowmeters to zero.e. Patient suction level adequate.f. Breathing system ready to use.
*If an anesthesia provider uses the same machine in successive cases, these steps donot need to be repeated or may be abbreviated after the initial checkout.
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These electronic checking p rocedures test the electronic as well as so me
mechanical components of the anesthesia machine. In addition, they may gather
information about breathing system resistance and
P.935
compliance and leaks. They may also remind the user to check functions that are
not included in the automatic checkout.
View Figure
Figure 33.1Electronic checkout procedure on a newermodel anesthesia machine.
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Most machines have a mechanism to l imit or sk ip the electronic checkout. This is
meant for emergency situations. Many clinicians routinely bypass the checkout
(42,43,44). This is not good pract ice. The electronic check may provide a more
comprehensive check than most people perform and may detect some problems
that probably would not have been found otherwise. I f an anesthesia machine has
been held in a ready-to-use state for emergencies, it should be turned OFF at least
daily and restarted with a new checkout procedure.
Whether a full electronic check has been carried out or bypassed is automatically
recorded in the machine's computer and can be accessed. I f a problem should
occur, fai lure to use the checkout may be cited as evidence of substandard care.
A pro bl em wi th e le ctr on ic chec kouts is th at some anes thes ia prov ide rs feel that the
electronic check is all that is needed. This is not true. The user manual should be
considered as the f inal authority on what tasks need to be performed on each
machine.
Since these electronic checkouts dif fer among manufacturers and dif ferent models
from the same manufacturer and since they are subject to change, it is not feasible
to discuss details of these in a text such as this. The Committee on Equipment and
Facil i t ies of the American Society of Anesthesiologists in conjunction with
manufacturers, the American Association of Nurse Anesthetists, and the American
Society of Anesthesia Technologists and Technicians is working to create a new
checkout procedure that wil l include anesthesia machines with electronic checkouts
(45). Anesthesia providers s hould follow this process cl osely.
Daily Checks before Beginning Anesthesia
Eme r g e n c y Ven t i l at i o n Equ i pm en t
Resuscitation Bag
Though rare, certain malfunctions can render the anesthesia machine inoperative
(36,46,47). Sometimes, the problem cannot be diagnosed or quickly corrected. In
this situat ion, a manual resuscitator (Chapter 10) wil l al low the user to provide
posit ive-pressure venti lat ion while the problem is c orrected or the machine
replaced.
The patient port should be occluded and the bag squeezed (Fig. 33.2). Pressure
should build up rapidly to a point at which the bag can no longer be compressed. I f
there is a pressure-limit ing device, it can be checked by connecting a pressure
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manometer between the patient port and the bag, using a T-f it t ing. I f there is an
override mechanism on the pressure-l imit ing device, this should be checked.
The resuscitator should be inspected for signs of wear such as cracks o r tears. A
reservoir bag should be placed over the patient port ( Fig. 33.3). Squeezing the
resuscitat ion bag should cause the reservoir bag to inf late. After the reservoir bag
is fully inf lated and the resuscitat ion bag has been released, the reservoir bag
should deflate easily. This tests both the inspiratory and exhalat ion paths for
patency.
To check that the bag ref i l l valve opens, the b ag should be squeezed, then the
patient port occluded, then the bag released. The bag should re-expand rapidly.
I f the resuscitator has a closed reservoir, i ts function can be checked by performing
several compression-release cycles with no oxygen flow into the reservoir. The
reservoir should deflate, but the resuscitat ion bag should continue to expand. This
checks that the air inlet valve functions with an empty reservoir.
Oxygen Source
A source of ox yg en to connec t to th e resuscitat io n ba g sho uld be avai la ble. An
oxygen f lowmeter attached to the pipeline outlet (Fig. 33.4) or the courtesy
f lowmeter on the anesthesia machine (Chapter 5) wil l provide a source of oxygen.
Difficult Airway EquipmentI f there is any indicat ion that the patient 's airway or tracheal intubation wil l be
dif f icult , the dif f icult airway cart should be in the room. Emergency airway devices
are discussed in Chapter 21. Whatever device expected to b e used needs to be
present and in working order.
Su c t i o n
The adequacy of suct ion can be checked by placing the end of the suction tubing
on the underside of the thumb ( Fig. 33.5). With the hand at waist height, the tubing
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should stay attached without support. A rigid suction catheter (Yankauer) should be
immediately available.
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View Figure
Figure 33.2Squeezing the resuscitation bag with the patientport occluded.
Gas Sup p l y
Cylinder Pressure
Oxygen cylinders should be checked for correct mounting. I f there is a date-expired
label on a cylinder it should be checked (48 ,49). Yokes should be scanned to make
certain that any yoke not c ontaining a c ylinder is f i t ted with a yoke (blanking) plug
(Chapter 5). All tags should indicate ful l or in use .
Before proceeding further, al l f low c ontrol valves should be closed by turning them
completely clockwise. Excessive torque should be avoided. Opening a cylinder or
connecting a pipeline hose when a f low control valve
P.937
is open may cause the indicator to shoot up to the top of the tube and be damaged,
stuck at the top, or not noticed.
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View Figure
Figure 33.3The resuscitation bag is further checked byplacing a reservoir bag over the patient port. Squeezing theresuscitation bag should cause the reservoir bag to inflate.The reservoir bag should then deflate easily when it issqueezed.
View Figure
Figure 33.4A flowmeter that is separate from theanesthesia machine can provide a source of oxygen in anemergency.
The pressure in an ox ygen cylinder is checked by turning the valve s lowly
counterclockwise while observing the related pressure gauge (Fig. 33.6). I f a
hissing sound occurs, the cylinder should be t ightened in the yoke. I f t ightening the
cylinder fai ls to stop the sound, the washer should be checked for damage. I f the
hissing sound persists, the c ylinder should be replaced.
The cylinder(s) should contain suff icient gas that in the event of a problem with the
pipeline supply, l i fe support can be maintained unti l the pipeline problem can be
corrected or more cylinders obtained. How low a pressure is acceptable wil l depend
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on whether addit ional cylinders a re readily available, how low a fresh gas f low can
be used, whether mechanical venti lat ion is necessary, and what type of venti lator is
present. Some venti lators use ox ygen to drive the bellows. Others use air or a
mixture of air and oxygen as the driving gas. A piston venti lator wil l not require any
oxygen to drive it . A full E c ylinder wil l contain about 625 L of oxygen with a
pressure of around 2000 psig. One full cylinder wil l last less than 3.5 hours at a
f low of 3 L/minute.
