-
Inspection and Preventive MaintenanceProceduresProcedure No.
Procedure No.Anesthesia Unit Vaporizers . . . . . . .
436-0595Anesthesia Unit Ventilators . . . . . . .
461-0595Anesthesia Units . . . . . . . . . . . . . 400-0595Apnea
Monitors . . . . . . . . . . . . . . 420-0595Argon Surgical Lasers
. . . . . . . . . . 462-0595Aspirators . . . . . . . . . . . . . .
. . . 433-0595Autotransfusion Units . . . . . . . . . .
449-0595Beds, Electric . . . . . . . . . . . . . . . 402-0595Blood
Pressure Monitors, Electronic
Indirect . . . . . . . . . . . . . . . . . 454-0595Blood
Pressure Monitors, Invasive . . . 434-0595Blood/Solution Warmers .
. . . . . . . . 445-0595Capnometers and Multiple Medical
Gas Monitors . . . . . . . . . . . . . . 450-0595Carbon Dioxide
Surgical Lasers . . . . . 446-0595Cardiac Resuscitators . . . . . .
. . . . 421-0595Centrifuges . . . . . . . . . . . . . . . .
456-0595Circulating-Fluid Pumps . . . . . . . . .
412-0595Conductive Furniture and Floors . . . . 441-0595Critical
Care Ventilators . . . . . . . . . 458-0595Cryosurgical Units . . .
. . . . . . . . . 457-0595Defibrillator/Monitors . . . . . . . . .
. 408-0595Defibrillators . . . . . . . . . . . . . . . 407-0595ECG
Monitors . . . . . . . . . . . . . . . 409-0595Electrical
Receptacles . . . . . . . . . . 437-0595Electrocardiographs . . . .
. . . . . . . 410-0595Electrosurgical Units . . . . . . . . . . .
411-0595Frequency-Doubled Nd:YAG
Surgical Lasers . . . . . . . . . . . . 464-0595General Devices
. . . . . . . . . . . . . . 438-0595Heart-Lung Bypass Units . . . .
. . . . 430-0595Heated Humidifiers . . . . . . . . . . . .
431-0595Hemodialysis Units . . . . . . . . . . . . 413-0595Ho:YAG
Surgical Lasers . . . . . . . . . 465-0595Hypo/Hyperthermia Units .
. . . . . . . 414-0595
Infant Incubators . . . . . . . . . . . . . 415-0595Infusion
Devices . . . . . . . . . . . . . 416-0595Intra-Aortic Balloon
Pumps . . . . . . . 432-0595Isolated Power Systems . . . . . . . .
. 439-0595Laparoscopic Insufflators . . . . . . . . .
466-0595Mammography Units . . . . . . . . . . . 467-0595Medical
Gas/Vacuum Systems . . . . . . 440-0595Mobile C-arms . . . . . . .
. . . . . . . 463-0595Mobile X-ray Units . . . . . . . . . . . .
468-0595Nd:YAG Surgical Lasers . . . . . . . . . 447-0595Oxygen-Air
Proportioners . . . . . . . . 444-0595Oxygen Analyzers . . . . . .
. . . . . . . 417-0595Pacemakers, External Invasive . . . . .
418-0595Pacemakers, External Noninvasive . . . 460-0595Peritoneal
Dialysis Units . . . . . . . . . 455-0595Phototherapy Units . . . .
. . . . . . . . 469-0595Physical Therapy Ultrasound Units . . .
470-0595Pneumatic Tourniquets . . . . . . . . . . 443-0595Portable
Ventilators . . . . . . . . . . . 471-0595Pressure Transducers . .
. . . . . . . . 435-0595Pulmonary Resuscitators,
Gas-Powered . . . . . . . . . . . . . . 448-0595Pulmonary
Resuscitators, Manual . . . . 422-0595Pulse Oximeters . . . . . . .
. . . . . . 451-0595Radiant Warmers . . . . . . . . . . . . .
419-0595Radiographic Units, General-Purpose . .
472-0595Radiographic/Fluoroscopic Units,
General-Purpose . . . . . . . . . . . . 473-0595Smoke Evacuators
. . . . . . . . . . . . 452-0595Sphygmomanometers . . . . . . . . .
. . 424-0595Suction Regulators . . . . . . . . . . . .
459-0595Temperature Monitors . . . . . . . . . . 425-0595Traction
Units . . . . . . . . . . . . . . . 427-0595Transcutaneous O2/CO2
Monitors . . . . 453-0595Ultrasound Scanners . . . . . . . . . . .
474-0595
257941456-0595
A NONPROFIT AGENCY
5200 Butler Pike, Plymouth Meeting, PA 19462-1298, USATelephone
+1 (610) 825-6000 Fax +1 (610) 834-1275 E-mail [email protected]
IPM Procedures
-
009006436-0595
A NONPROFIT AGENCY
5200 Butler Pike, Plymouth Meeting, PA 19462-1298, USATelephone
+1 (610) 825-6000 Fax +1 (610) 834-1275 E-mail [email protected]
Anesthesia Unit VaporizersUsed For:Anesthesia Unit Vaporizers
[10-144]
Also Called: By trade names (e.g., Fluotec 5, Vapor 19.1, Tec
6), which are registered trademarks and shouldbe used only when
referring to the specific devices
Commonly Used In: Operating rooms, emergency rooms, delivery
rooms, trauma rooms, and any areasrequiring the administration of
an inhalation agent (with anesthesia units)
Scope: Applies to the various anesthesia vaporizers used to
deliver a known concentration of vaporized liquidanesthetic
Risk Level: ECRI Recommended, High; Hospital Assessment,
ECRI-Recommended Interval UsedType Interval* By Hospital Time
Required
Major 6 months months . hours
Minor NA months . hours
* Additional periodic calibration and preventive maintenance is
normally required annually or biannually (seemanufacturers
recommendation). Only qualified personnel trained and experienced
in this function shouldperform this additional servicing.
OverviewAn anesthesia unit vaporizer is used to vaporize aliquid
anesthetic agent and deliver a controlledamount to the patient.
According to the American Society for Testing andMaterials
(ASTM)standard ASTM F1161-88, anestheticagent vaporizers are
required to be concentration cali-brated (i.e., a calibrated knob
controls the output con-centration). Older vaporizers, such as the
CopperKettle and the Vernitrol, do not have a single controlfor
selecting the concentration of anesthetic vapor.Where possible,
these units should be removed fromservice. Contemporary
concentration-calibrated va-porizers are of two types: variable
bypass and heatedblender.
Conventional (variable-bypass) vaporizers. In avariable-bypass
vaporizer, the total background gasflow that enters the unit is
split into two streams. The
smaller stream, which acts as the carrier gas, passesthrough the
vaporizing chamber containing the anes-thetic agent and becomes
saturated with agent vapor;the remainder of the gas bypasses this
chamber. Awick may be used in the vaporizing chamber to
provideincreased surface area for efficient evaporation of thedrug
and saturation of the carrier gas. The saturatedcarrier gas leaves
the chamber and mixes with thebypass gas. One adjustment is made to
set the desiredconcentration. This adjustment simultaneously
bal-ances the carrier and bypass flows to produce the blendrequired
for the set concentration. The mixture exitsthe vaporizer and is
delivered from the anesthesiamachine as the fresh gas to be
inspired by the patient.
Evaporation of the liquid agent contained in thechamber is
driven by heat absorbed from the walls ofthe vaporizer;
consequently, when evaporation is oc-curring, the vaporizer and its
contents cool. Becausethe equilibrium vapor pressure of an agent
changes
Procedure/Checklist 436-0595
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with temperature, a temperature-sensitive mecha-nism is used to
automatically adjust the carrier andbypass flows to compensate for
temperature changes.Figure 1 presents a schematic of a
variable-bypassvaporizer.
Desflurane (heated-blender) vaporizers. Desflu-rane, a volatile
inhalation anesthetic marketed byOhmeda Pharmaceutical Products
Division under thetrade name Suprane, has characteristics that
differmarkedly from those currently in use enflurane, ha-lothane,
and isoflurane; for example, its low solubilityallows rapid
induction of and emergence from anesthe-sia. Thus, by increasing
the speed of recovery, desfluranehas the potential to shorten
hospital stays (although thishas not yet been consistently
demonstrated).
The boiling point of desflurane 22.9C at 760 mmHg is just above
room temperature; therefore, smallincreases in ambient temperature
or decreases in atmos-pheric pressure can cause it to boil. Also,
because ofdesfluranes high minimum alveolar concentration, orMAC
(i.e., its low potency), evaporation of sufficientagent to achieve
a given anesthetic effect would requiremuch more heat absorption
from the vaporizer thanoccurs with other agents. Furthermore, the
change invapor pressure of desflurane per change in temperatureis
as much as three times that for the other volatileagents at
sea-level atmospheric pressure. These pro-found effects of
temperature and ambient pressure onthe vapor pressure of desflurane
make stabilizing thedelivered concentration at a set point
extremely difficultin a passive mechanical system, such as a
variable-by-
pass vaporizer. As a result, the variable-bypass designwas
abandoned for desflurane, and Ohmeda developeda new vaporizer, the
Tec 6, based on a heated-blenderdesign. Figure 2 shows a schematic
of this vaporizer.
A version of the Tec 6 (also manufactured by Oh-meda) has been
adapted for Drager machines and iscompatible with the Drager
triple-exclusion interlocksystem. As of this writing, neither
Drager nor Sie-mens has developed its own desflurane vaporizer.
A desflurane vaporizer requires electrical power toheat the
agent to a thermostatically controlled 39C,producing a stable,
saturated vapor pressure of1,500 mm Hg. No wick is used, and no
carrier gasenters the sump chamber. Instead, a stream of vaporunder
pressure flows out of the sump; this streamblends with the
background gas stream, which origi-nates from the anesthesia
machines flowmeters, toachieve the desired concentration.
The background gas stream passes through a fixed-flow resistor,
producing a back pressure upstream ofthis resistor that is
proportional to the background gasflow. The desired desflurane
concentration is set on thedial of the adjustable metering valve in
the vaporstream; this setting produces a predetermined aper-ture.
