chapter 33. equipment checkout & maintenance

8/11/2019 Chapter 33. Equipment Checkout & Maintenance

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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

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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

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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

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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

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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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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


20/51

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


21/51

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.

P.943


22/51

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


23/51

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


24/51

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.

P.945


25/51

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


26/51

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.

P.946


27/51

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.

P.947


28/51

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.


29/51

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


30/51

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


31/51

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


32/51

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 .


33/51

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


34/51

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


36/51


37/51


38/51

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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chapter 33. equipment checkout & maintenance

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