View Figure
Figure 33.5Check of suction. The strength of the vacuumis tested by determining that the weight of the suctiontubing can be supported at waist height by the seal between
the tubing and the underside of a finger. If the vacuum isunsatisfactory, the tubing will not remain in contact with thefinger.
The FDA checklist recommends that the cylinder be at l east half ful l (about 1,000
psig). I f there are two cylinders and one is completely ful l, a lower pressure in the
second cylinder may be acceptable. The authors believe that 500 psig in an oxygen
cylinder is adequate, provided cylinders wil l not be the primary oxygen supply ( i.e.,
there is a pipeline supply) and the anesthesia provider is aware of the steps
needed to conserve oxygen. Venti lators that use oxygen as the driving gas must be
turned OFF and manual venti lation used. Even if there is only one cylinder and it is
only 25% full, i t would deliver oxygen at 1 L/minute for over 2 hours. Empty or near-
empty cylinders should be labeled as empty and replaced with full cylinders (see
Chapter 1).
Anesthes ia machine cyli nd ers are frequen tly checked an d re pl aced by anesthes ia
technicians or other operating personnel. I f anesthesia providers are no t
accustomed to checking and replacing cylinders, they wil l not react eff icient ly and
effect ively in the event of an oxygen supply failure (50 ).
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I t has been suggested that merely checking a cyl inder for adequate pressure is not
enough (38 ,51). The check valve that prevents cylinder gas from being used when
the pipeline is connected may st ick, p reventing f low from the cy linder if the pipeline
is not in use. To check this valve, the pipeline hoses should be disconnected and
flow at the f lowmeters demonstrated after the cyl inder
P.938
is opened. This wil l also test the non-return valves in the pipeline hose inlet (see
Chapter 5). Oxygen should not leak back through the disconnected pipeline hose
(52).
View Figure
Figure 33.6Top row:Pipeline pressure gauges. Bottomrow:Cylinder pressure gauges.
The 1993 FDA recommendations do not mention checking cylinders containing
gases other than oxygen, because these are not essential for l i fe s upport. I f i t is
planned to use one of these gases, it is reassuring to know that c ylinder supplies
are available on the machine. As discussed in Chapter 1, the contents of a n itrous
oxide cylinder are not ref lected by the pressure unless all of the l iquid has
evaporated and the cylinder is nearly empty. The pressure gauge will continue to
read 745 psig unti l al l the l iquid has v aporized. I f the pressure is less than 600
psig, the nitrous oxide cylinder is nearly empty and should probably be replaced.
Af ter the pres sures are checked, a ll cyl in der valv es sho uld be closed , unless the re
is no pipeline supply for that gas. During use, there wil l be pressure f luctuations in
the machine and the pipeline hoses, especially when a venti lator is in use. As the
venti lator cycles, there wil l be a transient decrease in pressure in the machine. I f
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the pressure falls below that supplied by the regulator for the cylinder, gas can f low
from the cylinder if the cylinder valve is open. This gas loss wil l at some point
deplete the cylinder contents, and there wil l not be an emergency supply available.
When piped gases are not going to be used, there should be one full or n early ful l
cylinder of each gas to be used and the valve on one cylinder should be fully open
after the pressure is checked.
Pipeline Pressure
Some inst itut ions disconnect the pipeline hoses from the machine at night to allow
the anesthesia machine to be moved for cleaning and reduce gas loss from leaks. I f
this is the case, the hoses need to be reconnected to the pipeline system. Fit t ings
should hold f irmly, no leaks should be audible, and the hoses should be arranged toprevent occlusion. The pipeline pressure indicators (Fig. 33.6) should read 345 to
380 kPa (50 to 55 psig).
As discussed in Chapter 5, a pipeline pressure gauge will register only pipeline
pressure if i t is posit ioned upstream of the check valve at the pipeline inlet, as
required by the American Society for Testing and Materials (ASTM) workstation
standard (53 ). I f i t is located downstream of the check valve, as it is o n some older
machines, the pressure registered wil l ref lect the pressure in the machine, but not
necessari ly that in the pipeline (54 ).
L o w - p r e s s u r e Sy s t em
The low pressure system is discussed in Chapter 5 and diagrammed in Figure 5.1 .
Vaporizers
The low-pressure system check is begun by checking the l iquid level in each
vaporizer, adding more if needed. Fil ler caps and drain valves should be t ight.
Vaporizers should be checked to make certain that they are not t i l ted and cannot be
lif ted from their mountings.
LeaksLeaks in the low-pressure part of the anesthesia machine can cause hypoxia or
patient awareness (55,56 ). Profound hypercarbia can occur if a Mapleson system is
in use (57).
Select ing an appropriate leak check can be confusing, because some anesthesia
machines have a check valve either at the common gas outlet or just do wnstream of
the vaporizers. This check valve prevents gas that is
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under posit ive pressure in the breathing system from f lowing back into the machine
and through a leak.
View Figure
Figure 33.7The suction bulb is attached to the common gas
outlet and squeezed until it is collapsed. It should remaincollapsed for at least 10 seconds. Following this, eachvaporizer in turn should be turned ON and the maneuverrepeated.
The minimum mandatory oxygen f low on most machines may decrease the abil i ty to
detect small leaks (58 ). The leak test should be performed without the basal f low.
To eliminate this minimum mandatory f low, the machine needs to be turned OFF.
Irrespective of which test is used, the test should be repeated with each vaporizer
turned ON to its minimum sett ing. I f this is not done, the machine wil l pass the test
for leaks, but a leak associated with the vaporizer or its mounting wil l not be found
(59).
Neg a t i v e P r e s s u r e T e s t
The negative pressure test uses a suction bulb to create a negative pressure in the
machine (55 ,60 ). The bulb is attached to a tubing with a 15-mm adaptor, which wil l
f i t the anesthesia machine common gas outlet on the other end (Fig. 33.7). This
device is av ailable commercially or can be constructed by taking a
sphygmomanometer bulb, reversing the air i nlet valve in the bulb, and c onnecting
one end of a short tubing to the bulb and the other to a 15-mm tracheal tube
adaptor. When reversed, the valve wil l pull ai r from the machine side of the bulb.