The pressure in the vapor upstream of the aper-ture and the back
pressure in the background gasstream are continually sensed by a
differential pres-sure transducer. The transducer controls a
pressure-regulating valve in the vapor stream between the sump
Figure 2. Schematic illustrating the basic elements of theOhmeda
Tec 6 vaporizer
Figure 1. Schematic illustrating the basic elements of
avaiable-bypass vaporizer
Inspection and Preventive Maintenance System
Inspection and Preventive Maintenance System2 1995 ECRI. All
Rights Reserved.
-
and the adjustable metering valve. The pressure-regu-lating
valve permits only that flow from the sumpnecessary to cause the
pressure upstream of the ad-justable metering valve to equal the
back pressure inthe background gas stream. In this way, the ratio
ofthe adjustable metering valves resistance to the resis-tance of
the fixed-flow resistor determines the ratio ofthe flows in each
stream, and therefore, the concentra-tion of vapor in the blended
output. If the flow from theanesthesia machines flowmeters through
the vapor-izer is altered, the flow of vapor from the sump
isautomatically adjusted so that the pressures at the twomonitored
points remain equal, the flow ratio does notchange, and the output
concentration continues tomatch its setting.
The control circuits and heating elements in thevaporizer are
turned on by the act of connecting thevaporizer to electrical
power. The unit then heats toand remains at operating temperature
as long as itreceives power, whether it is delivering agent or is
inthe standby mode. Consequently, it is warm to thetouch while
plugged into a live socket.
Citations from Health DevicesAvoiding anesthesia mishaps through
pre-use checks,
1982 May; 11:210-3.
Water in halothane vaporizers [Hazard], 1985 Aug;14:326.
Anesthesia units with a flowmeter-controlled vapor-izer
[Hazard], 1986 Dec; 15:336.
Vaporizer leak with Mapleson breathing circuits [Haz-ard], 1986
Dec; 15:344-5.
Concentration calibrated vaporizers [Hazard], 1987Mar-Apr;
16:112-3.
Pre-use anesthesia check fails to find faults [Hazard],1988 Sep;
17:274-6.
Desflurane (Suprane): Considerations for introduc-ing the new
inhalation anesthetic agent into clinicalpractice [Guidance
article], 1994 Apr; 23:131-42.
Test apparatus and suppliesHalogenated anesthetics analyzer
Hoses and adapters
Special precautionsAs a general precaution, a vaporizer
containing an
anesthetic agent should not be tipped. If such tippingoccurs,
notify the user and follow the manufacturersrecommended procedures
for airing or drying the unit.
Do not fill a vaporizer with an inhalation agentunless you are
qualified to do so. Always use a scav-enging system or appropriate
ventilation when in-specting vaporizers. For personal safety,
wheninspecting vaporizers alone, notify other personnel ofyour
location. Be sure that filler ports are tightlycapped before
passing gas through the vaporizer.
ProcedureBefore beginning an inspection, carefully read this
procedure and the manufacturers instruction and serv-ice
manuals; be sure that you understand how to oper-ate the equipment
and the significance of each controland indicator. Also determine
whether any special in-spection or preventive maintenance
procedures or fre-quencies are recommended by the manufacturer.
Note: This procedure should be done simultaneouslywith
Anesthesia Units Procedure/Checklist 400,where leak testing of the
vaporizer has been includedwith the anesthesia unit.
Each vaporizer should have a separate controlnumber. Inspection
documentation for up to threevaporizers (on one anesthesia unit)
can be included onone inspection form (record each control number),
butsome hospitals may prefer to use a separate form foreach
vaporizer.
Be sure that the anesthesia system is level andsecure. Check
that all hoses and fittings are tight.
1. Qualitative tests
1.1 Chassis/Housing. Examine the exterior of theunit for
cleanliness and general physical condi-tion. Be sure that housings
are intact, that allassembly hardware is present and tight, andthat
there are no signs of spilled liquids or otherserious abuse.
1.2 Mount/Fasteners. Check security of mounts orsupport
mechanisms. Verify that the vaporizeris firmly mounted on the
anesthesia unit.
1.4 AC Plug. If the unit is so equipped, examine theAC power
plug for damage. Attempt to wigglethe blades to determine that they
are secure.Shake the plug and listen for rattles that couldindicate
loose screws. If any damage is sus-pected, open the plug and
inspect it.
1.5 Line Cord. Inspect the cord, if so equipped, forsigns of
damage. If damaged, replace the entirecord, or if the damage is
near one end, cut out thedefective portion. Be sure to wire a new
power cordor plug with the same polarity as the old one.
Anesthesia Unit Vaporizers
Inspection and Preventive Maintenance System1995 ECRI. All
Rights Reserved. 3
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1.6 Strain Reliefs. Examine the strain reliefs atboth ends of
the line cord, if so equipped. Be surethat they hold the cord
securely.
1.7 Circuit Breaker/Fuse. If the device has aswitch-type circuit
breaker, check that it movesfreely. If the device is protected by
an externalfuse, check its value and type against thatmarked on the
chassis, and ensure that a sparefuse is provided.
1.8 Tubes/Hoses. Check the condition of all tubingand hoses. Be
sure that they are not cracked,kinked, or dirty.
1.10 Fittings/Connectors. Examine all gas and liq-uid fittings
and connectors for general condition.Be sure all fittings are
tight.
1.13 Controls. Before moving any controls, checktheir positions.
If any of them appear inordinateor are left in the on position,
consider the possi-bility of inappropriate clinical use or of
incipientdevice failure.
Examine all controls for physical condition,secure mounting, and
correct motion. Where acontrol should operate against fixed-limit
stops,check for proper alignment, as well as positivestopping.
During the course of the inspection, besure to check that each
control performs itsproper function. Return all controls to the
offposition following the test.
1.16 Fluid Levels. Check all fluid levels. If the fluidlevel is
zero, we recommend that you have aqualified user fill the sump with
anestheticagent to continue the inspection.
1.17 Battery. Inspect the physical condition of thebattery and
battery connectors, if so equippedand readily accessible. Operate
the battery-pow-ered functions of the unit for several minutes
tocheck that the battery has an adequate charge.Check remaining
battery capacity by activatingthe battery test function or
measuring the out-put voltage. If it is necessary to replace a
battery,label it with the date.
1.18 Indicators/Displays. During the course of theinspection,
confirm the operation of all indica-tors and visual displays on the
unit, if soequipped.
1.20 Alarms/Interlocks. Operate the device in sucha way as to
activate each audible and visualalarm, if so equipped. If the
device has an alarm-silence feature, check the method of reset
(i.e.,
manual or automatic) against the manufac-turers specifications.
Check that the vaporizerinterlock allows activation of only one
vaporizerat a time.
1.21 Audible Signals. Operate the device in such away as to
activate any audible signals. Confirmappropriate volume, as well as
the operation ofa volume control, if so equipped.
1.22 Labeling. Check that all necessary placards, la-bels,
conversion charts, and instruction cardsare present and
legible.
1.24 Site Glass, O-Rings, Keyed Filler Mechanism. Ex-amine the
physical condition of the site glass,O-rings, and keyed filler
mechanism, if soequipped.
2. Quantitative tests2.1 Grounding Resistance. If the unit is
electrically
powered, use an ohmmeter, electrical safety ana-lyzer, or
multimeter with good resolution of frac-tional ohms to measure and
record theresistance between the grounding pin of thepower cord and
exposed (unpainted and not ano-dized) metal of the chassis. We
recommend amaximum of 0.5
2.2 Leakage Current. For electrically poweredunits, measure
chassis leakage current to thechassis of the device with the
grounding conduc-tor of plug-connected equipment temporarilyopened.
Operate the device in all normal modes,including On, Standby, and
Off, and record themaximum leakage current. Leakage currentshould
not exceed 300 A.
2.10 Concentration Check. Data for up to three va-porizers can
be recorded as Items 2.10, 2.11, and2.12. Record the type and
control number of thevaporizer being tested under each item.
2.11 See Item 2.10
2.12 See Item 2.10
Because there are various types of halogen-ated anesthetic
analyzers, follow the manufac-turers procedure for setup and use of
theanalyzer.
Vaporizers should usually be tested with anoxygen flow of 4 to 5
L/min (nitrous oxide mayaffect the readings of some vapor
analyzers).Test the vaporizers at low, medium, and
highconcentration settings in the normal clinical userange (e.g.,
0.5%, 1.0%, and 3.0% for halothane).
Inspection and Preventive Maintenance System
Inspection and Preventive Maintenance System4 1995 ECRI. All
Rights Reserved.
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At one concentration setting (e.g., 1.0% for ha-lothane, 10% for
desflurane), test the vaporizerat another flow (e.g., 1 L/min). We
recommendthat the concentration be 0.3% vapor or 10%of the measured
value, whichever is greater. Iferrors in concentration are
observed, allow thevaporizer to operate for a minute or two
andrecheck the unit. Some units may require ashort stabilization
period.
3. Preventive maintenance3.1 Clean the exterior.
3.2 Replace the battery, if so equipped (batteryshould be
replaced at least once annually).
4. Acceptance tests
Conduct major inspection tests for incoming vapor-izers and, if
a vaporizer is position sensitive, any timeit is demounted from an
anesthesia unit.
Before returning to use
Return all controls to the off position, level andsecure the
unit, and tighten all fittings and tubing.
Anesthesia Unit Vaporizers
Inspection and Preventive Maintenance System1995 ECRI. All
Rights Reserved. 5
-
238369461-0595
A NONPROFIT AGENCY
5200 Butler Pike, Plymouth Meeting, PA 19462-1298, USATelephone
+1 (610) 825-6000 Fax +1 (610) 834-1275 E-mail [email protected]
Anesthesia Unit VentilatorsUsed For:Anesthesia Unit Ventilators
[10-145]
Commonly Used In: Delivery rooms and operating rooms
Scope: Applies to ventilators used to deliver inhalation
anesthetic agents during surgical procedures thatrequire general
anesthesia
Risk Level: ECRI Recommended, High; Hospital Assessment,
ECRI-Recommended Interval UsedType Interval By Hospital Time
Required
Major 6 months* months . hours
Minor NA months . hours
* Inspection and preventive maintenance intervals should be
scheduled according to the manufacturersrecommendations. However,
units should have a major inspection at least every six months.
Pre-use checksshould be performed before each case by the
anesthetist who will be operating the equipment.
OverviewPatients undergoing surgery under general anesthesiaare
routinely paralyzed with muscle relaxants to sta-bilize the
surgical field. Consequently, they are unableto breathe on their
own and must be mechanicallyventilated either manually by the
anesthetist, whosqueezes a reservoir bag in the breathing circuit,
orautomatically by an anesthesia ventilator. A switchvalve allows
the choice of the method by which venti-lation is to be supported.
The anesthesia ventilator istypically turned on and off
independently of the switch-ing between manual and automatic
ventilation.
Anesthesia ventilators use positive pressure to in-flate a
patients lungs and deliver a prescribed mixtureof gases and vapors
to them. This mixture is producedby the anesthesia machine. The
ventilator can be builtinto the anesthesia machine or can be a
stand-aloneunit connected to the machine by gas tubing and,perhaps,
sensor cables. Some anesthesia ventilatorshave built-in displays
and alarms; others rely on thesensors, displays, and alarms of the
anesthesia ma-chine to monitor their performance.
In general, an anesthesia ventilator is less sophisti-cated than
a critical care ventilator, having only acontrol mode of operation,
with time cycling. (However,there is at least one ICU-type
ventilator that can beused to administer inhalation anesthetics.) A
pressurelimit prevents exposure of the lungs to excessive
pres-sure. Several other breathing waveshape parameters(e.g.,
inspiratory:expiratory [I:E] ratio, tidal volume,minute volume,
flow) are settable by the operator andcontrolled by the ventilator.
Ventilators designedsolely for anesthetic administration typically
do nothave compressors.
During extended procedures and procedures involv-ing open
breathing circuit configurations, a humidifiermay be included in
the breathing circuit. Otherwise, acircle system with an absorber,
along with one-wayinspiratory and expiratory valves, is used,
typicallywithout a humidifier. The ventilators pressure-reliefand
limit valve(s) should be connected to a waste gasscavenging
system.
Citations from Health DevicesAnesthesia systems [Evaluation],
1988 Jan; 17:3.
Procedure Checklist 461-0595
-
Who should service anesthesia equipment [User Expe-rience
NetworkTM], 1988 Feb; 17:70.
Barotrauma from anesthesia ventilators [Hazard],1988 Nov;
17:354.
Damage to elastic components from Loctite [Hazard],1989 Jul-Aug;
18:288.
Risk of barotrauma and/or lack of ventilation withventilatorless
anesthesia machines [Hazard], 1994Jan-Feb; 23:54.
Test apparatus and suppliesLung simulator with adjustable
compliance or ven-tilator tester
Pressure gauge or meter with 2 cm H2O resolutionfrom -20 to +120
cm H2O
Various breathing circuit adapters
Leakage current meter or electrical safety analyzer
Ground resistance ohmmeter
Additional items as required for specific manufac-turers
procedures
ProcedureBefore beginning an inspection, carefully read this
procedure and the manufacturers instruction andservice manuals;
be sure that you understand how tooperate the equipment, the
significance of each controland indicator, and the alarm
capabilities. Also deter-mine whether any special inspection or
preventivemaintenance procedures or frequencies are recom-mended by
the manufacturer.
Manufacturers recommended procedures for in-spection and
preventive maintenance of mechanicalanesthesia ventilators vary in
both methods and re-quired accuracy. In addition, ventilator
controls canvary greatly among manufacturers and models.
Thisprocedure provides the basic framework for completeventilator
inspection and preventive maintenance.Manufacturers recommended
procedures should beadded where appropriate. References to specific
pagesof the manufacturers manual should be added to thechecklist.
(The checklist includes blank spaces for theinsertion of these
reference numbers.)
IPM Task ManagerTM, the software component of theInspection and
Preventive Maintenance System, en-ables easy production of
customized procedures andchecklists for specific ventilator models
and clinicalneeds. Items performed by outside vendors can
beexcluded from the checklist; a separate checklist for
use by outside vendors can be produced to ensure thatthose items
agreed upon are performed by the vendor.
The following framework should be supplementedby the
manufacturers recommended preventive main-tenance procedures for
mechanical ventilators.
1. Qualitative tests
1.1 Chassis/Housing. Examine the exterior of theunit for
cleanliness and general physical condition.Be sure that plastic
housings are intact, that allhardware is present and tight, and
that there areno signs of spilled liquids or other serious
abuse.
1.2 Mount/Fasteners. Check that ventilatorsmounted in anesthesia
machines are properlyinstalled. If the device is mounted on a stand
orcart, examine the condition of the mount. If it isattached to a
wall or rests on a shelf, check thesecurity of this attachment.
Check the mountingsecurity of all components.
1.3 Casters/Brakes. If the device moves on casters,check their
condition. Verify that they turn andswivel, as appropriate, and
look for accumula-tions of lint and thread around the casters.Check
the operation of brakes and swivel locks,if the unit is so
equipped.
1.4 AC Plug. Examine the AC power plug for dam-age, if so
equipped. Attempt to wiggle the bladesto check that they are
secure. Shake the plug andlisten for rattles that could indicate
loose screws.If any damage is suspected, open the plug andinspect
it.
1.5 Line Cord. Inspect the cord for signs of damage,if so
equipped. If damaged, replace the entirecord or, if the damage is
near one end, cut out thedefective portion. Be sure to wire a new
powercord or plug with the correct polarity. Also checkline cords
of battery chargers.
1.6 Strain Reliefs. Examine the strain reliefs atboth ends of
the line cord, if so equipped. Be surethat they hold the cord
securely.
1.7 Circuit Breaker/Fuse. If the device has a switch-type
circuit breaker, check that it moves freely. Ifthe device is
protected by an external fuse, checkits value and type against that
marked on thechassis, and ensure that a spare is provided.
1.8 Tubes/Hoses. Check the condition of all tubingand hoses. Be
sure that they are not cracked,kinked, or dirty. Check that they
are connectedto the correct locations.
Inspection and Preventive Maintenance System
Inspection and Preventive Maintenance System2 1995 ECRI. All
Rights Reserved.
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1.9 Cables. Inspect any cables (e.g., for sensors) andtheir
strain reliefs for general condition. Care-fully examine cables to
detect breaks in the in-sulation and to ensure that they are
securelygripped in the connectors at each end, which willprevent
rotation or other strain. Where appro-priate, verify that there are
no intermittentfaults by flexing cables near each end and look-ing
for erratic operation or by using an ohmme-ter.
1.10 Fittings/Connectors. Examine all gas fittingsand connectors
for general condition. Gas fit-tings should be tight and should not
leak. Verifythat keyed connectors (e.g., pin-indexed gas
con-nectors) are used where appropriate, that allpins are in place
and secure, and that keying iscorrect. Connectors to hospital
central pipedmedical gas systems should have the appropri-ate DISS
or quick-connect fitting to eliminate theneed for adapters.
1.12 Filters. Check the condition of gas filters, if in-cluded
in the unit. Check for corrosion residueindicative of liquid,
gaseous, or solid particlecontaminants in the gas supply; if found,
notifyappropriate personnel. Clean or replace if appro-priate, and
indicate this on Lines 3.1 and 3.4 ofthe inspection form.
1.13 Controls/Switches. Before changing any con-trols or alarm
limits, check their positions. If anysettings appear inordinate
(e.g., alarm limits atthe ends of their range), consider the
possibilityof inappropriate clinical use or of incipient
devicefailure. Record the settings of those controls thatshould be
returned to their original positionsfollowing the inspection.
Examine all controls and switches for physicalcondition, secure
mounting, and correct motion.Check that control knobs have not
slipped ontheir shafts. Where a control should operateagainst
fixed-limit stops, check for proper align-ment, as well as positive
stopping. Check mem-brane switches for damage (e.g.,
fromfingernails, pens). During the inspection, be sureto check that
each control and switch performsits proper function.
1.15 Fan. Check physical condition and proper op-eration, if so
equipped. Clean and lubricate ifrequired, according to the
manufacturers in-structions, and note this on Lines 3.1 and 3.2
ofthe form.
1.17 Battery/Charger. Inspect the physical conditionof batteries
and battery connectors, if so equippedand if readily accessible.
Check operation ofbattery-operated power-loss alarms, if
soequipped. Operate the unit on battery power forseveral minutes to
check that the battery ischarged and can hold a charge. (The
inspectioncan be carried out on battery power to helpconfirm
adequate battery capacity.) Check bat-tery condition by activating
the battery test func-tion or measuring the output voltage;
forlead-acid batteries, measure the specific gravityand check the
fluid level. Check the condition ofthe battery charger and, to the
extent possible,confirm that it does, in fact, charge the
battery.Be sure that the battery is recharged or chargingwhen the
inspection is complete. When it is nec-essary to replace a battery,
label it with the date.
1.18 Indicators/Displays. During the course of theinspection,
confirm the operation of all lights,indicators, meters, gauges, and
visual displayson the unit and charger (if so equipped). Be
surethat all segments of a digital display function.Record the
reading of an hour meter, if present.
1.20 Alarms/Interlocks. Inducealarm conditionstoac-tivate
audible and visual alarms. Check that anyassociated interlocks
function. If the unit has analarm-silence feature, check the method
of reset(i.e., manual, automatic) against the manufac-turers
specifications. It may not be possible tocheck out all alarms at
this time since some mayrequire special conditions that must be
establishedaccording to the manufacturers recommenda-tions; include
these in Item 2.4. Verify that anyremote alarm indicator (e.g.,
within the main-frame anesthesia unit) functions properly.
1.22 Labeling. Check that all necessary placards, la-bels, and
instruction cards are present and legible.
1.23 Accessories. Confirm the presence and conditionof
accessories. Check the condition of reusableBain circuit and
adapters, if available.
1.24 Bellows. Check the physical condition andproper operation
of the bellows.
2. Quantitative tests
2.1 Grounding Resistance. Using an ohmmeter, elec-trical safety
analyzer, or multimeter with goodresolution of fractional ohms,
measure and recordthe resistance between the grounding pin of
thepower cord and exposed (unpainted and not ano-dized) metal on
the chassis of the ventilator or of
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the system in which the ventilator is mounted.We recommend a
maximum of 0.5 . If theventilator is a component within an
anesthesiaunit, grounding and leakage current measure-ments can be
referenced to that unit.