Al te rnate ly, the de vice can be cons tru cte d from the bul b pu mp of a d is posabl e
intravenous blood administrat ion set (61 ).
To perform the test, al l f lowmeters are turned OFF. I f there is a minimum
mandatory oxygen flow, the entire machine must be turned OFF. Squeezing the
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bulb unti l i t is remains collapsed creates a negative pressure in the machine. I f the
bulb remains collapsed for 10 seconds, there is n o signif icant leak present. I f there
is a leak, the bulb wil l inf late. This test should be repeated with each vaporizer
turned ON. The suction bulb is then removed and the fresh gas hose reconnected.
This negative pressure leak test wil l work for all makes and models of machines,
whether there is a check valve or not (55 ). For this reason, it is sometimes called
the universal leak test. I t dif ferentiates between breathing system leaks and leaks
in the machine. Studies comparing this with other leak tests found that i t was the
only one that identif ied all l eaks and was the most sensit ive at f inding small leaks
(55,56).
Unfortunately, i t is not possible to use this test on some new anesthesia machines
because the common gas outlet is not accessible to the user. An unintentional
continuous gas f low wil l resul t in a false-posit ive test (56).
Po s i t i v e P r e s s u r e T es t
When performing a positive pressure leak test, care must be taken that the
pressure does not increase beyond the prescribed l imits. There is l i t t le room for
compression in the machine tubing, and no bag to buffer pressure increases. I t is
possible that the pressure could increase to a point where a f lowmeter or other part
of the machine could be damaged.
Pressure Gauge Test
A pressure gau ge (t he gau ge from a s tandar d sph ygmo ma no me te r wi l l do ) is
attached to the common gas ou tlet (Fig. 33.8), and a f low control valve is s lowly
opened until the pressure on the gauge reaches 30 cm H 2O (22 mm Hg) (57,62).
The f low is then lowered unti l that pressure is steady. The f low rate on the
flowmeter is then equal to the leak rate in the machine at that pressure. I t should
be less than 50 mL/minute. This test cannot be performed if there is a minimum
mandatory f low, because these f lows are usually around 200 mL/minute.
Fresh Gas Line Occlusion Test
With this test, a f low of 50 mL/minute is set on the oxygen f lowmeter and the f resh
gas l ine kinked. The indicator in the f lowmeter tube
P.940
should move downward. An advantage of this test is that it can be performed during
a case (55 ). This test c annot be performed if there is a minimum mandatory f low,
because these f lows are usually around 200 mL/minute.
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View Figure
Figure 33.8A pressure gauge from a blood pressure cuff isattached to the delivery hose from the machine. Sufficientflow is established on a flowmeter to maintain a pressure of22 mm Hg on the pressure gauge. The flow that is requiredto maintain that pressure should be less than 50 mL/minute.
Combination Breathing System and Machine Leak Tests
The following tests can be used to check for leaks in the breathing system and
parts of the machine downstream of the check valves.
Re t r o g r a d e F i l l T e s t
The APL valve is closed and the patient port occluded. The master control switch
needs to be turned ON. The oxygen f lush or a high f low from the f lowmeter is used
to f i l l the reservoir bag. As the bag begins to distend, the pressure on the
manometer in the breathing system is observed. As the pressure starts to r ise, the
f low on the f lowmeter is adjusted so that a pressure of 30 cm H 2O is maintained in
the breathing system. I f this pressure is overshot, the APL valve should be opened
brief ly. The f low necessary to maintain a s teady pressure should be no greater than
350 mL/minute. The pressure should be released by opening the APL valve rather
than removing the occlusion from the patient port at the Y-piece.
The advantages of this test are that it can be performed quickly without accessoryequipment and that it checks the breathing system as well as the low-pressure
parts of the machine in those models that do not have a check valve (63). It also
allows the continuous airway pressure alarm to be checked. Disadvantages are that
it is relat ively i nsensit ive to small leaks, and it does not localize the source of the
leak between the breathing system and the machine.
Sq u e e z e B u l b T e s t
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With the machine master switch and f low control v alves turned OFF, the Y-piece is
occluded and the APL valve closed. A suction bulb with a 22-mm connector is
attached t o the reservoir bag mount and squeezed repeatedly unti l the breathing
system pressure gauge reads 50 cm H 2O. The gauge is observed. I f a drop in
pressure from 50 to 30 cm H2O takes 30 seconds or longer, the leak rate is
acceptable.
I n -u s e T e s t
During use, a leak in the machine or breathing system can be quantif ied by
lowering the fresh gas f low as low as possible (64 ). I f the venti lator bellows or
reservoir bag continues to f i l l , the leak rate is less than the fresh gas f low.
When a leak is suspected, a systematic search of the anesthesia machine andbreathing system should be made, following the route of gas travel. A leak can
sometimes be located by placing alcohol on the hands and moving the hands over
components while gas f low i s occurring. The leaking gas evaporates the alcohol
and cools the skin.
When the machine leak test is complete, residual vapors should be f lushed out of
the machine by turning ON an oxygen f low at 1 L/minute for 1 minute with all
vaporizers OFF (63 ). There should be no n oticeable odor in the gas coming from
the common gas outlet. Using the oxygen f lush control wil l not f lush vapors out of
the machine, because its f low enters the fresh gas f low downstream from the
vaporizers.
Turn the Machine's Master Switch and All Other Necessary
Equipment ON
To continue the checkout, the machine master switch needs to be turned ON to
enable the pneumatics and electronics. The machine should be allowed to complete
its own diagnostic checks and any a utomated checking procedure. Any electrical
equipment to be used during the anesthetic should be turned ON at this t ime withthe exception of a d ivert ing gas monitor, which should be turned ON after the
breathing system is checked for leaks.
Flowmeter
Each f lowmeter should be examined with the f low control valve closed to make
certain the indicator is at the zero posit ion (or at minimum f low if the machine is so
equipped). Each f low control v alve should be slowly opened and closed while
observing the indicator. The f loat should move smoothly and respond to s mall f low
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P.941
control valve adjustments. I f the indicator is a rotameter or ball, i t should rotate
freely. An indicator that moves errat ically or f ai ls to return to zero may be
displaying erroneous f low rates, and the machine should be taken out of service
unti l the problem is c orrected.