2.2 Leakage Current. Measure chassis leakage cur-rent to ground
with the grounding conductor ofplug-connected equipment temporarily
opened.Operate the device in all normal modes, includ-ing on,
standby, and off, and record the maxi-mum leakage current.
Measure chassis leakage current with all ac-cessories normally
powered from the same linecord connected and turned on and off.
This in-cludes other equipment that is plugged into theprimary
devices accessory receptacles, as well asequipment plugged into a
multiple-outlet strip(Waber strip) so that all are grounded
througha single line or extension cord.
Chassis leakage current to ground should notexceed 300 A.
2.3 Modes and Settings. Anesthesia ventilators areusually
equipped only with a control mode. How-ever, specialized units may
have additionalmodes such as assist/control and pressure sup-port.
Adjustable positive end-expiratory pres-sure (PEEP) may also be
available. The functionof these modes should be inspected and
verifiedfor proper operation. Check the operation andaccuracy of
ventilation controls, which may in-clude tidal volume, breath rate,
inspiratory time,expiratory time, I:E ratio, pressure limit, or
flow.Typically, these tests are performed by attachingthe
ventilator to a lung simulator or ventilatortester and comparing
measured values to set-tings on the ventilator. The manufacturer
shouldrecommend the appropriate ventilator settings(e.g., tidal
volume, rate, inspiratory time) to ver-ify proper operation and
accuracy (generallywithin 10%).
2.4 Monitors and Alarms. The following breathingcircuit
parameters may be monitored by the ven-tilator or by the system in
which the ventilatoris mounted. They should be inspected for
accu-racy (generally within 10%) according to themanufacturers
specifications:
Breathing rate
Inspiratory time
Airway pressure (e.g., PIP, PEEP, MAP, ap-nea)
Volume (e.g., tidal volume, minute volume,apnea)
Fraction of inspired oxygen (FIO2; see OxygenAnalyzers
Procedure/Checklist 417)
Alarm settings (e.g., high PIP, low MAP, lowpressure, low FIO2)
should be inspected forproper and accurate activation.
2.5 Gas Supply.
Pneumatic lines (including air filters). Verifythat appropriate
gas-specific connectors areused. Check gas filters, if so equipped
andaccessible.
Gas cylinders (and gauges and regulators, if soequipped). Verify
that these are present, se-curely mounted, and in good condition
andthat there is an adequate gas supply. Verifythat one and only
one washer is used to sealthe tank to its yoke. Verify that all
index pinsare present and protruding to the properlength to engage
the hole in the tank valvestem and in the correct positions for the
gas tobe supplied through the yoke.
2.6 Patient Circuit.
Breathing circuit (including filters). Verify thatthese
components are compatible with the ven-tilator according to the
manufacturers recom-mendations (see Health Devices 1988
Apr;17:109). Check for leaks, the absence of obstruc-tions, and
proper flow direction in the breathingcircuit, ensuring the proper
assembly and func-tion of fittings, adapters, the CO2 absorber,
in-spiratory and expiratory valves and PEEPvalves, the APL valve,
the scavenger, and othercomponents. With the ventilator connected
tothe anesthesia system, check for leaks in theentire system,
including the breathing circuit.This does not have to be duplicated
if done aspart of the Anesthesia Units procedure
(seeProcedure/Checklist 400).
Humidifiers. See Heated Humidifiers Proce-dure/Checklist
431.
Pressure-Relief Mechanism. Check the properoperation of the
pressure-relief mechanism byoccluding the breathing circuit and
measuringthe resulting peak pressure on the pressuregauge. Verify
that pressure is vented in thebreathing circuit.
Absorber. See Anesthesia Units Proce-dure/Checklist 400.
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3. Preventive maintenance3.1 Clean the exterior and interior, if
needed.
3.3 Calibrate according to manufacturers instructions.
3.4 Replace components according to the manufac-turers
instructions.
4. Acceptance testsConduct major inspection tests for this
procedure
and the appropriate tests in the General Devices
Pro-cedure/Checklist 438.
Before returning to useEnsure that all controls are set
properly. Set alarms
loud enough to alert personnel in the area in which thedevice
will be used. Other controls should be in theirnormal pre-use
positions.
Attach a Caution tag in a prominent position so thatthe user
will be aware that control settings may havebeen changed.
Recharge battery-powered devices, or equip themwith fresh
batteries, if needed.
Anesthesia Unit Ventilators
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009005400-0595
A NONPROFIT AGENCY
5200 Butler Pike, Plymouth Meeting, PA 19462-1298, USATelephone
+1 (610) 825-6000 Fax +1 (610) 834-1275 E-mail [email protected]
Anesthesia UnitsUsed For:Anesthesia Units [10-134]
Also Called: Anesthesia machines, anesthesia workstations
Commonly Used In: Operating rooms, emergency departments, trauma
rooms, delivery rooms, any areaswhere anesthetic agents are
used
Scope: Applies to anesthesia units; includes leak testing of
vaporizers and should be used in conjunction withAnesthesia Unit
Vaporizers Procedure/Checklist 436 (in the very rare case where an
anesthesia unit may stilluse flammable anesthetic agents, refer to
Conductive Furniture and Floors Procedure/Form 441); does notapply
to oxygen monitors with an alarm, spirometers, other monitors, or
ventilators that might be part of thebreathing system (see
Anesthesia Unit Ventilators Procedure/Checklist 461)
Risk Level: ECRI Recommended, High; Hospital Assessment,
ECRI-Recommended Interval UsedType Interval By Hospital Time
Required
Major 6 months months . hours
Minor NA months . hours
Overview
Most surgical procedures are performed while the pa-tient is
under general anesthesia. Usually, the patientis anesthetized by a
narcotic or barbiturate injectionfollowed by administration of an
inspired gas mixtureof oxygen, nitrous oxide, and the vapor of a
volatileliquid anesthetic, typically a halogenated hydrocar-bon.
The anesthesia unit administers this mixture ofanesthetic gases and
life-sustaining oxygen, varyingthe proportions to control the
patients level of con-sciousness. If respiratory assist is
necessary (e.g., incases of muscular blockade), a ventilator may be
con-nected to the patient breathing system to force the gasmixture
into the patients lungs.
Improperly modified or inadequately maintainedanesthesia units
have injured and killed patientsand hospital personnel. Gas leaks
can adverselyaffect the accuracy of gas delivery to the patient,
aswell as add anesthetic agents to the OR atmosphere.Trace levels
of anesthetics have been implicated as
a health hazard to chronically exposed OR personneland unborn
children. Inadvertent switching of gassupplies, failure of an alarm
to respond to an exces-sively low oxygen pressure, and misconnected
or im-properly calibrated flowmeters have also
causedanesthesia-related accidents.
Because mishandling and mistakes can have severeconsequences,
life-support devices such as anesthesiaunits should be operated and
inspected only by quali-fied personnel who have a thorough
knowledge of theunits and their functions. If you are unsure of
anyaspect of the procedure, consult the manufacturer be-fore
inspecting an anesthesia unit.
The anesthesia unit consists of four systems: the gassupply
system, the gas control system, the vaporizers,and the breathing
system.
Gas supply. This system delivers a variety of gasesto the
patient. Cylinders containing oxygen and othergases at high
pressure (see Table 1) are connected tothe high-pressure system of
the anesthesia unit by
Procedure/Checklist 400-0595
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yoke fittings that comply with the Compressed GasAssociation
(CGA) pin-index safety system (see Figure1). Unique placements of
pins and mating holes on thepin-index fittings prevent connection
of a gas cylinderto the wrong inlet. Inside the unit, each
high-pressuregas flows through a filter, a check valve (for
one-wayflow), and a regulator that reduces the pressure
toapproximately 45 psi.
Because oxygen and nitrous oxide are used in rela-tively large
quantities, they are usually drawn fromthe hospitals central gas
supplies, which are moreconvenient and economical than
compressed-gas cyl-inders. However, cylinders of these gases are
also
normally attached to the anesthesia unit as a reservesource if
the central supply fails or if central supplyoutlets are not
available.
Centrally supplied gases are delivered directly to
theintermediate-pressure gas control system at approxi-mately 50
psi through low-pressure hoses and connec-tors. These connectors
may not comply with a universalstandard safety system, but each is
designed to preventmismating the gas supply and the machine
inlet.
Some units may provide an oxygen power outlet todrive auxiliary
devices (e.g., a ventilator).
Gas control. This system regulates gas flow rates sothat the
gases can be mixed and delivered under accu-rate, constantly
metered control. The operator mustbe able to adjust the ratios or
make rapid gross changesin flow rates without inducing system
interactions thatcause temporary delivery of undesirable
mixtures.
The flow of each gas is controlled by a valve andindicated by a
glass-tube flowmeter. After gases passthe control valve and enter
the low-pressure system,they can be administered to the
patient.
A fail-safe provision in many anesthesia units pro-tects the
patient against a fall in pressure of life-sus-taining oxygen. If
the oxygen pressure drops belowabout 25 to 30 psi, some units shut
off the flow of allother gases, while others reduce all gas flow
rates inproportion to the drop in oxygen pressure. Neweranesthesia
machines have additional safety systemsthat provide a minimum
percent of oxygen (around25%) and/or deliver a minimum flow of
oxygen (usually150 to 250 mL/min) (see Item 2.11).
Vaporizers. These devices add the vapor of a volatileliquid
anesthetic (e.g., halothane, isoflurane, enflurane,sevoflurane,
desflurane) to the gas mixture, when de-sired, and aid in
controlling the vapor concentration.
According to the American Society for Testing andMaterials
(ASTM) standard ASTM F1161-88, anes-thetic agent vaporizers are
required to be concentra-tion calibrated (i.e., a calibrated knob
controls the
TABLE 1. Gases Used in Anesthesia Machines
Gas ChemicalFormula
Color Code:U.S.
Color Code:International
Service Pressure,psi 21C, Full Cylinder
Oxygen O2 Green White 1,800-2,400*Carbon Dioxide CO2 Gray Gray
838Nitrous Oxide N2O Blue Blue 745Helium He Brown Brown
1,600-2,000*Air Yellow White and Black 1,800
* Depends on cylinder size.