An atte mp t should be ma de to crea te a hy po xic mixture by adj us ti ng th e ni trous
oxide f low up or the oxygen f low down while both nitrous oxide and oxygen are
f lowing. Turning the nitrous oxide f low up should cause the oxygen f low to increase.
Similar results should occur if a high nitrous oxide f low is present and the oxygen
flow is adjusted downward. Some anesthesia machines will not alter the oxygen
flow but wil l l imit the nitrous oxide f low. I f th e machine has a ni trous oxide : oxygen
ratio alarm, it should be act ivated.
Ad j u s t a b l e P r e s s u r e -l im i t i n g Va lv e and Sca veng i n g
S y s t em
The APL valve and venti lator should be connected to the scavenging system
interface. I f an act ive disposal sys tem is being used, the f low should be adjusted.
Adjustable Pressure-limiting Valve
The scavenging system and APL valve are checked by closing the APL valve,
occluding the patient port, and f i l l ing the s ystem by using the oxygen f lush so that
the breathing system pressure gauge reads 50 cm H2O. The APL valve is then
opened. There should be a gradual loss of p ressure from the system. This
establishes proper APL function and transfer tubing patency. If the scavenging
system interface has a reservoir bag, it should inf late when the APL valve is
opened and then deflate (65 ).
I f the pressure is released by removing the occlusion at the patient port, the APL
valve and scavenging system patency wil l not be checked. In addit ion, this could
cause a cloud of a bsorbent dust to enter the breathing system ( 66 ,67).
Scavenging System
C l o s ed S y s t em
Air Intake Valve (Negative Pressure Relief)
With minimal or no f low from the anesthesia machine, the APL valve should be fully
opened and the patient port occluded. Scavenging suction should be turned ON. If
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there is a bag at the scavenging interface, it should collapse. The reservoir bag in
the breathing system may also collapse. At this p oint, the breathing system
pressure gauge should indicate a pressure of 0 to -2 cm H2O.
Positive Pressure Relief
To test the posit ive pressure relief valve on the s cavenging interface, the APL valve
is ful ly opened and the breathing system patient port occluded. The oxygen f lush is
act ivated. The breathing system pressure indicator should read less than 10 cm
H2O.
An al ternate tes t can be us ed. The vacuu m f lo w to the scav eng ing sys tem is tu rned
OFF and the APL valve ful ly opened. The reservoir bag and the scavenging system
bags are fully inf lated by using the oxygen f lush. A f low of 2 L/minute is then set onthe oxygen f lowmeter. The pressure gauge in the breathing system should read not
more than 3 cm H 2O.
Op e n S y s t em
Open scavenging systems do not have valves that need to be checked, as the
system is open to atmosphere. The f low indicator on the scav enging interface
should be checked to make certain that the flow is adequate.
B r e a t h i n g S y s t em
Oxygen Monitor Calibration
Not all oxygen analyzers require a daily calibrat ion check. The instruct ion manual
should be consulted to determine what procedures are needed and how often they
should be carried out.
I f daily cal ibrat ion is required, the sensor should be removed from the breathing
system and moved well away from sources of gas that might change the ambient
oxygen concentration. I t should be c alibrated to 21% and the low oxygen alarm
checked by sett ing it above 21%. The sensor should then be placed securely in its
mount in the breathing system and the breathing system flushed with oxygen. This
should result in a reading of over 90%.
Initial Breathing System Status
The breathing system should be inspected to determine that no parts are damaged
or missing and that all accessory equipment [e.g., humidif ier, heat and moisture
exchanger, f i l ter, posit ive end-expiratory pressure (PEEP) valve] for the proposed
anesthetic are in place. All connections should be made secure by push and twist.
I f a divert ing gas monitor is to be used, the sampling l ine should be checked for
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kinks or occlusion and connected to the breathing system, but the monitor should
not be turned ON at this t ime. Transparent breathing tubes should be checked for
foreign bodies (68). The bag-ventilator selector switch should be in the bag
position. The pressure gauge should read zero. If the absorber is detachable, it
should be checked to make sure that the a ttachment is secure.
The absorbent color should be noted. I f there is any color change, the absorbent
should be discarded and replaced with fresh absorbent. If there is a dual-chamber
absorber, both chambers should be changed at the same t ime. I f the machine is
rarely used or i f i t has been sit t ing with gas f lowing through it for an undetermined
time, the absorbent should be changed even if there is no color change, unless an
absorbent that does not cause
P.942
formation of carbon monoxide is being used. The effects of desiccated absorbent
are discussed in Chapter 9. Accumulated absorbent dust and water should be
removed from the absorber dust cup, taking care not to s pil l either.
View Figure
Figure 33.9Test for leaks in the breathing system. With allgas flows set to zero or minimum, the APL valve is closedand the patient port occluded. The reservoir bag is filled byusing the oxygen flush until a pressure of 30 cm H2O isshown on the gauge. With no additional gas flow, the
pressure should remain at this level for at least 10 seconds.
Leaks in the Circle Breathing System
I f leaks in the circle s ystem were checked for previously in combination with
machine leaks, this test does not need to be performed.
To init iate the breathing system leak test, al l gas f lows should be at zero. The APL
valve should be closed and the patient port occluded. The breathing system should
be pressurized to 30 cm H 2O by using the oxygen f lush (Fig. 33.9). I f there is no
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leak, the pressure wil l remain near this level for at least 10 seconds. The APL valve
is then opened. The p ressure should decrease.
The leak can be quantified by adjust ing the oxygen f lowmeter to maintain a
pressure of 30 cm H2O in the breathing system (with the Y-piece occluded and the
APL valv e clo sed ). The breath ing system s ta nda rd requ ires that th is do es no t
exceed 300 mL/minute (69 ).
Leak in a Mapleson Breathing System
A Ma ples on breath ing system shou ld be con nec ted to the f resh gas source wi th the
APL valv e clo sed . With the pa tien t port occlude d, the sys tem shou ld be pre ssurize d
using the oxygen f lush. I f there is no leak, the system wil l retain the pressure for at
least 10 seconds. The pressure should be released by opening the APL valve.The leak rate can be quantif ied by attaching a manometer to the patient port and
determining the f low needed to s ustain a certain pressure (70).