Figure 1. Pin-index safety system
Gas Index PinsCGA ConnectorNumber
Oxygen 2-5 870Nitrous Oxide 3-5 910O2 - CO2 (CO27%) 1-6 940O2 -
HE (He > 80%) 4-6 930O2 - HE (He < 80%) 2-4 890Air 1-5
950
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output concentration). Older vaporizers, such as theCopper
Kettle and the Vernitrol, do not have a singlecontrol for selecting
the concentration of anestheticvapor. Where possible, these units
should be removedfrom service. Contemporary
concentration-calibratedvaporizers are of two types: variable
bypass and heatedblender.
The variable-bypass (conventional) vaporizer isused for most
volatile agents (e.g., halothane, isoflu-rane, enflurane,
sevoflurane). The total backgroundgas flow that enters the unit is
split into two streams.The smaller stream, which acts as the
carrier gas,passes through the vaporizing chamber containing
theanesthetic agent and becomes saturated with agentvapor; the
remainder of the gas bypasses this chamber.A wick may be used in
the vaporizing chamber toprovide increased surface area for
efficient evapora-tion of the drug and saturation of the carrier
gas. Thesaturated carrier gas leaves the chamber and mixeswith the
bypass gas. One adjustment is made to set thedesired concentration.
This adjustment simultane-ously balances the carrier and bypass
flows to producethe blend required for the set concentration. The
mix-ture exits the vaporizer and is delivered from theanesthesia
machine as the fresh gas to be inspired bythe patient.
A heated-blender vaporizer is used only for desflu-rane. It
requires electrical power to heat the agentto a thermostatically
controlled 39C, producing astable, saturated vapor pressure of
1,500 mm Hg. Nowick is used, and no carrier gas enters the
sumpchamber. Instead, a stream of vapor under pressureflows out of
the sump; this stream blends with thebackground gas stream, which
originates from theanesthesia machines flowmeters, to achieve the
de-sired concentration.
(Desflurane, a volatile inhalation anesthetic mar-keted by
Ohmeda Pharmaceutical Products Divisionunder the trade name
Suprane, and sevoflurane,marketed by Abbott under the trade name
Ultane,have characteristics that differ markedly from
thosecurrently in use enflurane, halothane, and isoflu-rane. For
example, their low solubilities allow rapidinduction of and
emergence from anesthesia. Thus,by increasing the speed of
recovery, desflurane andsevoflurane have the potential to shorten
hospitalstays, although this has not yet been
consistentlydemonstrated.)
Breathing system. Although it is designed primar-ily for
sustained, efficient gas delivery to the patient,the breathing
system may also remove carbon dioxideand provide mechanical or
manual ventilation of a
patient who cannot breathe spontaneously, as well aspositive
end-expiratory pressure (PEEP), if required.The breathing system
typically includes a scavengingsystem to remove waste gases.
Two types of breathing systems are used to deliverthe anesthetic
mixture from the unit to the patient,although they may assume a
variety of configurations.
The T-piece or open system may be a nonrebreath-ing system
consisting of a reservoir bag and a gas-de-livery hose connected
through a nonrebreathing(one-way) valve to the face mask or
endotracheal tube.The patient breathes the anesthetic mixture
directlyfrom the machine, and exhaled gas is vented out of
thesystem. T-piece systems that do not include the nonre-breathing
valve may allow partial rebreathing, de-pending on the inflow of
fresh gas.
The circle or closed system is a continuous loop inwhich check
valves allow gas to flow in only one direc-tion. The patient
inhales from and exhales into thesystem. Fresh gases from the
anesthesia machineenter at one point, mix with previously exhaled
gases,and pass to the patient, who inhales the mixture.Newly
exhaled gases are channeled to a carbon dioxideabsorber, which
removes almost all the carbon dioxideproduced by body metabolism
and routes the scrubbedgases back toward the patient. En route, the
scrubbedgases become mixed with fresh machine gases.
A scavenging system should be included to removewaste gas from
the vent port of a T-piece breathingsystem or from the adjustable
pressure-limiting (APL)valve and relief valve of a ventilator of a
circle systemto reduce the quantity of gas that escapes into
theoperating room. Such a scavenging system is neces-sary because
trace levels of anesthetics are believed tocause an increased
incidence of spontaneous abortion,congenital anomalies in
offspring, and neoplastic dis-ease and may affect the mental and
physical abilitiesof exposed personnel. The breathing system should
bechecked before each use for leaking gases. It is alsorecommended
that the concentration of waste anes-thetic gas in the operating
room be surveyed quarterly.The scavenging system must include
pressure-reliefmechanisms so that abnormal pressures cannot
de-velop in the scavenging system and interfere withoperation of
the breathing system.
Anesthesia units either come with physiologicalmonitors
integrated into the unit or provide shelvingto support such
monitors. Most also provide mountingfor a suction regulator and
canister and other accesso-ries, along with storage for drugs,
supplies, and relatedparaphernalia.
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Citations from Health DevicesAnesthesia units with a
flowmeter-controlled vapor-
izer [Hazard], 1986 Dec; 15:336-7.
Vaporizer leak with Mapleson breathing systems[Hazard], 1986
Dec; 15:344-5.
Concentration calibrated vaporizers [Hazard], 1987Mar-Apr;
16:112-3.
Pre-use testing prevents helpful reconstruction ofanesthesia
components [Hazard], 1987 May;16:178-9.
Anesthesia systems [Evaluation], 1988 Jan; 17:3-34.
Who should service anesthesia equipment [User Expe-rience
NetworkTM], 1988 Feb; 17:70-1.
Pre-use anesthesia check fails to find faults [Hazard],1988 Sep;
17:274-6. (Contains pre-use checklist foranesthesia units.)
Anesthesia systems [Evaluation Update], 1988 Dec;17:366-7.
Anesthesia units and breathing systems [Standard],1989 Oct;
18:363.
Monitoring and anesthesia systems: integration and anew option,
1991 Mar-Apr; 20:131-2.
Use of inadequate (old) anesthesia scavenger inter-faces
[Hazard], 1993 Dec; 22:592.
Anesthesia systems [Evaluation]. To be published in1996.
Test apparatus and suppliesPressure gauge or meter, -10 to +80
cm H2O (accu-racy 5 cm H2O at 30 cm H2O)
Flowmeters with ranges of approximately 0.1 to 1.0L/min and 1 to
10 L/min, 2% accuracy, calibratedseparately for each of the gases
used with the anes-thesia machine, and one flowmeter for 10 to
100L/min (10% of reading)
Stopwatch or watch with a second hand
Hoses and adapters for connecting pressure gaugesor meters and
flowmeters to equipment being in-spected
Cylinder of each type of gas used with the unitbeing inspected;
each cylinder on a unit that isready for use should be more than
half full if thegas is normally stored in gaseous form (e.g.,
oxy-gen) and should contain some liquid if the gas isnormally
liquefied for storage; cylinders should
have a minimum pressure of 745 psi for nitrousoxide and 1,000
psi for oxygen
Nondisposable corrugated breathing hose (dispos-able tubing may
not provide reliable connections)
Test lung (reservoir bag with 3 or 5 L capacity)
Sphygmomanometer bulb with tubing and adapter
Leak-detecting solution
Conductive lubricant for conductive casters (e.g.,Dow No. 41,
graphited oil)
Trichloroethylene cleaning solvent or solvent rec-ommended by
the manufacturer (be sure to reviewthe manufacturers Material
Safety Data Sheet andsee the special precautions below)
Lubricant as specified by manufacturer
Special precautionsECRI is aware of a number of incidents in
which
improperly serviced ventilation or anesthesia equip-ment was
implicated in patient injury or death. Do notperform any
procedures, adjustments, repairs, ormodifications unless you
thoroughly understand thedevice and have verified the
appropriateness of theintended actions. Resolve any questions or
uncertain-ties with the manufacturer, the anesthetist, or
ECRIbefore placing a unit into use.
To avoid the adverse effects of exposure to anes-thetic gases,
all testing should be done with an operat-ing scavenging system in
place or an alternative meansto vent excess gases from the vicinity
of inspectingpersonnel. If a flammable anesthetic is used, be
sureall traces of the gas are cleared away before performingany
electrical tests. Check that all valves, includingthe gas cylinder
stem valves, are turned off at thebeginning of the inspection. Turn
all valves off againwhen the inspection is complete.
When testing cyclopropane flowmeters, observenoted procedures to
avoid a buildup of explosive levelsof cyclopropane.
Trichloroethylene is a common solvent particularlyrecommended
for cleaning oxygen fittings because itdoes not leave a residue
that is flammable in high-con-centration oxygen. However, this
solvent reacts withthe soda lime used in carbon dioxide absorbers
to formseveral poisonous gases, including phosgene. Al-though
concentrations may not be lethal, the presenceof these gases to any
degree is highly undesirable.
To prevent the generation of these gases, make surethat
equipment recently cleaned with trichlo-roethylene is completely
dry before using. When clean-
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ing parts of the anesthesia unit with this solvent,
firstdisconnect the line to the carbon dioxide absorber.After
cleaning, allow time for the solvent to evaporate.When the parts
appear dry, take the added precautionof briefly flushing them with
a high oxygen flow rate.
ProcedureBefore beginning an inspection, carefully read this
procedure and the manufacturers instruction andservice manuals;
be sure that you understand how tooperate the equipment, the
significance of each controland indicator, and the alarm
capabilities. Also deter-mine whether any special inspection or
preventivemaintenance procedures or frequencies are recom-mended by
the manufacturer.
1. Qualitative tests
1.1 Chassis/Housing. Examine the exterior of theunit for
cleanliness and general physical condi-tion. Be sure that plastic
housings are intact,that all assembly hardware is present and
tight,and that there are no signs of spilled liquids orother
serious abuse.
1.2 Mount. Check any shelves, brackets, or sup-porting
structures. Check the security of theattachments.
1.3 Casters/Brakes. If the device moves on casters,check their
condition. Look for accumulations oflint and thread around the
casters, and be surethat they turn and swivel as appropriate.
Checkthe operation of brakes and swivel locks, if theunit is so
equipped. Check that gas hoses do notlie on the floor or loop near
the casters.
1.4 AC Plug/Receptacles. Examine the AC powerplug for damage.
Attempt to wiggle the bladesto determine that they are secure.