Bain System Inner Tube
The integrity of the Bain breathing system inner tube (Chapter 8) is essential to
avoid excessive dead space. Profound rebreathing and hypercarbia can occur if the
inner tube has a hole, is detached at the machine end, or does not extend to the
patient end of the outer tubing. For this reason, it is essential that this is tested.
I n s p e c t i o n
The Bain system should f irst be inspected to determine if the center tube is
properly connected to the absorber end of the tube. The inner tube must also be
connected near the patient end. Any retract ion or disconnection from either end
should cause the system to be rejected.
In n e r T u b e O c c l u s i o n T e s t
NOTE: I f the sys tem has side holes or slots at the patient end of the inner tubing,
this test wil l not work (75 ,76 ).
To perform this test, a 2 L/minute f low is set on one of the f lowmeters
(26,71,72,73 ,74 ). The plunger from a small syringe or a f inger is inserted into the
patient end of the outer tube, occluding the inner tube (Fig. 33.10). The f lowmeter
indicator should fall.
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View Figure
Figure 33.10Bain system inner tube test. The plunger froma small syringe is inserted into the patient end of the systemover the end of the inner fresh gas delivery tubing. Theflowmeter indicator should drop.
A varia tion of th is pro cedure is to atta ch a mano me te r to the en d of th e in ner tub e
and determine the f low needed to cause a sustained pressure (70 ).
Ox y g e n F l u s h T es t
To perform this test, the reservoir bag is f i l led (77). The patient port must be open
to atmosphere. The oxygen f lush valve on the machine is act ivated. The high gas
flow through the inner tube wil l p roduce a Venturi effect, which lowers the pressure
in the larger outer tube. I f there are no problems with the inner tube, the bag
should deflate. I f the bag does not deflate or i nf lates, the inner tube should be
checked. This test may fail to detect major faults that can be detected by the inner
tube occlusion test (74,78,79,80).
Lack System Inner Tube
To test the integrity of the inner l imb of the Lack sys tem, a tracheal tube can be
inserted into the inner tube at the patient end (81,82 ). Blowing down the tracheal
tube with the APL valve closed will produce bag movement if there is leakage
between the inner and outer l imbs.
An al ternati ve method is to occlude bo th the inne r and ou te r l imbs wi th the APL
valve fully open (82). There should be no gas escape when applying pressure to the
reservoir bag. I f the inner l imb is defect ive, gas wil l f low through the APL valve,
and the bag wil l collapse.
A third tes t is to insert a tr acheal tub e into th e inne r tube at the pa tient end (83).
The cuff is inf lated to obstruct the opening between the outer and i nner tubes. With
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the APL valve fully open, the reservoir bag should be f i l led using the oxygen f lush.
Squeezing the bag should cause the f lowmeter indicator to drop, but no gas should
be released through the APL valve.
Still another test uses a pressure manometer and inflating bulb ( 62 ). A 7-mm nasal
airway that is connected to the bulb and manometer is inserted into the inner tube
with the APL valve closed. The inf lat ing bulb is used to pressurize the inner tube to
30 cm H2O. There should be minimal decline in pressure over 30 seconds. The APL
valve is then opened. The pressure should fall i mmediately.
Coaxial Circle System
Hypercarbia related to a faulty coaxial circle s ystem has been reported (84 ). This
can be detected by having the anesthesia provider or patient breathe through thesystem with the APL valve open and observing the capnograph. I f there is a
connection between the two l imbs, the capnograph baseline wil l be elevated.
Smell Test
Some authors recommend that the anesthesia provider smell the gas from the
patient port with a 3 L/minute f low of oxygen set on the f lowmeters. No odor
indicates that a vaporizer is not leaking or left ON (85 ).
Manua l an d Au t o m at i c Ve n t i l a t i o n S y s t em s
A sec ond re serv oi r bag sho uld be pl ac ed on the pa ti en t port (Fig. 33.11). The
oxygen f lowmeter should be s et at the minimum f low or 300 cc/minute if there is no
minimum f low. The bag-venti lator selector switch should be in the bag posit ion. As
the reservoir bag on the bag mount in the breathing system is squeezed, the bag on
the patient port should inf late (Fig. 33.11). The bag on the patient port should then
be squeezed. The reservoir bag on the bag mount should inflate. System resistance
and compliance should be evaluated during this test. This is useful to detect
inadvertent PEEP or an obstruction in the system (86,87 ).
Ventilator parameters appropriate for the patient should be set and the bag-
venti lator selector switch placed in the venti lator mode. The oxygen f lowmeter
should be set at the minimum f low or 300 cc/min if there is no minimun f low. The
bellows and reservoir bag on the patient port should be f i l led by using the oxygen
flush and the ventilator turned ON. The bag on the patient port should inflate and
deflate (Fig. 33.12). The appropriate t idal volume should be delivered and the
bellows f i l l completely during expirat ion. I f use of the PEEP valve is anticipated, it
should be adjusted to dif ferent values and the breathing system pressure gauge
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observed to verify c orrect performance. The bag should be removed from the
patient port and the venti lator allowed to continue cycling (88). The low airway
pressure and t idal o r minute volume alarms should annunciate after an appropriate
delay.
P.944
View Figure
Figure 33.11Test of manual ventilation system. A reservoirbag is placed on the patient port. The bag-ventilator switchis turned to the bag position. As the reservoir bag in the
breathing system is squeezed, the bag on the port shouldinflate. Squeezing the bag on the patient port should causethe reservoir bag in the breathing system to inflate.
View Figure
Figure 33.12Test of ventilator. A reservoir bag is placed onthe patient port. The oxygen flowmeter is set for a flow of300 mL/minute. Ventilator parameters that are appropriatefor the next patient are set. The bag-ventilator selectorswitch should be in the ventilator position. The bellows andreservoir bag are filled, and the ventilator is turned on. The
bellows should move freely and fill completely as theventilator cycles. The unidirectional valves should be
observed to make certain that the discs open properly.
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With the venti lator st i l l c ycling, the patient port should be occluded and the bellows
fi l led using the oxygen f lush. The breathing system pressure should rise no higher
than that set on the high pressure safety relief pressure device. The high pressure
alarm should sound.
To check for a leak in an upright bellows, the bellows should be occluded, the
patient port occluded, and the f lowmeters turned OFF. Al ternately, the bag-
venti lator selector switch can be set to bag. The bellows should stay inf lated. I f i t
fal ls, there is a leak.
To check for a leak in a venti lator with a hanging bellows (Fig. 33.13), al l
f lowmeters should be turned OFF or to the minimum f low and the venti lator turned
ON. When the bellows is ful ly contracted, the patient port is occluded (or the bag-
venti lator selector switch is put in the bag posit ion) and the venti lator s witched
OFF. The bellows should remain contracted at the top of the housing. I f i t expands
downward, a leak is present. Another way of performing this test is to occlude the
patient port (or put the bag-venti lator selector switch in the bag p osit ion) with the
ventilator turned OFF and lower the bellows stop. The bellows should not expand
downward.
View Figure
Figure 33.13Test for leak in ventilator with hangingbellows. The flowmeters should be turned off or at
minimum flow. The APL valve is closed and the ventilatorturned on. When the bellows is fully contracted against the
head of the bellows assembly, the patient port is occluded(or the bag-ventilator selector switch is put in the bag
position), and the ventilator is turned off. The bellowsshould remain at the top of the housing for at least 10
seconds.
Un i d i r e c t i o n a l Val v e Tes t s
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The FDA checklist does not specify how the unidirect ional valves are to be c hecked
(89). Many pract it ioners feel that watching the inhalat ion valve disc rise during
inhalat ion and the exhalat ion valve rise during exhalat ion while the venti lator is
cycling is an adequate check. This v erif ies that they open but not that they close
completely.
During use, incompetent unidirect ional valves c an be detected by an inspired
carbon dioxide greater than zero when using a capnograph (Chapter 22). Some
respirometers can detect reversed f low.
Unidirect ional valves may be checked by several methods.
Breathing Method
With the APL valve cl osed, the inspiratory l imb of the breathing system is detachedfrom the absorber and occluded. Wearing a mask, the tester tr ies to breath through
the Y-piece (Fig. 33.14A). I t should be possible to exhale freely but not inhale.
Next, the exhalat ion tube is detached and occluded. The tester should be able to
inhale but not exhale (Fig. 33.14B).
Valve Tester
This method ut i l izes a device consist ing of a bulb with a 22-mm female f it t ing that
can attach to the inspiratory and exhalat ion ports (90 ,91 ). To test the inspiratory
valve, the compressed bulb is attached to the inspiratory port. I t shouldimmediately reinf late. When the bulb is compressed, it should meet f irm resistance
(Fig. 33.15A).
To check the expiratory valve, the tester is attached with the bulb i nf lated. I t s hould
be possible to squeeze the bulb, and it should remain deflated (Fig. 33.15B).
Pressure Decline Method
To check the v alves by this method, an extra reservoir is placed on the inspiratory
port (92 ,93 ,94). The other bag remains on the bag mount. The fresh gas f low is s et
to a minimum and the APL valve is closed. The circle system is p ressurized to 30cm H2O by using the oxygen flush. If the bag on the bag mount remains inflated,
the expiratory valve is competent. Next, the APL valve is opened. I f the reservoir
bag on the inspiratory port does not deflate, the inspiratory valve is competent.
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View Figure
Figure 33.14Checks for incompetent unidirectional valves.A:The inspiratory limb is detached and occluded. The testertries to breathe through the Y-piece. It should be possible toexhale freely but not inhale. B:The exhalation tubing isdetached and occluded. The tester should be able to inhalefrom the Y-piece but not exhale.
F in a l Con f i g u r a t io n a n d Ob s t r u c t i o n Che c k
At thi s po int, bre ath in g sys tem accessory eq uipment (e.g., PEEP valve, hea te d
humidif ier) should be in place and turned ON. Obstruct ions in the breathing system
can be detected by having the patient b reathe 100% oxygen through a mask,
provided a t ight mask f it is achieved (95,96 ). This can also be done by the
anesthesia provider wearing a mask (Fig. 33.16) (97). The reservoir bag should
inf late and deflate, and the breathing system pressure indicator should show no
PEEP. Negative pressure wil l reveal an obstruct ion in the inspiratory l imb; posit ive
pressure wil l reveal an obstruct ion in the expiratory l imb (98 ). While this is being
done, the capnogram should be checked to make certain that a normal waveform
appears.
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View Figure
Figure 33.15Checking the inspiratory unidirectional valve.The bulb should be compressed (A)and then attached to theinspiratory port. It should inflate. Then, it should not be
possible to compress the bulb. B:Testing the expiratoryunidirectional valve. The bulb should compress easily andremain compressed.
Mon i t o r s a n d C o n t r o l s
All mo ni tors sho ul d be tu rned ON (36 ). Alarms should be tested by s imulat ing alarm
condit ions, and appropriate l imits should be set.
The f inal status of a ll controls should be checked before the machine is put in use.
This includes having all f low control valves closed, all f lowmeters indicat ing zero
f low, all vaporizers turned OFF, the bag-venti lator switch set to BAG, the PEEP
valve OFF, and the APL v alve open. The breathing system should be ready to use
with all components connected by using a push and twist mo tion. The scavenging
system vacuum should be ON.
Subsequent Checks on the Same Machine on the Same
Day
I f a thorough check is pe rformed before the f irst case of the day, a less complete
procedure can be used before s ubsequent cases. Those steps are indicated inP.948
Table 33.1 by an asterisk (*). The tests so ma rked may not be repeated or may be
abbreviated if the machine is used b y the same anesthesia provider fo r successive
cases on the same day.
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View Figure
Figure 33.16Breathing system patency can be confirmedby inhaling and exhaling through the patient port.
I t is important for the breathing system to be c hecked before the next case begins
(47). One of the most common alterations made between cases is changing of the
carbon dioxide absorbent. The absorber may not be c losed properly. This may
cause a large leak and inabil i ty to venti late.
Procedure at the End of the Case
At the conclus ion of a case, f lowmeters , vap ori ze rs , and suc ti on should be tu rn ed
OFF. Monitors that would need recalibrat ion if turned OFF should be left ON or put
in a s tandby mode. The absorbent should be checked for signs of exhaustion and
changed if indicated (Chapter 9).
Other Machine and Breathing System Checks
While the FDA checkout recommendations are adequate for daily use, other parts
may need to be checked either daily or as the need arises. This is especially true
after the machine has been altered or serviced.