Shake theplug and listen for rattles that could indicateloose
screws. If any damage is suspected, openthe plug and inspect
it.
If the device has electrical receptacles for ac-cessories,
insert an AC plug into each and checkthat it is held firmly. If
accessories are pluggedand unplugged often, consider a full
inspectionof the receptacle.
1.5 Line Cord. Inspect the cord for signs of damage.If damaged,
replace the entire cord or, if thedamage is near one end, cut out
the defectiveportion. Be sure to wire a new power cord or plugwith
the correct polarity. Also check line cords ofbattery chargers.
1.6 Strain Reliefs. Examine the strain reliefs atboth ends of
the line cord. Be sure that they holdthe cord securely.
1.7 Circuit Breaker/Fuse. If the device has aswitch-type circuit
breaker, check that it movesfreely. If the device is protected by
an externalfuse, check its value and type against thatmarked on the
chassis, and ensure that a spareis provided.
1.8 Tubes/Hoses. Check the condition of all tubingand hoses. Be
sure that they are not cracked,kinked, or dirty.
1.9 Cables. Inspect the cables (e.g., sensor, elec-trode) and
their strain reliefs for general condi-tion. Examine cables
carefully to detect breaksin the insulation and to ensure that they
aregripped securely in the connectors of each end toprevent
rotation or other strain.
1.10 Fittings/Connectors. Examine all gas and liq-uid fittings
and connectors, as well as all electri-cal cable connectors and
sockets, for generalcondition. Electrical contact pins or
surfacesshould be straight, clean, and bright. Check thatpins used
with the pin-index safety system com-ply (location and length of
protrusion) and areintact. Check the yoke clamping screw andmake
sure empty yokes have plugs. Check thatappropriate keyed or indexed
fittings are beingused with corresponding gases.
1.12 Filters. Check the condition of all compressed-gas filters.
Clean or replace as needed, and indi-cate this on Line 3.1 or 3.4
of the inspection form.
1.13 Controls/Switches. Before moving any controlsand alarm
limits, check their positions. If any ofthem appear inordinate
(e.g., a pressure alarmcontrol at maximum, alarm limits at the ends
oftheir range), consider the possibility of inappro-priate clinical
use or of incipient device failure.Record the settings of those
controls that shouldbe returned to their original positions
followingthe inspection.
Examine all controls and switches for physicalcondition, secure
mounting, and correct motion.Where a control should operate against
fixed-limit stops, check for proper alignment, as wellas positive
stopping. During the course of theinspection, be sure to check that
each control andswitch performs its proper function.
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Check that the concentration dial on eachvaporizer moves freely
and that only one vapor-izer can be on at a time. Observe the float
motionas its flow control valve is turned on. The valveshould turn
smoothly with only slight drag.Each valve should have a definite
shutoff posi-tion at which the float should be motionless atits
zero level. Check for free play in the controlvalve by pushing,
pulling, and gently rocking thestem from side to side without
rotation. The stemshould feel firm, and the flowmeter float
shouldnot move. The control valve knob should requireturning
through at least 90 to change the flowrate from 10% to 100% of full
scale. (Note: Allrecent anesthesia units should now have differ-ent
sized and shaped knobs for oxygen and ni-trous oxide to aid in
differentiating between thetwo controls.)
1.17 Battery/Charger. Inspect the physical condi-tion of
batteries and battery connectors, if read-ily accessible. Check the
battery-operatedpower-loss alarms on AC and pneumatic devices,if so
equipped. Operate the unit on battery powerfor several minutes to
check that the battery hasan adequate charge. Check remaining
batterycapacity by activating battery test function ormeasuring the
output voltage. If appropriate,check the condition of the battery
charger and,to the extent possible, confirm that it does, infact,
charge the battery. When it is necessary toreplace a battery, label
it with the date.
1.18 Indicators/Displays. During the course of theinspection,
confirm the operation of all lights,indicators, meters, gauges, and
visual displayson the unit and charger, if so equipped. Be surethat
all segments of a digital display function.
1.19 Directional Valves. Check that directionalvalves are free
from cracks and chips and fitsmoothly against the valve seats.
Check for freemovement by shaking or lightly squeezing thehose
connecting the two valves. The valvesshould flutter up and down and
should not stickto their seats.
Check for the possibility of reverse flowthrough directional
valves by removing thebreathing hoses from the absorber and
attach-ing a thin disposable reservoir bag to the exha-lation port.
Attach a piece of hose to the bagmount, set the control for manual
mode, closethe APL valve, and occlude the inspiratory portwith the
palm of your hand. Then, connect a testlung to the hose and
generate about 5 cm H2O
of pressure on the pressure gauge. Watch for anyinflation of the
flattened bag as a sign of expira-tory valve leakage.
Reconnect the bag to the bag mount and thehose to the inhalation
port. With your hand oc-cluding the expiratory port, use a test
lung toagain generate about 5 cm H2O of pressure andcheck for
inspiratory valve leakage by watchingfor any inflation of the
bag.
1.20 Alarms/Interlocks. Operate the device in such away as to
activate each audible and visual alarm.Check that any associated
interlocks function(particularly the vaporizer interlocks,
whichshould allow activation of only one vaporizer at atime). If
the device has an alarm-silence feature,check the method of reset
(i.e., manual or auto-matic) against the manufacturers
specifications.
1.21 Audible Signals. Operate the device in such away as to
activate all audible signals. Confirmappropriate volume, as well as
the operation ofa volume control, if so equipped. Check that
theaudible signals are appropriate for the test con-ditions
used.
1.22 Labeling. Check that all necessary placards, la-bels,
conversion charts, and instruction cardsare present and legible.
Check for proper colorcoding for corresponding parts (e.g., green
foroxygen, blue for nitrous oxide).
1.23 Accessories. Verify accuracy and function of anyaccessories
(e.g., spirometer, sphygmomanome-ter gauge). (Inspect ventilators,
vaporizers, andoxygen monitors separately using the appropri-ate
procedures, and record on separate forms.)
1.24 Fail-Safe Oxygen Valves and Alarms. Close allcontrol
valves. Open all cylinder stem valvesand external gas source
valves. Connect gasscavenging or other evacuation system to com-mon
gas outlet. Turn on the main gas control,and open the flow control
valves until the flow-meter for each gas reads midscale. Then
discon-nect or turn off all oxygen sources. The flow ofother gases
should fall or stop as the oxygen flowdecreases to half its
previous level. All gas flowshould cease when the oxygen flow
reaches zero.(Cyclopropane flow rate normally falls moreslowly than
the others.)
In addition to the automatic shutoff or reduc-tion of gas flow,
audible or visual alarms signify-ing low oxygen pressure should
have beenactivated, if the unit is so equipped. Silence the
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alarm by raising the oxygen pressure above thepreset alarm
limit. If the unit has an alarm thatdoes not respond, check for
exhausted batteriesor other source of the malfunction.
1.25 Common Outlet Back-Pressure Check Valve.Most anesthesia
units manufactured after 1968with mounted bubble-through vaporizers
have acheck valve in the gas delivery system to preventpressures at
the outlet (e.g., produced by a ven-tilator) from being transmitted
to other parts ofthe unit where they could affect the accuracy
ofgas delivery and the concentration of anestheticgases.
To test this check valve, attach the -10 to +80cm H2O pressure
gauge or meter to the commongas outlet. Turn off all vaporizers,
either filledor empty. Adjust the oxygen flow control valve
tomaintain an outlet pressure of 30 cm H2O. Turnon the vaporizer
flow, and readjust, if necessary,to maintain 30 cm H2O. Carefully
open thevaporizer filler cap (to prevent a sudden flow ofoxygen
into the vaporizer) and observe the outletgauge pressure. A sudden
pressure drop sug-gests a leaky check valve. If the check valve
ismissing or defective, replace it or alert appropri-ate personnel
to replace the valve to avoid apossible hazardous buildup of vapor.
Note: Thistest may not be possible on newer machines thatalways
maintain a minimum flow of oxygen. Onsuch devices, follow the
manufacturers instruc-tions for testing the common outlet
back-pres-sure check valve.
2. Quantitative tests
2.1 Grounding Resistance. Use an ohmmeter, elec-trical safety
analyzer, or multimeter with goodresolution of fractional ohms to
measure andrecord the resistance between the grounding pinof the
power cord and exposed (unpainted andnot anodized) metal on the
chassis. We recom-mend a maximum of 0.5 .
If the device has an accessory outlet, check itsgrounding to the
main power cord.
2.2 Leakage Current. Measure chassis and patientlead leakage
current to the chassis of the devicewith the grounding conductor of
plug-connectedequipment temporarily opened. Operate the de-vice in
all normal modes, including on, standby,and off, with all monitors
and accessories con-nected to the units accessory power
receptacle(s),and record the maximum leakage current.
Measure chassis leakage current with all ac-cessories normally
powered from the same linecord connected and turned on and off.
This in-cludes other equipment that is plugged into theprimary
devices accessory receptacles, as well asequipment plugged into a
multiple-outlet strip(Waber strip) so that all are grounded
througha single line or extension cord.
Leakage current should not exceed 300 A.
2.3 Oxygen Flush Valve. Attach the 100 L/min flow-meter to the
common outlet. Set the oxygen flowrate to a 2 L/min indication on
the machinesoxygen flowmeter and actuate the oxygen flushcontrol.
The rate should rise to between 35 and75 L/min. The machine
flowmeter indicationshould remain near 2 L/min unless the
manufac-turers specification shows otherwise. If it fallsmore than
1 L/min, check for an inadequateoxygen supply, a partially occluded
oxygen linein the machine, or a dirty oxygen inlet filter.
Cycle the flush control slowly several times; itshould move
smoothly and not have a tendencyto stick. Check that the oxygen
flow returns to2 L/min within 2 sec each time the flush valve
isclosed.
2.4 High-Pressure Leaks. Close all flow controlvalves on the
machine. Open all cylinder stemvalves one full turn, noting any
motion of theflowmeter floats. Float movement indicates aleaky
flowmeter valve. Record pressure gauge ormeter readings, verifying
that they are close tothe service pressure values listed in Table
1.Close the cylinder stem valves. The pressuredrop over 30 sec
should be negligible. Excesspressure drop indicates an unacceptable
leakthat should be located and repaired.
2.5 Intermediate Pressure System. Close all flowcontrol valves
on the anesthesia unit. Connectthe hoses to the external pipeline
gas source andtest the supply line hoses with
leak-detectingsolution. Note the pressure on the pipeline/cen-tral
gas supply pressure gauge. (Most machinesshould have such a gauge.
If not, contact themanufacturer for instructions for testing the
in-termediate pressure system.) Disconnect the gassupply line hose
from the machine, and checkthat the pressure drop in 30 sec is
negligible.Excessive pressure drop indicates an unaccept-able leak
that should be located and repaired.
2.6 Low-Pressure Leaks. Attach the -10 to +80 cmH2O pressure
gauge or meter to the units common
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gas outlet and pressurize the outlet section, in-cluding
vaporizers, to approximately 30 cm H2Oby opening the oxygen flow
control valve slightly(this is about three times the average
workingpressure). Now reduce the flow rate to 30mL/min. (Connect a
flowmeter to the commongas outlet if necessary.) If the gauge or
meterpressure continues to rise, the leak rate is lessthan 30
mL/min at 30 cm H2O (10 mL/min at 10cm H2O), which is acceptable.
If the pressurefalls, the leakage rate is excessive. Locate theleak
by shutting off all vaporizers and repeatingthe test with each
vaporizer added in turn.
For anesthesia units for which low flow ratescannot be generated
(units that deliver mini-mum flows of oxygen), the low-pressure
systemcan be tested in combination with the breathingsystem.
Connect the -10 to +80 cm H2O pressuregauge or meter to a piece of
breathing systemtubing that is connected to the inspiratory
andexpiratory valve outlets. Occlude the outlet tothe manual
reservoir bag and close the APLvalve. Turn on the minimum flow of
oxygen.The pressure gauge or meter should read at least30 cm H2O. A
reading of less than 30 indicatesan unacceptable leak that should
be corrected.Proceed to Item 2.7 to identify whether thebreathing
system is the major source of the leak.Alternatively, follow the
manufacturers recom-mendations for testing for low-pressure
leaks.
2.7 Breathing System. Check the carbon dioxide ab-sorber housing
for cracks or broken edges in theglass or plastic canister and in
the check valvedomes.
Remove the canister from its holder, withoutinverting it, and
inspect the gaskets for anyabsorbent dust and wear. Remove any dust
fromthe bottom of the absorber. If the amount of dustseems
excessive or if the canister appears seri-ously pitted, check for
dust in the inspiratoryvalve and piping, and report the condition
todepartment personnel.
Check the absorber-elevating mechanism andclamps for proper
operation.
For anesthesia systems without minimumoxygen flows, connect a
breathing hose from thepatient inspiration valve to the patient
expirationvalve of the absorber. Close the pressure-limit-ing
valve. Remove the reservoir bag, and replaceit with a -10 to +80 cm
H2O pressure gauge ormeter. Pressurize the system with oxygen to
a
steady 30 cm H2O, indicated on both the testgauge or meter and
the pressure gauge in thebreathing system, and verify that both
gaugeshave the same readings. The oxygen flow rateshould be less
than 150 mL/min above the leakmeasured in Item 2.6.
For anesthesia systems with minimum oxy-gen flow, turn the
anesthesia machine off andconnect the -10 to +80 cm H2O pressure
gauge ormeter to a piece of breathing system tubing thatis
connected to the inspiratory and expiratoryvalve outlets. Close the
APL valve. Remove themanual reservoir bag. In its place, connect
astopper with a fitting for a sphygmomanometersqueeze bulb. Use the
bulb to pressurize thebreathing system to 50 cm H2O. It should
takeat least 30 sec for the pressure to drop from 50to 30 cm H2O.
Less time indicates a leak in thebreathing system that should be
corrected.
Open the moisture-relief valve. (Note: Due todust and moisture,
some of these valves on olderunits will not turn and might break
when forceis applied.) The pressure should drop immedi-ately. If
the pressure does not drop, clean thevalve of dried soda lime,
repeat the pressuriza-tion, and open the relief valve again.
2.8 APL Valve. Leave the setup as in Item 2.7 butremove the
pressure gauge or meter, replacing itwith the breathing bag, and
restore the normalpressure-limiting valve setting.
If the APL valve is not the bleeding type,squeeze the bag and
verify that the valve holdspressure until a specific level is
exceeded, andthat it then opens. Check that the opening pres-sure
is adjustable from approximately 1 to atleast 30 cm H2O. Other
valves, such as theGeorgia and Drager valves, may operate in
acompletely different manner and at a higherpressure and should be
tested according to themanufacturers specified procedure.
2.9 Scavenging System. Insert the pressure gauge ormeter between
the APL valve or exhaust port andthe scavenging system intake.
Leave the setup asin Item 2.8, with the APL valve closed or in
itsminimum-flow condition. With the scavengingsystem operating at
maximum suction, the pres-sure gauge or meter reading should be
between-0.5 and 0 cm H2O. Partially open the APL valve,and set a 10
L/min oxygen flow rate. With thescavenging system at the minimum
vacuum, thegauge reading should be near ambient.
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Repeat the last measurement with the APLvalve fully open while
occluding the vacuum hoseand activating the flush valve for 5 sec.
Thepressure should remain at less than 10 cm H2O.
2.10 Flowmeters. The following procedure applies toeach
flowmeter on the anesthesia unit. Recordthe data on Line 2.10
(i.e., oxygen, nitrous oxide,and air). If other flowmeters are
provided (e.g.,helium, carbon dioxide), make similar checksand
enter data on the back of the form.
Examine flowmeters for signs of damage orabuse (e.g., internal
nicks, scratches, cracks,condensation, debris).
For each flowmeter, observe the float motionas the associated
valve is turned. The floatshould rise and fall freely as the flow
is raised orlowered. At maximum flow, the float should stillbe
visible at the top of the flow tube.
Connect one of the calibrated flowmeters tothe common gas outlet
with its discharge di-rected into the scavenging or other gas
evacu-ation system. Level the flowmeter. For each gasin turn, set
the flow rates at a high and lowsetting for each flowmeter that
lies within therange of the calibrated flowmeter. Record
thereadings of both the machine and the calibratedflowmeters.
Repeat the tests with the secondcalibrated flowmeter and the second
group offlow rates.
The readings on the units flowmeters shouldagree with those on
the calibrated flowmeters towithin 10% of set values or the
manufacturersspecifications. If the error is excessive, check
fordamaged, inverted, or interchanged flowmetertubes, condensation,
or damaged floats.
2.11 Minimum Oxygen Flow and Percent. The follow-ing procedure
applies to those systems that pro-vide a minimum flow of oxygen or
a minimumpercent of oxygen.
Close the valve to the anesthesia units oxy-gen flowmeter.
Connect the 0.1 to 1.0 L/minoxygen flowmeter to the common gas
outlet.The flowmeter should read the minimum flow
stipulated by the manufacturer (usually 100 to250mL/min).
Set the flow of oxygen to around 200 mL/min.Turn off the flow of
nitrous oxide. Using anoxygen monitor, verify that at least the
mini-mum percent of oxygen (stipulated by the manu-facturer) is
delivered as the flow of nitrous oxideis increased.
2.12 PEEP Valve. Set up the breathing system witha test lung.
Use the -10 to +80 cm H2O pressuregauge or meter to measure the
airway pressureat the test lung. Manually ventilate the test
lungwith the PEEP valve set to deliver 0 cm H2Owater pressure. The
end-exhalation pressure inthe breathing system should be less than
1 cmH2O, although this depends on the fresh gas flowand APL valve
setting.
If the PEEP valve is calibrated, set it to deliver5 and 10 cm
H2O water pressure. The pressurein the breathing system at the end
of exhalationshould be within 1.5 cm H2O of the set value.
3. Preventive maintenance
3.1 Clean any excess leak-detection solution fromthe exterior
and interior of the unit; clean allcompressed-gas filters, if
needed.
3.2 Lubricate per the manufacturers specifications.
3.4 Replace compressed-gas filters and alarm bat-teries, if
needed.
4. Acceptance tests
Conduct major inspection tests for this procedureand the
appropriate tests in the General Devices Pro-cedure/Checklist
438.
Before returning to useDepressurize external gas supply; return
all flow-
meters to zero position; turn all vaporizers to off posi-tion;
and reconnect all tubing (e.g., main common gasoutlet tubing).
Return all controls to pre-use settings.Attach a Caution tag in a
prominent position so theuser is aware that control settings may
have beenchanged.
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Apnea MonitorsUsed For:Apnea Monitors [12-575]Apnea Monitors,
Recording [17-885]Impedance Pneumograph Monitors
[12-621]Respiration Monitors [12-662]
Also Called: Cardiorespiratory monitors, apnea alarms and
respiration monitors, ventilatory effort monitors,apnea
detectors
Commonly Used In: Pediatric departments, homes, critical care
units, nurseries, delivery rooms, ambulances
Scope: Applies to apnea monitors, which alarm if a patient stops
breathing, and respiration rate monitors,which display the patients
breathing rate and alarm when previously selected high or low
limits are exceeded;applies to adult and infant monitoring units or
modules, as well as impedance-, motion-, thermistor-,
andairway-pressure-type monitors; does not apply to other types of
monitors with respiration monitoring functions(e.g., capnometers,
pulse oximeters); some apnea monitors also include other monitoring
capabilities (e.g.,ECG and blood pressure), which should be checked
using the appropriate procedure/checklist unless thefunction is
very limited (e.g., heart rate alarm without other ECG
features)
Risk Level: ECRI Recommended, High; Hospital Assessment,
ECRI-Recommended Interval UsedType Interval By Hospital Time
Required
Major 12 months months . hours
Minor 3 months * months . hours
* Minor interval applies only to units used for home care.
009007420-0595
A NONPROFIT AGENCY
5200 Butler Pike, Plymouth Meeting, PA 19462-1298, USATelephone
+1 (610) 825-6000 Fax +1 (610) 834-1275 E-mail [email protected]
Procedure/Checklist 420-0595
OverviewOur evaluations of infant apnea monitors havestressed
that apnea monitoring is still an imperfectscience. An ECRI poster
(Poster HD 602-980) warnedof the susceptibility of these monitors
to artifact andprovided succinct reminders and hints for clinical
per-sonnel. An additional poster (Poster HD 625-290) andwarning
notice (Health Devices 1990 Apr; 19:142-5)provide guidance for
apnea monitors used in the home.