Oxyg e n P r es s u r e F ai lu r e A l a rm
Most anesthesia machines are equipped with an oxygen pressure failure alarm,
which is act ivated if there is no o r low oxygen pressure in the machine. To test this
alarm, the oxygen pipeline hose is disconnected and all oxygen c ylinders closed.
Any pressure rema ini ng in the mac hi ne shou ld be bled of f by us ing th e ox yge n
flush. The alarm should sound. This s tep was not included in the FDA checkout
recommendations, because isolated failure of this component wil l no t injure a
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patient (36 ). The Associat ion of Anaesthetists of Great Britain and Ireland
recommend that this alarm is tested on a weekly basis (39).
Lea k s a t t h e Yoke
I f a cylinder is not properly t ightened in a yoke, there wil l be a gas leak when the
cylinder is turned ON. A large leak wil l be quite apparent by the sound. A small leak
wil l not be heard but could cause signif icant gas loss. To check for a leak at the
yoke, after the cylinder pressures have been checked and the v alves closed, the
cylinder pressure indicators should be observed for 2 to 5 minutes, with no f low on
the f lowmeters. A drop of more than 50 psi g indicates signif icant leakage. I f there
is a minimum mandatory oxygen flow, the machine must be turned OFF. The
minimum f low wil l mask any l eaks in the high-pressure system.
Oxyg en Fa i l u r e Saf e t y Val v e
The oxygen failure safety valve was included as a routine test in the f irst edit ion of
the FDA checkout but was not made part of the later version because it rarely fai ls,
and there are many other methods of detecting oxygen pressure failure (36 ). This
test can be performed by using either the pipelines or cylinders as the gas source.
A cylinder of each gas on th e machine is tu rned ON wh i le the pipel in e hoses are
disconnected. Flows of 2 L/minute are established on the f lowmeters for each gas.
The oxygen cylinder is then turned OFF. As the oxygen pressure falls, the f lows of
all other gases except ai r in some machines, as indicated by their f lowmeters,
should decrease in proport ion to the decrease in oxygen f low and eventually shut
OFF. Restoring the oxygen pressure should cause the indicators to return to their
previous p osit ions.
To perform the test by using pipeline gases, all c ylinder valves should be closed
and the f low control valves opened unti l the cylinder pressure indicators register
zero. The pipeline hoses are connected and f lows established on all f lowmeters.
The oxygen hose is then disconnected. The indicators of the anesthetic gasflowmeters should fal l just before the oxygen indicator.
Spar e Com pon en t s
Extra components of the breathing system should be immediately available (99 ).
These include an addit ional disposable system or individual components of
reusable systems (Y-piece, tubings, bag).
E l ec t r i c a l S y s t em
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Tests of the electrical sys tem vary with the dif ferent makes and models of
machines. Most have a means to test the reserve battery. In addit ion, there is
usually an indicat ion that the machine is working on the battery power. To check
this, the machine is disconnected from the mains power. The battery power
indicator should be i l luminated. Many electronic machines wil l have an indicator of
the battery charge (see Chapter 5).
Vapo r i z er E x c l u s i o n S y s t em
Most anesthesia machines have a mechanism to allow only one vaporizer to be
turned ON at a t ime (Chapter 6). To test the vaporizer exclusion system, one
vaporizer should be turned ON and an attempt made to turn each of the other
vaporizers ON, one at a t ime.
P.949
Other Equipment
T r a chea l Tub e s
Appropri ate tra cheal tubes of the size s useful for the pa tien t sho ul d be re ad y for
use. Lumen patency should be checked. With clear tubes, simple observation wil l
suff ice. With other tubes, it is necessary to look in both ends or insert a s tylet. The
cuff should be held inf lated for at least 1 minute to verify that there are no leaks.
The cuff should inf late evenly and not st ick to the tube wall or decrease the size of
the lumen. One larger and one smaller than the tracheal tube that is intended for
use should be readily available.
R ig i d L a r y n g o s c o p e s
Laryngoscope malfunction is a frequent problem. At least two handles should be
present, each f it ted with the type of blade that the user anticipates wil l be best forthe patient. The lights should be checked for adequate intensity. Blades of other
sizes and s hapes s hould be immediately available and checked for p roper function.
Ac c e s s o r y In t u b a t io n Equ i pm en t
A stylet and boug ie shou ld be imm ed iately avai la ble. I f a rap id sequence in tu bati on
is planned, the stylet should be f it ted to the tracheal tube. An intubating forceps
should be immediately available. I f a dif f icult intubation is anticipated, specialized
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equipment for dif f icult intubation described in Chapters 18and 21 should be in the
operating room and checked for c ompleteness, defects, and proper assembly.
Mas k s a n d A i r w a y s
An as sortment of mas ks and ai rways in a vari ety of s izes should be re ad i ly
available.
O t h e r Equ i pm en t
Special equipment that is required for part icular cases, such as ex tension pipeline
hoses, extension breathing hoses, patient warming equipment, and i nfusion
devices, should be present and checked before use.
Procedures at the End of the DayFollowing the last case, the pipeline hoses should be disconnected at the wall or
ceiling (not at the back of the machine) and coiled over the machine. If the hoses
are disconnected at the back of the machine, they will continue to be pressurized,
and gas may be lost into the room through leaks. I f a f low control valve is open and
the pipeline supply is connected, dry gas can desiccate the absorbent, promoting
the formation of carbon monoxide (Chapter 9). Cylinder valves should be c losed.
Each f low control valve should be opened unti l the cylinder and pipeline pressure
gauges read zero, then closed. I f the f low control valve is left open, restorat ion of
the gas supply may forcibly raise the indicator to the top of the tube, causing
damage.
Vaporizers should be f i l led at the conclusion of the day after most operating room
personnel have vacated the room. This wil l decrease personnel exposure to
anesthetic agents.
Checking New or Modified Equipment
Each new anesthesia machine, ventilator, or other complex piece of equipment
should be checked for proper functioning before being put into use. This is bestperformed by a manufacturer's representat ive, who may give in-service instruct ions.
A doc um en t cert i fying th at the equ ip me nt ha s be en chec ked for p roper as sembly
and function should be obtained and kept.
A ma nu al that conta in s assemb ly an d ins ta llat io n ins truct io ns , ma inten anc e
requirements, checking procedures, and instruct ions for use is su pplied with each
piece of equipment. This must be read carefully and reviewed periodically. A copy
should be kept in the central equipment f i les and with the equipment itself .
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Preventive Maintenance
Many items in an anesthesia machine and ventilator deteriorate with time and use.
Preventive maintenance is d esigned to anticipate predictable failures and replace
weakened components before they fail. In some cases, an improved part has
become available and can be substituted. The recommended frequency of
preventive maintenance (usually every 4 to 6 months) is determined by the
manufacturer and wil l be s tated in the operator's instruct ion manual.
Proper preventive maintenance has been shown to be effect ive in preventing
equipment fai lure (100 ). One study determined that an adequately maintained
anesthesia machine that was 10 years old had no more failures than new machines.
Lack of a preventive maintenance program may lead to an unacceptably high rate
of breakdowns, premature replacement of major equipment, and unnecessary risks.
There are a number of ways that equipment can be serviced.
P.950
Equ i pm en t Manu f ac t u r e r Se r v i c e Con t r a c t
With a service contract, the manufacturer's se rvice representat ive comes to the
health care facil i ty. Dif ferent levels of s ervice are available. The cost wil l d epend
on the number of parts covered, the frequency of the visits, and the necessary
response time.
In d e p en d e n t Se r v i c e Comp an y
Independent companies that are not associated with a pa rt icular manufacturer may
perform service on certain equipment on a contractual basis. I t may be dif f icult for
the anesthesia provider to determine the qualif icat ions of an independent service
provider. Some manufacturers cert if y independent providers to service their
equipment. To become certif ied, they must satisfactorily complete the same
courses as the company's own service technicians. I t may not be possible for an
independent company to procure manufacturer-approved parts unless the s ervice
technician has been cert if ied by the manufacturer. Alternately, the facil i ty may be
able to p urchase parts from the manufacturer.
Laws enacted in at least one state (New Jersey) require that the credentials of each
servicing person are approved by the machine manufacturer or determined by the
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physician director of the anesthesia department to be equivalent to the credentials
of the manufacturer's service person (101 ).
In - h ou se B i om ed i c a l Ser v i c e s
In-house biomedical services may be a satisfactory option for much equipment,
especially in inst itut ions where there are a large number of similar machines.
Biomedical technicians can attend courses and become cert if ied to s ervice specif ic
equipment. Often, a combination of an outside se rvice agency and in-house
biomedical services is used. The in-house biomedical technicians do intermediate
checks and respond to immediate problems between services from the outside
service agency (10 2).
Adv an ta ges of in -house biom ed ic al ma intena nce include mi nima l respons e ti me and
the abil i ty to observe problems while the equipment is in use. The service intensity
from outside sources and down t ime for equipment can be reduced. The biomedical
technicians can assist with cl inical education, provide l iaison between users and
manufacturers, help with equipment select ion, and keep abreast of modif icat ions
and service bullet ins issued by manufacturers.
The question of liability exposure must be addressed when considering in-house
service (10 3). I f a problem occurs as a result of the act ions of a biomedical
technician, the facil i ty wil l l ikely have l iabil i ty.
Record Keeping
Record keeping on equipment has frequently been neglected in the past. Often, it is
assumed that the service representat ive who does periodic preventive maintenance
wil l take care of this task. Experience does not support this assumption. Record
keeping is important for several reasons.
I t provides proof that an effort has been made to keep the equipment in
prop er work in g order. This c ould have medicolegal or Joint Commission for
Ac cre dita t io n of Hea lth care Organi za tio ns (J CAHO) signi ficance.
The state of New Jersey requires that records be maintained of all service
and maintenance performed on all anesthesia machines, venti lators, and
vaporizers. The record must include machine identif icat ion, servicing agent,
work performed, and date of the work. The maintenance must conform to that
required by the machine manufacturer. The servicing agent's credentials
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must be determined to be equivalent to the credentials of the manufacturer's
service agents. New York has similar requirements ( 10 1).
JCAHO requires that an equipment management program designed to assess
and control the clinical physical r isks of equipment for treatment, care, and
patient monitoring be in place. Writ ten criteria must include the
characteristics of equipment function, maintenance, and incident history
(101 ).
I t provides a means of communication with the service representative.
Representatives frequently come in the late afternoon or evening, after
anesthesia personnel have left . I f there is no writ ten record of problems that
have occurred with the equipment, the service representative may not
perform the indicated repair(s).
I t provides a complete, up-to-date record for each piece of equipment. I f one
piece of equipment malfunctions more f requently than others, considerat ion
should be given to replacing it .
I t provides a w rit ten record that maintenance by a service representative was
perfo rmed and sho ws what was done . Service representat ives may present
only a bil l for s ervice and parts and no record of what was actually done to
which machine.
It provides a check on the service rendered by the representative . After
equipment is serviced, it should perform well. I f a machine develops a
problem soon after servicing or if there is an increased frequency of repairs
that can be traced to a change in service representat ives, one may wish to
question that representat ive's abil i t ies.
With pieces of equipment such as vaporizers that need to be sent to the
manufacturer periodically for servicing or oxygen analyzers that need to have
certain
P.951
components replaced at intervals, records serve to remind the user when the
equipment needs to be serviced or a component replaced. After a vaporizer
is serviced, it may be held in reserve before being put into use. This would
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insurance carrier, health care facil i ty safety off icer, patient representat ive, or
equipment manufacturers should be conducted. The investigation should consist of
an in-depth examination of the equipment similar to the checking procedures
described earl ier in this chapter. Vaporizers should be calibrated and checked to
determine if vapor is delivered in the OFF posit ion. An analysis should be made of
the
P.952
vaporizers' contents, i f necessary. Following the investigation, a report should be
made that details all facts, analyses, and conclusions.
If a problem with the equipment is found, an attempt should be made to reconstruct
the accident if this can be done without danger to anyone, and the equipment
should again be locked up unti l any l i t igat ion is sett led. I f the investigation reveals
no problems, the equipment can be returned to service with the consent of all
part ies.
The Safe Medical Devices Act of 1990 requires medical device user facil i t ies to
report incidents that reasonably suggest there is a probabil i ty that a medical device
has caused or contributed to the death, serious injury, or serious i l lness of a
patient (87 ). The report is due as soon as possible but no later than 10 working
days after the user facil i ty becomes aware of the incident.
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