When inspecting these monitors, in addition tomaking a
qualitative and quantitative inspection ofthe monitor itself, be
alert to indications of incorrectequipment usage and
misapplication. Confirm thatusers are aware of proper monitoring
techniques andthe monitors limitations. See the devices
operating
manual and the Health Devices evaluations cited belowfor
specific information.
Some apnea monitors have documentation capabili-ties that
typically can record two or more channels ofpatient event data
ranging from several hours to sev-eral months, depending on the
amount and format ofdata and the parameters stored. Recorded data
areavailable in two categories: patient (respiratory rate,heart
rate) and equipment (power on/off, low battery).Patient data can be
recorded and printed as eithertabular data or waveforms. These data
can be used toensure that the monitor is being used properly,
todistinguish true from false alarms, and to troubleshootequipment
problems.
-
Activation of memory waveform recording can beautomatic or
continuous. Automatic activation is trig-gered when an event occurs
that exceeds preset moni-tor limits. In the continuous mode, all
data from theselected channels are recorded for a specific
duration.The data stored in the memory can be managed one ofthree
ways. Some units overwrite the old data withmore recent events;
others keep the data that satisfyspecific criteria based on the
duration of the events;and some documentation monitors stop storing
datawhen the memory is filled.
Citations from Health DevicesInfant apnea monitors [Evaluation],
1980 Aug-Sep;
9:247-83.
Connection of electrode lead wires to line power [Haz-ard], 1987
Feb; 16:44-6.
Infant apnea monitors [Evaluation], 1987 Mar-Apr;16:79-88.
Infant home apnea monitors [Evaluation update],1987 Dec;
16:385-7.
Infant home apnea monitors: Essential safety fea-tures and
practices, 1990 Apr; 19:142-5.
Infant home apnea documentation monitors [Evalu-ation], 1992
Oct; 21(10):342-79.
Air-Shields System V Model HRRM71-2 heart rate andrespiration
monitor [User Experience NetworkTM],1992 Oct; 21(10):383.
Risk of electric shock from patient monitoring cablesand
electrode lead wires [Hazard], 1993 May-Jun;22(5-6):301-3.
Infant home apnea documentation monitors [Evalu-ation update],
1993 Dec; 22(12):564-5.
Infant home apnea monitors: Essential safety featuresand
practices [Hazard update], 1993 Dec;22(12):598-601.
Loose-lead alarms resulting from dried-out disposableelectrodes
[User Experience NetworkTM], 1994 Jul;23(7):309-10.
Test apparatus and suppliesLeakage current meter or electrical
safety analyzer
Ground resistance ohmmeter
Stopwatch or watch with a second hand
Respiration simulator (needed for impedance-typemonitors only)
that includes controls to vary therespiration rate, variable base
impedance from 100
to 5,000 , variable respiration resistance changeamplitude from
0.1 to 1 , and an apnea function;simulators with fewer capabilities
may be used forinspection, but additional equipment may be
requiredto supplement missing functions
ECG simulator with variable rate may be required(may be part of
the respiration simulator or may bea separate unit)
Memory interface and documentation hardwareand software (where
applicable)
ProcedureBefore beginning an inspection, carefully read this
procedure and the manufacturers instruction andservice manuals;
be sure that you understand how tooperate the equipment, the
significance of each controland indicator, and the alarm
capabilities. If the monitorhas memory and documentation
capabilities, make surethe memory contents have been successfully
downloadedand documented. Also, determine whether any
specialinspection or preventive maintenance procedures
orfrequencies are recommended by the manufacturer.
Do not test the monitor while it is in use. If asubstitute
monitor is not available, ask the nursingstaff whether the patient
can be temporarily removedfrom the unit. It may be necessary for
someone towatch the patient in the interim. Alternatively, ar-range
to be notified when the monitor is available.
1. Qualitative tests
When performing IPM on apnea monitors with mem-ory and
documentation capabilities, a log identifying theorder, type, and
duration of patient and equipmentalarms and events should be
recorded (e.g., using theIPM checklist). At the end of the
procedure, the memorycontents should be compared to the log
contents.
1.1 Chassis/Housing. Examine the exterior of theunit for
cleanliness and general physical condi-tion. Be sure that plastic
housings are intact,that necessary assembly hardware is presentand
tight, and that there are no signs of spilledliquids or other
serious abuse. If there are signsof fluid spills, inspect the
interior of the monitorfor intrusion of fluids into electronic
circuitry.The monitor top should not be used as a storagearea for
other material (e.g., formula).
1.2 Mount. If the unit is mounted on a stand or cart,check the
mounts condition. Be sure that allfasteners are tight and that the
mount is sturdy.Apnea monitors should not be placed on top
ofincubators where they can be easily dislodged
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or obscure the view of an infant. A wall-sup-ported shelf or
bracket dedicated to the monitoris recommended.
1.4 AC Plug/Receptacles. Examine the AC powerplug for damage.
Attempt to wiggle the bladesto determine that they are secure.
Shake theplug and listen for rattles that could indicateloose
screws. If any damage is suspected, openthe plug and inspect it. If
the device has electri-cal receptacles for accessories, insert an
AC pluginto each and check that it is held firmly. Ifaccessories
are plugged and unplugged often,consider a full inspection of the
receptacle.
1.5 Line Cord. Inspect the cord for signs of damage.If damaged,
either replace the entire cord or, ifthe damage is near one end,
cut out the defectiveportion. Be sure to wire the new power cord
orplug with the same polarity as the old one. Also,check battery
charger line cords.
1.6 Strain Reliefs. Examine the strain reliefs at bothends of
the line cord. Be sure that they hold thecord securely. If the line
cord is detachable (bythe user), affix the cord to the unit so that
itcannot be removed by the operator. (See HealthDevices 1993
May-Jun; 22[5-6]:301-3.)
1.7 Circuit Breaker/Fuse. If the device has aswitch-type circuit
breaker, check that it movesfreely. If the device is protected by
an externalfuse, check its value and type against thatmarked on the
chassis, and ensure that a sparefuse is provided.
1.9 Cables. Inspect the cables (e.g., patient sensor,remote
alarm) and their strain reliefs for generalcondition. Examine
cables carefully to detectbreaks in the insulation and to ensure
that theyare gripped securely in the connectors of eachend to
prevent rotation or other strain. Elec-trode leads and cables are
often fragile and maylack adequate strain relief; intermittent
contactcan provide false indications.
The lead-electrode connector should be of thetype that cannot be
inadvertently plugged into a115 VAC outlet or power cord. Attach a
pair ofelectrodes to the patient cable and hold the RA andLA
electrodes face to face. Connect the patientcable to the monitor,
turn the unit on at maximumsensitivity, and jiggle the leads. If
either breathsor lead faults are indicated, suspect damaged ca-bles
or weak contact with the electrodes.
For monitors using belts, bands, a thermistor,a mattress pad, or
other sensor, connect thesensor to the monitor, turn on the
monitor, andjiggle the sensor cable, being careful not to dis-turb
the sensor in such a way as to simulate abreath. Observe the
monitor for artifacts thatwould indicate a defective cable or
connector.
1.10 Fittings/Connectors. Examine all fittings andconnectors,
including electrical cable connectors,for general condition.
Electrical contact pins orsurfaces should be straight, clean, and
bright.
1.11 Electrodes/Transducers. Confirm that any nec-essary
electrodes and/or transducers are on handand check their physical
condition. If disposableelectrodes are used, be sure an adequate
supplyis on hand.
Verify that the insulation on thermistor sen-sors is intact.
Check that air mattresses are freeof leaks and that the tubing that
connects thesegments of the mattress to the manifold fitswell,
without the use of tape. Keep spare tubingon hand to make necessary
repairs. Carefullyexamine sensor belts, bands, or pads
(magnetic,capacitive, or pressure transducer) for intact
in-sulation. If there are cracks or defects in theinsulation,
remove the sensor from service.
1.13 Controls/Switches. Before moving any controlsand alarm
limits, check their positions. If anyappear inordinate (e.g., a
gain control at maxi-mum, alarm limits at the ends of their
range),consider the possibility of inappropriate clinicaluse or of
incipient device failure. Investigatequestionable control settings
on a home caremonitor. Consult with the patients physician
todetermine correct settings. The parents shouldreceive additional
training if required. Recordthe settings of those controls that
should bereturned to their original positions following
theinspection. Examine all controls and switchesfor physical
condition, secure mounting, and cor-rect motion. Where a control
should operateagainst fixed-limit stops, check for proper
align-ment, as well as positive stopping. Check mem-brane switches
for membrane damage (e.g., fromfingernails, pens). During the
course of the in-spection, be sure to check that each control
andswitch performs its proper function.
1.17 Battery/Charger. Inspect the physical condi-tion of
batteries and battery connectors, if read-ily accessible. Check
operation ofbattery-operated power-loss alarms, if so
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equipped. Operate the unit on battery power forseveral minutes
to check that the battery ischarged and can hold a charge. Check
the condi-tion of the battery charger and, to the extent pos-sible,
confirm that it does, in fact, charge thebattery. When it is
necessary to replace a battery,label it with the date.
1.18 Indicators/Displays. During the course of theinspection,
confirm the operation of all lights,indicators, and visual displays
on the unit andcharger, if so equipped. Be sure that all seg-ments
of a digital display function.
1.19 User Calibration. Confirm that the calibrationor test
function operates.
1.20 Alarms/Interlocks. Operate the device in sucha way as to
activate each audible and visualalarm. Check that any associated
interlocksfunction. If the device has an alarm-silence fea-ture,
check the method of reset (i.e., manual orautomatic) against the
manufacturers specifica-tions. Some apnea alarms that reset
automat-ically when breathing resumes have a separateindication
that an apneic episode has occurred;this reminds clinical personnel
that the patientneeds closer attention. To verify that this
indica-tor functions properly, halt simulated respira-tion until
the apnea alarm sounds, then resumethe simulated respiration. Check
that the resetcontrol functions. If the unit is used with aremote
a